jeff88

I just bought a 90 TII with 113xxx miles, i had the compression tested and it is 85-90 psi and even bounces. According to the autometer boost gauge it is making about 7 psi of boost. The car has the complete racing beat exhaust, an unknown brand cone filter, fuel cut defenser, kenne bell fuel pressure regulator, fuel pressure guage. There are all the mods I can see, not sure if the injectors are stock or the fuel pump. I am assuming they are because I have the installation receipts for the above mods.

I think there is a pretty good vacuum leak somewhere that I am having a hard time finding. Should I hear hissing or sucking noises near the intercooler when the engine is idling? It idles roughly too and will sometimes stall. I just replaced the plugs and put on ngk wires, changed the oil+filter. What is the best way to find a vacuum leak? Brake cleaner work? I don't want to get everything oily, or rot the rubber hoses.

Also a few times the engine will basically stop making power between 5000 and 6000 rpm. It just stops reving and just kinda bogs. Feels almost like a rev limiter. Could a vacuum leak cause this also? Dirty injectors? If so what is the best in tank injector cleaner?


Thanks for all responses.

bkapold@aol.com

could be alot of things....Get new fuel filter, plugs and check your TPS....If it has any kind of intake leak it will run like **** and or stall.....Check the "S" tube going to the inlet of the turbo and poke around for leaks...You may hear hissing....If the car is cold spray carb cleaner around the area and listen for idle changes.....Water is safer

Barwick

I've had the same problem on my '90 TurboII.. it only boosts to 5.5 psi until it starts to creep. I'm 99.9% sure it's electrical. Either the duty solenoid valve wiring (the valve itself works fine), or the pressure sensor wiring TO the ECU, so maybe the ECU isn't seeing 5.5lbs of boost, and not telling the DSV to open.

jeff88

Thanks for the help guys

If it is not raining today like it has been for the past week I am planning to take apart the TID and the intercooler and try to find the vacuum leak and go from there.

bkapold@aol.com

I'm not saying it isn't a bad connection as the previous guy stated, but if it was you'd probably have a "check light" and would be easy to detect then. As I said, any intake leaks with a stock ecu and you will have idle boost problems.....7psi is pretty normal using those Inter heaters/IC. Your fuel pressure maybe to high as well. try 40-42psi. My guess is you have an intake leak after the AFM....

Josepi

I've had a similiar problem, turned out that the small hose coming from the rear passenger side of the IC had popped off, I had rough idle and lost a bit of boost. As far as hearing it goes, just use your ears. Move from side to side, front to back...just listen...kinda hard to describe. You could always invest in one of those things doctors use to hear your lungs and heart. Great for finding air leaks. As far as spraying anything onto hoses to check for leaks, use carb cleaner. It's combustable, so you don't worry about harming your engine. Just take it one part at a time. You'll get it.

jeff88

I am pretty sure i located and corrected 2 problems.

First was an air leak. It was on the pipe that shoots off the hose that connects the turbo to the intercooler. The hose connects to a metal fitting under the bac valve. It was cracked big time and the fitting on the hose going to the hose connecting the turbo and ic was broken right off. I fixed it with a piece of heater hose couple hose clamps and a couple of threaded metal fittings from the home depot plumbing section.

Second was the turbo inlet duct was cracked and was loose on the turbo i epoxied the crack and taped the hell out of it. It was only a small crack and it will hold till i can fab another tid. I also clamped it on tightly to the turbo intake.

Car idles good now. I just need to tweek the idle speed a bit.

But still not much boost max is about 7 psi on an autometer boost guage. The boost still bleeds off at about 5500 rpm and up.

I am basically new to turbo cars. I have had an NA for several years, but this is my first turbo.

Thanks again guys.