Slight Hesitating Issue!?!?!
#1
Slight Hesitating Issue!?!?!
Car’s been hesitating quite a bit lately at steady rpm cruising; hopefully someone can diagnose the problem or tell me where to start looking. It’s not a violent hesitation but very settle; be driving at say 50mph and you feel a little sputter (doesn’t sound like a misfire) very lite jitter jitter jitter (gradual and most of the jitter feel is threw the gas pedal) will clear up and do the same again. Now if I drop a gear get on it seems to clear up. Anyone?!?!
Not sure if it's related but replaced the o2 sensor little while ago and seem to have cold start issues. Starts fine but sounds like the motors getting flooded and more you press the gas the more it dies. Then will clear up go again. Same thing if I get on it or get it up to operating temp doesn't seem to do it.
Dunno?!?! Maybe a bad o2 sensor, MAF, Coilpack, Something Fuel Related (Pump, Filter, FPR, FMU)?
Specs:
90 Miata 1.6L
Greddy Turbo Kit (stock)
TurboXS BOV (atmospheric)
Olderguys o2 Clamp
8.5 Magnacore Wires
Denso Plug (one step cooler that stock)
Not sure if it's related but replaced the o2 sensor little while ago and seem to have cold start issues. Starts fine but sounds like the motors getting flooded and more you press the gas the more it dies. Then will clear up go again. Same thing if I get on it or get it up to operating temp doesn't seem to do it.
Dunno?!?! Maybe a bad o2 sensor, MAF, Coilpack, Something Fuel Related (Pump, Filter, FPR, FMU)?
Specs:
90 Miata 1.6L
Greddy Turbo Kit (stock)
TurboXS BOV (atmospheric)
Olderguys o2 Clamp
8.5 Magnacore Wires
Denso Plug (one step cooler that stock)
#8
This is the same problem as what I was having when I first got my turbo installed. It turned out that I needed to open up the afm and clean the contacts, it will read in spec, until you tear it open and start moving the wiper along the rheostat, at that point the resistance values jumped all over.
#17
Boost Czar
iTrader: (62)
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,507
Total Cats: 4,080
Throw a FP gauge on it and see how it reacts under boost.
should be:
35psi at idle.
50psi at 0~hg. (recreate this by removing vacuum line to FPR)
With the 12:1 vortech the FMU should hit your max FP output at full boost while driving.
or written as 12 (ratio) x (boost) + 50 = PSI
To test the output of the pump:
Turn your Miata to ON but do not start it. Open the diagnositics box and put a paperclip on F/P and GND. That will run your fuel pump. With a pair of pliers, squeeze the return fuel line shut that connects the FPR to the original fuel pressure regulator. When squeezed shut, the pump will be forced to maximum output.
should be:
35psi at idle.
50psi at 0~hg. (recreate this by removing vacuum line to FPR)
With the 12:1 vortech the FMU should hit your max FP output at full boost while driving.
or written as 12 (ratio) x (boost) + 50 = PSI
To test the output of the pump:
Turn your Miata to ON but do not start it. Open the diagnositics box and put a paperclip on F/P and GND. That will run your fuel pump. With a pair of pliers, squeeze the return fuel line shut that connects the FPR to the original fuel pressure regulator. When squeezed shut, the pump will be forced to maximum output.
#20
Well got some time today to take the AFR out an clean it. Looks brand new inside but clean it anyways. Took it for short drive and seem to be worse. Cold start issue deal again. I sat and the end of the neighborhood tring to clear it up. If I touch the gas the rpm's drop almost to die instead of going up. If i sit there and get it out of the stumble and hold the rpm's steady at 2.5k or so it's intermittend. It will start to do the stumble drop rpms, come back up. Just putt it in first and nailed it high rpms or full throttle pulls i have no problems. It's gotta be timing, but don't understand why greddy would provide a FMU that would flood the car due to the retarted timing it calls for. Then again maybe i'm wrong.