I am stumped. I just finished installing a new LS1 5.7 and 4L60 into my 68 RS/SS camaro and i am having some sort of fuel issue. I have tested the fuel pressure at the fuel rail and I am seeing 58/60 psi there. I am using the corvette fuel pressure filter\ regulator and a MSD external fuel pump with -6 An fitting and -6 S/S line. My problem is the engine will start and run fine as long as I keep triggering the fuel pump on and off. "More off than on?" "THE ENGINE IS FLOODING" If I connect power to the fuel pump for more than 1 seconds it will kill the motor. I can keep the engine running as long as I cycle the positive pump wire to the battery directly very quickly? The pump is on its own wiring system. The engine acts like there is "TOO MUCH FUEL"? "Its acting like the injectors are staying open". The injectors are stock 5.7 This cam crank combo has never ran together. It has MTIX1 cam and 28x reluctor wheel crank. The guy i purchased the motor from said it ran well until it spun a rod bearing in his CJ5 jeep. I believe the PCM has been tuned before. Soon as i can get it straighten out i will put some miles on it to break it in and have it Dyno tuned.

I am getting code PO1336

Here's a thought. Can the ECU be keeping the injectors wide open due to the crank relearn issue? BTW I have taken the fuel rail off the motor and put 58 psi to it and none of the injectors leaked.

I cant wait to get it on the road.

It has 2000 PCM, after market wiring harness, It came with the motor. The 02's are hooked up.

Any help would be appreciated. Where's all the LS Guru's LOL . I am sure this has happened to someone before. This is very frustrating.


This is a old picture..

 

Has the PCM had the VATS turned off in it?

 

sounds like the vehicle anti theft is still on, and since its not reading the chip in the key it kills the fuel, just tune it out and your good to go

 

The problem is it is getting "TO MUCH FUEL." the pump is on a stand alone system. Please read 1 post complete.

 

See 1st post. please read complete. "ITS FLOODING ENGINE" As soon as it see's fuel pressure it loads up a dies. 58\60 psi at fuel rail...

 

I agree

 

Fuel pump system is a stand alone system.

"Its getting to much fuel." as soon as i manually connect fuel pump, even for more than 1 second it loads up and dies. As I say as long as i cycle the fuel pump on off, by hand at the battery and it dont see fuel pressure it will run fine??? It seems as if the injectors are staying open.

thanks for your reply though.

 

Hmmm.....

What kind of a return line are you using? Is it restricted? Well...you said you are getting the correct pressure though. Are you leaving the pressure gauge hooked up so you can watch it when it dies?

Now...just spit balling to see what sticks... What size injectors and MAF? You may need to have a tune to get it to run if these have been changed significantly.

 

Yes to the fuel pressure Gage. As soon as it, the fuel pressure Gage, see's any pressure at all the engine it will DIE. Stock MAF Stock injectors. I 1st thought it had a bad injector or 2 due to the fact that it is getting to much fuel. Then i thought the corvette fuel regulator/filter was bad and was making to much pressure. Fuel pressure is correct at 58\60???? This 2000 PCM and aftermarket harness was used on this motor in a CJ5 and the guy spun a rod bearing.

I went thru the engine. Purchased a new crank, Installed new MTIx1 cam. Installed Ls6 intake. I used the injectors that came with the engine.

I could see if it ran like crap. It would need a tune, But it is dumping fuel into the cylinders When it see any fuel pressure? its like the injectors aren't even there at all?????? Its probably the PCM . But it ran before it spun the rod bearing? or did it LOL...

 

Put a scanner on it. It could be so many things it's almost impossible to diagnose without some sort of data. How can you pin it on a bad PCM when you have absolutely no data at this point?

 

I have a scanner on it. As it says in the 1st post. It shows code PO1336 .Needs Crank relearn. No other codes. I am just trying to figure this out. Something seems to be keeping the injectors open. As long as I trigger the fuel pump intermittently and keep "no" fuel pressure at all it will run some what normal.


It is triggering the coils. Your guess is as good as mine? I have checked all the grounds, connectors, looked for wires that may be shorting out. It doesn't make any since.. I am going to get another PCM from Chris a member here and try that. Like i say I AM STUMPED LOL

Thanks for your input.

 

First off, you didn't say you had a scanner on it. You said it had a code. You can pull the codes with a code reader. You mention nothing about scan data.

If you have a scanner on it, look at your scan data. Half the time codes don't mean squat. What is the coolant temp? IAT? TPS? MAP? Injector PW? There has to be a reason it's running so fat. If all the scan data looks good, maybe the injectors are way bigger than you think? Pull the number off them and do a search.

Again, forget about codes. Look at your scan data and try to figure out what would cause a long IPW.

 

When you said scanner I thought you ment hand held scanner. Code reader. If I had a data logger I would know my problem, at least see what was not normal..The

The injectors are stock. I have already checked the numbers on them.

Thanks for playing. Now ware going to the lightnig round lol..... Where all correct answers are worth double...

 

Just tried new Stock unmodified PCM out of 2000 it will stay running now, but not for very long, and that's with the fuel pump connected. Of coarse its throwing all kinds of smog codes but that's normal. I didn't get a crank relearn code. I think i will need to send it out and have the PCM Tuned just to get a baseline. Can anybody recommend somebody close to me. i am in Long beach ca 90805. Question Should i send the original PCM out that has been tuned before or the stock one? Any thoughts

 

My thought is that any decent tuner should be able to dial it all in on a dyno.....and you mentioned that you were going to have that done anyway....so I'm thinking you should just take it in. Unless, of course, you're thinking that there is still an underlying issue....in which case, you'd be wasting dyno time trying to figure it all out.

My suggestion; Get a mail-order tune from one of the reputable vendors here (Frost comes to mind along with some others) and see what happens. If the problem clears up, it was the tune. If not, then you need to keep looking for the problem....but at least you'll be relatively certain that it's not the tune.

Just my $.02

-James-

 

Yes I believe its the tune. I actually hooked the orginal pcm up again. I let the motor warm up by triggering the fuel pump on and off to keep it running.Then I keep letting the fuel pressure build up and I am now able to keep the fuel pump on . But its running real rich. The more out runs the better it gets?

I am going to have it dyno tuned but it is a new motor so I want to break out in first.

I also heard good things about frost tuning. I think I'll check into it. I used shawn church for my Procharger C6 corvette. ed wright did the canned tune which was a gods base line.

Any Local tunners in near long beach that could do a base tune on the PCM? Cam, headers, ls6 intake,MAF delete.

All the vats, cats, rear 02, egr etc are already off.

I should just purchase efi live or hp tunners lol

 

Personally, I would not even run the car now....until you get a good "base tune". Washing the cylinders with so much fuel is no good at all....

And yeah...you SHOULD get EFI Live or HPTuners, IMHO.

 

Ok believe it or not but the PCM relearned it self and now it runs pretty good. The more it runs the better it gets. Its now running at full 58\60 psi. It will start right up like normal.

I would have never thought it would fix itself. Before it was just pumping gas right thru the injectors via the PCM. I am stoked that is is running well now. I think it will only get better as it continues to self adjust.

It sounds tough with the MTI X1 cam. Soon as i can get the video up linked i will post it.

I think i might need a stall converter now. It still needs a base tune

http://www.youtube.com/watch?v=BjNa2_H7PKE

 

I would sure like to know what is programmed in that original PCM...

 

I think it might just be a simple issue of a near-stock VE table flooding the idle. The fuel trims might be able to help it learn some. But, it needs to be tuned for the setup and not rely on the fuel trims to make >20% adjustments.