I've searched the archives, done a general web search, looked at the Cadiero (Yahoo!) board, etc. and haven't been able to find a step by step build thread for this, so I'm gonna document my attempt with dialogue and pictures, I hope. I'm starting from a zero sum--I pretty much know nothing about this, so if this gets a little basic with me asking and answering my own questions bear with me. Time's a little short today (Christmas Eve) so no actual wire cutting is gonna get done today. Just a few organizing principles to start.

My engine and harnesses are from an '92 Seville.

First question & answer to date. What do I need, what do I have? I need an engine with all the of the sensors, fuel delivery components, and ignition components (check.) I need an engine harness for the 4.9, a caddy cabin harness with PCM (check.)

I need a Fiero engine harness to rob components from--I will harvest the C500 connector (that's the one near the battery) and the C203 (which is a clear connecter on the center hump in the area of the ECM.) I have a couple of these from V6 engines--tho I don't think it matters whether it's 6 or 'Duke harness. Harvesting these parts will involve grabbing the connector and as long lengths of the wires going into the connectors as possible, at least 1' , I think. I need to strip the C500 part of the harness back, tho to get the wiring and connectors for the A/C & alternator, temp sender gauge and light, fan switch, and so on--for more info: http://fp.enter.net/~rockcrawl/c203c500
A really good table of pinouts on the C203 and C500

Tools I need for this initial stage, a pair of wire cutters (dykes) and a razor blade for stripping of tape.

What can I eliminate to make life easier. I've been reading up on this a bit, and part of the reason the cabin portion of the Caddy harness is so daunting is that there's a bunch of stuff that connects to cabin systems that won't be used. Basically, I need to connect this harness to the engine harness and connect a few components (more on this later) to the Fiero through the C203.

So in the picture below, the PCM is on the left, the multi connector for the engine harness is at the bottom, and everything to the right can be eliminated (snip-snip!) Leave about a foot or more of wire from this portion, tho, what aint' used can be trimmed later.



Next: Snip-snip, pictures & some discussion of the trimmed down harnesses.

Homework for extra credit: An A+ to the person who can show me in a picture what the Passkey module & connection look like.Rockcrawl has a passkey bypass schematic at

http://fp.enter.net/~rockcrawl/passkey.html

[This message has been edited by Brian Lamberts (edited 12-24-2006).]

Passkey or VATS is easy to bypass.......There is a single wire from the computer that needs to be connected to an aftermarket bypass module. (I don't mess around trying to rig factory anti-theft body modules to cooperate)

Aftermarket bypass modules can be found pretty easy these days for around 25 dollars. Here's a couple.....

http://cgi.ebay.com/ebaymotors/GM-VATS-or-PASSkey-II-Bypass-Module-For-LS1-and-LT1_W0QQcmdZViewItemQQcategoryZ33720QQhashZitem220062538897QQihZ012QQitemZ220062538897QQrdZ1QQsspagenameZWDVW

http://mysite.verizon.net/vze7erz1/id14.html#known30hz

Looks good, I'll save it in with the rest of my 4.9 files. Thanks!

quote Originally posted by Brian Lamberts: http://fp.enter.net/~rockcrawl/c203c500

Needs a .html

http://fp.enter.net/~rockcrawl/c203c500.html

Hey cool man when you figure it out do you plan on doing more?

Cause I realize that a lot of work goes into making a harness but I can't see anyone paying $700 for a harness. So let me know what you figure out cause my buddy really wants to do this swap but it's the harness that is holding him back.

I might do some, but mostly the thread is to take the damn mystery out of the swap harness. I guess I could be oversimplifying, but after 10 years and who knows how many of these swaps, if there's a cook book-step by step writeup of how to do the harness I haven't been able to find it. There are sites about peoples swaps, but they mostly go into the mechanical aspects of the swap--and that looks relatively easy to me. Or they wax poetic about how wonderful their car is, broken crutch helpful, that is. I don't particularly enjoy wiring harnesses (and it isn't an area I have any basic expertise in, much less knowledge of)--so if in the end I get my harness done satisfactorily, and others (dummies like me?) are able to see and understand what I did to get there, that should be enough.

The 4.9 conversion is supposed to be the most affordable swap there is--in our wrecking yards here, the 4.9 engines are plentiful and cheap--cheaper that 60 degree V6's in fact. Spending bunches of bucks to pay someone else to do something we car geeks should be able to do ourselves seems wasteful. Money much better spent on powercoating and chrome, imho. This swap should be a valid alternative to all the 3.2/4/5 buildups--and should even be a desireable conversion for folks with tired iron dukes.

It's nearing midnite on Christmas eve, I'm gonna go to bed and start the actually cutting and splicing tomorrow.

[This message has been edited by Brian Lamberts (edited 12-25-2006).]

Brian,
If it helps, I have a Ed Parks (Fuel Inj Tech) wiring harness, and first thing I did was trace down all of the connections and pins, and write it all down so another harness could be fabricated. If it would help, I can fax (or whatever) you my notes.

David Breeze

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Pantera Rebody Kits

quote Originally posted by opm2000: Brian, If it helps, I have a Ed Parks (Fuel Inj Tech) wiring harness, and first thing I did was trace down all of the connections and pins, and write it all down so another harness could be fabricated. If it would help, I can fax (or whatever) you my notes. David Breeze

I don't have a fax, but if you could email them that's be great, or photocopy them and mail them (I'd reimburse for the cost, of course!!!) THAT WOULD BE WONDERFUL!!

quote Originally posted by opm2000: Brian, If it helps, I have a Ed Parks (Fuel Inj Tech) wiring harness, and first thing I did was trace down all of the connections and pins, and write it all down so another harness could be fabricated. If it would help, I can fax (or whatever) you my notes. David Breeze

I'd like to see that as well---

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Proud Member of the North Florida Fiero club

4T60E Parks harness/ Rockcrawl chip-- more to come--

Okay, a little progress this morning.

Figuring out this wiring harness is 90% research, figuring out, and thinking. And unfortunately, the Caddy factory service manual is pretty cryptic. It's info that just isn't too important for working on a Caddy.

Fortunately, I found another source for a fairly complete wiring schematic--Chiltons repair book has the harness organized in a much easier format--they have the pinout number for the ecm (there are three major connectors) with the corresponding wire color/trace, with lines that point you to the component. (They printed the entire schematic on an half page--so a little photo magic was needed to get it up to something more than microscopic. What I aim to do is decode this a little further so that I have a table of wire color codes with the name of the circuit. This sounds more difficult than it actually is, I think, since the wires that go through the firewall connector to the engine harness are for now done deals, they won't get cut.

What I need are the wires that will go to the C203 to connect up to the Fiero cabin harness and there are only a max of 15 positions on this connector. And using the C203 connector diagram from Fieroaddiction site, I can get a fair idea of what circuits out of the PCM need to connect to the C203.

This morning, looking at the caddy pcm harness, I found the ALDL. I figure that this is a fairly important component and so when I made my first set of wire cuts, the snip area is about 8" on the cab side of the ALDL away from the PCM. This first cut preserves a bunch of wiring around the PCM, but also gets rid of 3 feet and a couple of pounds of wiring I don't think I'll need.

I pulled a spare Fiero V6 harness out of storage--it's mostly stripped of all the harness coverings. I'll be harvesting the two main connectors today. The C500 has a bunch of functions (mentioned in a previous post) that for now need to be preserved, so greater care will be used to harvest this connector. It appears to me that any C500 wiring that heads back towards the ECM can be snipped (leaving some length of course.) The components that aren't physically connected to the C500 can be teased out. The end of the long purple cable terminates with an eye and then branches off with an orange wire (smaller gauge) , this is the starter control circuit I clipped the orange wire with a short lead incase splicing is necessary. The green white wire with a connector on the end of it is the fans switch. The other connectors that are maintained in the part of the harness are the temp gauge sensor connector (dark green & green w/yellow trace) and the tach (white & pink wires.) C500 is harvested now. If anyone does this harvest, besure to keep the heavy red wire that goes from the hot connector on the alternator to the terminal block near the C500. The harness I'm working with doesnt' have an alternator plug. I think the alternator on the Caddy is a CS type, so I'll need to do the CS alternator wiring conversion (there was a thread on this which I saved.)

I harvested the C203. For now, just clipped all the wires at the strain reliever that went through the firewall (saving this strain reliever in case I need it to get through the firewall with the new harness) and clipped whatever wires connect the C203 to the Fiero ECM connector, I left the wiring for the Fiero ALDL that connected to the C203 unclipped.

I'll do some pics later of what things look like. Later.

[This message has been edited by Brian Lamberts (edited 12-25-2006).]

Great post! I'm planning on this conversion myself and the wiring seems to be my biggest obstacle.
I'm looking forward to seeing where this goes!

Later: Here's the harvested C203



I ended up having to get a second one from the parts car--the spare harness had a power lead (orange wire) missing. Once you know what to expect, it's not even scary--just cut all the wires at the plastic strain reliever on the firewall, snip all the wires at the ECM that run between the ECM connectors and the C203 and a ground wire about mid harness and you've got it. The connectors for the old fiero ecm just pull away from what is now just a C203 harness. As seen in the pic, the ALDL stays with the C203.

Here's the harvested C500.



I think the main reason for harvesting this one is to get the big purple wire that goes to the starter, the wiring for the a/c compressor, the connector for the fan sender, and the temp gauge sender, and the gauge wire for the alternator. On the harness, there's also a connector for the tach circuit. This one may need to be adapted to connect to the distributor, my thinking is that the Caddy didn't have a tach, so the PCM circuits may not have any provision for one--my thoughts are in an early stage on this.

This is fun so far. I've run into a couple of setbacks--what I thought was the PCM for this project isn't--it doesn't have enough slots for three connectors. I don't recall seeing one with all the stuff I got either--so I may need to make the trip to the self service wrecking yard to get the right one. And then there was the missing wires on the C203--I'm scratching my head wondering about that.

Finally when I speak of the strain reliever--this is what I'm speaking of.



This is the connection block of the engine harness, and to the right of the block is the part that goes through the rear bulkhead. I removed the caddy strain reliever and put the Fiero one in. The Caddy one I mangled pretty well getting it off--it's put together with black goop on the engine side and then this resin material inside the plastic outer pieces. There's a trick to getting the resin goop out and off the the wire and the internal loom. You need to freeze the wiring harness and then smack the clear stuff with a hammer to shatter it, then pick the remainders out so that the wiring can fit in Fiero specific part.

Next, I'm going to start connecting the C203 to the PCM harness. There's still some trimming to be done on the PCM harness.

[This message has been edited by Brian Lamberts (edited 12-26-2006).]

The caddy PCM has three connectors that go up the left side. The harness connectors are male plugs, with female pins (does that make sense?)
The most common Caddy PCM part number ends in "2240", if that helps. The access panel for the calpak will be bulged out, about 1/4 inch. Required for the memcal.

I have pulled several caddy pcm's
you will find that it is on the passenger side footwell and the very furthest one towards the firewall. It is usually not the first one you see when you bend down there. I usually lay upside down with my feet up on the headrest and unbolt it.
Just remember to make sure it is the furthest one towards the firewall and it has three connectors.

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Proud Member of the North Florida Fiero club

4T60E Parks harness/ Rockcrawl chip-- more to come--

I'm loving this thread since a 4.9 swap in in my near future but scrolling side to side to read everything is making it a little less enjoyable. V8Fiero400 could you please edit your link?

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When I change the way I look at things,
the things I look at change.

quote Originally posted by Brian Lamberts: The Caddy one I mangled pretty well getting it off--it's put together with black goop on the engine side and then this resin material inside the plastic outer pieces. There's a trick to getting the resin goop out and off the the wire and the internal loom. You need to freeze the wiring harness and then smack the clear stuff with a hammer to shatter it, then pick the remainders out so that the wiring can fit in Fiero specific part.

That's a good idea... I haven't had to freeze anything yet (is the Fiero C500 filled with the same stuff?). The stuff inside the bulkhead passthrough is hot glue. You can take that apart by warming it up with a heat gun first.

I think you're making more work for yourself down the road than you realize. It's always good to have as much wire as you can get. When I pull a C500 or C203, I make sure I get as much of each wire as I can. It may be more complicated up front, but it can save you a lot of splices down the road. Check out the CarQuest "Wire and Cable" book. The "terminals and connectors" section has most of the pins you'll need as well as some rudimentary tools to install them. The terminal removal picks in that book are very useful.

quote Originally posted by Will: That's a good idea... I haven't had to freeze anything yet (is the Fiero C500 filled with the same stuff?). The stuff inside the bulkhead passthrough is hot glue. You can take that apart by warming it up with a heat gun first. I think you're making more work for yourself down the road than you realize. It's always good to have as much wire as you can get. When I pull a C500 or C203, I make sure I get as much of each wire as I can. It may be more complicated up front, but it can save you a lot of splices down the road. Check out the CarQuest "Wire and Cable" book. The "terminals and connectors" section has most of the pins you'll need as well as some rudimentary tools to install them. The terminal removal picks in that book are very useful.

I didn't know that it was hot glue--it must be a different heat range (hotter) than the home stuff. The home stuff would melt at engine compartment temps. Heating up the fitting certainly would have helped get it open tho.

Your second paragraph leads me to the conventions I'm using during this project. How I'm doing basic things.

I have been leaving long leads on the connectors I've harvested. I figure the main harness to work on is the one that connects between the bulkhead (and connects to the engine harness,) the PCM, and the C203. When I assemble this harness, I'm going to do it on my parts car so that I can get the measurements correct (but will still error towards making the harness a little big.)

For connections, I'll be doing inline twists (like a butt connection) then solder the twists and cover the connections with heat shrink tubing (cheap from Harbor Freight.) The wire bundle will then get liberally wrapped with electrical tape. Should provide an oxidation resistant connection.

If anyone is interested in how to read the PCM connectors and how to relate the service manual trouble code diagnosis pages, let me know and I'll post the info. (I'm leaving this out because if I do as planned, I'll post the connections for the C203 in a "solder the blue wire on the pcm harness to the brown wire on the connector" format. Connections for Dummies, sort of.)

You'll have to change the length of NEARLY EVERY wire in the Cadillac harness. Think about it... in the stock configuration the PCM is at the right/rear corner of the powertrain. In the Fiero it's at the left/front. I prefer to take enough wire that I don't have to splice. It's much easier to crimp on a pin and plug it into the destination connector than splice the two wires.

I went out and had a look on the parts fiero. You're correct, compared to the Fiero the distances wiring travels in the front right corner of a Caddy are huge. I'll look into getting the materials you mentioned earlier. Thanks!

quote Originally posted by Will: You'll have to change the length of NEARLY EVERY wire in the Cadillac harness. Think about it... in the stock configuration the PCM is at the right/rear corner of the powertrain. In the Fiero it's at the left/front. I prefer to take enough wire that I don't have to splice. It's much easier to crimp on a pin and plug it into the destination connector than splice the two wires.

Or as an option --some have relocated the pcm to the engine bay.
Now before everyone screams---heat moisture vibration consider that a lot of automobiles were built at the factory this way including my Jeep Cherokee-----don't imagine there would be any heat moisture or vibration in a Jeep huh? lol

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Proud Member of the North Florida Fiero club

4T60E Parks harness/ Rockcrawl chip-- more to come--

This is only an option with PCM's DESIGNED for mounting in the engine bay. The 2240 is NOT such a box.
Putting it in the trunk is a hack, IMNSHO.

[This message has been edited by Will (edited 12-26-2006).]

I agree with Will on this. And part of it is that neatness does count. The problem isn't that there's too little wire, it's that there's too much. So it looks like to me that wires need to be shortened, not lengthened. On the PCM, this could probably be avoided by looping the harness around the PCM mount and then covering the whole mess with the upper console, not exactly the way I want to do it. In the engine compartment, there's at least a foot of extra harness from the junction box to where the splits for components start--it cries out to be shortened to look right and keep the engine bay from getting cluttered (adding the V8 will add enough clutter to the bay.)

So I will be doing some more surgery on the harnesses to custom fit them to my car.

On another note, forum member Al Davis (not THAT Al Davis, THE Al Davis who's into Fieros) sent me an 8 page pdf file with everything about making the connections. Great stuff! Confirms all of my suspicions of where wires are supposed to connect.

I have permission to distribute it, and will send it out as an email attachment (just under 2 mb of data.) I'm still planning on the short (cookbook) version for this thread, but the info on these pages is pretty cool.

[This message has been edited by Brian Lamberts (edited 12-27-2006).]

Keep up the good work I know several guys that would like to do the 4.9 swap but are scared off by the wiring and can't afford a "pro built harness". If you can pull this off it will help many fellow fiero lovers merry christmas

The Northstar harness has over 150 wires in it. The 4.9 harness won't be too far from that. ALMOST NONE of them are the right length. That's why I'm so intent on getting all the wire I can get with a connector... if it happens that I can trim it and crimp a pin on the end and plug it in... that's one or two fewer splices that I have to make.

Brian,
I think you will be pleasantly suprised when you find out that the 4.9 fits better in the engine bay than the 2.8 does.

And looks may matter to you---------but I tell you what really matters is when you pull into a gas station and people come over and say, If you don't mind me asking, what do you have in that thing?

When I built my harness I had the complete power train mounted on the cradle and ready to go into the car. I stripped the tape and looming off all the wires. I then took the bulkhead pass throughs apart (they can be seperated take your time) that cuts down on the number of splices that you have to do. I then layed the harness on the engine and started the process of making the harness fit buy cutting one wire at a time and making it the length it needed to be. I would use ty wraps to creat temporary looms to help get the harness to lay correctly on the engine. It took me about to days to complete the process. There are some wires not needed and some splicing of the Fiero harness to the Caddy harness needed. I used the wiring diagrams from my 88 shop manual and the caddy diagrams from Rockcrawls web site.
I found it very straight forward other than figuring out how to wire in the fuel pump relay.
I used butt splice crimps and srink tubing to do my splices

My car has been running for 3 years now with no problems

Good Luck
Joe Sokol

quote Originally posted by Will: The Northstar harness has over 150 wires in it. The 4.9 harness won't be too far from that. ALMOST NONE of them are the right length. That's why I'm so intent on getting all the wire I can get with a connector... if it happens that I can trim it and crimp a pin on the end and plug it in... that's one or two fewer splices that I have to make.

Actually, WIll, the C225 ( the connector between the PCM harness and the engine harness) has 49 connections and some of them are not used in the swap. I'm not using the caddy cruise and that's about 4 connections (tho I may use one of those sets of wires to wire the fuel pump relay.) I guess wiring that's simple makes the 4.9 somewhat more attractive as an engine choice. And A/C and some of the Fiero originating wiring (alternator, A/C, temp lite and gauge, coolant fan switch and tach) comes in through the C500 and will never be integrated into the caddy wiring. (I didn't know that 3 days ago, so I guess I am making some progress.)

And the 4.9 engine harness (I seem to have two duplicates :WTF: ) really is too long for the Fiero engine bay. On the Fiero engine, the wiring comes through the bulkhead and take a turn towards the battery and the C500. On the 4.9 it goes immediately to the area of the distributor which is on the driver's end near the front of the engine. On the caddy, the wire came in from the back of the motor (further away from the distributor, so the cable run had to be about 3 feet The run of the main cable is probably only a foot or so when installed in the Fiero. (I know that's confusing, think about how the engine sits in the engine bay--in the caddy the dist. is located on the front of the engine near the radiator---on the fiero, it's on the front of the engine near the bulkhead pass through.) The 4.9 engine harness can easily be removed and put on the motor when it's installed , too. They didn't resort to runs of wiring between the valve covers and the intake the way they did on the Fiero.

I'm not going to have the 4.9 in anytime soon (I need a trans, an pcm, mounts, the prom reprogrammed (found a source btw.)) And my garage is full of parts car at the moment (ramping up to get that out, tho.) THis is a relatively inexpensive conversion to do, but it take some money, and it's THAT tight here right now.) But I want to get the wiring done and ready to install. I figure I can guestimate the distance from the 4.9 distributor (where wiring distribution to engine systems starts) by picturing where it will be in relation to the tranny. My guess is that the 4.9 distributor will end up about where the 2.8 distributor sits (and that will give me a margin of error.)

Sorry, I didn't get any wiring decoding done tonite--fell asleep on the sofa after dinner. Chinese take out tonite. Fell asleep and an hour later I was hungry again!!!

[This message has been edited by Brian Lamberts (edited 12-27-2006).]

quote Originally posted by Fieroking: When I built my harness I had the complete power train mounted on the cradle and ready to go into the car. I stripped the tape and looming off all the wires. I then took the bulkhead pass throughs apart (they can be seperated take your time) that cuts down on the number of splices that you have to do. I then layed the harness on the engine and started the process of making the harness fit buy cutting one wire at a time and making it the length it needed to be. I would use ty wraps to creat temporary looms to help get the harness to lay correctly on the engine. It took me about to days to complete the process. There are some wires not needed and some splicing of the Fiero harness to the Caddy harness needed. I used the wiring diagrams from my 88 shop manual and the caddy diagrams from Rockcrawls web site. I found it very straight forward other than figuring out how to wire in the fuel pump relay. I used butt splice crimps and srink tubing to do my splices My car has been running for 3 years now with no problems Good Luck Joe Sokol

This is also basically what I did on my completed Quad 4 and the 4.9 I'm working on. To help get the wiring length right, I also install a mock plywood firwall on the cradle and mount the PCM to it in the same location that it will be in the Fiero under the center console. Cut a hole in the plywood where the pass through grommet in the harness will go. I also solder every connection and heat shrink.

As Will has pointed out the wires could also be shortened by pulling the pins from the PCM connectors, cutting the wire to the proper length, crimping on a new pin and reinstalling the pin in the connector. This way there are no intermediate splices in the harness. But the installing new pin approach is not foolproof either. I know Ed Park's has had a couple of problems with poor crimps in his purchased new harnesses. As far as time I personally think it about a wash installing new pins versus cutting and splicing. If the harness is shortened by splicing all the wires, the best practice is not to locate all the splice in one area but to spread them. When soldering don't leave icicles of solders that can later work there way through the heat shrink and cause a short

You only really need the info on Rockcrawls site for the Caddy pinouts. Also get yourself a copy of the pinout (C500 and C203) for your year of car (there are differences in the years, so make sure you use the correct one for your car). Wiring for the engine sensors is unchanged except for the lengths of the wires.

If you have a hard time at understanding wiring (can NOT grasp the basic concept) - you SHOULD NOT attempt this. The concept is simple, but if you can't read a wiring diagram you will have a hard time with this.

DO NOT USE ANY TYPE OF CRIMP ON WIRE SPLICE (ie: butt connectors) - always solder and heat shrink your connectors (use weather proof heat shrink in the engine bay to help keep water out). I made a post here: https://www.fiero.nl/forum/A...060206-2-067482.html on how to solder correctly.

Pull apart the harness (remove all the tape), run the wires as you see fit, make the connections (ie: tps sensor wiring goes to the tps inputs on the ECM). The real wiring comes where you have to merge it into the Fiero harness.

How I like to do it (WARNING: this is MY perfered method, I have done several of these swaps and this is the method that I have developed for myself, may not be to your liking so please research before you cut wires).
- I cut the harness at the block that pass through the Caddy firewall.
- remove all tape and loom
- connect up each sensor and lay the wiring on the motor how I like to route them.
- bundle each sensor group of wire together and mark them (ie: tape all the tps sensor wires together and lable tps).
- temp tape the bundles together as they will lay on the motor and feed the ends through the Fiero's firewall.
- remove the drivers seat and sit on the floor
- take each separate group of wires and start splicing them to the correct ECM plug location (cut to length or lengthen as needed). This part you will need is the diagrams that shows the 3 Caddy plug pinouts (2 pages). Once you identified the pins you simply solder the wires together (the wires colors will be the same color so this makes it simple to match up the correct wire).

The Pass-Key module is just a black box it feeds the ECM at pin F10 - you are better off to build the circuit on Rockcrawls site - with the original module you will still have to figure out what resistor value is needed. It can be done as I have done it, but there is no advantage over using the original module (plus it is a lot bigger in size vs the 555 timer circuit). My car currently runs the 555 timer circuit.

For the stuff not on the website (or obvious):

The engine harness is straight forward (will have to lengthen and shorten some wires), some things you simply delete and don't worry about them, and others you have to fool the ECM.

wire your car as a 91 DeVille (regardless of what it really is) - the memcals are programmed using 91 DeVille base code (plus it is simpler).

power steering ECM input has to be connected to +12v

if you are running a standard tranny, you must connect ECM C10 & F7 to ground, the other transmission pins can be removed.

oil pressure switch (use the one for a 2.8 88 Fiero) and wires as:
PNK/BLK - C203 positive feed for fuel pump relay (hot at all times).
TAN - C203 oil gage feed
TAN/WHT (or GRY) - C203 positive side of fuel pump, to the COM terminal of the relay also ECM E/13
BLK - ground
You will also have to change out the temp sender in the thermostat housing (from a 2 wire unit to a 3 wire):
use these parts numbers for the correct sender:
GM 10096181
AC-Delco 213-815
Borg Warner WT3024
CarQuest TX66
Filko CS-43
GP Sorensen 38-5124
Niehoff DR134TA
Napa/Echlin ECHTS4020
pin "A" BLK wire on the switch goes to ecm "E11"
pin "B" YEL wire on the switch goes to ecm "E16"
pin "C" GRN wire on the switch goes to C500 gage connection

You will also have to deal with the passkey - build the module or have it programmed out.

Modify the tach

build the speedo clamp circuit as on Rockcrawls site (this connects to the VSS high signal (yellow wire)).

ALDL port wiring:


Throttle cable:
the 88 Fiero 2.5l throttle cable is a direct bolt in - these are no longer available new, so you will have to find a used one or crimp an end to your original cable that will fit the 4.9 throttle body.

Tensioner system I use (I am told it is similar to Ed Parks): https://www.fiero.nl/forum/A...050818-2-052483.html

C203 connector - you can delete the VSS feed for ECM - on the 4.9 the VSS feeds the ECM first then the speedo (the Fiero - VSS to speedo, then ECM).

[This message has been edited by Mickey_Moose (edited 01-21-2009).]

Wow, great writeup.Thanks.

quote Originally posted by sanderson: As far as time I personally think it about a wash installing new pins versus cutting and splicing.

Crimping new pins is a LOT faster than cutting and splicing.
I can't vouch for InjTech, but none of MY crimps are bad.

delete

[This message has been edited by Brian Lamberts (edited 12-28-2006).]

quote Originally posted by Will: Crimping new pins is a LOT faster than cutting and splicing. I can't vouch for InjTech, but none of MY crimps are bad.

1) this assumes you have the proper crimping tool - which I can pretty much guess that not everyone has one. You can't do a proper crimp with standard plyers. Here is the crimper you need (yes I have one):


2) if the wire is too short, you will still have to splice. In my experience of doing several of these swaps, most of the wires were too short. Sure I could probably route them differently so that they are not too short, but my installs are done so that that bulk of the wires are hidden from view. The 4.9 is not the nicest looking motor to begin with - having a big bundle of wire on top of the motor does not help it's apperance.

3) no pins to buy

anyways, each to thier own - like I said not everyone has or will go and buy the 'correct' crimper (there are many different styles and sizes - mine just happen to do 2 sizes, but I still splice and solder.

Folding the wires to shorten then is fine - my first swap was done like this (the owner wanted it done this way). There is a BIG DRAW back to this however - it increase the size of the wiring harness and makes it look bulky. My method trys to keep the harness as small as possible and trys to keep it hidden (easier to hide when smaller).

[This message has been edited by Mickey_Moose (edited 12-27-2006).]

Yowz, I need to buy a new crimping tool. (known that for years.) We all have our own ways of doing this--neither approach is wrong--just different.

I wanted to thank again member Mickey Moose for his writeup--writing this stuff takes thought and a fair amount of time. Your contribution helps fill in some gaps. I can read a schematic okay, but some of the stuff I've got is pretty cryptic and your post is gonna help.

And again, thanks. S'cuse me while I go build a cut and solder sheet.


Edited: Will answered the question about the o/p sender (below)

[This message has been edited by Brian Lamberts (edited 12-27-2006).]

quote Originally posted by Mickey_Moose: sorry, for the additional post... I will say this for everyone...part number or application of sender please... also of note: I did say 88 sender, which is much smaller than the previous years. I don't think the 84-87 Fiero oil senders would fit between the oil lines anyways.

Try '96 truck with Vortec 350. I didn't realize the '88 senders were different than those of the early years. I just checked on my Formula and that sender is almost as compact as the ones I was talking about. The newest ones can be a significant fraction of an inch shorter, however.
I don't know the exact application of the MOST compact ones. The ones that are just switches and don't have gauge senders in them are extremely compact.
Basically, go to a CarQuest and look in the book that has the oil pressure senders in it. Find the one in the GM section that looks the smallest and has a gauge sender. Buy it.

quote Originally posted by Brian Lamberts: I wanted to thank again member Mickey Moose for his writeup--writing this stuff takes thought and a fair amount of time. Your contribution helps fill in some gaps. I can read a schematic okay, but some of the stuff I've got is pretty cryptic and your post is gonna help. And again, thanks. S'cuse me while I go build a cut and solder sheet. Edited: Will answered the question about the o/p sender (below)

No problem, glad I could help some...

Will >> thanks for the info

Getting to the meat of things--wiring connections--I'll be adding and editing to this post. Edited 1-13-07 edited parts in italics.

[I} 1-13, sorry I've been working on other projects and haven't had time to do more than shorten some wires. I was looking at my C203 last night and realized that some of the wires were in the wrong positions. It's very important to verify that the color corresponds to the connector position on all connectors--that means checking the physical position of every wire you connect. In a post on the next forum page, I'll post a scan of a table that tells what wire is what.on the c203. [/I]

Here are the connectors I'll be talking about in this post. C203 is the clear connector that connects to the Fiero Cabin harness. C225 is the Caddy PCM harness connector that connects to the engine harness. Wiring references to A or B plus a number refer to the small black PCM connector; C or D plus a number refers to the larger black PCM connector: E or F refers to the large green PCM connector. ALDL is the aldl (using the caddy one.) For this post, the C203 is the base we're working from in this post and the letters for this connector range from A to R. So here goes:

Pin
A Tan/Black Upshift lamp
Not used, Pcm Has no provision for this

B orange Fuel pump relay 12v 10a
Connect through C225 to fuel pump relay orange black (pick a wire through the C225, but the orange wire from
the C203 must end up connected to the orange black wire
of the fuel pump relay. This wire is alway hot, so it's a good
candidate for powering the PCM--connect C16 red and B1 Red to this
circuit

C brn/wht SES lite
To A10 brn/wht

D light blue Power feed for A/C, Hot when A/C is on.
We’ll deal with the a/c later.

E Tan Oil gauge
Run through C225, it needs to connect to pin b of the oil pressure
sender.

F Pink/white 12v 10 a with key on/ start
E7 grn/yel , E3 pnk/blk, C9 lt blu/orange, A6 pink blue, to 1k ohm of speedo filter


G Yellow VSS high
To 22k ohm of speedo filter See diagram at this url (build instructions for the filter, too.) Green wire from filter goes to PCM B11 dk green http://fp.enter.net/~rockcrawl/speedo.html )

H Brown VSS feed to pcm.
Not used no provision

J pink may be pink/white Injector 12v source
N6 red through C225

K pink Injector 12v source
N7 white through c225

L tan /white 12v for the fuel pump
Connect through the C225 to the tan/white wire on the fuel pump relay and either G or K position on ALDL

M Black VSSB ground
Hook up normally (gotta do research about what normal is)


N Black 12 v for a/c compressor control relay contacts
Hook up normally--run a jumper to the control relay

P purple TCC brake, Hot R, T, & S when brake not depressed
G3 Purple on C225—manual changeover/ Don’t know what this means.

R purple/wht VSS input to speedo
Use this as the ground (third leg) on the speedo filter.
All black/white wires on the PCM are grounds, need to be grounded to the
Chassis.

ALDL
Tan to A8 Tan
Wht/black to E12
Purple runs to 12 v tan/white for fuel pump (the tan/white wire on the C203 pin L)
Blk/white ground to chassis

[This message has been edited by Brian Lamberts (edited 01-15-2007).]