Used a Scan , and here's the result: (1st try) Not able to crank the car, but it did turn over, codes 36 High Res Pulse Circuit, 42 Ignition Control Ground Circuit, 48 MAF Circuit, 51 PCM PROM Flash Error. Cleared the codes. (2nd try) Got it to crank, car backfired, sputtered, would not idle, and couldn't keep it running under half throttle, would not turn high rpm, black fuel smoke everywhere. Scanned for codes, 36 popped up again, but no others. Cleared codes, (3rd try) Car ran the same, code 36 was there again, but nothing else. Are we talking Optispark prob here?


Thanks!

 

DTC 36 is loss of high resolution pulse from the Opti. It shouldn't make the engine any harder to start. The high res pulse pattern is just used to keep a very accurate track of where the cam is, in between the 8 cylinder-specific low resolution pulses. If you lost the low res pulse (DTC 16) the engine would not start.

Check the connectors on the Opti harness. They could be corroded or have damaged pins. If the high and low res pins short together, it can cause DTC 42 (but there are several other causes for DTC 42).

I would check the MAF as well. Since DTC 48 was set, it may be a problem with the MAF sensor not providing the correct air flow. The code might clear, and then not be able to reset until the engine is running stable.

And, with the PCM error code, you have to start looking at all the engine and PCM grounds.

 

Decided to mess around with the car today. Thanks for the input! I found something odd, wet connectors for the opti (how the heck?) I'm wondering if there isn't something real odd going on. Dried them out, got it to start, but it still won't idle. Have to keep the trottle at least half to get to run. Now, it's misfiring, and backfired once. Still getting the fuel smoke out the pipe. I also found that it seems someone rigged the pipe for the cold air. Looks like one of the longer ones cut to fit in there. Part of the pipe was shoved into the MAF, I mean way in. What I do know is, I have to get new injectors cause the 24# must be cranked wide open by the ADFR. It must be set at 60, and the prev owner just didn't bother to mention it. That's how they got it to run. Prob explains the loading at idle problem it was having before. Any further suggestions? Should I just replace the opti and harness for it? Planning on taking it off for a closer look by the weekend.

 

I didn't know the stock fuel pump could muster 60psi... too much fuel pressure can cause the engine to run very rough if at all

 

What all has been do to the car that you know of? It sounds like someone made some serious modifications and you are left to sort it out. Your fuel pressure stock should be in the 40's. If it has an adjustable fuel pressure regulator it might be set wong. The computer if it hasn't been tuned will set the fuel pressure to it desired psi even if you try to change it. Maybe it is so far off it that it is running rich as hell and that can cause the car to run like crap and load up to the point you have to floor it to get it to run. My other car should have been at 50 psi and was putting out 100+ so the car ran like it was running on half it cylinders. I would fix the intake to make it fit correctly or replace it. The maf if it isn't working correctly might be trying to add more fuel than the car needs making a rich condition causing the smoke. The injector issue is interesting because unless the engine is seriously modified they should be more than sufficient. Whats adfr? Im guessing adjustable fuel pressure regulator. This could be part of your problem. One thing at a time and then we will go from there.

 

1. Tell us everything you know about the engine. Appears you bought the car already modified? You need to try and figure out everything that is not stock. But if you do know about some things that have been changed, you have to list them. You also have to give us the basics of the car. We can guess from the description that its a 94 or a 95.... those are the only ones that would have an MAF and the 2-digit DTC codes (unless its a 96/97 with an OBD-I conversion). But it makes no sense to make people guess about the car. Go to Shoebox's Tech Pages and compare your car to the photos there. Look for things that have been altered on your car.

If you've alread posted about some of the problems, and provided some info in another thread, post a link to those threads in your new post. That gives people the benefit of knowing what you've already tried.

2. Check the bottom of the water pump housing for leaks from the weep holes. That would explain a wet Opti connector. Check all the Opti terminals and the end of the plug wires and the coil wire for dampness and/or corrosion.

3. Measure the fuel pressure. Why would anyone crank the fuel pressure up to 60psi? In any case, you need to figure out what its running at. What do you mean by "cranked wide open"? If its been running previously with a 60psi fuel pressure, the PCM may have been programmed for the resulting higher injector fuel flow (stock 24's would be flowing over 29 #/HR), or the long term fuel corrections should have pulled out some of the excess fuel. If you let the battery go completely dead, or pulled the cable off at any time, the PCM would have reset, and lost the long term fuel corrections. But there is no need to replace the injectors just because they were exposed to 60psi.

 

I went back and looked at your previous posts.... and I found this one:

http://web.camaross.com/forums/showthread.php?t=546155

Not a good idea to start a new post, when discussing the same problem. Just continue under the old thread, or at least provide a link to the old thread, like I did. There are so many posts that no one is necessarilly remember all the info in your earlier post.

 

Here's the latest news..... Decided to pull the cap off the opti, found moisture and somewhat corroded contacts. Cleaned the contacts (waiting on new cap) and dried it out. Set the fuel pressure at 45psi, and discovered the previous owner had removed the vaccum fitting on the regulator and also plugged the vaccum line behind the intake. Thinking this simulates a WOT? Cleared all the codes, and so far no more codes. It started and runs pretty well, but still rich. Some black smoke on heavy acceleration, strong fuel smell from exhaust. Any ideas? Ordered 42# injectors, bought 255 Walboro fuel pump, and racetronix harness to install. We will send the PCM back to PCMforless to adjust for new mods (injectors, transmission shift points, and 160 therm). And yes, we have been in the dark for the most part, trying to figure out what has been done to the car. We did have the cam/rocker/head info as a place to start. So far, these following are the mods we are certain that have been done to the car.......

LT1 5.7L, BBK headers, MSD6AL, Stage 2 ported and polished heads, port and polish intake by Craig Caulk Racing Heads, 2.0 INT valve 1.6 EX, 52mm throttle body ported and polished, port, polish, descreened MAF, 290/307 Comp Cam .510 INT .540 EX, 112 lobe seperation, 1.6 Comp Mag rockers, Holley 510-502 AFPR, TB bypass, MSD6al, Hypertech air foil, underdrive pulleys, Magnaflow 3" catback exhaust, soon to be installed, rebuilt (killed it) 4l60e with kit from Probuilt Automatics w/ Edge Racing 3000 stall, 3:42 gears, cold air induction, 26 lb Venom injectors, LT4 Knock module, MSD 8.5 mm wires, Custom tuned PCM by PCM for Less.

 

Things i can remember that cause the car to run to rich. Tune off, throttle position sensor bad, injectors wrong size, leaking or working incorrectly, maf calibrations off, bad O2's, fuel pump pumping to much fuel, fuel pressure set to high or fuel return line restricted. Plus all the sensors that figure the temperature, altitude and more.