Ryans99ls1

iTrader: (16)

Just like the title says, i got my dual lonnies pumps in, installed fast rails with 80lb injectors, aermotive brfpr on the return side, brand new fuel lab fuel filter. No leaks anywhere, builds set pressure when you turn the ignition on. It fires right up (just like in the vid) but wont catch an idle.

The car is a 99 and my tuner flashed it to an 01-02 operating system. He eliminated the MAF and everything associated with it because the car will be run on SD (obviously). I cant scan the car because i dont have HPtuners. Ive been pulling the computer and taking it to my tuner and he uploaded the start up tune. Basically i just wanted something so i could start the car and check for leaks before i tow the car to him for a tune (he's 2 hrs away, where i go to school). He's a very competent tuner and he just tuned a 600whp stock bottom end setup very very similar to mine, so i know he's close on the startup tune.

Ideas:

He mentioned the IAC but i started the car last year on the stock fuel system and it ran fine, this was the first time it was started since then.

When i replaced the MAP i reused my old grommet, would it cause this big of an issue if its leaking there? I would think it should at least catch an idle and run shitty then maybe die off. Its not like that would be a HUGE vacuum leak, because the grommet is there..

The only other thing i can think of is VATS? I say this because even giving it gas does absolutely nothing. It idled for like 3-5 sec at less than 500rpm last night but it would die as soon as i blipped the throttle. Today it just starts and immediately dies. I just remember reading in the past that VATS will sometimes let the car start but immediately kill the injectors.

Im basically trying to put a list of things together before i go see him so we can check as many angles as possible.

Any other ideas or people with the same issue?

Heres a vid of what it does.

Wicked69

I had this issue with mine and we were at wits end. This was when I had my HPtuners on it. The problem was that the pcm that was used was from a DBW vehicle and we were using DBC. As soon as you blipped the throttle it wouldn't work and would die. They changed the tune to a DBC and problem solved. Just a thought.

Ryans99ls1

iTrader: (16)

Any idea is good at this point. It doesnt die because i give it throttle, it has no ability to idle with or without moving the throttle any.


I also tried lowering and rasing the fuel pressure above and below what we set, which is 58psi, and didnt really get a change.

HydroStream6

iTrader: (16)

At one point in my tuning schenanegans, I remember when I switched to SD that on the very first startup, the car would not stay running to save its life. What was happening was, since the MAF was gone, it wasn't staying running long enough to default into SD mode. I had to play with the throttle a lot to somehow keep it running for 5 sec or so until it defaulted into SD, then it was fine from there on out.

Stangkilr

iTrader: (47)

I just had the same issue. Mine ended up being a TPS issue. I re-pinned the TPS and problem went away.

Ryans99ls1

iTrader: (16)

That makes sense, ill keep it in mind. The only effect the throttle has right now is how high it revs on that initial crank. after it turns over, no effect whatsoever, so idk how ill keep it running like that

Yeah i remember seeing your thread and it has been in the back of my head.. as a last resort thing. thanks for the input guys.

Ryans99ls1

iTrader: (16)

do you guys think switching back to a MAF tune(just for troubleshooting) would eliminate the TPS issue that Stangkiller had, IF it decides to idle when switching back?

93camaro_zzz

iTrader: (13)

I would have some things to try if you had hptuners, but you said you don't. No offense to your tuner, but I would have checked everything that he changed. I would also make sure the TPS is working correctly. Maybe try taking out a spark plug and seeing if it is at least getting spark through this entire thing.

Also, iirc, an ls1 should still idle with both the map and the maf disconnected. I could try it on my Z when I get home if that will help you.

Ryans99ls1

iTrader: (16)

When it talked to him yesterday, he compared my start up tune to the tune he did recently on a speed density, stock shortblock, E85 ls1 and said nothing stood out. He made sure the MAF was off but we are still going to go back through it when i see him.

But yeah that would be cool if you could try it real quick and get back to me, unless someone just confirms it.. FWIW the last time it ran, was maf-less. its really starting to point to VATS or the TPS issue stangkilr had

willizm

iTrader: (10)

I had a similar issue after getting my car back from my tuner. Ran great driving it home and then got progressively worse over the next few days/startups. Keep in mind that e85 loosens **** up and guess where that goes. Right into the filter. I replaced the fuel filter and whala, car runs like a champ again. You might have to replace it a few times in the coming months because it will loosen up deposits in the tank and start to clog the filter.

willizm

iTrader: (10)

I should clarify that my car ran A-ok while with the tuner. After a few startups and putting miles on the car the idle quality suffered to the point where I'd idle terrible and stall, put it in a gear and stall, farted in the car and stall, mean mugged an old woman and stalled, give it some throttle and stall.

Ryans99ls1

iTrader: (16)

it was started less than 5 min after i put fuel in tank so i doubt it sucked enough up to clog it that fast, although crazier things have happened.. but i will definitely be on the look out for it to start getting clogged. thanks for that.

willizm

iTrader: (10)

were the injectors newly installed and injector tables updated with hptuners? Hmmm, do you have any CEL's thrown? Do you have a fuel pressure gauge?

Ryans99ls1

iTrader: (16)

yeah i installed them that night. i specifically remember him asking me what injectors and i said 80lb'rs and the base fuel pressure will be around 58psi. Then he went adjusted some tables.

idk about CEL's my dad was starting the car, we'll check when i plug the computer into my tuners laptop.

I do have a fuel pressure gage, if you watch the video youll see thats what im aiming at. the needle is around 60psi, i know its blurry.

Stangkilr

iTrader: (47)

I would check fuel filters too. The first tank is always the dirtiest with all the stuff from making the lines and stuff. My filters were super dirty after 4-5 tanks.

93camaro_zzz

iTrader: (13)

Ryan,

I checked it for you. It is proven that an LS1 will start without a MAP or MAF hooked up. Hope that helps.

98Camarod

iTrader: (43)

If you have it set at 58psi, it shouldn't be at 58psi at idle. It should be quite a bit lower. You set the base pressure with the vacuum line unhooked and plugged, just a thought.

Ryans99ls1

iTrader: (16)

you know, i thought about that and wasnt very sure.. in all honesty, this is my first go around in messing with a fuel system. just to be clear, i remove the the vacuum line from the regulator and plug it. then i start the car and adjust the fuel pressure to 58psi?? after that i hook up the vacuum line again correct?

Ryans99ls1

iTrader: (16)

thank you very much. it will help in troubleshooting for sure.

98Camarod

iTrader: (43)

Yes. That will have your base pressure set. You need to find out what is in the tune. He should have you set with whatever your injectors are a flat IFR for the 58psi.