boostinfc3s

Heres my problem with my FC. At cold I can't hold an idle, and when its finally warmed up after 5-10 minutes of sitting there stepping on the gas pedal it idles between 300 and 500. Its driving me crazy cause i've checked all the possibilities i know of; Compression, vac. line leaks, and coupler leaks. On top of that, At times I can't go pass 5k rpm while under heavy throttle. It'll wind up fine all the way up to 5k then it'll act as if it hit a brick wall. It sounds like i'm just dumping a lot of fuel into the exhaust and its not getting ignited. I'm really stumped, so hopefully one of you FC specialists can chime in and help me out. thanks!

t24todd

iTrader: (7)

cheak injectors for leakage/TPS is out of wack/its idling way to low, stock they idle @700 but id bump it up to 9 or so.
need the year and model of car to give you more detail instructions on the matter

boostinfc3s

its an 88 tII

arghx

iTrader: (3)

did you pressure test it for vacuum leaks or just do a visual test? what modifications do you have?

eage8

iTrader: (9)

5000 rpm wall is probably fuel cut due to overboosting (overpowering the stock waste gate)

as for the idle, do you have the thermowax removed? post a picture of your throttle body if you can.

boostinfc3s

I don't think its fuel cut, but it sure does feel like it. I have a FCD. I have the TB mod. As for vac. leaks i just did a visual check. I'm going to change my spark plugs today and see how that goes..

eage8

iTrader: (9)

if you have the TB mod than that's the answer to your warmup problems... you took out the system that raises the idle when it's cold... (the thermowax, the thing with the coolant going to it)

do you have the stock injectors? they might be getting stuck open, I would have your secondaries (and your primaries while your at it) cleaned.

boostinfc3s

yea im going to have my injectors out as soon as i can get my hands on a s4 turbo mani so I can install my BNR 4 in at the same time.. so do i need to undo my TB mod or whats the deal?

eage8

iTrader: (9)

you can undo that part of it... leaving out the secondary throttle plates is fine.

there is no reason to get rid of the thermowax except for simplifying the coolant system, and being able to remove the TB and UIM without having to drain some coolant.

boostinfc3s

did someone ever write a DIY/tutorial on how to install the TB mod? the previous owner had it on way before i bought the car.

eage8

iTrader: (9)

if that's the case I would just try and buy another throttle body... you don't have the parts to fix it anyway. check the for sale section.

arghx

iTrader: (3)

I undid the previous owner's TB mod by just buying an unmodified one. It will probably still need to be adjusted however.

boostinfc3s

will the FSM show me how to readjust it to spec if i buy a new throttle body?

arghx

iTrader: (3)

It will show you but I had bad luck with the procedure. It tells you to measure clearances that are impossible to do accurately even with feeler gauges. I followed the procedure exactly and it didn't idle right--that procedure is for a completely stock car, remember? I just fiddled with the thermowax screw and the throttle stop screw until it idled right.

Magpie57

Start from the basics and go forward. Fuel pump delivering the proper preasure? Fuel filter not clogged? No rust in the fuel tank? Then go from there. The solution could be simple. Then of course go to the throttle body, injectors etc.. Good luck 13BTran. I'm interested in seeing what the problem and solution is, Mag

THEMOBBS

i had the same exact problem, had to due with not getting enough fuel. 1. i got a walbro pump 2. got an adjustable fuel pressure regulator 3. got my ECU mapped. runs great now
oh, i also changed my fuel filter, that thing was disgustingly old

HAILERS

FUEL AND EMISSIONS SECITON of the FSM.

Also it sounds like the BAC isn't up to snuff, what with the 500rpm idle.

Magpie57

OK 13Btran what ever became of this dilema? Curious is all, Mag

boostinfc3s

thanks for everyones help, the car is still as is until my manifold comes in from japan2la and i install my new turbo set up. If i fix it i'll let everyone know what the problem is. don't worry i'll keep you guys updated, thanks!