I Give Up! Need LS1 Gods... Options

[SuperCricket]

This is likely a giant shot in the dark, but I thought I would try telling my problems here. I've posted at every other LS1 message board, including LS1tech.com which I was sure would help me out, but to no avail.

The LS1 was running great in the 94 Camaro, until randomly, one day these problems occured.

Symptoms:
- Car will barely start, most of the time afterfires and shoots flames out the exhaust, but wont start up. Sometimes it will not start after 10 minutes of trying, sometimes it will fire right up.

- Tachometer doesn't work (it used to). When you turn they key on, the tach will move up a milimeter from the bottom and sit the entire time.

- *FIXED* Speedometer thinks you are moving. When I let the clutch out after starting the engine, with the tranny in neutral, the speedo goes up to 10 mph. If you rev the engine, it goes up thinking you are moving.

Things we've tried/checked:
- Ground wires on each side of the dash, and by the drivers seat are all good
- Main engine ground strap good
- Smaller 2 grounds on each side of the engine bay are good
- Every fuse inside engine bay and inside cab are good
- Unplugged and plugged back in all transmission wiring connectors
- Unplugged and plugged back in the 3 front and rear ABS sensors
- Unplugged and plugged back in ABS module connector
- Installed new crank position sensor
- Installed new cam position sensor
- Gone through every connector in the entire harness of the car

On LS1tech and everywhere else I received lame responses like (you've got your speedo plugged into your tach!) I don't know anyone else who has transplanted an entire drivetrain into another car and used the stock wiring harness. Seems like most transplants end up with a Painless harness or something else.

At any rate, the blasted car is ready to run... if it would just run. Everything else on the car is ready to let it move and drive!

/Cries for help

[mitchntx]

Frustrating to be so close and have these gremlins ...

I wish I were a sparky, so I could help ...

[68 Camaro]

I don't have any direct answers... but just for the hell of it...

pull a wire from a plug or two and check for spark. just to make sure your getting a good spark to the cylinders...

along with that... now i don't know how difficult it is on the LS motors but pull an injector off and crank the motor to make sure its spraying fuel (you may want to do this to each injector to make sure that they are all spraying)

just make sure you have the fundamentals there (air, fuel, spark)

If you have access to a scan tool, run it for codes. I think if you go to Autozone you can rent one or they can scan it for you.


on a side note of that, i had a similar problem in my MX6 where the car if it ran at all ran like absolute garbage. turned out that on my VAF (mass air for those cars) a wire had severed from comming into contact with my cruise control. causing a pethora of codes to trip and thankfully i had access to a scanner to see what went on.

[firehawkclone]

it's very time consuming but check all voltage's coming from/and to all sensor's and pcm.It just seem's to be something(a wire)has come lose or broken.Becuase all was fine at first.

keep us posted

[Ojustracing]

What about the 2 grounds on the back of the heads? can you be more specific, on what the engine came out of and stuff like that. You also say the stock wiring harness. Is this the harness out of the donor car? Now I have seen some cars speedo go up when in park when reved up. Not at idle. How high does the speedo go. The more info you can give us the better. The stuff you have listed is a start. I just need more. I will try and help you the best I can. What connections have you spliced. Later John

[SuperCricket]

Im sorry, I assume everyone knows about this project for some reason.

I had a 1999 Camaro SS that ended up backwards into a tree. Purchased a 1994 V6 Camaro to transplant everything over to.

Everything from the 99 car moved over, I mean everything. Inside and outside wiring harness, engine, transmission, rear end, everything.

The only spliced connections in the harness right now are for the drivers side oxygen sensor. I checked it out and it looked ok.

I will check the grounds on the back of the drivers side cylinder head. I had totally forgotten about those grounds.

Also, today we got the speedo to stop acting up. I got the car up in the air and put the driveshaft in. The speedo was going crazy until we turned the rear end over, then it sat at 0 like it should. I suppose either the speed sensor in the tranny or the ABS sensor in the rear end was in a dead spot and sending false signals?

So now the main problem is the no tach, hard starting, and bad running when the engine is on.

[mjf454]

Have you checked for fuel pressure? There is a little cap on the fuel rail, if the key is on, gas should come out when you press in the valve.

[GlennCMC70]

its your grounds on the back of the head. you will have 2 separate bolts w/ grounds on the drivers side.

[GlennCMC70]

previous post

[SuperCricket]

Yeah fuel pump is hot wired straight from the alternator feed through a 30 amp relay and has good pressure.

Glenn, I checked on my grounds on the back of the head. I have the 3 ground wires all going to one bolt on the drivers side head. This shouldn't matter should it?

When I put the harness on the engine before we stuffed it back into the car, we could not find the 2nd bolt for those ground wires. Because of this I grounded all 3 with one bolt.

[John_D.]

I would definitely scan it for any codes. That could narrow it down fast.

My first thought when I started reading was crank or cam sensor. But if you swapped those out, then that almost eliminates those... (unless there is a bad connection)

The afterfires and shooting out the exhaust sounds like a car that has "jumped" time (timing chain). Except you said it starts and runs fine sometimes, so it's probably not the timing chain, and I keep coming back around to thinking it's a bad sensor. The pcm will try to find the right firing cycle if it gets a read from the crank but not from the cam...

The three grounds to one bolt should be ok.

[Ojustracing]

Ok the more info the better. So one thing is fixed..

Now onto the drivabilty complaint. You said your tach worked, is this before the swap or after. Can you relate the tach not working to the bad running? Now to the bad running, Once the car is running is it smooth, ruff, other. You say its hard to start does it crank over normal or is it normal cranking then does it act the timing goes way wrong. Will it idle without being on the gas. Also you say it shooting flames out of the exhaust, which side, and is the flames while the car is running.

Sorry for all the question, but if the car was at my shop I'd ask you the same and possibly more depending on your response to the above question. John

[SuperCricket]

Tach worked after the swap for a couple weeks. One day we went out to start the car and the problems began.

Once the car is running, it seems to run ok, but still a little rougher than it used to with this cam (TR224).

The car only afterfires (blue fire from exhaust) when trying to crank the car over. It cranks over perfectly well, but it just wont start. Fuel accumulates in the exhaust and you get obnoxious bangs that sound like a shotgun, accompanied by lots of light and fire from both headers.

The weird thing is, you can leave it for 2 minutes, and it will fire right up. Then you can turn it off, try to start it again, and go through hell with the afterfiring.

Again, no fire or flames when the car is running, just when trying to get it to start. If this was a carbed car, I would look straight to the timing for such a problem. But with the LS1... who knows.

Thanks for all the help folks!

[mitchntx]

That sounds like an open lop closed loop thing.

Isn't that controlled by the O2s and engine temp?

[GM01SS]

Had ( have:) ) a friend who had a similar problem. His was with a LT1 car, but found a bad o2 sensor that was causing all kinds of problems. It would run fine then act like it was out of tune, then fine...... you get the picture!.This was AFTER putting in a new one (it was bad) Also check wiring to the o2 sensors, if bad ( broken) they will give a false reading to the PCM and cause more problems.

Hope all works out

Gary

[SuperCricket]

I have two extra O2 sensors, I will also swap those out in the morning. I will also comb through the O2 wires again and make sure they havent been heated up by the headers lately.

[Ojustracing]

I just had a nice thing typed out and hit a wrong key. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/banghead.gif) I guess im the only one that goes to work at 11:00 on a Sat to help a perfrect stranger.

You need to put the car on a scanner. Beg Borrow or steal one. You need to see what the computer is seeing. The tach signal wire is one wire coming form the Pcm so if it was cut it shouldnt casue a complaint. The computer controls spark and fuel based in inputs from different sensors. If the computer is getting wrong info from something thing will be off. So spark and fuel might both be off together. Is the check engine light working or funtional. Is the OBD 2 port working. I cant say this enough, you need to put this on a scanner.. Are you 100 % that there is no issue with the cam gear sprokets, and chain. You do say that the car is not running like it used too. Can you do one thing for me, Disconnect the MAF sensor and try starting the car that way and see what it does.

Oh there another ground in the area of the starter and Crank sensor.

While typing I saw a cuople people post about o2's. If he is starting the car they wont give you a starting complaint that way. If the signals were wrong you would see that on the scanner which hasnt been mentioned yet I assume it hasnt seen one. If you could answer some more info and will go from there. John

PS wait till he get the bill from me for this (IMG:http://www.frrax.com/rrforum/style_emoticons/default/rotf.gif) (IMG:http://www.frrax.com/rrforum/style_emoticons/default/nutkick.gif) (IMG:http://www.frrax.com/rrforum/style_emoticons/default/beerchug.gif)

[Ojustracing]

Well you can try the o2's, but they wont fix your starting complaint. You could start the car with both of them disconnected and it wont make a damm until the car warms up. Im going to bed. Later Super cricket

[SuperCricket]

Thanks for all the help Ojust and everyone. Tomorrow I will disconnect the MAF and start her up. I also understand the O2s arent used until after the car is warmed up and changes loops, so I suppose that wont help the starting problem either.

The car "should" be able to drive, but I'm just not sure about getting it down to an Autozone without insurance on her, and I don't have a trailer. I do have a friend who works down there, so I will try to get him to borrow the scanner on his lunch break or something.

Will report back in the morning with the results.

[sgarnett]

The only spliced connections in the harness right now are for the drivers side oxygen sensor. I checked it out and it looked ok.

I hope you just mean that you spliced in an extension cable ....