sleepertib

Took the tib out for a spin tonight after finally finishing the turbo install. Idles just fine, but the problem hits when I start to accelerate. Just for anyone that hasn't read my other thread posted earlier, I am driving an automatic, which is soon to be undergoing a manual swap. Anyways, as I accelerate, Everything seems about fine until I get to around 5 psi, at which point, it seems like the car decides to seriously hesitate, at which time the boost immediately dissipates (prolly via the BOV). The problem is that I cannot decide if the problem is because my fuel system cannot keep up, or if the automatic trans is having trouble shifting. Right up until the shift point, it seems to be spooling just fine, and as soon as it would normally shift, it hesitates.

Also, I keep having problems with a rogue oil leak somewhere in the engine bay. It's not the oil feed/return either. Oil keeps accumulating on the top of the valve cover, as well as a spray on the firewall kind of to the left of the engine.

Any help would be great, as I'm seriously debating I'd just taking it to the local speed shop.

KustomizedTiburon

Do you have a wideband? I think it may be your fuel cutting out, that was the problem I had with mine, what type of tuning are you using?

sleepertib

yep, got a wideband, but it's kinda hard to tell. KT, you had a UEGO for awhile so you might know what I'm talking about. It DOES start to read a bit lean, and it then reads two sideways dashes "--", which is kinda why I figured I'm hitting fuel cutoff. But it's just strange that it keeps happening and hesitating right around the shift point...and I thought that the car completely dies when fuel cutoff occurs. Is this not the case?

And as for tuning, I was told that for low boost, usually 5psi and under, you dont need any tuning, so long as you watch ur A/F and boost levels. So I'm a little confused as to why I'm hitting fuel cutoff at such a low psi. But not to worry, as I do have an SMT-6 waiting to be put in! I was just trying to figure out that if it IS fuel cutoff, or if my trans doesn't want to play nicely.
Thanks for your help

KustomizedTiburon

Thats the EXACT same thing that was happening with me, it seems people on here although not recommended had ran it without tuning ( I even added injectors, an FPR and an FMU in the mix) and it STILL had the exact same effect, I was beginning to think it was a flaw in my setup, glad to know someone else had the same problem. As for the answer, I have NO clue, I guess it really is all in the tuning. But up until the cut off my AFR never read too bad at all.

sleepertib

Ah well now at least I can rule out the transmission. Thanks for the help KT. I suppose I'm off to begin the tuning then! Did you do the actual tuning yourself? If so, where would you suggest learning how to tune with an SMT-6? Cause I have one laying around gathering dust, awaiting the day I get off my lazy ass to hook it up. I can handle the physical install, but there doesn't seem to be many "how-to's" floating around.

Thanks again fing02.gif

Alex01tib

Its most likely the ecu pulling timing to save itself from detonation or the fuel system not being able to keep up. I am usually the one saying that low boost with no tuning is POSSIBLE, not advised but possible. Some people like to say things like "impossible" and I have the bad habit of needing to correct them and at the same time it looks like I'm telling you to go do it even if i say "not advisable."

Whether your car can handle it is the result of many factors, engine condition, fuel grade used, condition of fuel system (injectors, filter, pump), turbo size, etc.

Even little stuff like how well the injectors flow can make a huge difference, if your injectors are partially clogged or just not flowing as much fuel it might not have a problem flowing enough fuel for stock demands, but boost + no tuning is pretty much maxing out your already straining fuel system; You see where I'm going here?

Big things are, make sure your running 93 or higher (if your not running 93, slap yourself then sell your car), make sure all your fuel/spark related items are cleaned/new/or in real good shape, and make sure you reset the ECU.

If your car still can't handle it, don't fight it, some cars can and some cars can't. Lower the boost until it can handle it or just buy some tuning gear and do it right.

Yah, my car did it, for a long time, 5psi daily with accidental spikes as high as 7-8psi, i got lucky, see the fine print, results will vary. I was doing it with a pampered engine that had like 30k on it, Mobil 1 since i bought it, regular FULL fuel system cleaning (not just fuel cleaner additive), sparks changed every 1500-2k, new TPS, clean MAF, etc, etc, the works.

I'm not recommending anybody run boost without tuning, as you risk a hell of a lot of engine damage to save a few bucks, and it's far from a guaranteed thing, it's really a toss up.

Ericy321

Ive got 3psi on my setup right now completely stock fuel and it still cuts a little bit. Im sure thats what you are experiencing. At 5psi though you may be able to get away with just raising the Fuel Pressure some but if you have the SMT ready to go then go for it.

sleepertib

Well thanks for the input guys. Alex, you DID say not adviseable and I certainly wasn't trying the pin anything on you as you made it more than clear what the consequences could be. I understand that you never said that I should go ahead and do it. I can even pull up the old thread just to prove to people that you only said it was theoretically possible, and that you in no way tried to convince me it was the way to go, so sorry if it sounded like I was blaming you or something cause I certainly wasn't. I just wanted to see if my car could handle what yours did, which it obviously cannot, and i'm not going to try to push it to.

Anyways, I am currently running 93 octane as well as the BKR7 spark plugs to help a little with avoiding all those predetonation woes. Ericy was good enough to cut me a pretty decent deal on an SMT unit. So like Alex has stated, it is a better thing to tune it to be safe than risk a crap load of damage just to cut costs. So starting today, the SMT-6 is going in. Thanks for the tips and help Alex and Eric, I appreciate it. I wouldn't be anywhere without the advice you guys have given me up until now.

Oh yeah, any advice on how to learn to use the SMT? Or is it just learn as you go and don't do anything stupid? Thanks guys fing02.gif



well here's a pic of my setup if it'll help anyone in deciding what my problem is. Either way I'm getting it tuned before I go and drive anymore, but the idea that my MAF is in the wrong place has been brought to my attention, as well as the idea that maybe I should be recirculating my BOV. Any ideas/opinions?

tdonnell

How is your maf in the wrong place? Looks fine to me other than the possibility of the quick 70 degree bend right after causing problems. I wouldn't worry it.

As far as the --, that probably means the a/f ratio is lean beyond the units ability to read it, so more than 20:1. Definately do NOT let this happen again!

So have you tried putting the shifer into 1st and pulling all the way to redline without a shift?

What happens at what rpm?

BTW: Clean install!

DTN

This is just theory, but can someone answer this for me?
We don't have a barometeric pressure sensor. The MAF sensor is designed to read air flow based on air temperature with no elevation compensation. Being that the ECU is unaware that the engine is receiving presurized air, it reads it as normal hot air, when actually, much more warm air is being passed through then the MAF sensor can read. Could this be causing the lean condition, and would relocating the MAF to the atmosphere side of the turbo be more sensable under boost with the exception of a rich condition when the butterfly valve is closed and boost is venting through the BOV?