when the car is cold it boosts fine, but once warm it breaks up at around 5krpm when the gas pedal is more than 1/2 way down and can't build ANY boost.

does this sound like a bad fuel pump or an ignition problem?

 

When was the last time you changed the plugs and wires? Could be as simple as a loose spark plug wire.

 

i'm going to replace the plugs as soon as a store opens up so i can buy them.


something else i notice, once WARM with the accelerator fully depressed in neutral it revs to around 5k before breaking up, my narrowband pegs out LEAN during this condition.

also when the car is cold it CAN rev to redline and build boost at 100% throttle, this problem only arrises after running for a few minutes.

if it were an ignition problem wouldn't i peg out rich due to the unburnt fuel?

also the best i can tell its either a secondary injector problem or fuel pump problem.


fuel pump is a walbro 255lph, wish i had a guage to check fuel pressure...

 

An oxygen sensor will read full lean during a misfire.

 

damn..ok i'll wait for new plugs.

 

ok new plugs are in, was still the same problem.

i unhooked the wastegate door so it would essentially not build as much boost and the problem is still there even only building 1 or 2psi.

also i unhooked my MAP sensor in the engine bay and this had no affect on the performance of the car, is this normal?

 

Fuel filter is good? Can you check the voltage your coils are getting?

 

any vaccum leaks?? sounds like an intercooler hose popping off or something...

 

i've got a system for pressurizing my intake tract, and i think i've gotten all the boost leaks under control.

fuel filter is recent, i'll go check my coil voltage.

 

double check to see that your BOV isnt opening...I had this same problem and I traced it back to a leaky BOV.

 

it might be possible, i'll give it a look.

im using a stock mazdaspeed protege BOV routed back into the stock TID behind the AFM.

 

ok...2 questions.

first one, i have red injectors, does this mean i don't need an injector resistor pack?

also what color are the wires that plug into the stock boost pressure sensor?

thanks!

 

Does this happen when you free-rev the engine as well? Might be a CAS wiring issue that is caused by heat. Check the CAS, plug, harness, etc.