I installed a 1994 Lt1/T56 in my 87 Camaro. I tried to make all the splices myself and that didnt work, so I bought a Painless Wiring Harness and thought taht maybe my wiring was wrong. It's not, the PWH is doing the exact same thing the old one did. It cranks, hits and sputters, but never really runs. Any ideas. Im desperate.

 

check out this link. then check all the wiring. the painless harness is just the same as the lt1 you already had. the only doffrence is the painess can only use certian sensors and if just 1 is not the right part number it wont run right. put the lt1 harness back on and wire it up per my write up. Also make sure all the splices are soldered. if you splice the wires together with anything else but solder the car will see false signals. using butt connectors, crimp terminals, wire nuts, twisting with electrical tape. all of that can cause excessive resistance and or rf noise and send false signals to the computer.

When you bought the painless harness did you verrify that your ecm part number matched one the 2 part numbers that painless specified? if it doesnt match it wont work. I suggest selling the painless on ebay and reinstalling the stock lt1 harness and following my guide. If you wire it up per my guide it will start on the first try.

Heres the link to the write up. its also in my sig. http://web.camaross.com/forums/showthread.php?t=474185

 

I dont think I have a wiring problem. I think it is engine related. Like a timing issue. I was looking for a crank position sensor, but cant find one. i think I had the wiring done right with the LT1 harness, but I didnt know for sure, that's why I bought the Painless. Thank you.

 

Before 96, LT1's didn't have a crank sensor. The crank sensor in those didn't have anything to do with a running condition. They merely monitor misfires.

Regarding your running problem, assuming you have spark, fuel and compression!!!! You do have fuel pressure and spark don't you? Let's assume the older car used a lower fuel pressure and ask what your current max fuel pressure is????????

How old is the fuel in the car?

 

In effect, the Optispark low resolution pulse signal serves as both the crank and cam positions sensors. Did you remove the Opti at any point? If so, are you sure you indexed the splined drive shaft correctly to the Opti and to the cam sprocket? Mis-indexing would cause the problems you described.

 

I did remove and replace it. Twice actually. Thinking that this might be my problem, I pulled it again just to double check, and it is correct.

That being said, I took my ignition control module off and had it tested at the local Auto parts store, and it proved bad. I replaced, and now it is hitting a little bit better but still no dice.

 

It's an 87 and it formerly had a TPI in it. They (being you guys) say it should work accordingly. I put a gauge on it, and its at 40psi.

The gas is probably about 4 months old.

 

Just something that is out their but can be hard to find, fouled plugs...

When my car was running really bad after letting it sit for a few days it wouldnt start. The problem was that the plugs got too fouled to even start the car but it ran "ok" the last time i drove it.

I replaced the easy half on the drivers side and my car fired up with a bad hesatation/stumble. replaced the other half and every thing was fine.

Have you had a chance to hook a scanner up to it yet maybe you can get a clue as to what the problem is.

Also more infor on if it is getting spark and posably how good of a spark its getting (hook up a plug wire to a plug out side of the car and see how srong the spark looks.

Also check your coil wire..pull it off and put it back on checking for any corrostion

 

Here's what I have...

94 LT1 + ECM/Painless Wiring Harness

Items Replaced:
Opti-Spark - reman. from O'rielly's
Cap + Rotor - MSD
Plugs and Wires
Installed Hooker LT's
few sensors here and there.

I have checked the firing order at least 10 times, replaced the opti 2 times, thinking maybe the first one was bad, replaced coil and ignition control module. I have checked the fuses, the wiring, everything I can think of.

When cranking, it's hitting pretty good, and every now and then, I'll go out to the car and it will start and run for about 5 seconds and then die. And then I cant get it to start. It just cranks and hits.

Question: I sill have open headers on it, is it possible that Im not getting enough back pressure? Or that my fuel pump is going out? Thanks guys.

 

Is the vats programmed out of the PCM? Assuming it is, the injectors could be stuck. While someone cranks it over, tap on the body of the injectors with the handle of a screwdriver (plastic) one by one. That should free them up.

 

I pulled the fuel rail while i cranked it to make sure each one was spitting. They are all functioning properly. The Painless harenss comes with a VATS module.

 

to test if it is the fuel dump some gas into the intake and see if it wil run like that.

Any chance you can swap computers with some one local? or maybe pick one up from a junkyard.

Also check your grounds

 

I used my brothers computer from his 95 Z28. It did the same thing.

Where would you pour the fuel? I know how this works on carburated engines, but theres really no where to dump it. I thought about spraying ether (sp??) into the TB. Bad Idea? I dont know.

I am going to check all of my grounds again. How many should I have? Does anyone know exactly which grounds I need?

 

You never mentioned if all the sensors on the engine matched the part numbers that painless found to work with there harness. Or if your ecm number matched one of the 2 that painless reccomends. When we did the swap in my friends car he was thinking about the painless harness and i spent 3 hours on the phone with one of there reps and he said every sensor and the ecm has to match there recomended part numbers or the harness wont let the engine run right if at all. These harness were designed to go into hotrod swaps and retrofits in 4x4's and such. painless told me that even tho the sensors will hook up the harness wont send the proper signal to the ecm. so they tried every sensor that will fit the lt1 and made a list of the ones that worked with there harness.

Heres a link to the harness manuel. It should list the sensors and the ecm that will work with the harness. http://painlesswiring.com/Manuals/90517Manual.pdf

 

Listed below are the sensors that are known to work with the painless harness. some of these sensors ans switches are gm part numbers and some are ac delco part numbers.

This list came straight from the painless manual for the harnes, and i have confirmed that the haness will only work with these partnumbers listed. I confirmed this over the phone while speaking to a painless rep.

Ecm service number 16188051

brake switch gm # 25524845

IAT Gm # 12110319

ICM Ac Delco # D-1986-A

Fuel pump relay Gm # 14089936 or Ac delco # 15-8240

Coolent temp sensor Gm# 25036979

Ignition coil Ac Delco # D-573

O2 sensors Gm# 25312184 or Ac Delco # AFS 75

TPS sensor Gm # 17106680

Egr solenoid Ac Delco # 214-396

Gear indicator switch Gm # 15705308 or Ac Delco # D-2286A

MAP sensor Gm # 16137039

IAC sensor Gm # 17113099

Knock sensor Ac Delco # 213-96

Air pump relay Gm # 14100455 or Ac Delco # 15-8426

Air pump Ac Delco # 2604-4885

MAF sensor Ac Delco # 213-252

Canister purge solonoide Gm # 1997201 or Ac Delco # 214-565

Componets with partnumbers other than listed may plug into Painless harness numbers 60502 and /or 60505, but the part numbers must match the list above for proper opperation.