Weird sensor problem...PLEASE HELP

[sonicnofadz]

OK here is my problem...on my logger my tps is reading a steady 97% (basically WOT) and my knock is staying at a steady 43 counts of knock the entire time (flatline) no matter if I am at idle or reving, etc. However on my SAFCII my throttle is reading fine...0% when at idle and when I step on the gas it goes to 100 % open...I checked the wiring of the safc to tthe computer but everything is ok. I switched TPS sensors but it made no difference. My O2 Sensor reading is also LOCKED at a steady value of 4.98 Volts....WTF?!!!!?!?!?! My car (91 GS-T) just started to do this out of the blue last night for no reason...I have lost all power because of the timing advance is gone because of the knock. What can be causing this problem, seems like alot of my sensor readings are fux0red....dead computer maybe?

 

[sonicnofadz]

UPDATE: The computer still seems to be acting strangely...I tried leaving the computer unplugged for a while (resetting it) but it didn't help...I also check for bad capacitors...I am at a total loss. The codes 21 25 and 13 were also thrown...which are the coolant temperature, barometic pressure, and intake temperature sensors...why are all my sensors going haywire? Maybe it is a grounding issue or something wrong with the harness?

 

[sonicnofadz]

I am really suprised NO one has any input on this. This really seems like a issue with the wiring harness because only certain sensors are failing. The MAF is fine, as well as the RPM reading...argh...

 

[ddavisaf]

Alot of times your caps will leak underneath of where you can see. If it's starting to small then you need to replace it. I would also change out the CTS as they can cause alot of havoc, then we can go from there.

 

[sonicnofadz]

Hmmm yeah I didnt look under the main circuit board so maybe there are more capacitors that I didn't see. I will check this out. What is CTS?

 

[ddavisaf]

Coolant Temp Sens.

 

[sonicnofadz]

OK I have checked every single capacitor on the whole ecu and all of them are 100% OK. Next I will check the coolant temperature sensor...this is the one that is connected to the thermostat correct? I have to say...this is the weirdest dsm problem I've ever come across...

 

[ddavisaf]

Correct.
DSM's are very moody. Let me ask you a question. Were you talking bad about your car while it was close by? They have very sensitive ears, and if they hear you talking bad about them it hurts their feelings. I wouldn't recommend any negative talk when you're close to your car as problems will start springing up.

 

[sonicnofadz]

OK I replaced BOTH sensors in the thermostat housing with sensors that were known to be functional off my other 1G DSM. But the problem is still there. I can tell without even starting the car. I plug my logger in, and I turn the ignition to on (to turn the ECU on) and I watch my readings go haywire, the O2 sensor sky rockets to 4.98V, the tps sensor stays locked at 99% and won't change regardless if I press the gas pedal or not (while my safc throttle reading responds just fine to my foot moving the pedal). WHAT GIVES!? WHAT IS GOING ON!? Im starting to think that my ECU took a nasty shit on me.

 

[ddavisaf]

Go and double check your AFC wiring.
Double check the caps in your ECU.

Go an unplug your O2 Sensor, leave the sensor in the housing. Test for volts at the connector. See if your logger is picking up on faulty signals from the ECU, or if you are infact getting 4 volts to your O2.

 

[sonicnofadz]

Go and double check your AFC wiring.
Double check the caps in your ECU.

Go an unplug your O2 Sensor, leave the sensor in the housing. Test for volts at the connector. See if your logger is picking up on faulty signals from the ECU, or if you are infact getting 4 volts to your O2.

Wow good thinking! Thanks!

 

[sonicnofadz]

in a fit of frustration I ended up buying a rebuilt ECU. Once I swapped in the new ECU all of my weird sensor problems went away. The weird thing about it is my capacitors were NOT leaking. Must have been something weird with the analog to digital converter...who knows...oh well thanks for your help ddavisaf