Ok, the car refuses to stay running. I literaly was inches from smashing the hood in with frusteration. In the past 2 weeks I have had codes33,36,42. Had a maf and tps crap out, and all other kinds of these stupid electrical problems. trouble shooting has only gotten me so far before another problem arises.
Ok now that I finished venting a bit, Would you guys suggest that this could be need of a whole new harness? I dont want to keep replacing the same stuff every 5 months. Most part are already new. The main wiring harness is not. Anyone know where to get a good price on one of these?

 

take a deep breath... as bad as the mid-80s harness can be, and can get, replacing the entire thing is not a simple solution.

The engine harness enters into the interior via a portal on the firewall, behind and below the distributor.

In short, it's a bitch.

The harness is then integrated with the ECU and IP harnesses. This thing is a total cluster ****, if you want my opinion.

Now, what I would suggest, take the convolute off the harness and start to inspect the harness. See what kind of condition it's in. I would not be surprised if the insulation is cracking, splitting, chaffing and otherwise grounding out when it shouldn't.

I have some catalogs that have access to more connectors than you can think of, plus some other links to sources for wire and such.

What happens is that heat, chemicals, etc, all conspire to eat the **** out of the wire insulation. The insulation will shrink and make a total mess of things. This was resolved by the SAE requiring a new material for the insulation.

What I would suggest... and it would give you a lot of functionality, and I think help in many ways... find the end of the harness at the firewall, carefully count all the wires, and get a big *** weatherpack molex connector to create your own firewall harness plug.

From there, start rewiring.

It won't be easy, but when done, it will be a huge improvement. Just document the hell outta the newly constructed firewall junction. That would suck if when you turned on the lights, the car started...

 

So it is possible to buy this harness peice by peice? Im going to have to spend a day digging in this thing. It is possible that if somthing is grounding out it can ruin different sensors, right? If you can send me some of those links for the wiring I would very much appretiate it.

Im almost to the point now where I just want to pull the engine back out of the car and make it the way I wanted in the first place. A bigger cam, lots of head work done and port my aftermarket base manifold and runners.
Thanks bogus.

 

to be blunt, removing the engine is a great way of making this happen.

it will give you a ton of room at the firewall.

I was gonna send an email, but that ain't turned on, and your PM box is full....

abbogus@yahoo.com

 

Chris,

If you want to try a different ECM, I think I have a spare that you can use, I need to check on applications (just to see before you start yanking wires and what-not).

 

Let him confirm the harness first. If the harness is bad, the shorts could harm your ECM.

Besides, if either of you are planning on doing performance mods, you will want an ECM from a 1989. It's faster...

 

I really admire you for undertaking this...me, I wouldn't have the slightest I can tell you I was totally shocked when I checked the wires to my fuel pump relay.Soulda been a recall.

 

I think there was some kinda TSB for the wires... every new FP comes with a new harness now.

I didn't have the reason to replace my 92, the wires looked good.

 

ok, now ive really done it. I was checking the codes and accidently left the paper clip in the aldl. I removed the key but the next time i went to start the car the battery was dead. I went to napa today to have it charged and the bat is ok. I put the battery in and now when i try to start the car all the power cuts off, just like if I was disconnecting the battery. everything shuts off. Checked all the fuses, all ok. Have no idea what to do now. voltmeter reads 12 volts on the bat still.
Did i just perhaps burn out somthing else now?

Pulling the engine and starting over is sounding really good right now, I can have a new cam put in and my heads worked on too.
But i need to figure out this problem i have gotten my self into.
Thanks for all your help so far.

 

Ok now it acts like it has no battery. No power what so ever. The battery still has 12.6 volts to it. What did I do?

 

nothing that I can figure.

can you pull codes?

the battery may show 12v, but it might not have the amps... try putting a charger on the battery. Also, be sure the battery terminals are good, and that the main ground isn't corroded.

 

Dang, sorry to hear you're having so many problems. Electrical problems suck. I've got my top end torn down again looking for a grounded injector harness.

What happens if you reinstall the paper clip and turn the key on?

I thought mine was a bad battery...then I found all of the cylinders filled with fuel.....

 

If you do pull the harness, send it to www.jimsperformance.com

for $150 he will replace conecetors and or necessary wiring, and test the complete harness.

 

awsome, thanks guys. Im gonna spend the day tommorow looking at this thing and calling these contacts with my findings.
Thank you for all your help!

 

Ok, I took the battery out. Inspected all the wires I could get to and found nothing of suspect. One thing I did find was the o2 sensor connector burning on the header tube. I might need a new connector for that. The funny thing is no code for o2 sensor ever came up even with that happening.
The car now starts up again, I think due to clear the ecm memory by disconnecting the battery.
No codes yet, I drove it for about 10 minutes. It misses alot when the engine reaches operating tempature. So Im expecting it to crap out on me again considering that I havent found much.
At least its running again though.
does anyone have any ideas?

 

Could be your ICM, you can have it checked at Autozone. Since you've been down the road with some past problems, you know if it's a sensor normally it will throw a code.The ICM does not, and usually it shows it's ugly head when it gets hot. The other things fuel and spark are easy to check..once again a problem with either won't prompt a code to be thrown.One of our members was pulling his hair out (a few of us lost some too trying to help) his turned out to be a dying fuel pump.

I would begin by ohming the injectors, doing a fuel pressure test, get a noid light and check the injector signals, and have AZ check that ICM.
You may also want to ohm the pickup coil.Most of these test will help eliminate potentials, BUT, I'm really leaning toward the ICM, just because it sounds like the problem comes on after the car hits operating temps.

 

Do you have a FSM? You will need to make sure of the codes. By following the FSM it should lead you in the right direction. By checking the volts of various wires and wiggling them it should tell you if the wiring is good and you can follow it all the way back to the firewall. You can even check the ECM for proper connection and volts. The codes you listed could all go back to the MAF relays. The Code 42 is the EST and make sure it is connected and the wires are not bare and touching ground. As Rick suggested the ICM does start showing faulty after the engine temp has rised.

If you don't have a FSM, that is what I would get next.

 

Tested all the relays (which are new) the maf (also new). The codes that were showing up were 33, 36 and 42. They havent come back though.
I ran tests from the fsm. When it asked to clear codes and see if they come back they dont come back for about a week.
The tests conlude for 36, replace relay. 33 bad maf, replaced maf. And 42 was only there for a day. Im getting the multimeter to test the dist. today.
im going to follow your advice and have the pcm checked too.