AngryScientist
Probationary Member
- 4
- 0
- Feb 26, 2004
-
DFW,
Texas
Yes i searched "car wont rev" and read all 3 threads. That being said:
Ok, so here it is. The car has been sitting for a while, 6+ months. I started it regularly to make sure everything was cool, drove it around the block to make sure she ran ok under load. Thats the background right now.
Fast forward to now, I had installed a PLX wideband O2 and long story short it turns out I wired the narrowband emulator into the white KNOCK SENSOR wire instead of the white O2 SENSOR wire. Yes, idiotic move, completely idiotic. I discovered this today while trying to troubleshoot the problem.
What happens exactly is that the car will rev freely build 1-2 lbs of boost under 5k, but as soon as you hit 5k it starts to pop from the exhaust (sounds like the car is pulling timing perhaps) and the car simply will not rev.
So, ive unwired the NB emulator and i actually put the stock o2 sensor back in, and reconnected the KNOCK SENSOR wire (again, mistook it for o2). Ive verified the function of the o2 sensor with my blinky a/f gauge.
Ive tried twice now to reconnect the knock sensor wire i cut into, i thought maybe since i was using wire couplers it was introducing too much resistance so ive just twisted in a piece of wire and have the ecu sitting in the floorboard until i can get this sorted out.
I did some searching on the forums (dsmtalk, etc) and saw one guy with the same issue who had shorted his MAF signal wire and blown a ground inside the ECU. I do not think this occurred in my situation.
The stupid move with the knock sensor wire is the ONLY thing that changed between when the car ran fine, and when this started.
Could i have potentially burned part of the ECU by sending o2 voltage to it? Seems unlikely since o2 voltage is less than 1 volt and im reading ~4volts while running, but it does not vary greatly when i rev the car, even when it hits the wall at 5k rpm.
Im thinking i should at the very least attempt to acquire a known good ECU and a known good MAF (again, the maf seems like an unlikely suspect).
Im sure this will end up being something fairly simple to fix, just looking for ideas.
Anyone have any insight?
-----
UPDATE:
snap, my brothers old work laptop had a serial port and i managed to get some logs:
ill list rough RPM numbers and the other values that corrospond to it:
RPM 2813
KNK 43!!
O2 .92/.76/.90/.53/.45
TIMING 28*/21*/3*
THRTL 92%
For o2 and timing i listed points on the line that fall within the scope of the throttle blip, they are in sequential order
RPM 4813
KNK 43/41/16/0 (@ exactly 4813 we had 16 counts)
O2 .90/.86/.61/.94/.53
TIMING 28*/15*/30*/14*
Looking at this, and knowing what ive seen in the past on this car that knock by itself isnt going to stop the car from revving. Ive checked fuel pressure @ idle and its ~26psi, i replaced the fuel filter too much earlier today just to be sure the engine wasnt starving.
The o2 numbers look wayyy ####ed. I may be thinking backwards but lower voltage = rich and higher volter = lean?
I zero'd out the AFC on another quick run and saw the o2 value go as high as 1.09 volts at one point.
Im getting what appears to be a good MAF reading on the AFC itself and in the logs here.
The timing isnt really ridiculous, any of this make any sense to anyone?
---
Now in one of the threads i looked at, the last poster mentioned checking the knock sensor, but then the thread dies...
Ive seen the knock sensor pegged before and the car did not exhibit anything like not revving beyond X rpm.
Ok, so here it is. The car has been sitting for a while, 6+ months. I started it regularly to make sure everything was cool, drove it around the block to make sure she ran ok under load. Thats the background right now.
Fast forward to now, I had installed a PLX wideband O2 and long story short it turns out I wired the narrowband emulator into the white KNOCK SENSOR wire instead of the white O2 SENSOR wire. Yes, idiotic move, completely idiotic. I discovered this today while trying to troubleshoot the problem.
What happens exactly is that the car will rev freely build 1-2 lbs of boost under 5k, but as soon as you hit 5k it starts to pop from the exhaust (sounds like the car is pulling timing perhaps) and the car simply will not rev.
So, ive unwired the NB emulator and i actually put the stock o2 sensor back in, and reconnected the KNOCK SENSOR wire (again, mistook it for o2). Ive verified the function of the o2 sensor with my blinky a/f gauge.
Ive tried twice now to reconnect the knock sensor wire i cut into, i thought maybe since i was using wire couplers it was introducing too much resistance so ive just twisted in a piece of wire and have the ecu sitting in the floorboard until i can get this sorted out.
I did some searching on the forums (dsmtalk, etc) and saw one guy with the same issue who had shorted his MAF signal wire and blown a ground inside the ECU. I do not think this occurred in my situation.
The stupid move with the knock sensor wire is the ONLY thing that changed between when the car ran fine, and when this started.
Could i have potentially burned part of the ECU by sending o2 voltage to it? Seems unlikely since o2 voltage is less than 1 volt and im reading ~4volts while running, but it does not vary greatly when i rev the car, even when it hits the wall at 5k rpm.
Im thinking i should at the very least attempt to acquire a known good ECU and a known good MAF (again, the maf seems like an unlikely suspect).
Im sure this will end up being something fairly simple to fix, just looking for ideas.
Anyone have any insight?
-----
UPDATE:
snap, my brothers old work laptop had a serial port and i managed to get some logs:
ill list rough RPM numbers and the other values that corrospond to it:
RPM 2813
KNK 43!!
O2 .92/.76/.90/.53/.45
TIMING 28*/21*/3*
THRTL 92%
For o2 and timing i listed points on the line that fall within the scope of the throttle blip, they are in sequential order
RPM 4813
KNK 43/41/16/0 (@ exactly 4813 we had 16 counts)
O2 .90/.86/.61/.94/.53
TIMING 28*/15*/30*/14*
Looking at this, and knowing what ive seen in the past on this car that knock by itself isnt going to stop the car from revving. Ive checked fuel pressure @ idle and its ~26psi, i replaced the fuel filter too much earlier today just to be sure the engine wasnt starving.
The o2 numbers look wayyy ####ed. I may be thinking backwards but lower voltage = rich and higher volter = lean?
I zero'd out the AFC on another quick run and saw the o2 value go as high as 1.09 volts at one point.
Im getting what appears to be a good MAF reading on the AFC itself and in the logs here.
The timing isnt really ridiculous, any of this make any sense to anyone?
---
Now in one of the threads i looked at, the last poster mentioned checking the knock sensor, but then the thread dies...
Ive seen the knock sensor pegged before and the car did not exhibit anything like not revving beyond X rpm.
