engine lag

[craigb]

I have a 1984 t-type. If I accelerate slowly, I have no problem, but if I accelerate hard as soon as I reach about 2 psi of boost the motor bogs down and if I hold it pedal there it will stall, but if I release the pedal the engine will be fine, and I can accelerate again but not hard. Any thoughts as to the problem would be great.

[Keller]

Likely a fuel control issue of some sort.

- What is the mileage of the car?
- What injectors are in the car? Have they ever been removed to be cleaned?
- What fuel pump is in the car?
- What chip is in the car?
- What exhaust is on the car?
- Does the car still retain the catalytic converter? Is it original?
- Do you have a scan tool?
- Do you have a fuel pressure gauge?

[PaCemkr86]

is the check engine light on ??

[craigb]

The engine was rebuilt 2yrs ago . It has less then 5000 km. the injectors are new this year 42.5 lbs. The fuel pump is new last year walboro 340 I beleave along with up graded wire harness to pump. I have a performance chip from turbotweak. Lt-1 800 cfm maf with translater. cold air induction. No cat. 2.5 inch exhaust. fuel pressure is adjusted to 42 lbs. The check engine light is not on.
Is it possible that the fuel sock is collapsing under hard acceleration, but not under slow acceleration?

[Keller]

The Walbro sock does not really have collapse issues.

Have you run the FP gauge during WOT so see if it goes up with boost?

Is the chip cut for the injectors?

I assume you are running an 86/87 ECM, correct?

The Translator may need some fine tuning to insure it works with your combo correctly. You have a lot of fuel and air potential for what I assume is a stock 84/85 turbo.

[craigb]

The chip was cut for the size of the injectors. The translater is set at maf base #1 3.5" lt1/ls1 maf sensor (richer at idle) 2% rich at WOT. The ecm is a 86/87. the car will not reach WOT before the engine dies. The fuel pressure is stable then begins to rise as the turbo begins to build then about 2 psi the engine bogs down.

[Keller]

The fuel pressure is stable then begins to rise as the turbo begins to build then about 2 psi the engine bogs down.
Can you clarify the fuel pressure behavior? Does it raise 1 PSI for every PSI of boost? Can you clarify or explain the "2 PSI" comment?

You never answered whether you had a catalytic or not. Or if it is original.

[craigb]

no the car does not have the catalytic anymore. as the accelerates the boost builds to about 2 lbs of boost then no power.

[Keller]

Stock boost gauge or aftermarket?

Sounds like you have a massive air leak or a failing turbocharger.

[pfredricks]

Have you checked your coil pack?

Which coil pack are you running, stock 84 or newer 86/87?

Do you have a coil pack that you can swap for testing?

[craigb]

The coil pack is the 86/87 and is brand new. I just replace the tps thinking that might be the problem but it made no difference. if it is a massive air leak where would the leak be? At the turbo and the intake?

[craigb]

the turbo inlet adapter. does anybody know who might sell them or the o-rings for the adapter? I had some leakage at the up pipe that is now fixed. thanks for the suggestion of it being an air leak.

[craigb]

Thanks for the suggestion of the major air leak. The turbo inlet adapter o-rings are shot and the bearings in the turbo are toast. Where can I get a large turbo for my car?

[Keller]

Any of the major turbo sources should be able to help you. (i.e. Precision Turbo and Engine, Limit Engineering, etc.)