PyroMechanic

iTrader: (1)

Alright guys, mods are in my sig, I have 115k miles, just seafoamed and maintained. I cant seem to get it to idle, its been like this since I got a zzp tune, 60's and phenolic. No vacuum leaks, vacuum is about 21inhg at idle. After I got zzp's tune, got help from big boy lsj tuners and got a good tune, but the car still doesn't idle right. What I just noticed was that the car idles great when..the purge solenoid turns on. What does this mean? Bad evap canister? low fuel pressure, high fuel pressure? Idles like **** if that thing isn't clicking. HPT says Im getting some misfires, random, every cylinder, and they max at about 6, average are 2-3. When going WOT, the car is amazing, full power, no knock, no misfires, good afr. Any thoughts? Im getting to my ends with the car, if I cant figure this out, im going to have to part with it and get another car. I cant go driving around with the engine bouncing from 400-1500 at lights and people think im nuts. Oh, and mpg is about 14. Goes up or down depending if I do more cold starts, which is understandable. 10* weather doesn't help mpg. Thanks guys.

mrbelvedere

iTrader: (3)

you need to post this in problems and service no the performance section

sounds lean check the tune

Gelladuga69

iTrader: (4)

This happened to me.. Trying to remember how I fixed it. I did replace the evap purge in the engine bay though. That might've been the fix honestly.

I do remember the car would stop doing it if I pulled the EXH fuse.

PyroMechanic

iTrader: (1)

Lol I didn't know we had a section called that, if a mod could move this, that's okay with me, I didn't know haha. And yeah.. since I have just noticed that.. I changed the minimum pulse width to 1.1... lol I have been fighting this problem for almost half a year, and been dealing with knock at idle with e85! Funny to say, I think me changing the minimum allowed pulse width made the car actually idle.. EXH fuse? I have already replaced the evap solenoid as well. Other symptoms include my gas gauge going to 0/nothing every now and then, including on start up, and the first time it was cold this winter, I started it and the dash said check gas cap. When I got the car about a year ago, I got a new locking gas cap, fyi.

PyroMechanic

iTrader: (1)

On that comment, what should be the minimum pulse width for 60's on e85? Idle still jumps a little, especially with ac on, and lots of strain on the alt.

I feel like this is a temporary bandage for a bigger problem.. Alan McClure and a few other guys have tried to help me but cant find anything either..

Gelladuga69

iTrader: (4)

Exhaust fuse. It's labeled EXH under the fuse box in the bay.

PyroMechanic

iTrader: (1)

Why the hell would we have an exhaust fuse? o2 sensors? But anyways.. Everyone, disregard what I said about the minimum pulse width fixing the problem, it turns out it didn't, it was just because the solenoid was open the entire time, I cant get it to repeat a good idle unless I let it bounce and hunt for like 15 minutes.

mrbelvedere

iTrader: (3)

disconnect the purge from the throttle plate and cap both ports and what is the afr at idle

PyroMechanic

iTrader: (1)

So I capped both of them off, no difference. Still horrible. Im thinking Ill make a video of the idle and my HPT logging at the same time. I capped off the vacuum port on the manifold and did the boost bypass just to test and no difference. I unplugged the MAF when car was off, tried to start, RPM's flew up then fell and wouldn't idle and sounded like crap. Did the same test with the MAP sensor, acted the same way so Im assuming those aren't the problem. I did the same test for the barometric sensor and it didn't make a difference and went for a drive with it unplugged, no difference again. Car idled decently when I found the evap open again. Its definitely not the tune btw, Ive got the best of the best helping me tune with HPT and nothing helped.

MrSlickSter06SS

What kind of Cold Air Intake you running? Injen? either way go back to stock and see if the idle stops bouncing. For whatever reason that positioning of the MAF sensor makes the idle bounce horribly, even coming to a stop at a red light, stop sign, driveway, girl friends house and her dads laughing at your **** sounding horrible, etc.. If that happens to be the case either go back to stock readjust your tune for it or get a zzp CAI. Reason being, if I am not mistaking they are one of the one's whom found this problem with the Injens and made corrections with their CAI's. Sounds crazy man but I had an Injen and always had idle bounce and drove me up the wall. Went back to my factory intake, and made some pretty adjustments to it and it corrected the idle bounce issue. Hope this helps, good luck friend.

PyroMechanic

iTrader: (1)

Lol everyone that hears my car and knows about cars says they think its cammed, and normal non car enthusiasts say it sounds awesome, but im the only one who really know what my PCM is doing and what is actually happening. I was thinking about going back to stock intake but that shouldn't matter. I have a K&N Typhoon intake for the Redline, I have a redline. The idle even bounced when I got the car, just everytime I added mods this bouncing was enhanced, and now getting it on the LS4 with 60's and e85, its pathetic.

MrSlickSter06SS

I know what you mean mine has too, and still does here and there but now its less common and tolerable. Give it a try man what's it going to hurt? Odds are you will be happy and take a nice breath or you will still be scratching your head. Lol I hope it works out for you, and to be honest I disregarded it myself because it didn't make since to me either, but I am glad I did it, I even still have some hair left.

smitzk01

iTrader: (6)

Can I just ask if by "sea foamed and maintained" you mean you changed plugs after right?

PyroMechanic

iTrader: (1)

Ha I put a step warmer plugs in after I seafoamed...The car ran worse. So I put the step colder plugs back in.

Idk if you ever actually seafoamed before, but fowling out a spark plug with seafoam rarely happens.

PyroMechanic

iTrader: (1)

Heres a video of the **** it does.

And the video actually does exist, just click the link for the video.

andrewcarr1993

iTrader: (5)

Is the throttle body clean? I highly doubt it's that but I know it's a common issue.

PyroMechanic

iTrader: (1)

Its sparkling. Im going to check fuel pressure maybe.

MrSlickSter06SS

lol dude Im telling you. My car did the exact same thing, did you try putting on your stock box? Sounds exactly the same as to what mine was doing and is very annoying.

MrSlickSter06SS

My AM Uego would show the same spike then blank out like yours. If it isn't that then bad throttle positioning sensor which is built inside of the throttle body so ordering a new or used one might be what you need to look into.

PyroMechanic

iTrader: (1)

Alright so update.. I got a ticket for loud exhaust because my idle was so fucked up.

A week ago I traded maf sensors, map sensors, barometric sensors with another redline. didn't change anything. I just put my stock injectors on with e85 still in the tank, I put a 30% boost cap in the tune. I don't plan on flooring it anyways, this is just testing purposes. It still jumps up and down during idle. And my throttle body? The car did the same when I had my sparkling clean lsj tb on, vs my new sparkling ls4 tb on.

I even cleaned and checked my main engine ground, didn't do anything. I replaced coils, plugs, etc. NOTHING.

Im starting to think a bad pcm might be it. But that doesn't make any sense... And btw, with my new injectors in, I cant get the car to show rich at all. I can add all I want to the VE table, doesn't change one thing. I even made the stoich afr 9 and it still reads 18 afr on the wideband and STFT/LTFT's are 30%.

Im about done with this car. I never have any luck, and this shows that like a sore thumb.

PyroMechanic

iTrader: (1)

So after getting upset, I think I might have found the problem. And Im not sure if what I found is normal, im pretty sure its not. Anyways, fuel pressure seems to be the problem to me. Stock is 58-60psi from what I read. Key on, engine off, fuel pressure was mid 30 psi. Engine on, at idle, and I got it so my 36lbers' would idle again, and that took some tuning in itself, psi was 80! Next, when revved, psi jumped anywhere from 60-80. So im guessing when my idle hunted that bad before, the fuel pressure jumped too, making it impossible to get a good AFR.

So, anyone else agree with me? I feel like I became sane again after 6 months of finding an actual problem.

And if so, can I fix the regulator? Because clearly the pump is in good working order. But idk if the regulator is part of the pump. And if I do replace the pump, what is a good pump for e85? Thanks guys!

reddragon72

the regulator is part of the pump.

I am not sure that the fuel pump is your issue though. If you have low pressure then the car would die and have issues reaching the top end.

Have you looked at the throttle body? the fly plate? is it bent at all? getting stuck? Remember we don't have a bypass valve for idle control like some vehicles, the throttle plate regulates it.

PyroMechanic

iTrader: (1)

Read the entire thing I said.. After the car starts, fuel pressure hits 80psi and pretty much stays there. Meaning there is too high fuel pressure when the car is running.

The fly plate? Lol I had my old LSJ TB on before, changed it with a new LS4 throttle body, so that is not the problem.

reddragon72

I thought I read on another post that the pressure didn't matter as long as it wasn't low. Something about putting a high performance pump on it that pushed 100psi and no change to anything because the injectors would control the fuel...

just saying that is what I read..

PyroMechanic

iTrader: (1)

You've been misinformed. Fuel pressure is very important. Direct injection on the LNF relies very heavily on precise fuel pressure. The LSJ is less. Why do you think ZZP makes a boost reference fuel pressure system? Bigger injectors can use high fuel pressure, but it will give way too much for what is needed under vacuum.

But anyways, Im going to be getting a new fuel pump, then testing fuel pressure after that.