I have the Injection Technology harness for my 4.9L '88 Coupe and I've found two errors (so far) so I thought it would
be a good idea to have a thread so others can be on the look out for them.

My harness is for a '94 Deville 4.9L with 4T60E:
1) The ECM was wired to the connector for the head temperature sender instead of the CTS in the T-stat housing, while
the CTS signal was being sent to the temp gauge only. The head temp sender is only an on/off thing to light up a dash
warning light, so the ECM was getting no signal at all. To feed both the gauge and the ECM, you need to get a 3-wire
CTS and connector (see Mickey_Moose's "My 4.9 wiring thread".) and hook it up to the I.T. harness.
2) There was no SES wire to connect the ECM (A10) to the C203 (C-pin). The lack of a CTS signal would have caused
an SES light, otherwise.

In addition, Dan (previous owner, "Frizlefrak") found a '94-'95 specific error:
3) One set of O2 sensor wires missing (i.e., only has provisions for one O2 sensor and should have had two).


All the other sensors (MAP, MAT, VSS, TPS, the one O2 sensor), as well as the EGR, Evap, PCM grounds, and Power
steering @12V, appear to be correct. The harness was originally purchased in March of 2006, so hopefully, things have
improved since then, but if you've had issues with Injection Technology harness (regardless of which engine you've swapped
to), this would be a good thread to post them in to have them all in one place.

[This message has been edited by BigGuyTinyCar (edited 02-18-2011).]

on my 3800 sc harness, the power and ground wires were reversed at the PNP connector

They did the same error with the head temperature switch with my harness. I had to correct this so I could connect up my gauge. They trashed my correct connector, requiring my to purchase a new one.

They also ignored my request to use the old style oil pressure switch and installed the 88 V6 style oil pressure switch connector. I had to purchase a new oil pressure switch. They trashed my connector.

The O2 sensor wire was 6" to short to plug in.

I had one ECM pin not seated.

[This message has been edited by josef644 (edited 02-16-2011).]

quote Originally posted by BigGuyTinyCar: I have the Injection Technology harness for my 4.9L '88 Coupe and I've found two errors (so far) so I thought it would be a good idea to have a thread so others can be on the look out for them. My harness is for a '94 Deville 4.9L with 4T60E: 1) The ECM was wired to the connector for the head temperature sender instead of the CTS in the T-stat housing, while the CTS signal was being sent to the temp gauge only. The head temp sender is only an on/off thing to light up a dash warning light, so the ECM was getting no signal at all. 2) There was no SES wire to connect the ECM (A10) to the C203 (C-pin). The lack of a CTS signal would have caused an SES light, otherwise. In addition, Dan (previous owner, "Frizlefrak") found a '94-'95 specific error:

This would explain why the ECM is not turning on my fan, no?

quote Originally posted by lou_dias: This would explain why the ECM is not turning on my fan, no?

Yes, it would explain it perfectly.

The transmission wiring was off when I got the harness too Tim. It was wired for 91-93, and the drivetrain is a 94. It wouldn't shift at all when I did the swap....fortunately some folks here helped me out, and a few splices later, I had all 4 gears.

The other swap we did using the I. T. harness had two problems....distributor wired 180 degrees off, and an issue on the C500 as well. Gave us fits when it wouldn't start....fixed it the old fashion way.....tracing wires.

The harnesses were designed by Ed Parks originally, and built by I.T. They intentionally left the SES light circuit open due to the fact that The Fiero Factory was using a stock Caddy chip....and the light would have been on all the time anyway due to no ABS, no BCM, etc. These would have to be programmed out in a chip reflash. They were looking for someone to reflash the PCM's on their swaps at one point, but it never panned out. They relied solely on performance and fuel economy as indicators of a malfunction. This was all relayed to me from Ed via someone who bought an early swap kit.

Tim....I'm not surprised you found more errors. Sounds like you're on the right path to getting the wiring sorted. Good job finding the error on the CTS.....I missed it completely.

I forgot all about my C500 error. The car's C500 is wired for a stick shift. They wired my harness for an automatic. The srart signal wire is pinned in a different socket from the key switch to the C500. It was a fairly easy fix, but took some time to trace down , and they knew before hand the correct wire socket. Once again the ignored my information before building the harness.

quote Originally posted by josef644: I forgot all about my C500 error. The car's C500 is wired for a stick shift. They wired my harness for an automatic. The srart signal wire is pinned in a different socket from the key switch to the C500. It was a fairly easy fix, but took some time to trace down , and they knew before hand the correct wire socket. Once again the ignored my information before building the harness.

Same issue we had on the first swap.....standard car going to auto....C500 was mispinned. Easy enough to fix, but aggravating as they were told how it would be configured.

If I were to ever do another swap of any kind, I will wire it myself and just factor the time needed to do that into the swap.

quote Originally posted by Frizlefrak: The transmission wiring was off when I got the harness too Tim. It was wired for 91-93, and the drivetrain is a 94. It wouldn't shift at all when I did the swap....fortunately some folks here helped me out, and a few splices later, I had all 4 gears.

Ah, yes, I remember reading that in one of your posts. Thanks for the reminder.

quote The other swap we did using the I. T. harness had two problems....distributor wired 180 degrees off, and an issue on the C500 as well. Gave us fits when it wouldn't start....fixed it the old fashion way.....tracing wires. The harnesses were designed by Ed Parks originally, and built by I.T. They intentionally left the SES light circuit open due to the fact that The Fiero Factory was using a stock Caddy chip....and the light would have been on all the time anyway due to no ABS, no BCM, etc. These would have to be programmed out in a chip reflash. They were looking for someone to reflash the PCM's on their swaps at one point, but it never panned out. They relied solely on performance and fuel economy as indicators of a malfunction. This was all relayed to me from Ed via someone who bought an early swap kit.

Oh...Okay, I can forgive them for that, then. I guess I'll leave it unhooked for now.

quote Tim....I'm not surprised you found more errors. Sounds like you're on the right path to getting the wiring sorted. Good job finding the error on the CTS.....I missed it completely.

Actually, I only found that one because I happened upon Mickey_Moose's wiring thread and he mentioned that it has to be a
3-wire CTS to run both the gauge and the ECM. I knew my CTS had only 2-wires and my gauge was working, soooo....I had to investigate.

quote Originally posted by Frizlefrak: If I were to ever do another swap of any kind, I will wire it myself and just factor the time needed to do that into the swap.

I don't blame you. Although, checking every wire (and probably correcting a few) is still considerably less work than wiring it yourself.
Still, saving $650 is like earning $25/hour tax free for 26 hours (over three work days).

Edit: corrected the price according to josef's post below.

[This message has been edited by BigGuyTinyCar (edited 02-17-2011).]

quote Originally posted by Frizlefrak: If I were to ever do another swap of any kind, I will wire it myself and just factor the time needed to do that into the swap.

If I was to do another one I would purchase new pins for the connectors, and new wire then build it on the car so it is laid out correctly.

Mine ran correctly the first time I made it. Every thing shifted right, all my gauges worked . It would just quit running when I added the console or wiggled the wires in the area of the C203. I got tired of working on it and not driving it. I was very frustrated in the end. Then the harness came and my EPROM had gone south. Had to get a new one made by Stickpony. I think I killed the EPROM by plugging in the ECM connectors before I disconnected the battery. I was in full time limp mode then. I had removed the harness and verified all connections with my meter trying to get out of limp mode. The new EPROM fixed the limp mode. All I found was one pin not seated in its ECM connector. Plus the C500 incorrect hole, so two errors were made. The rest were incorrect connectors added, not errors. For $650, this was unacceptable

Worth $650.00 ? Never again for me. This amount of money could purchase a good set of wire crimpers, pins,wiring and shrink tubing. I am not against soldering, just would prefer to install new pins and insert them in to the connector sockets.

[This message has been edited by josef644 (edited 02-17-2011).]

quote Originally posted by BigGuyTinyCar: I don't blame you. Although, checking every wire (and probably correcting a few) is still considerably less work than wiring it yourself. Still, saving $650 is like earning $25/hour tax free for 26 hours (over three work days). Edit: corrected the price according to josef's post below.

...I would have to disagree with this statement - it is harder to troubleshoot someone else's work as you have to still trace every wire and understand the process of why something was done in such a manner. If you don't understand the process you really don't know if something is correct or not. If you wire your own unit, you would understand the process a bit better. Besides you are not wiring the whole motor, technically you are only adding wires that connect the Fiero to the 4.9 - anything more and you are just ‘cleaning’ up the factory wiring to fit the Fiero engine bay. There is no need to modify the ‘engine harness’ except to make it look better.

It also takes considerably less than 26 hours to build a harness - I personally can put one together in 3-4 hours and this would be far less if I was building a new harness on a shop bench with some kind of a jig, which in am sure IT is using. With everything handy and on a work bench, a couple of hours at the most as it is nothing to pull wire from a spool at a certain length, cut and install pins/connectors on the ends. Takes longer in the car since you have to route/measure/cut/splice/heat shrink - on a bench with a jig, this is way easier.

I do know, if I was to spend $700 and then have to spend time to troubleshoot and fix a harness, I would not be impressed - buying one means that you should not have to worry about wiring problems. It sounds like this is the way they originally made it and haven't changed - and custom requests are ignored since that will take extra time. Once a system is in place it is easier to bang out orders without changes.

BTW - this thread is a good idea and may help others in the future.

[This message has been edited by Mickey_Moose (edited 02-17-2011).]

quote Originally posted by Mickey_Moose: ...I would have to disagree with this statement - it is harder to troubleshoot someone else's work as you have to still trace every wire and understand the process of why something was done in such a manner. If you don't understand the process you really don't know if something is correct or not. If you wire your own unit, you would understand the process a bit better. Besides you are not wiring the whole motor, technically you are only adding wires that connect the Fiero to the 4.9 - anything more and you are just ‘cleaning’ up the factory wiring to fit the Fiero engine bay. There is no need to modify the ‘engine harness’ except to make it look better. It also takes considerably less than 26 hours to build a harness - I personally can put one together in 3-4 hours and this would be far less if I was building a new harness on a shop bench with some kind of a jig, which in am sure IT is using. With everything handy and on a work bench, a couple of hours at the most as it is nothing to pull wire from a spool at a certain length, cut and install pins/connectors on the ends. Takes longer in the car since you have to route/measure/cut/splice/heat shrink - on a bench with a jig, this is way easier.

You are, no doubt, right. I was just arguing with myself...I still don't know who won. Making it yourself did get the last word, though.

quote I do know, if I was to spend $700 and then have to spend time to troubleshoot and fix a harness, I would not be impressed - buying one means that you should not have to worry about wiring problems. It sounds like this is the way they originally made it and haven't changed - and custom requests are ignored since that will take extra time. Once a system is in place it is easier to bang out orders without changes. BTW - this thread is a good idea and may help others in the future.

Thanks. I figured it could spare others some serious headaches. Looks like it may have already helped lou_dias.

Just thought I'd revive this thread to keep it out of the archives for a while.

How's she runnin' Tim?

quote Originally posted by Frizlefrak: How's she runnin' Tim?

Very well, Dan. After stickpony programmed the '93 Deville ECM, and I replaced the ISC with
josef644's used one, everything just fell into place. I'd also hooked up the SES light and at first
had the SES light come on while driving (didn't have an OBD1 code reader), but it went out
(but the light still tests at start), so that's done...gotta love the rare times in life when a problem fixes
itself.

On another subject, after giving it a full wash and spit-shine, I had someone at a gas station tell me that
mine was the best looking Fiero he's ever seen. Of course, he's never seen all the cool Fieros on this
site, but it was nice to hear, anyway.

quote Originally posted by Frizlefrak: The transmission wiring was off when I got the harness too Tim. It was wired for 91-93, and the drivetrain is a 94. It wouldn't shift at all when I did the swap....fortunately some folks here helped me out, and a few splices later, I had all 4 gears. The other swap we did using the I. T. harness had two problems....distributor wired 180 degrees off, and an issue on the C500 as well. Gave us fits when it wouldn't start....fixed it the old fashion way.....tracing wires. The harnesses were designed by Ed Parks originally, and built by I.T. They intentionally left the SES light circuit open due to the fact that The Fiero Factory was using a stock Caddy chip....and the light would have been on all the time anyway due to no ABS, no BCM, etc. These would have to be programmed out in a chip reflash. They were looking for someone to reflash the PCM's on their swaps at one point, but it never panned out. They relied solely on performance and fuel economy as indicators of a malfunction. This was all relayed to me from Ed via someone who bought an early swap kit. Tim....I'm not surprised you found more errors. Sounds like you're on the right path to getting the wiring sorted. Good job finding the error on the CTS.....I missed it completely.

they approached me back in the day to to do the reprogramming, but didn't want to pay me more than $30 per chip reprogrammed. i told them they were out of their minds. every car has some customization that is specific enough to the caqr so that a simple bulk lot of reprogrammed chip modules will not work, whether it be simple tire size change, or thermostat temp, or desired rev limit, etc.... if you want it done right, you must pay for it. i was certainly open to giving them a substantial discount, considering the number of customers they used to have, but they wanted to be cheap....


i can see there is a distinct need for creating reliable 4.9L wiring harnesses. this is further motivation to create a jig to work from, because i know i can beat fiero factory/ Injection technologies on both price and quality.

quote Originally posted by stickpony: bro.. i would still hunt down a scanner and scan that beast.. it will store the code history until you clear the codes.. better to be safe than sorry

Agreed. Got one on the way, as we speak.