Jsw396

Hi guys im a new member to this fourm, current member of ls1lt1. I come to this fourm in look of help. I know its a b body, but i figured its worth a shot. So i have a 94 caprice, it had a 4.3 i swapped in a 94 lt1 with its pcm. I put new timing chain and gears in properly lined up, new opti (installed properly), new wires, plugs fairly new even though the current condition of the vehicle it trying to r.i.p. those, coil swapped to test, icm tested good, fuel pressure at 43ish key on, 38ish running, new air filter. So the car idles a bit low at 6-700 ish, and starts nice almost instantly. It does somtimes sputter when reving from park, but mostly idles and revs good. When i put into drive, it sucks underload, barkey drives, when i finally got through the sputter got it up to like 30-40 before i ran out of road. The manifolds start getting red (not ran much to prevent meltdown) my uncle said its running too lean. I cant find any leaks or believe timing is off. I dont understand. I ran some tests using laptop. http://www.mediafire.com/?jbm2zch26ndipm8 thats my file from scan94/95. I have readings pdf. By injuneer. Im still having a hell of a time trying to figure this out. Please help. And thank you.

DrewHMS97SS

6-700 seems low for idle. Is the engine pretty much stock? Can you give any detail on what had been done to the engine before you got it?

Jsw396

Hey, so the motor is pretty much stock i dont believe the previous owner did anything fancy. I just got the hockey puck, with elblow to filter, and true duals no cats. The more i look at the readings, it does idle more 7-800 ish but it has been between 6-700ish.

Jsw396

Also the map sensor readings seem a bit high i suppose. They read about 60kpa i seen it just jump to 80-99kpa for a couple seconds at idleing aswel. Looks odd. Il add also i blocked off all hoses to egr, and yanked a.i.r. out.

DrewHMS97SS

A bit technical for me on the sensor readings. I was wondering if there was a cam done without a tune. It seems strange that the fuel rail PSI is good, but you're seeing a lean situation; it just sounded like tuning to me. Have you tested the fuel injectors?

Jsw396

I havnt checked them. I was gonna rent noid light. Someone said if i unplug each injector 1 at a time it might weed out a bad one. My uncle says the cam is stock. Your right its weired, when i hooked up that fuel pressure gauge i was praying it would be low. Im gonna put a pic of one of my plugs. Every plug looked the same except 1. Which looked close just wasnt wet.

Jsw396

http://www.mediafire.com/view/v6oklfo0l6gljs7/20161018_134512.jpg

bw_hunter

6-700 idling in gear? I think 550-650 is normal for an LT1 automatic....

If it still has a cat, look there. Glowing manifolds can be that too. The choking under load can indicate blockage....

Good luck!

Injuneer

Retarded timing. Are you absolutely sure you got the timing set dot-to-dot, and the exact spline alignment on the Opti? In the 18 years I've been doing this, you would be amazed how many people were absolutely certain they did it right...... but didn't.

How tight did you adjust the valves?

Both the above could cause your high MAP readings, assuming it's a stock cam.

A4 factory idle setting is 550 RPM in gear, 650 RPM in neutral. That's with the coolant fully warmed up. Higher idle settings for cold engine.

Jsw396

I took my uncles word on the timing mark, and i know for sure the opti is in correct position. My uncle put that same timing chain on the 4.3 before it crapped out and it ran great so im now hoping he aligned it same as last. When it comes time i suppose will have to tear it back apart to confirm timing mark. Better safe than sorry. But injun if it was retarded timing wouldnt it show up on scan 94/95. Sorry im still learning lol

Injuneer

Scan9495 tells you the ignition advance the PCM is setting. If the Opti is indexed correctly, the PCM values will be the actual values, spark occurs when it is supposed to. If the Opti is indexed incorrectly the spark will not occur when it is supposed to, because the PCM has no way to tell if the Opti cam position is correct, which means it does not know where TDC is.

Ditto with the timing set, the Opti reports the cam position, and assumes that the cam is correctly aligned with the crank. If it's not meshed correctly, TDC is not where the PCM thinks it is.

Briefly.... who installed the Opti? How are you positive the splined shaft is inserted correctly into the cam sprocket? I'm not trying to argue with you or criticize you. I'm just trying to help you understand that many people have come here positive they did it right. But after begrudgingly checking, found there was a mistake. I'm not making this up. Just trying to alert you to the possible source of the specific problems you are experiencing.

I will also freely admit that I could be wrong.

Jsw396

I had my uncle help me put the opti on, i had a cheap mechanic do it before? The cheap mechanic did actually have it on wrong, so i got new opti and me and my uncle put it on. It has 3 spots 2 are kinda round the 3rd spot is more of a square shape, we put it on that. It also had a dot on the opti shaft where it lined up. Im pretty sure we got it on right. When we went to take the one off to inspect that the other mechanic did it kinda pushed intself off when we loosened in. This one we put on sat nice an flush. But yeah i would like to eliminate everything i can before i tear her back apart. Nice to know about the scan9495 timing info. I kinda thought it worked like that. So should i check the injectors, or is it sounding more like a timing issue. Not sure if you checked my scan i did, if you did does it show anything. Thanks injuneer

I forgot to ask, can the car start great and idle decent and still have bad timing. It does idle steady. Sounds good until you try the throttle. I hope its not the timing, but its kinda sounding like it.

Injuneer

When you mention "3 spots" it sounds like you are describing this:

Courtesy of Shoebox



That unit would not be used on a 94 LT1 from an F-Body. Was the 94 LT1 from a B-body?

Didn't get a chance to look at the log. I've got a waiting list of people looking for help with scan logs. I don't think any else is doing this any more. I'll see if I can sneak in a look.

Most systems actually retard timing on start to reduce the compression load on the starter. It would probably idle OK, but MAP would be higher than expected at idle, which is a symptom that you reported. That's what caught my eye, suggesting a timing problem or the valves not adjusted properly.

Maybe focus on the earlier suggestions, and if none of those work out, examining the timing set alignment and Opti indexing may be all that's left.

Jsw396

Sounds good injun. Yes that dowl pin spot is where we aligned it, nice pic by the way. Also the lt1 and pcm are out of another 94 caprice. I will check everything i have left, leaving valve check and timing check at the end. I understand about helping everyone, if you get a chance to check the log or need more just let me know. Thanks for helping.

Fatdog2

Jay Leno bought an old Chrysler and had a problem with it not going over 40mph.Come to find out the engine rebuilder didn't correctly install the timing chain as it was one tooth off.Hope this helps.