As you can the the harness that goes to my ECU has the strain relief and the square plug doesn't. The harness has the connectors for the engine sensors, injectors, etc, and all the ECU plugs as you can see. I also have the relays but understand that I don't need them. So, any ideas about whether I can scrap that large plug. I suppose I'll get the answer when sort out the harness but don't want a huge surprise either. The harness is from a 94 Caddy Deville.

Does anyone have the pinout diagram for the 1991 Caddy Seville ECU?


Also,Started sorting out my harness this weekend (finally). There was a LOT of extra wire but my understanding of this is that once the engine is wired correctly to the PCM the extra wiring can be eliminated. Again this has been a very helpful post and thanks again to everyone. The bird's nest of wiring is starting to look better.

I have them. They are large (500k) jpegs. 2 images. I'll email them to you, full size so you can blow them up if you like.

(edit I tried, but the email address in your profile bounces.


The engine connections go through the C225. They don't need to be disturbed, tho you will need to shorten the harness on both sides of the connector. Read the warning posted earlier in this thread, GM uses same color wires in the same bundle but with different functions, so go slow and don't cut a whole lot of wires at once.

[This message has been edited by Brian Lamberts (edited 03-12-2007).]

Corrected my email link: chrisbracey@yahoo.com

Thanks!!!

quote Originally posted by Brian Lamberts: I have them. They are large (500k) jpegs. 2 images. I'll email them to you, full size so you can blow them up if you like. (edit I tried, but the email address in your profile bounces. The engine connections go through the C225. They don't need to be disturbed, tho you will need to shorten the harness on both sides of the connector. Read the warning posted earlier in this thread, GM uses same color wires in the same bundle but with different functions, so go slow and don't cut a whole lot of wires at once.

Throw the whole harness in an oven at 250 'F for about 20 minutes and then you can remove the C225 connector and all the hot glue like sealant. Do the same thing for Fiero harness and transfer the connector grommet to the Caddy harness in the right location to get the proper length of wire to the PCM. Then you only have to shorten the wires in one place.

If you don't mind making two splices per wire and then I'd add wire to the harness and route the main harness down by the transaxle and up to the firewall instead of over the top of the engine. This would make for a much cleaner look. The Caddy engine has a lot of wire on it.

The C225 isn't the thing that does the pass thru for the firewall. It has the pin connectors and bolts together with a small bolt.


The pass thru for the caddy can be discarded--either heat it with a glue gun or put it in the freezer for a couple of hours (my favorite method) once that hot glue is frozen, it will shatter if you smash it with a hammer a couple of times. The fiero pass thru can be salvaged using the same method, just be sure to pry the pass thru open before smashing the hot glue--and don't hit the wire loom directly (the loom looks like a comb.) You need to use the Fiero pass thru, btw.

Any new progress?

quote Originally posted by Brian Lamberts: The C225 isn't the thing that does the pass thru for the firewall. It has the pin connectors and bolts together with a small bolt. .

Yup, my bad. I was talking about the pass through grommet.

But seriously heating the whole harness up in the oven works like a charm to get the pass through grommet off.

[This message has been edited by sanderson (edited 04-07-2007).]

I guess I'll post one last time to this thread (and keep it out of archives, maybe.)

I am completely out of the 4.9 conversion--don't have the target car, motor, wiring, or any of it (well do have a set of Energy Suspension mounts and some transmission mounts.) Anyhow, I never was a guru, just a facilitator.

But with this post, I'm resigning as even a facilitator--it's out of my mind, I'm not among the 4.9ers anymore. It was fun to dream, tho.

I am still in the 4.9 hunt, getting close to having it installed actually, but decided to go another route. (7730 computer, painless wiring harness and TCI transmission controller). I know the way I'm going is more expensive but also should be much more tunable and allow the addition of paddle shifting.

That said, I've got a Caddy computer and most of the wiring harness if anyone is interested.

quote Originally posted by vafierro: I am still in the 4.9 hunt, getting close to having it installed actually, but decided to go another route. (7730 computer, painless wiring harness and TCI transmission controller). I know the way I'm going is more expensive but also should be much more tunable and allow the addition of paddle shifting. That said, I've got a Caddy computer and most of the wiring harness if anyone is interested.

Just be advised that the 7730 ECM does not have the circuitry to control the idle motor that the Caddy 4.9L uses. That ECM was made to run a IAC valve.

------------------
87GT 3.4 Turbo- 0-60 5.2 seconds
2006 3800SC Series III swap in progress
Engine Controls, PCM goodies,
re-programming & odd electronics stuff
" I'M ON THE LOOSE WITHOUT THE JUICE "

Some allante/7730 info you might find interesting. From here to the msn list and back again....

"I got a reply for this question on the Pennocks site using the PM option there. I just throught I would share it with all here also. The reply came from Pennocks member "v8fiero400" . I am starting to track down the parts needed since I have already purchased the allante intake off of e-bay. Thanks again v8fiero400.

I used Painless harness # 60103. I uses a 1990-1992 Camaro/firebird computer ( 305 tuned port injection). I runs perfect on the 4.9, fuel efficient and powerful. Good thing about using a camaro/firebird ecm is that there are lots of sources to get aftermarket proms for modifications like nitrous, boost, etc. If you can adapt the camaro/firebird throttle to the allante intake that would make things easier. I used an Allante throttle but had to add a remote IAC valve. You will need to get a knock sensor from a 1994 saturn and use it on your 4.9 with this computer (the camaro/firebird knock sensor will not screw in a 4.9). Do not use the Allante injctors. Use the 4.9 injectors...they are the same part number as Camaro/Firebird injectors. All the other sensors are pretty much interchangeable. You will need to buy a VATS bypass module on ebay for like $20 so that the camaro/firebird prom will run the engine without the chip-in-the-key anti theft feature. The ecm part number is 1227730. they use it in a lot of different GM vehicles.... but the prom inside must be for a 1990-1992 305 tuned port injection engine."

quote Originally posted by Dennis LaGrua: Just be advised that the 7730 ECM does not have the circuitry to control the idle motor that the Caddy 4.9L uses. That ECM was made to run a IAC valve.

It works with the allante intake but not the 4.9 intake. The 7730 is also the ECM that PBJ used in his 4.9 swap including the addition of the turbo.

bump, and:

quote Originally posted by Fieroseverywhere: It works with the allante intake but not the 4.9 intake. The 7730 is also the ECM that PBJ used in his 4.9 swap including the addition of the turbo.

My understanding is you still have to convert the Allante throttle body over to an IAC system.

Now a question about the Allante intake: is it the complete Allante intake that improves hp?? What I am trying to get at here is, the intake basically consists of 3 separate items: the manifold, the runners and the throttle body. Now, say a person was to use the Allante manifold only and build an adaptor to mount the throttle body directly on top, would that hurt the performance or are the runners 'tuned' for the motor to help with the power increase and have to be used with the other parts? To me the runners seemed to be flawed as they do not seem to be of equal length (the top group is longer).

Any thougths?

[This message has been edited by Mickey_Moose (edited 12-19-2007).]

quote Originally posted by Mickey_Moose: bump, and: My understanding is you still have to convert the Allante throttle body over to an IAC system. Now a question about the Allante intake: is it the complete Allante intake that improves hp?? What I am trying to get at here is, the intake basically consists of 3 separate items: the manifold, the runners and the throttle body. Now, say a person was to use the Allante manifold only and build an adaptor to mount the throttle body directly on top, would that hurt the performance or are the runners 'tuned' for the motor to help with the power increase and have to be used with the other parts? To me the runners seemed to be flawed as they do not seem to be of equal length (the top group is longer). Any thougths?

When I got my 4.9 running.... I was using the stock 4.9 intake.... I was impressed by the torque this engine put out and didn't think there was much improovement to swapping to another intake..... but a few months later I found a deal on ebay and bought the Allante intake because it just looks so much better.

.... well to my surprise it made a big improovement in the 3000-5000 rpm range. The runners are not equal in length,,, but they are all much longer and much straighter all the way to the heads. I think the biggest problem with the stock 4.9 intake is that the area directly below the throttle has too much of a sharp turn and sharp edges where the intake air has to turn into the individual runners.


P.S. Yes.. if you use the 7730 ECM... you cannot use the 4.9 or Allante 'pusher' idle control motor. I used a remote IAC valve that is compatible with the 7730 ecm

quote Originally posted by Fieroseverywhere: It works with the allante intake but not the 4.9 intake. The 7730 is also the ECM that PBJ used in his 4.9 swap including the addition of the turbo.

Huh? Didn't remember typing that. Don't listen to that guy he doesn't know a damn thing.

Anyways, I've learned a bit more since then and now I know that the allante idle control motor will not work with the 7730 ECM either. I'm going with the caddy ECM to start with anyway. Any other mods will be later on down the road. I still think there needs to be a thread like this one that finishes a walkthrough for making your own harness. Anyone up to the challenge? I'll be starting the wiring on mine in the next month or so. Mine is a slow moving, entire car teardown and rebuild, not just an engine swap so its taking a long time to complete.

I will be starting my harness within the next month, but I don't know how it will go. I have electronics experience thanks to the U.S. Air Force but this is a new animal.
My engine is built and I will be starting on the 4T60E rebuild shortly. I did remove the computer, harness, ignition key, vin numbers and even the tire size data plate from my donor caddy. I wish this thread would have continued because, like many, I rely on the expertise displayed here by the Fiero gurus. Maybe enough of us can contribute our do's and don'ts and what ifs, start another thread or continue this one and help each other. I will continue to search for more info locally from my auto computer genius friend and share the info here. I will post what I come up with. (maybe within the next month or so)
Tim

quote Originally posted by majesticpools: I will be starting my harness within the next month, but I don't know how it will go. I have electronics experience thanks to the U.S. Air Force but this is a new animal. My engine is built and I will be starting on the 4T60E rebuild shortly. I did remove the computer, harness, ignition key, vin numbers and even the tire size data plate from my donor caddy. I wish this thread would have continued because, like many, I rely on the expertise displayed here by the Fiero gurus. Maybe enough of us can contribute our do's and don'ts and what ifs, start another thread or continue this one and help each other. I will continue to search for more info locally from my auto computer genius friend and share the info here. I will post what I come up with. (maybe within the next month or so) Tim

Sounds good. I look forward to seeing what you come up with.

One question for you. What does that tire size plate say? And what year/model of cadillac was it? I forgot to look with mine and always wondered.

This is what I want to do next is a 4.9 swap . I will be here in the background reading. You guys with the harness just keep posting.
Joe Crawford
Texas

If I remember correctly (the label is in my garage) the tire size is 205-70R15. 1992 caddy deville. I read somewhere here the correct diameter tire was important for computer tuning or speedo calibration or something like that. I will check the label tomorrow to be sure, will repost if different.
Tim

quote Originally posted by majesticpools: If I remember correctly (the label is in my garage) the tire size is 205-70R15. 1992 caddy deville. I read somewhere here the correct diameter tire was important for computer tuning or speedo calibration or something like that. I will check the label tomorrow to be sure, will repost if different. Tim

The correct tire size is for speedo calibrating. The good thing is that a custom chip can be programed with any tire size you want. Pick your size just keep to total diameter under 27" to keep things from rubbing. Increasing the overall diameter will change the way the car acts also so you have to take that into consideration. Larger diameter = lower RPM's at cruising speeds and a higher top speed but you lose out on lowend torque also and your brakes will take more load. There is always a compromise. Going smaller will have the opposite effect. Be careful when going custom sizes. It can cause some problems when taken too far and not just rubbing.

I just always wondered what the caddies ran from the factory just never checked it out myself. I am using a 93 deville so they are basically the same motor. Either way you want to wire it as a 91. You have the choice of a 91 deville with a single O2 sensor or 91Seville/eldorado which has dual O2 sensors. Aaronrus here on the forum does chips for both.

I will be installing most of the brakes this weekend and need to finish the exhaust. Once that is done I have a few other things (like more plumbing) to do but will start the wiring before too long. I will get lots of pics as I usually do and post some here aswell as my build thread (link in sig).

Thanks for that info Tim I appreciate it.

Hey Joe. If you have questions let me know and I will answer what I can or point you in the direction of someone who can. Later

[This message has been edited by Fieroseverywhere (edited 12-20-2007).]

Oops. Sig.

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84 SE auto. - a fun original
85 SE V6 4 speed - stock, fully loaded - daily driver
85 GT 4 speed - build thread
88 Coupe 5 speed - runs and drives, needs work, patiently waiting for its turn.

I have been through your threads several times...very inspiring. I bought my 4.9 because I was so impressed with your results. I did use the stock cam though, trying to build on a budget for now (pool business is a little slow in winter) funny part is, I bought the car last september, it ran fine, but me being a motorhead, I needed a V8. The 4.9 so far has only cost me approx. $500.00 counting new parts etc. I have only driven the car 100 feet...from my tow trailer to my garage and then out came the v6. Label me kooky!! I owned a fiero in 89 and loved it. I can't wait until she is on the road.
Keep up the good work. Seems to me you have your sh^^ together and stacked neatly so I'm following your lead.
Tim

bump

quote Originally posted by Brian Lamberts: More stuff. I got this from forum member Al Davis--he deserves ALL the credit, I made a few alterations, but he did all the hard work.

I have a question about the fuel pump circuit.

It is my understanding that the stock Fiero oil pressure sender can shut off the fuel pump when the oil pressure get to low. Correct?
It looks to me like this diagram voids this function. Is there a reason for this?
A 12V hot should go to the "C" on the oil pressure sender from the F. Pump fuse at fuse block ( B of C203 ). This would run the fuel pump any time the oil pressure is "normal" and make the ECM control redundant. As this diagram is, the oil pressure is not going to send a signal anywhere? Mite as well just take all the Fuel pump wires out of your oil pressure sender harness and only run a single wire from the sender to the oil pressure gage.

Shouldn't this have the "E" and "D" combined and the switch inside the relay hinge from the "E" "D" towards the "B" ?


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[This message has been edited by Rickady88GT (edited 02-25-2008).]

quote Originally posted by Rickady88GT: It is my understanding that the stock Fiero oil pressure sender can shut off the fuel pump when the oil pressure get to low. Correct?

Incorrect. The ECM drives the fuel pump relay when the engine is running (i.e. when its seeing ignition reference pulses). The oil pressure switch is in parallel with the ECM circuit. This is how it is on the stock Fiero..


EDIT: I found an archived thread about this: https://www.fiero.nl/forum/A...020825-2-019022.html

[This message has been edited by Steven Snyder (edited 02-25-2008).]

OK, so the oil pressure switch is not a "cut out" it is still a redundant power to the pump. So in this diagram, what good is the switch to the pump? The oil pressure switch don't supply power ( none is run to it ) and cant give feedback ( the circuit opens and does not see power ).

Seems like "C" at the switch should splice into the "E" "D" on the relay and not to the C225 or E13 if the hinge inside the relay were on the " E" "D" side. OR flip flop the E and D with the B.

Lemmee see. Been forever since I wrote that. Also I have never installed a 4.9 so I have no experience. I made these in preparation to installing one in my car which never happened.

Disconnect the wire to E of the relay and hook it up to (139 PNK/BLU) D of the same relay along with the wire already there. That way 12V goes to the relay and the oil pressure switch. If the relay does not close, when oil pressure builds the switch will pass power around the relay to the pump. If the relay does close, no problem - pump will run and when oil pressure builds they will run in parallel so you can have one failure in the system without killing the pump.

I am pretty sure that is the way it should be so it was an error on my part. Sorry,
Al

So basically run it just like the stock Fiero? That was my plan, but I needed to know if this switch was left out for a reason?

Thanks.

Yes it should function the same as the original wiring. I left the note next to it as a reminder to make sure it was checked. I also thought some of the Fiero wires may need to be moved around because of the Caddy harness connectors or routing.

Wire as originally in the Fiero.

of note: there are some mistakes in the 4.9 diagrams that are posted on Rockcrawls website - use the diagrams as a guide only, always verify with the ECM pinout diagram.

quote Originally posted by Mickey_Moose: Wire as originally in the Fiero. of note: there are some mistakes in the 4.9 diagrams that are posted on Rockcrawls website - use the diagrams as a guide only, always verify with the ECM pinout diagram.

I have seen some of the differences but I don't have the pin outs for the 95. I have just a few of the ECM pin outs, Mainly the engine tranny emissions stuff. I don't know what the other wires go to from the ECM. I don't have the C225 or the Black Plug that some of the ECM wires go thru. So I just figured the differences were between years?

...there are differences between the years and models. You need to wire the car for the year of EPROM you are putting in. Mostly you wire it as a 91 Deville or a 91 Seville - these 2 have the simplest wiring of the bunch (plus the available "modified" EPROMS). No need to look through the other wiring diagrams. If you are using the stock programming, then wire it for that EPROM.

General rule: hook it up to the Fiero as the previous motor was. ie: use as many stock parts as you can (fuel pump relay) and connected engine components to the same location (starter hooks up the same way, etc). Only the engine "electronics" are different - these you hook up as the are in the Caddy - by these I mean, injectors, distributor, sensors - things that are physically bolted to the block and feed the ECM. The only changes to the 4.9 wiring that are done are those that connect to the C500, C203, ALDL, fuel pump relay and temp sensor (to account for the new type sensor installed). Some 4.9's also have a head temp sensor (switch) that turned on the idiot light on the dash (can be deleted on the Fiero or used for an additional light).

Hope that helps...

[This message has been edited by Mickey_Moose (edited 02-27-2008).]

I need some clarifications on some things?

What temp sensor adaptor is used to put the stock temp sensor in the 4.9 head? the one I found is to short for the Fiero sensor prob to fit in it. Or is some other sensor used in the T stat housing to run the temp gauge and temp light. That would leave the head sensor unused?

I have seen several ALDL pin outs. What one should be used on the 95 Devil? Looks like these two are the same but flipped?



I cant find a wire diagram for the Tach adaptor?

I cant find the wire diagram for the Speedo filter conversion? I have a filter I made a while back for my 94 3100SFI conversion but it has a 22K resistor a 1K resistor AND a 0.1 Ceramic Capacitor. The posted diagram does not have a Capacitor in the circuit? Also in one post the "filter" is grounded and in other diagrams it is 12v+ whats up there?
It is kind of hard to see but it looks like the Cap is between the G of C203 and 22K?
[/QUOTE]

Also, again on the A/C. What High pressure cut out switch do I use? The Fiero has a HEAVY gage black wire that uses an internal switch. The Caddy does not.

Can I just use a Fiero A/C compressor and change out the Pulley?

[This message has been edited by Rickady88GT (edited 04-24-2008).]

quote Originally posted by Rickady88GT: I need some clarifications on some things? What temp sensor adaptor is used to put the stock temp sensor in the 4.9 head? the one I found is to short for the Fiero sensor prob to fit in it. Or is some other sensor used in the T stat housing to run the temp gauge and temp light. That would leave the head sensor unused?

(from my post on the 1st page)
You will also have to change out the temp sender in the thermostat housing (from a 2 wire unit to a 3 wire) - the "head location" is a temp switch - use the stock 4.9 sensor here, but this is only good to turn on the temp light in a car that does not haved a temp gauge. Use these parts numbers for the correct sender in the thermostat housing:
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

quote Originally posted by Rickady88GT: I have seen several ALDL pin outs. What one should be used on the 95 Devil? Looks like these two are the same but flipped?

This is my method and it works 100% with my scanner - can not comment on the other one you posted (it has an extra pinout - wire jumpered over).

quote Originally posted by Rickady88GT: I cant find a wire diagram for the Tach adaptor?

There is no diagram - this is the 'simple' V8 tach mod - many different threads on Pennock's on how to do this. Use either the capacitor or resistor method (I prefer the resistor (pot) method as it is adjustable).
See here (resistor version): http://www.fieros.de/en/articles/tach.html

quote Originally posted by Rickady88GT: I cant find the wire diagram for the Speedo filter conversion? I have a filter I made a while back for my 94 3100SFI conversion but it has a 22K resistor a 1K resistor AND a 0.1 Ceramic Capacitor. The posted diagram does not have a Capacitor in the circuit? Also in one post the "filter" is grounded and in other diagrams it is 12v+ whats up there? It is kind of hard to see but it looks like the Cap is between the G of C203 and 22K?

What I have looks like what you have above, basically this is what I use (sorry to the original poster of this picture as I forgot who you are and I can't find the original diagram that I got from PBJ (I also forget who the original author was of this mod) and Rockcrawl remove the diagram from his site) - basically all engine swaps use the same circuit:
edit: notice in the diagram you posted above you have the power steering input (C9) going to ground - this HAS to connect to +12v (ign source) - the ECM will go into limp mod otherwise

quote Originally posted by Rickady88GT: Also, again on the A/C. What High pressure cut out switch do I use? The Fiero has a HEAVY gage black wire that uses an internal switch. The Caddy does not. Can I just use a Fiero A/C compressor and change out the Pulley?

I hear you can just swap the pulley - can not be of any more help as I have never done one with a/c.

[This message has been edited by Mickey_Moose (edited 04-25-2008).]

Thank you.

Ok, I found the original speedo info I got from PBJ:

[This message has been edited by Mickey_Moose (edited 04-25-2008).]

Both Aaron (stick pony) and Jon (rockcrawl) can now program the 4.9 ECM to directly run the speedo. Tire size is programed in also. There no longer is a need for the speedo conversion if you have a custom chip made.

EDIT: At least this is my understanding. I will confirm for sure in a week during my test drives. I'll keep you all posted.

[This message has been edited by Fieroseverywhere (edited 04-27-2008).]

quote Originally posted by Mickey_Moose: bump, and: My understanding is you still have to convert the Allante throttle body over to an IAC system. Now a question about the Allante intake: is it the complete Allante intake that improves hp?? What I am trying to get at here is, the intake basically consists of 3 separate items: the manifold, the runners and the throttle body. Now, say a person was to use the Allante manifold only and build an adaptor to mount the throttle body directly on top, would that hurt the performance or are the runners 'tuned' for the motor to help with the power increase and have to be used with the other parts? To me the runners seemed to be flawed as they do not seem to be of equal length (the top group is longer). Any thougths?

it is my belief they are tuned, especially since the allante throttle body is a two stage throttle body, almost liek primaries and secondaries on a carburator

quote Originally posted by Fieroseverywhere: Both Aaron (stick pony) and Jon (rockcrawl) can now program the 4.9 ECM to directly run the speedo. Tire size is programed in also. There no longer is a need for the speedo conversion if you have a custom chip made. EDIT: At least this is my understanding. I will confirm for sure in a week during my test drives. I'll keep you all posted.

Nope, does not work. Main reason: the output of the Caddy ECM is too small to drive the Fiero speedo. The 'conversion' circuit a bias voltage so that the Fiero speedo can 'see' the correct signal.

Programming the ECM only changes how many pulses per mile is outputted - compensation for different tire sizes and different VSS senders (the stock Caddy VSS sender output 26000 ppm vs the Fieros VSS sender at 4000 ppm (if you are using a standard tranny)). Joe's write up (above) explains it