I've always kinda wondered about wiring on an engine swap. Then my wife and I were talking about engine swaps today, because she is driving a BMW 325i and I was kicking around the idea of doing an engine swap on it. We started talking about wiring and I was telling her about how they make stand alone ECM's for a lot of engines and she asked me what is the deal with the wiring on the car...

I really don't have an answer, I know the interior lights, radio, power options, etc all have there own wiring, and the engine if removed with all it's wiring intact can run outside the car... So what really are we integrating on an engine swap? the only thing I can really think of is the guages?

So I would really like your input on what all has to be mended together (and I'm sure that engine/car specific but give me a rough idea) and what would happen if you used a standalone ECM like a megasquirt?

Thanks a ton

-Brandon

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The List;
-98 Jetta TDI (55+ MPG) DD -95 BMW 325i 5 spd Wife's
-82 Chevette Diesel 50+ MPG spare -87 Fiero 3800 S1 S/C 5spd project for sale
-88 Fiero Formula 5 spd for sale -85 Fiero SE (7730 ecm, 3500)
-87 GT (7730 ecm, hybrid 2800, izusu 5spd swap soon)
-85 S10 diesel 5spd (engine donor) -84 S10 (receiver)
-91 Mercedes 190E (diesel 5spd swap) -84 Mercedes 190D (donor)

quote Originally posted by cooguyfish: I've always kinda wondered about wiring on an engine swap. Then my wife and I were talking about engine swaps today, because she is driving a BMW 325i and I was kicking around the idea of doing an engine swap on it. We started talking about wiring and I was telling her about how they make stand alone ECM's for a lot of engines and she asked me what is the deal with the wiring on the car... I really don't have an answer, I know the interior lights, radio, power options, etc all have there own wiring, and the engine if removed with all it's wiring intact can run outside the car... So what really are we integrating on an engine swap? the only thing I can really think of is the guages? So I would really like your input on what all has to be mended together (and I'm sure that engine/car specific but give me a rough idea) and what would happen if you used a standalone ECM like a megasquirt? Thanks a ton -Brandon

With older car's like Fiero's, there really isn't that much that is really integrated, maybe stuff like the A/C and charging system, nothing too major of a job.
But with new cars, nearly everything is integrated, its crazy. Here is an example. My neighbors had there daughter come over to visit one day in her new 2009 Ford Edge. It was a few months old at the time, but she got there, and when she wanted to leave, it wouldn't start. all the lights/gauges/etc worked but it acted like there was not a starter there. Towed it to the Ford dealership. The cause of the no-start condition? A bad seat belt ground. I rest my case.

quote Originally posted by cooguyfish: I was telling her about how they make stand alone ECM's for a lot of engines and she asked me what is the deal with the wiring on the car... -Brandon

I think you hit the nail on the head... the issue is the stand alone ECM. MOST new cars have an ECM that is totally integrated into the new car and does not want to run outside of that car, let alone in a Fiero. So junk yard swaps keep getting harder and harder to do.

But all is not lost...there are increasing numbers of crate motors that DO come with stand alone ECMs that only need 4 wires to run, (Power, ground, ign, and start) That is the way most of us are going to have to go in the future because it's too difficult to figure out how to hack the ECMs. That's the main headache with the Northstar.

As for Megaquirt, it's a nice tool for the tuning enthusiast, but it's not a plug and play solution for the novice.

[This message has been edited by jscott1 (edited 07-11-2010).]

So in a fiero, it's not a matter or making the fiero work with the engine. It's a matter of tricking the engine to think it is inside the car it came in.

It makes so much more sense now Like I feel stupid it makes so much more sense

Thanks guys

-Brandon

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The List;
-98 Jetta TDI (55+ MPG) DD -95 BMW 325i 5 spd Wife's
-82 Chevette Diesel 50+ MPG spare -87 Fiero 3800 S1 S/C 5spd project for sale
-88 Fiero Formula 5 spd for sale -85 Fiero SE (7730 ecm, 3500)
-87 GT (7730 ecm, hybrid 2800, izusu 5spd swap soon)
-85 S10 diesel 5spd (engine donor) -84 S10 (receiver)
-91 Mercedes 190E (diesel 5spd swap) -84 Mercedes 190D (donor)

When specifically talking about the fiero, the engine harness is pretty much standalone from 85-88 in that only engine related wires are in the harness (a lot of mid 80's front engined RWD car had more than just engine/ecm wires in the harness, some had headlights, HVAC and other functions).

The other nice thing about the fiero is that all the dash guages, fuel pump, Alternator, AC and transmissions can run w/o the ecm with very little work. This makes running carburators and integrating standalone ecms that only control the engine/fuel/timing a rather simple process.

When you start installing later model engines/harness, you often have to decide if you are going to reduce the newer ecm/harness to just running the engine/fuel/timing/transmission and retain the fiero harness (non-ecm) wires for everthing else (keeps you with older style alternators/AC compressors and often requires bracket fabrication to install these on newer engines), keep the newer engine/ecm controlling everthing and adapt the fiero to this newer setup, or a combination of the two. The newer ECMs (OBD2) were setup to have alot more control over the alternator, ac and feedback from many other systems... so you either have to add all those systems, trick the ecm into thinking everything is like it should be, or program those portions out.

Here is a turn key 5.3 V8 that drops right in...okay it needs 5 wires, but I think you could handle that.

http://www.turnkeyenginesup...1&eid=1&key=packages

quote Originally posted by jscott1: Here is a turn key 5.3 V8 that drops right in...okay it needs 5 wires, but I think you could handle that. http://www.turnkeyenginesup...1&eid=1&key=packages

Thats an LS4. Good and easy solution for swapping in a V8 but quite high priced. I believe that this engine has the transverse FWD bolt pattern. Although its plug and play the stand alone ECM makes no provision for shifting a modern auto. You could use an older 4T60 but it probably wouldn't hold the power.
I also believe that with a stick, there is little provison for mounting a starter. I often wonder how the Fiero LS4 owners made their swaps work.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

quote Originally posted by Dennis LaGrua: I also believe that with a stick, there is little provison for mounting a starter. I often wonder how the Fiero LS4 owners made their swaps work.

The starter problem is what's stopping me from doing an LS4...because there is no way in the world I'm going to use an auto.

quote Originally posted by jscott1: Here is a turn key 5.3 V8 that drops right in...okay it needs 5 wires, but I think you could handle that. http://www.turnkeyenginesup...1&eid=1&key=packages

Since you mentioned it, I'm actually not afraid of wiring things. I will not lie, as much as I understand about engines, turbo's, transmissions, suspensions, car's in general, etc. I understand almost nothing about electricity. It's not for lack of trying I just don't get it for whatever reason.

Now, having said that, I have a father in law that is an electrician, and a friend's dad design's/programs/repairs PLC panels. THEY understand electricity and if I have questions I'll ask them or the forum. As far as doing wiring, that's a non-issue as well as I used to build PLC panels for said friends dad. landing wire's I get I just need someone to tell me where to put them

Also, I am not a V8 guy. at least not in a fiero. I drove my friends 04 GTO LS1 6 spd and it's pretty sweet, but I wouldn't want that engine in my fiero. Mostly because of the gearing on the fiero tranny being way to short for it, and the fact that it's way more power (and fuel consumption) than I would want. I have all the parts to build a 2.8 hybrid.

3100 block, heads, intake + fiero 2.8 crank, rods, pistons + Custom camshaft = gen 3 2.8 with 13:1ish compression, excellent heads/intake, and the camshaft to make it work together.

Now for the wifes BMW a V8 is not out of the question since I can utilize a T56 tranny.

-Brandon

quote Originally posted by Dennis LaGrua: Thats an LS4. Good and easy solution for swapping in a V8 but quite high priced. I believe that this engine has the transverse FWD bolt pattern. Although its plug and play the stand alone ECM makes no provision for shifting a modern auto. You could use an older 4T60 but it probably wouldn't hold the power. I also believe that with a stick, there is little provison for mounting a starter. I often wonder how the Fiero LS4 owners made their swaps work.

FWIW, that is Not an LS4, it is the RWD aluminum 5.3L.

All complete LS4 swaps to date have used the stock 4T65e-HD tranny and the stock ecm/tranny controller.

This starter setup on the F40 would work with an LS4:

quote Originally posted by cooguyfish: gen 3 2.8 with 13:1ish compression

What do you plan to run for fuel?

quote Originally posted by fieroguru: This starter setup on the F40 would work with an LS4:

I can't exactly tell what I'm looking at...is that starter mounted in reverse on the bell housing side? What is that application from? Does anyone have a working LS4 Manual Transmission?

quote Originally posted by Bloozberry: What do you plan to run for fuel?

There are three choices I'm looking at.
Option 1) I can get 94 octane at the pump here, and as long as I tune it well it will run it.
Option 2) I was looking into propane, being 105 octane it would be much less likely to knock. There are a lot of benefits to propane as well, like the fact that the engine will still look brand new even after 100K miles, the oil will never turn black, etc.
Option 3) I am currently doing a lot of research into producing ethanol, E98 is 105+ octane (I forget exactly what it is off hand) and can handle 15:1 compression if I felt compelled. Ethanol has the same benefits as propane as far as not contaminating oil, and your engine will stay shiny forever.

I want to say, I have been keeping the ethanol thing to myself for a while because there are a lot of negative things said about it that are not 100% true. I was going to wait til I did it myself before I mentioned it on here.

-Brandon

I think there is a little misinformation going on here. I am currently doing a 2007 LS4 swap into a 86 Fiero. The ECM and TCM need power from the battery to run the engine/transmission. The integration with the Fiero requires a power on signal ( from the key switch) a start signal (to engage the starter) the only other inputs to the engine needed are the throttle pedal (6 wires) and the signal from the brake booster (3 wires).
Now there are a few other systems that get signals (cruise control, tap shift) and there are the signals that come from the engine to the Fiero for information (speedo, tach and other gauges).
In my 97 3.4 DOHC it was pretty much the same.
There are a number of computer systems that are used in modern cars that can and are used to control the engine. The major one is the Body Control Module. Modern cars run most systems VATS, Lights, radio, navigation through the BCM and it can stop the engine from running. However the BCM can be gotten around. I am building Jeff's LS4 without the BCM.

Not trying to start any flame wars just putting out information.

Joe Sokol

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85 SE Daily driver with a 3.4 DOHC OBD II
88 Formula/GT 4.9 Allante Intake (My Baby)

What I want to know is why so many people spend so much time and effort rewiring Fieros to suit the later stock electronics when swapping? I mean for the effort a lot of people apply, you could just as easily install an aftermarket ECU... There's gotta be a reason for not going standalone that I'm not getting!

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quote Originally posted by Carcenomy: What I want to know is why so many people spend so much time and effort rewiring Fieros to suit the later stock electronics when swapping? I mean for the effort a lot of people apply, you could just as easily install an aftermarket ECU... There's gotta be a reason for not going standalone that I'm not getting!

I won't lie, I am with you. The only reason's I can think of, are stand alone's are usually very expensive, and 2nd, they may not be made for every engine.

I think with the proliferation of things like the megasquirt, you might start seeing more and more people going that route. I've at least considered it.

[This message has been edited by cooguyfish (edited 07-13-2010).]

quote Originally posted by jscott1: I can't exactly tell what I'm looking at...is that starter mounted in reverse on the bell housing side? What is that application from? Does anyone have a working LS4 Manual Transmission?

guru made a cut out in the F40 and welded in a flat plate for mounting the reverse starter onto the bell housing for his SBC swap.

I don't have a working LS4/F40 swap yet, but I will soon enough. I can at least say I'm doing it, and I will see it completed. The starter isn't that big of an issue really. I have some other ideas on solving it, but I need to do a little more research on what the costs would be.

quote Originally posted by dobey: guru made a cut out in the F40 and welded in a flat plate for mounting the reverse starter onto the bell housing for his SBC swap. I don't have a working LS4/F40 swap yet, but I will soon enough. I can at least say I'm doing it, and I will see it completed. The starter isn't that big of an issue really. I have some other ideas on solving it, but I need to do a little more research on what the costs would be.

Interesting...do you have a build thread?

The lack of a working example of an LS4/F40 has me paralyzed to where I would not even try it. I'm sure you will figure it out and then everyone will copy it.

The newer electronics will freshen up the interior of the Fiero, but I would rather not have to try and trick an engine into thinking it was in another car. The 5 wire setup sounds ideal to me. But to get that you need the standalone ECM, not the OEM version.

quote Originally posted by jscott1: Interesting...do you have a build thread? The lack of a working example of an LS4/F40 has me paralyzed to where I would not even try it. I'm sure you will figure it out and then everyone will copy it. The newer electronics will freshen up the interior of the Fiero, but I would rather not have to try and trick an engine into thinking it was in another car. The 5 wire setup sounds ideal to me. But to get that you need the standalone ECM, not the OEM version.

I do have a build thread. https://www.fiero.nl/forum/Forum2/HTML/109387.html

It's going a little slow at the moment. I spent a bunch of money to rent a new Camaro for the weekend of the 4th on vacation; have been away for a couple weeks; and the weather has been silly. I should be getting neck deep back into it soon though; as soon as I get the state inspection done again (sticker expires this month).

I'm not worried about tricking the ECM into thinking it's in another car. A few properly placed 1s and 0s in the programming will fix that right up.
With the GMPP LS2 crate ECM, you have to trick it into thinking it's an LS2. Of course, that probably won't be an issue on my build, since it practically will be an LS2 for all intents and purposes. Just over a half liter shy of it for displacement though.

quote Originally posted by dobey: With the GMPP LS2 crate ECM, you have to trick it into thinking it's an LS2.

Thanks for the link...

but you lost me on the last part. How is it that you have to trick an LS2 into thinking it's an LS2?

quote Originally posted by jscott1: Thanks for the link... but you lost me on the last part. How is it that you have to trick an LS2 into thinking it's an LS2?

He has to trick an LS4 into thinking it's an LS2

quote Originally posted by cooguyfish: He has to trick an LS4 into thinking it's an LS2

Have to trick the LS2 crate ECM into thinking the LS4 is an LS2, rather.

They aren't exactly the same, and I think the LS2 expects true duals with 2 o2 sensors on each side, while the LS4 is normally a Y-piped exhaust with only 2 o2 sensors. The cam position sensors are also 180 degrees off from each other, and the fuel/air programming will have to be slightly different. If I'm going to have to do most all the changes anyway, I might as well just use an ECM and harness out of a car, and start from somewhere more reasonably close to what I want.

[This message has been edited by dobey (edited 07-13-2010).]

First you have to understand that the Fiero ECM will not run a different engine (except a PR 3.4) so when doing a engine swap you have to make choices. First is the engine you are going to use then and MOST importantly HOW ARE YOU GOING TO MAKE IT RUN. The easiest and most successful method is to use the ECM and Wiring harness from the donor car, this is usually also the most economical. This must be intergrated into the Fiero Electrical system HENCE all the wiring you are trying to avoid.
There are a few Aftermarket computers to control some of the engines that people swap into their Fiero's HOWEVER YOU STILL HAVE TO BUILD A WIRING HARNESS TO INTEGRATE THE ENGINE SYSTEMS WITH THE FIERO SYSTEMS.
You mentioned the Mega Squirt computer system now it will run a number of engines HOWEVER it will not control modern electronic transmissions. So if you want a SBC with 4T60 (Not a 4t60e) transmission or a manual your fine. BUT if you want a modern LS series engine i.e. LS4 with a Tap shift 4 speed electronic transmission then you can only use the ECM and TCM that GM developed to run the system, Mege Squirt won't work.


Remember ECM stands for Engine Control Module TCM stands for Transmission Control Module

Sorry if this sounds like a rant (it is) and if you don't understand how the electronis in modern 1984 to 2010 cars work, then hire someone to do your swap

Joe Sokol

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85 SE Daily driver with a 3.4 DOHC OBD II
88 Formula/GT 4.9 Allante Intake (My Baby)

quote Originally posted by Fieroking: You mentioned the Mega Squirt computer system now it will run a number of engines HOWEVER it will not control modern electronic transmissions. So if you want a SBC with 4T60 (Not a 4t60e) transmission or a manual your fine. BUT if you want a modern LS series engine i.e. LS4 with a Tap shift 4 speed electronic transmission then you can only use the ECM and TCM that GM developed to run the system, Mege Squirt won't work. Remember ECM stands for Engine Control Module TCM stands for Transmission Control Module Sorry if this sounds like a rant (it is) and if you don't understand how the electronis in modern 1984 to 2010 cars work, then hire someone to do your swap Joe Sokol

I don't think anyone in this thread was trying to get smart enough to actually make a wiring harness. It was more of a theoretical discussion on why engine harnesses are so complicated.

My response is that it doesn't have to be.

Me personally I'm only going to consider manual transmissions, so controlling the auto and tap shift and all that is not a concern.

I understand now what was being said that you need to make the LS2 ECM think it's controlling an LS2 when in fact it's controlling an LS4.

An LS4 crate engine with the LS4 ECM already programmed to run the LS4 would be perfect but I don't think any such thing exists.

So if I were to build a harness I would go with the stand-alone ECM and the 5 sire hookup. Yeah I know that is just to make it run and you need a lot more for a/c and instrumentation and all that crap, but that stuff is easy.

quote Originally posted by Fieroking: First you have to understand that the Fiero ECM will not run a different engine (except a PR 3.4) so when doing a engine swap you have to make choices. First is the engine you are going to use then and MOST importantly HOW ARE YOU GOING TO MAKE IT RUN. The easiest and most successful method is to use the ECM and Wiring harness from the donor car, this is usually also the most economical. This must be intergrated into the Fiero Electrical system HENCE all the wiring you are trying to avoid. There are a few Aftermarket computers to control some of the engines that people swap into their Fiero's HOWEVER YOU STILL HAVE TO BUILD A WIRING HARNESS TO INTEGRATE THE ENGINE SYSTEMS WITH THE FIERO SYSTEMS. You mentioned the Mega Squirt computer system now it will run a number of engines HOWEVER it will not control modern electronic transmissions. So if you want a SBC with 4T60 (Not a 4t60e) transmission or a manual your fine. BUT if you want a modern LS series engine i.e. LS4 with a Tap shift 4 speed electronic transmission then you can only use the ECM and TCM that GM developed to run the system, Mege Squirt won't work. Remember ECM stands for Engine Control Module TCM stands for Transmission Control Module Sorry if this sounds like a rant (it is) and if you don't understand how the electronis in modern 1984 to 2010 cars work, then hire someone to do your swap Joe Sokol

1st, I don't think it's necessary for me to hire someone else to do my swap. I'm not capable of understanding why electricity does what it does but I know how to wire things up correctly, which is really all that matters.

2nd, I want to be clear in that I despise automatic transmissions. The only reasons I'll put one in a car I drive is if it's a bracket drag car, or I loose my left leg (Well, or right arm)

3rd, It's not that I am trying to avoid wiring something, I knew it had to be done I just never understood why. Or rather exactly what we were wiring on our cars/engine swaps.

And why does everyone that post's in this thread keep talking about me swapping in a V8??? I like small engines, and turbo's. I like small light cars and short gears. I had a saturn that was 2300 lbs, had 165 HP, and 4.063 FD 5 spd and I managed 14.47 @ 99 MPH in that car with a 2.41 60'

I imagine (and this is theory I know) that a fiero weighing in 2500-2600 lbs, with an isuzu (with a 3.83 FD), with 200-225 HP, and TRACTION, would run a low 13/high 12. High 12's being my goal and all.

I do like V8's, I really started to dig them after driving my friends GTO. Just not in a fiero (or at least MY fiero). Plus I like the way ford V8's sound 10X over chevy's, and my dad has an 83 Mustang GT that's been sitting for years I plan on confiscating when I get caught up on my other projects.

-Brandon

quote Originally posted by cooguyfish: And why does everyone that post's in this thread keep talking about me swapping in a V8??? I like small engines, and turbo's. I like small light cars and short gears. I had a saturn that was 2300 lbs, had 165 HP, and 4.063 FD 5 spd and I managed 14.47 @ 99 MPH in that car with a 2.41 60'

We're not assuming you are doing a V8. But I am doing the LS4 swap, and jscott1 would like to as well it seems, with the manual trans. And the LS4 is a good reference point for discussing what all might be required in terms of wiring on a modern engine swap.

Yeah I was talking hypothetically. The concept is the same regardless.

The talk of the LS4 is a bit off topic, but related to the need to integrate the transmission into the discussion.

A manual is essential to me as well, but you run into a problem with the starter on many manual transmissions. As far as I know the LS4/manual starter problem has not been solved. Hopefully soon someone will, and then the LS4/F40 would be my combination of choice.

quote Originally posted by jscott1: Yeah I was talking hypothetically. The concept is the same regardless. The talk of the LS4 is a bit off topic, but related to the need to integrate the transmission into the discussion. A manual is essential to me as well, but you run into a problem with the starter on many manual transmissions. As far as I know the LS4/manual starter problem has not been solved. Hopefully soon someone will, and then the LS4/F40 would be my combination of choice.

It's been semi-solved. fieroguru has solved it, by hacking up the bellhousing on an F40 and making a mount on tranny side, to fit a starter.
I've solved it another way, but I have no idea how much it will cost to implement yet, so I haven't really discussed it.
And there's also the possibility of using a belt-driven starter on the front of the engine, but I don't think anyone's engineered the appropriate bracketry and pulleys to implement it yet either.

On the LS4, there's a sort of notch in the block, where the starter snout protrudes past the edge of the bell housing. I'm not sure if that same small notch exists on other blocks or not. The FR block bolt pattern is larger and different, so I doubt it does have the same notch. As for other FWD engines, I have no idea if they have it or not, but I doubt it. So my solution may or may not work for other engines as well, assuming that the cost is low enough to make sense. If the cost is too high, I'll probably look into doing the belt-drive starter.