Odd power issue (not sure what to name it)

[jmatyas]

When i am driving down the road under no boost the car will act as though it has power then none. I will keep the pedal at the same amount of throttle but the car will give then let off over and over. Im thinking fuel or a ignition problem maybe.

Car info:
97 gst spyder only 50k miles
evo 3 16g turbo
pr fmic
cold air intake
few other minor mods.

Please help

 

[g4ebguy90]

I call it the *g4ebguy* effect. Does it act fine when on boost? or does it fall flat on its face and then take off?

 

[jmatyas]

When i boost it will hit about 5 to 6k rpm under light boost before it hesitates, but if i wot it will just hesitate and pop and shudder. No fuel cut though, thats what I thought at first.

Sorry for any spell errors, having to type quick at work haha.

 

[LandoAWD]

No fuel mods? What PSI on the EvoIII?

I'm guessing it's knock based on the sparse info...

 

[jmatyas]

The turbo is under stock boost right now, from the pipe to the wastegate. I'm afraid to go above that with the issues right now. Running no fuel mode that I know of, I was thinking it may be a bad injector.

 

[LandoAWD]

So...no boost gauge either, I'm guessing? Just the estimated boost on the factory gauge?

 

[jmatyas]

Aftermarket boost and oil pressure gauges, its reading 12lbs of boost. It holds at that no problem. I have tested for boost leaks and cannot find any more. I put on a 1g bov and that fixed my boost leak.

 

[josh1095]

would ecmlink show a loss of spark? im guessing it would. if you can afford it, have a shop hook up a datalogger and take it for a drive. that may tell you where the problem is. sounds like spark to me but thats a wild a$$ guess. keep us posted..

 

[Boostinsideways]

It sounds like the ECU is pulling timing to me. Knock maybe?

The only 3 possible things would be a lack of fuel, bad spark (out of time 1-2 teeth, bad coil, bad ignitor, bad plugs, etc), or your getting knock / phantom knock and the ecu is pulling timing.

 

[jmatyas]

Thank you all for the suggestions so far. Let me throw one more option out there.... Maybe a bad vacuum line? Just because it surging made me think of that. I'm trying to sell the car so ecmlink is not an option, even though it is an eprom ecu. I will be sure to keep you all posted, problem just started today.

 

[jmatyas]

Ok after many more tests we've done we are still scratching out head. Fuel pump, filter, injectors, etc are all in good working condition. Spark plugs were replaced and gaped correctly, new spark plug wires were installed. Ecu was swapped with my old one to see if that did anything, and sadly is still doing the same.

One thing I have noticed is that my spark plugs will be black and covered in gas after just a 5 mile drive. So apparently I am running rich, that may be part of my issue. I went out to try to find another boost leak and could not find anything on the soap and water test...I am stuck again haha.

 

[fretmelter]

If the BOV is not recirculated would that mean it would run rich?

 

[LandoAWD]

Buy


A



Logger

 

[jmatyas]

Any logger that you would recommend?

 

[LandoAWD]

What's your price range to know what your car is actually doing?

 

[ryanh1985]

Have you checked the O2 sensor?

 

[jmatyas]

O2 sensor should be ok, replaced it about a year ago. I'm not throwing any codes right now and last time my o2 went out a code popped but anything can happen.

I'm willing to spend what it takes to have this car in good running shape. I guess installing ecmlink may help me sell the car faster, but that's a lot of money to put in to the car here soon. At least I have an eprom ecu ready for it.

 

[612 Performance]

It sounds to me like you're having misfires, I would try checking compression as well as doing a cylider leakage test to see if you're losing some compression since you said that the fuel system is good and you replaced a lot of the ignition system.

 

[PieEyedPiper]

The problem is happening when not in boost.

Have you checked all the easy cheap stuff?
i.e. plugs and wires, etc?