Quick: Car will run fine for around 30 min and then all of a sudden starts misfiring/stalling at idle and when pushing the car. Here's the issues i pretty much notice . .
Quick note....
Vacuum at idle = -18 to -20 (depending on what the idle is at)
Boost holds all the way to redline when car isn't misfireing
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Info:
94 Blacktop
Nistune Daughterboard
740 Nismo injectors
Z32 MAF
Nismo FPR
Walbro 255
GT2871 64 AR
HKS Wastegate actuator
Apex-i ACV-R
WideBand gauge and sensor
NGK BKR7E @ .032
NEW coil packs
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Issue:
Car starts up fine
Drive around for 30 minutes and get to operating temp
Car will begin to start reading lean on the Wideband
Car will begin to misfire/stall and read VERY LEAN (15 -17:1)
As car stalls I have to give it WOT to keep it running and during this time, it sounds like cylinders are misfiring (almost like a WRX engine)
Once car completely stalls, I am unable to start car again (must wait like an hour before starting it again. Even then, it barely runs and is misfiring like crazy)
What I've done:
Coil Packs: Replaced
Spark Plugs: Replaced (even gapped smaller to .028)
Walbro 255: Replaced
Fuel Filters: Replaced
Z32 MAF: Cleaned and checked connections
Coolant Temp Sensor: Replaced and checked resistance. all within spec.
What I've checked:
Z32MAF - Possibly Dead?
- Igniton on Voltage: 0.42
- Idle Voltage: 1.1 - 1.2
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My Link for instructions
TPS- Seems OK
- Closed: 0.52
- WOT: 4.2
- ECU correctly shows 'throttle closed' flag when throttle closed
- FSM states 0.4 CLOSED - ~4.0 WOT
FPR- Could be bad
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Found instructions for testing FPR without a gauge. Thoughts?
Fuel Pump
- Fuel pump is working and has full 12V (direct line to battery with inline fuse)
Ignitor Chip: I do not know how to test this. I looked it up and the directions didn't match with my chip. My chip shows "22020-50F00" for part number. On one side it shows E1,E2,E3,E4 and on the other side it shows (I1,I2,G,I3,I4).
FPR: I thought this could be it, and will be purchasing a fuel pressure gauge soon to run inline before the fuel rail to see if I'm losing pressure for some reason.
So...
Ignitor Chip: It could be that the ignitor chip is getting to hot (operating temp) and failing at that point. This would explain why I can drive it in the morning without problems, but after about 30 minutes it starts having the misfires and stutters and then just dies.
MAF: The readings seem low for the MAF. I could also see this being the problem as more air is getting through than the MAF is reading which is causing the lean condition I see on my wideband.
Fuel Pressure: Clogs in the fuel filters/flow could be causing the starvation and thus misfires and stumbling. I already replaced all filters and pumps, but the problem still stands.
Any help at this point is greatly appreciated, as I've basically gone as far as I can think of. I have Nissan Data Scan I and used it for logging the ECU while driving to capture if any sensors were going crazy. This looks to be unhelpful at this point. I have the logs if anyone would like to look at them.