Yesterday night, everything was working perfect. But tonight, as soon as I press the gas pedal a little more than usual, I lose all kind of power. I mean, when the car is supposed to start boosting, it doesnt just accelerate slowly, it litteraly decelerates.

its the 5th time i drive my FD since I bought and I've never pressed the gas pedal more than like an inch so far. I was waiting till all of my maintenance work was done to start driving like a man. but I know for a fact that the turbos (at least the primary one) were working, because sometimes I would press the pedal a little too far and I would feel the boost kicking in and I could hear the BOV when I let it go. Only tonight, it started decelerating instead of boosting...there is no special noise, it just feels like I release the gas pedal instead of pressing on it. It happened 2 times in a row, and then I stopped trying just in case. I thought it might be detonation or something, but I actually have no clue of what detonation sounds like as I have never had a car with engine donating or been in one.

the idle is perfectly stable and as long as I drive softly, everything runs great, no weird vibrations, no noises what so ever. I drove back home for about 30 minutes and everything was running smooth, exept I didn't even try boosting. I'm gonna install my boost gauge soon to see what kind of vacuum it pulls at idle.

Any ideas of what my probleme could be?

 

Is there a "check engine" light on the dash? Do you have a boost guage? What you describe sounds like Limp Mode.

 

i had the same problem and it was a vacuum line under the UIM... check it.

 

There is no CEL and I'm gonna intall my boost gauge today.

The vacuum line under the UIM, that means one of the thousands rubber lines on the rats nest?

 

on the boost gauge I see about 400-420 mmHg vacuum on idle, I guess that's fine. I tried to pull out the codes and got nothing.

I'll take it for a spin and see if it does it again

 

400-420 is ok. A little low if it is @ idle rpms. Ideal is more than 460.

Turbo trouble shooting is always a Pita. Possible solution is also a broken check valve. Only way to test easily is to have a boost gauge and check for 10-8-10 boost pattern.

 

edit

 

This is a long shot, but could it be a slipping clutch?

 

it was limp mode, this afternoon I had to unplug my battery to work under the hood and the ECU reset, and now everything works fine, boosting good and everything.

Now what I'm wondering, is what caused the limp mode. Because it might happen again...and I dont want to damage stuff

 

Limp mode could be caused by a solenoid problem. You have ZERO cel codes????

 

there are a couple of things where the ecu will get a limp home, and no CEL. it should still store the code though

 

I tried to check for codes, bridged TEN and GND, then plugged a small light bulb between FEN and B+ (it's a JDM). Got no flashes at all...

is it possible that the gar gets into limp mode for no good reason?

 

You don't need a light. The check engine flashes in pulses.

 

it's a JDM, I don't have a CEL

 

ok I got another shot of limp mode today, now I'm starting to be worried...

Just wondering, my battery poles were losse (I went to buy new ones today) and they kept disconnecting while I was driving, so I had to put them back on when I wanted to start the car again etc. Is it possible that this was causing the limp mode? I mean the ecu resetting like every day or two..

 

No, battery poles won't put you into limp. I'm not familiar with the JDM cars, but there has to be a way to pull stored codes. That's your first step.

 

I'm no mechanic, so maybe someone can figure this out here.

My car exhibited this same EXACT symptoms (the more I pressed the gas,,the slower it would go...very dangerous to drive!) after the body shop (at the Mazda dealership) had put my car back together (yeah right!) after I'd been in a collision on 02/23/1999....yeah I remember the exact date (lol). They had the car a 2 full months...about 8K worth of damage.......a guy hit me from the back, and I then slammed into the car in front of me...damaging the passenger front of the car...headlight/directional signal area.

So I took the car into Mazda..it was still under factory warranty...and even though it took them 8 hours to fix it...they weren't sure exactly what they did. They just told me "we found some frayed wires in the area behind the directional signals/right headlamp, and we just twisted them together and it stopped doing it!"

Maybe this layman description will give the experts some idea what to have you checked.

 

I'm having a limp mode issue myself, and I think the very circumstance you're talking about is what's happening to me. I'm ruling one thing out after another. I'm changing my management system in a few weeks and replacing my harness. I'll try to remember to come back and relay any info that I attain to help Benji out. If changing the previously mentioned items doesn't better my situation i'm willing to bet its the other harness that goes along the front of the car to the drivers side wheel well.