Well, changed the throttle body and its better, bout 75% of what it used to be. I can boost now; it still has some slight stutters and it still has some idle issues; but I still have the CEL to deal with. Once I fix that sucker I should be good.

 

All I can tell you is get rid of the unichip, plain and simple, I have worked on a few alpine kits in hyundai's and they all had the same problem, the supplied unichip tuning just sucks and the stutter is a result, the bigger throttle body just makes it worse. I run the emanage now with 380cc injectors in the rail and still use the fifth injector and the car has ran great ever since. Trust me on this one, all your problems lay in the tuning of the unichip and you will be waisting your time trying to work around it, I tried everything to get rid of that problem, You would not beleive how much better my car ran when I got rid of the unichip, both power and all around drivability have improved greatly, if you drive my car you would swear it came from the factory turboed, so smooth.

 

Whats odd is the car ran fine beforehand; first few weeks the car was running pretty well for a rough-tuned car.

Either way, I have a Unichip tuner relatively near to me so I'll probably try that first.

 

Did you try to reset your ecu, that always made it a little better for me, for the first year i had the kit in my car I rigged up a power switch to the stock ecu so everytime I shut the car down I could kill the power to the ecu as well to reset it, it would run fine for a few days the the ecu would begin to learn around the unichip again. From what I understant the unichip is a great piggyback, it was just my luck there was nobody around to tune the thing so I never got to try that option and I hear it's not cheap, there was a guy about 5 hours away in PA but he wanted $250 just to hook the car up and $100 per hour afterward and he didn't even have a dyno, he said he road tunes with a wideband, I said no thanks.

 

Yea, it does run a bit better with the ECU shut off for a few cold starts, then it starts to become aggrivating again.

From the research I've done on the internet, it seems to be expensive like you said, like $350ish for a full road tune and dyno time as well, but the Unichip does have a lot of tuning points.

Some guys swear by it; Alpine reflashes it themselves so I guess the maps they use are iffy.

Basically my code is P0121; meaning my MAF and my TPS are not agreeing. So either the TPS isn't working properly, or the Unichip's clamped signal of the MAF is messed up.

On a side note, at about what temperature can that MAF stand? My setup is basically Turbo -> 4inch long coupler -> MAF -> Filter at the moment... so I'm sure it sees some decently high temperatures.

 

ok with ur first problem is because its MAF... the reason i say this is because if you build boost slow the MAF can read and record the amount of air coming in, when u just get on it and throw 8psi (or what ever your running) at the MAF it cant read it fast enough and your prob leaning out your engine A LOT, which causes misfires....BUT if u have an A/F gauge and its not seeing lean, or you have a MAF off a car that was designed for boost or massive amount of air (such as T/T 300Z) then my theory is probly incorrect. In which case it ALL comes down to tuning! what MAF do you have?

 

^^ I don't think so my friend. wink1.gif

Do you have facts to support your claim about the MAF not being able to register boost "fast" enough? I have proof that isn't the case.

 

Everyone and their mom running a turbocharged Tib thats not converted to MAP is running the stock MAF sensor.

The car is running lean when making higher boost pressures at the moment; don't need a gauge to tell me that much. I don't have access to the scan tools here at college to trutfully diagnose this problem (HMAServce wants me to check the % the throttle is open at idle, etc.), I do have an ohm-meter and will check to make sure the wiring is grounded and working properly, although the chances of wiring not being good probably isn't going to happen, although it seems possible.

The car ran well the first few weeks, and has slowly degraded downhill with a few upsides every now and then when I work on it. I'll take it somewhere with the proper scantools this weekend if the wiring turns out ok and fiddle with it once in a while. If the clamped MAF signal is whats causing the problem, then the Unichip has to go.

 

Ham,
i know exactly why you're having the p0121 code..
tps and maf voltage don't match that's all

some guys will have the code everyday some won't have it for years, depends a lot on driving style and on turbo spool up time

the turbo box we made can help fix that but i'm not sure if the unichip could control it, worst case we'd have to build a "standalone" version for your case

 

Aha, so really nothing I can do about it then most likely. I'll still run through and test the system just in case.

Does it cause any other issues besides the obvious limp mode in the ECU (which I can get the Unichip tuned to compensate with anyway)?

My funny lil idle stall issues (the car hates "cold" starts even though its about 50 degrees outside) and "pop"ing issues (aka timing seems to be off) related to that code, or should I be focusing somewhere else (even though I don't know where else to turn at this point as I've went over about everything)?