Sinister_Z28

Ok so as some of u know i wrapped up my first LS build a while ago. So the motor runs good and has now major problems that i can find. Heres what is wrong. 1: So i went to start my car tonight after it had sat for probly 7-8 hours. It started right up then died. So i restarted it and it sputtered for a sec then idled like normal. So i drove it to a gas station thats was like 1 mile away ran inside for a couple minutes came out and started it and it died. So i restarted it and it sputtered and then idled. So is this normal on cold starts? I read somewhere on here a while back that camed cars sometimes do this, so i just want to know if this is something to worry about?

2: So the next issue is occasiinally when i do a wot pull the motor will just fall on its face around 3500 RPM's and a check engine light will flash and so will the low oil light, they flash on for like 2 seconds then turn off leaving no codes. Now this is only at wide open throttle and it doesnt do this at all if i accelerate gently. Now the car isnt fully tuned but it has a base tune and my tuner said its safe to drive its just not going to be making maximum power. I suspect that this might be a bad cat because i knew my stock cat was going out when i bought the car a year ago. So is this a symptom of a bad cat? If not what in the hell is it?

3: The next issue that has been driving me CRAZY is the ASR Off light, i mean it comes on randomly when im driving and i cant turn it off. It eventually shuts itself off. I mean i cant figure out whats causing it. The tires are stock size and my rear end is the stock ten bolt. Any ideas guys?

So thats the issues in a nut shell. Oh and im about ready to replace my entire exhaust system with tsp true duals and there 1 7/8" long tubes as well as improving my entire drive train.

Sinister_Z28

Just noticed the random typo in the title my bad guys.

lemons12

iTrader: (71)

I wouldn't be getting on it with a base tune... You're asking for big trouble. Load is good to seat the rings but i wouldn't advise anything past 4000 rpms or so. You have zero clue what your af looks like.

Are you sure you have enough oil?

The dying on the first start should be fixed with a proper tune.

Take it easy until you get a full tune and check everything man.

Sinister_Z28

I get what ur saying. The motor has the rev limiter set at 4k from what the tuner said. I dont get on it very often but this just doesnt seem right. Could it be the cat? As far as the low oil light flash i dont know what causes it. I replaced all engine sensors when i built it. And my oil level is right where it should be.

lemons12

iTrader: (71)

Highly doubt it is a cat issue.

Does oil pressure drop at all?

Im not a fan of replacing all sensors..

Sinister_Z28

Well since i three w a couple rods on my old motor i didnt want to take any chancea of puting anythingback on the motor that could have metal on it. Oil preasure is strong and it drives smooth. When it lost power it droped from like 60psi to a little above 40psi and when i shifted and gently accelerated to mantain speed the oil preasure went back up. Like i said this is my first build and i cant think of what could cause this. Everything seems to check out from what i can tell. Any things i should check?

lemons12

iTrader: (71)

When it lost power? It lost power during one of these low oil pulls?

parks450

iTrader: (17)

Personally I wouldn't drive it until it gets dynoed. Your just asking for trouble, sounds like most of the issues are in your tune. Even if you tell yourself I won't beat on it you will still find yourself getting on it lightly, still not good with a half *** tune. If you keep doing WOT with a half *** tune, your next thread will be I blew my motor up.... If you have another vehicle drive it...period....

As far as your oil pressure it's good still, but I'm curious as to why it drops 20??? When you say looses power, do you mean it just stumbles or it physically has the power cut from the motor then comes back in?? If so could very well be a short or a pinched wire.

Sinister_Z28

When the oil pressure drops it is when the engine loses power. Like the car is idling right now at like 45psi but with load it raises to 60. Basically when i say that the engine loses power i mean it just stops accelerating like it just hit a wall and the rpms drop about 500rpms. And no its not tge rev limiter because the rev limiter is set at 4k. My tuner reworked the maf and told me i could drive it around it just wouldnt make peak power. So ur saying i shouldnt drive it until it gets a full dyno tune.

parks450

iTrader: (17)

Do you have a wideband? If not I suggest you get one, your AFR could be really lean or rich both not bein good. I'm saying if you don't have to drive it then don't until you get a dyno tune. How good is this guy with tunes? He new or been doing it man years?

Sinister_Z28

Hes been tuning LS cars for about as long as they have been around. He is highly recomended here in southern California. And what exactly is a wide band?

parks450

iTrader: (17)

Wideband oxygen sensor, it basically measures your exhaust fumes to tell if your car is running rich or lean, in short. They are very accurate for timing vehicles and getting the fuel maps and parameters set. Without your basically just guessing. It without live data and reading it, it's difficult.

Did your tuner actually hook it up and take it for a spin??? Or did he just download a pre-set map and say your fine?

Sinister_Z28

No he took it for a spin before i got it back.

RonSSNova

iTrader: (3)

Check all of the engine grounds. Almost sounds like you have an intermittant electrical issue.
The starting issue sounds like tune.

lemons12

iTrader: (71)

I was leaning this way...

Sinister_Z28

Any specific grounds to check? I can only think of the grounds on the back of the heads. Any others to check?

Silver408z

iTrader: (1)

On C5's there is 1 ground on the frame pretty close to the head lights on each side. There is also at least 1 ground to the block on the drivers side of the block under the head. There might be one on the passenger side also but I am not sure and this is for c5's

Slowhawk

iTrader: (12)

Check all grounds and power cables first then bring it to the tuner to finish up.

lemons12

iTrader: (71)

One ground on alternator that goes to frame. iirc two on frame rail by fuses under ps.. one behind pass light. three on back of pass head.. One by battery and one that gets moved when you do wire mod.

i have some of mine moved around though in order to clean the bay up. But Im pretty sure if you have those accounted for you are good.

theoneeyedbandit

iTrader: (3)

Evan there is only two on the back of the head the last thing is a way to bolt the harness to the head.