knock sensor vs. bad bearing in power sterring pump.

[freefly-j]

First off, I have a 93 twin turbo which I love + hate. Love it when it runs right, wish I had smaller hands when it don't. Anyway, here is my problem:

When I get to 3500+ RPM the engine starts to sputter as if the timing is off. I have read that the knock sensor will retard the timing if it detects a knock or a vibration if you will. Is it possible that the vibration from a noisy power steering pump could affect the knock sensor???

I have done some mods to the car, pettit intake, pettit power pully mod, pettit cat back exhaust, down pipe, high flow cat (mid pipe section)9.75lb flywheel, boost gauge {runs 10-12psi then drops to 4-5psi when 2nd turbo comes on line then slowly back to 10psi (getting both new turbo control solenoid to hopefully fix, checked vac & pressure to accuator both ok.)}, A/F gauge which reads rich at idle, fluctuates between rich and lean during closed loop and goes rich after 3200 rpms or so.(Measured .82 -.9 volts from O2 sensor under load using multi meter.)

Anyway, this is my sticky situation that I am trying to get through. I am going to get a new PS pump soon to eliminate the possibility of it setting off my knock sensor, I am just wondering if anybody has had a simular problem or if you have any idea of how sensitive the knock sensor is?

Thanks in advance for any input ;-)

Freefly

[D3rELiC]

got any kind of engine management ?
and ive never heard of knock sensor being messed up by the power steering pump. it must be something else, maybe a vaccum problem or bad turbo transition?

[freefly-j]

Nope, stock ECU but I'm looking at apix power fc. A/F looks ok still though, if I was short of fuel it would go lean as it started to sputter would it not?

[freefly-j]

PS. I work nights, going to bed. Will check replys tonight around 6 PM.

Thanks,

Freefly

[D3rELiC]

your engine will blow before the A/F reading turns to lean, its just not accurate at all.
the only good thing to have to know if your lean is a wideband o2 sensor, but it cost alot, some ppl also use EGT to get fast reading.

i'll explain something if you dont mind
your engine setup doesnt have a MAF (Mass Air Flow) sensor to calculate how much air is entering your engine, it has a MAP (Manifoil absolute Pressure), this MAP will correct the air:fuel ratio according to the air/gaz/water temp AND with the TPS (throttle position sensor) that means if you get a less restrictive exhaust and intake, the engine will receive more air than its supposed to do, and the fuel system wont react the same has it would if it was controled by a MAF device like so many other car.

this is the exact reason why you need engine management when touching to your exhaust betwen the cats and the engine. you now run too lean and risk to blow your engine.

the rule of 3 is applied here, its not safe to go further these 3 mods without engine management : intake, catback and downpipe
that might be why your knock sensor is retarding the timing, because your car runs lean. dont fuck your engine, get that apexi power FC as fast as possible. i wouldnt even run the car, you are increasing your engine's wear as you run too lean, it heats up inside and you'll end up popping a seal or cracking a waterjacked

and consider upgrading the radiator and have a hose job done...

[freefly-j]

Forgot to mention that, I have a aluminum radiator and also the vac hoses have been done.

If I install the stock intake, would it be safe to run with the exhaust the way it is until I get a FC?

Also, does the check engine light come on if the knock sensor detects a knock? (My check engine light is not on so I don't know if the engine is detonating or not.)

You mentioned that the O2 sensor is not sensitive enough to detect a lean condition before the engine blows. When I monitored it with a meter the voltage went up from .82 to .88 even .9v. My auto meter A/F sensor also shows it going more rich on the scale so I don't think it is leaning out but I could be wrong.

Thank you for explaining the MAP system, did not know how that worked exactly.

[D3rELiC]

maybe its the injector stagging,
bring the car to a rotary specialist, dont change uselessly unbroken parts..

[D3rELiC]

maybe the o2 sensor is bugging
does it happens only when the car is cold ?

[freefly-j]

No, it happens all the time I believe. I don't rev it above 4k before the temp gauge shows normal operating temp. It happens in all gears too. I sneak up on 4k in 3rd or 4th (depending on where I am) and it starts to sputter sputter sputter. After the 2nd turbo has come online and it's boosting 8-10 psi at about 5500 - 6k rpm it seems to get a little better but it still sounds like it is missing. in first gear full throttle it gets over the 4k - 6k gap alot quicker but that is where it seems to be the worst.

What do yu think about the idea of installing the stock air box for now??

[D3rELiC]

i think if your problem is that your engine runs lean, it wont do much. you'd better put your cats back on.

[drftk1d]

i was looking at a 93 turbo a/f map and at idle its supposed to be running approximately 13.5:1. so the wideband 02 is a good way to go. if your motors running lean, well...
its probably a vaccum problem; the turbo is supposed to go 10-8-10 (8 being the changeover).

maybe i should shut up since i dont have a 3rd gen.