MazdaSpeedDan

iTrader: (4)

Ok as you all know the person who rebuilt my motor accidentally put 1300cc injectors in the motor which was why I could not rev past 4k rpms and I was only getting a few PSI . Well it had no turbo restricter pills is what I beleive my mechanic told me, so got that fixed.

So on my stock ECU the car will only pull 8psi, Hook a Power FC up to it and it runs 10 PSI........Thats just doing a 1 for 1 swap, not changing anything with the engine.

The only code that comes up is a bad knock sensor. I have looked but cannot find if the knock sensor can change the boost pattern if its bad, has anyone ran into this problem or has any advice? Im trying to figure out if the knock sensor is directly related to the boost issue.

TLR
Stock ECU= 8psi
Power FC =10psi.
Bad knock sensor.

RotaryEvolution

iTrader: (30)

iirc, a knock sensor fault will retard timing 10 degrees until the code is repaired. usually the code is set due to the wire pinched, sensor connector swapped with the power steering switch(yes they are identical plugs) or a faulty patch job on the wiring grounding out on the shielding of the wire inside.

the PFC does not have a correction for knock, it's a simple reading.

zeroG

iTrader: (28)

Just to clarify something: The size of injectors in your car, has nothing to do with the cars revs or ability to boost. The restrictor pills do, if they're missing the boost will be low, 6-7 psi max.

To answer your question about the knock sensor, no, a bad knock sensor does not affect boost. A knock sensor will retard timing when it detects excessive knock. It's a preventative measure to not blow the engine, but it doesn't have anything to do with boost.

MazdaSpeedDan

iTrader: (4)

Yeah I know that, It was the turbo restrictor pills that was causing it low boost. That was fixed and now Im scratching my head as to why when a PFC is hooked up it runs fine but when stock ecu is its running @ 8.

I am just dumbfounded.

RotaryEvolution

iTrader: (30)

try fixing the knock sensor code. i semi recall the one car i had that was throwing that code ran like ***, but also had a munched front harness with an intermittent map sensor issue so may have been unrelated.

severely retarded timing will cause low/laggy boost and response, i just don't know if or how much it retards timing when that code is present.

MazdaSpeedDan

iTrader: (4)

I think I read in the FSM it was 7 degrees, but never said anything about boost issues. But you never know with these cars

Bowtie7

iTrader: (8)

.059 pills are installed in both hoses. Pills that were in it originally were big enough to drive a truck through as they had been drilled. Knock sensor wiring appears to be good. Code only sets for open or short and FSM does not show any kind of failsafe other than retarded timing. Anyway, I'll keep plugging away at it.

Bowtie7

iTrader: (8)

OK, It is fixed. Knock sensor in car was open circuit, confirmed with dvom. Good knock sensor read between 59-61 mohm. Knock sensor in car was open circuit. Snaked in a good used sensor and performance is back.

Now that performance is back, it is really evident how awful the suspension is!!!

MazdaSpeedDan

iTrader: (4)

Nice! Thanks!!

MazdaSpeedDan

iTrader: (4)

Ill work on the suspension after my next tour, I have a feeling its going to take some $$$ haha.

ppritchard

Did you have any trouble getting the knock sensor out?
Where did the wire plug in, can't tell from the fSM.

Same error issue as you had.

thanks