Low Boost

[GreedyTurbo529]

I was driving my 94 TT hard on the accelerator today a few times, about 5 separate time from almost a dead stop. The first few runs I did everything worked the way it should. Boost gauge was reading 14psi even tough Im on stock boost, turbos worked, car was doing what a 3S should. But out of no where, when Im on the throttle, the car sputters, boost gauge drops all the way down pops back up to the top, and does that twice really fast within a second.

So I let off, originally thinking it was the Y pipe. But no. Y pipe didnt pop off. And now my gauge doesnt read anything at all when it should be at -7 and it doesnt go up to 14 anymore itll go up to about 8 then very slowly make its way to 12 then stops. And the car is acting normal, other than it seems like Im running off one turbo. Ive looked ath all the vacuum lines, and the turbo pipes and they all are where they should be.

Im not sure where to start searching, Im still new to turbos. Advise?

[GreedyTurbo529]

BTW it has been surging at low boost as of late. if that helps.

[YoshiBishi]

I'm assuming this is all stock? The stock boost gauge doesn't give you actual PSI, just engine load. Therefore, it probably isn't actually 14psi. Do you have ECS on your car? I had sputtering issues as well and it was the ECS module messing with my ECU.

Does your ECS work? I disconnected mine and it fixed the sputtering issues, but this may not be the same problem you are having.

3SX Performance - 3000GT / Stealth ECS Control Module*-*Mitsubishi 3000GT*/*Dodge Stealth Parts

A lot of us with TD04 turbos have surging at low boost . I'm not sure how to fix that either.

[GreedyTurbo529]

Yeah its all sotck, except for a few boltons K&N filter, Flywheel, Tien S Techs, ect. I know the stock gauge is dumb but its usually consistent for when it reads and now its all weird. I do have ECS and it does work. Why would ECS mess with the ECU? Just a minute ago, before I saw your post, I unhooked my battery so stuff can reset. Well see if that works.

[YoshiBishi]

The ECS sends garbage signals to your ECU which basically confuses the hell out of it. Then it doesn't know what to do, so it flips out. My ECS was working fine, and then the stuttering started. A few days later the dreaded Tour Sport flash started. Then the stuttering got worse. Finally after I unplugged it, it fixed it right up.

It is worth a shot, very easy to do and is easily reversible, just plug it back in if it didn't fix it.

Hopefully some other people will have more ideas =).

[dpartinvr4]

this sounds like his MAF is screwed up, try unplugging and replugging it?

[GreedyTurbo529]

Be great if I knew what those were, lol, I know what wastegates are. Ive never messed with mine but I know the general location. The actuators are a different story. Isnt that the thing bolted to the turbo housing? How do I pull them off, if need be? Looking up info on that now. Just figured Id ask.

[green-lantern]

Stock boost gauge? I don't think they even work off actual pressure.

You need to pressure test the IC system. It sounds like you have an intake leak. Something popped off the plenum or you have leak at the gasket, that's probably why your not getting any vacuum in the plenum. Or your PCV hose popped off the intake.

[dpartinvr4]

Stock boost gauge? I don't think they even work off actual pressure.

Correct, the stock "boost gauge" is actually an "interpenetrated load gauge" the ecu takes the maf reading, and displays it as what it thinks the boost should be.

[green-lantern]

Correct, the stock "boost gauge" is actually an "interpenetrated load gauge" the ecu takes the maf reading, and displays it as what it thinks the boost should be.

I thought so, never had one in my car lol.

I'm still willing to bet a bunch he has something leaking between throttle body to engine.


or he has broken ring lands

steve