MFJ

iTrader: (4)

Ok, my friend brought me his LT1 Camaro. It was at two different shops before he brought it to me with it still not running. It was a V6 car originally. He had them swap his LT1 in along with a cam, headers and heads. After 8 months it still wasn't running. So he brought it to me. Keep in mind their was a tune put on the car from his previous car. When I got the car some sensors weren't wired up, the harness had sensor connectors cut, grounds weren't hooked up, vacuum lines weren't hooked up, hell there was **** everywhere.

So I hooked up the vacuum lines, sensors, etc... with the exception of the oil pressure sensor as it had no plug on the harness and no cut wires in the harness for it either. After that I noticed the fuel pump wasn't priming. I replaced the fuel pump and it would crank and run, but badly then die. The only way to get it to start after that cold or hot would be to hold the throttle wide open and it would start and idle. If you slowly give it gas it'll rev up but it's running rich and backfiring.

Now I start digging into the "job the other shops did". I find the plug firing order is wrong on bank one. I correct that. I also find the dist is broken. I replace that (yeah those are fun on a LT1) It will crank and idle but it's rich as hell. It has an OBD2 port but my scanner won't read it. Says no connectivity.

Other things I've corrected. New temp sensor, new plugs, new wires, new opti, repaired and connected the grounds. My scanner won't see any live data so I can't give you anything on that. If I could see the live data I could probably figure it out. I did try to swap a stock computer back in it and it ran worse, but like I said, it has a cam, heads, open headers (which I know will make it run a little richer than normal).

So, I am open to ideas. TPS sensor?

ahritchie

iTrader: (1)

I'm confused about this tune from his previous car.....is the PCM tuned specifically for the cam and mods? Maybe the tuner screwed up? Who tuned it?

Are the O2s hooked up? Exhaust leaks around the headers maybe?

hrcslam

What is the year of the car? PCM?

myltwon

iTrader: (1)

I would verify proper cam and distributor installation along with checking the valve lash

moehorsepower

iTrader: (3)

If the service number on the pcm ends in 88051 then its an OBDI pcm..

MFJ

iTrader: (4)

It is an OBD1 pcm. It was a mail order tune for those modifications including larger injectors. It's a 95 Camaro. OBD2 port OBD 1 pcm. I changed the distributor so I know that part is right. Now whoever did the cam swap may not have it timed correctly. I did check valve lash and adjusted a few to get them right. The exhaust gaskets aren't leaking but it's open headers (which means no back pressure). O2's are hooked up. I think I can get my Genisys to work if I can find the right cable. A friend of mine says he thinks he has one. Other than that, I'm kinda at the point of tearing down the front to check that the cam was installed correctly.

hrcslam

Open headers plus 02's will give false AFR readings at low RPM.

Start here.

MFJ

iTrader: (4)

Sorry, its a 1995. I did get my Genysis cable to read OBD1.
What stands out to me is coolant temp sensor shows -40*, fuel trims show 128.

hrcslam

Can you post up the log?

MFJ

iTrader: (4)

No, I had to take the cable back. New temp sensor and still doesn't read it. So I guess I'll have to figure out which wire to this (Tandy 1000) pcm is and make a jumper wire. Old *** POS obd1 crap. The other thing I saw was it was only commanding 328 rpm at idle. So the tune is obviously wrong too.