cel codes 34 & 45

[xpertsnowcarver]

im very sorry if this is posted somewhere else. i can't find anything on them..

so my ecu is throwing codes 34 & 45.. the cel turns on and off every 3 - 4 days. codes 34 is apparently the detonation or knock sensor? not sure how to understand that. is my 85k mi engine no good already? i just bought it from an old lady who went to the dealership for EVERYTHING, lol. my 91 SE still has a warranty some things like the alternator. i dont race the car like a mad man and i put 91 octane with the lucas fuel stabilizer.
code 45 is apparently an injector leak. so i guess i have to replace my fuel injectors at some point.. that doesn't seem as crucial as code 34.. can anyone elaborate on this for me?? i figured maybe one of the injectors isn't allowing enough fuel into one of the cylinders which may not be enough for combustion, which may cause the ecu to throw both codes??
thanks and again, sorry if this is a repost.

[pbcstylez]

try searching for "leaky injector" ive seen this topic in the past

[xpertsnowcarver]

try searching for "leaky injector" ive seen this topic in the past

dude, thanks so much. cant believe i couldn't find that thread. looks like im replacing my injectors..
+ rep for u

[Neejay]

Did you ever get code 34 taken care of? Im getting that code too, and I have no idea where to start.

[MELLO*SOS]

code 34 usually comes because there is a short in your Knock Sensor wiring harness. look inside the plastic harness sheath above the fuel rail. Supposedly you can trace the KS wire and see the shorted section.

Search my posts for "bogging" and you'll find a nice long thread on curing code 34

The other thing code 34 can be thrown for is if the sensor itself is melted or bad... That happens sometimes. Code 34 doesn't seem to be thrown when the ECU detects knock, there is a different code for that IIRC.

Good luck

[xpertsnowcarver]

yea, wat mello said pretty much is the case for most 240s, but not for me. it hasn't come up since i replaced one of the leaky injectors and used the lucas fuel cleaner stuff. i usually pour a bit of the cleaner every 2-3k miles. hasn't come up since.

[projectRDM]

Code 34 can come on for anything from bad gas to actual rod knock. Diagnose the problem through other means before replacing the sensor itself, they rarely go bad.

[idlafie]

See my response to a previous post...

http://www.zilvia.net/f/showthread.php?t=165317

Also ran across the following info on the Net while doing a search:

CODE 45

Trouble Code 45 indicates that the O2 sensor is showing a persistently low exhaust oxygen content (rich), despite the efforts of the ECM to decrease injector on-time (thus decreasing fuel delivered). Integrator and BLM numbers may indicate < 128 by a substantial margin.

The conditions for setting this code are:
no Code 34 or Code 35 (MAF error) present, and
the O2 sensor voltage remains above 752 mV, and
the ECM is in Closed Loop control, and
throttle position is < 2 percent or > 20 percent, and
the above conditions exist for more than 20 seconds.


Typical causes for this code include:

1) O2 sensor defective or contaminated (if incorrect RTV sealant or too much RTV is used, this may happen)
2) Leaking fuel injectors
3) Fuel pressure too high
4) EMI interference from poor plug wires
5) Evaporative Emission system defect
6) TPS and/or EGR problem
7) MAF sensor reading higher airflow than is actually present

Kinda makes sense to me. Anyhow, hope this helps...

ID

PS:
Russ...what do you think??

[Neejay]

I meant to report back too, that my knock sensor is cracked. The wiring is there, seemingly untouched/stripped. I would assume that's why Im getting code 34...

[projectRDM]

See my response to a previous post...

http://www.zilvia.net/f/showthread.php?t=165317

Also ran across the following info on the Net while doing a search:

CODE 45

Trouble Code 45 indicates that the O2 sensor is showing a persistently low exhaust oxygen content (rich), despite the efforts of the ECM to decrease injector on-time (thus decreasing fuel delivered). Integrator and BLM numbers may indicate < 128 by a substantial margin.

The conditions for setting this code are:
no Code 34 or Code 35 (MAF error) present, and
the O2 sensor voltage remains above 752 mV, and
the ECM is in Closed Loop control, and
throttle position is < 2 percent or > 20 percent, and
the above conditions exist for more than 20 seconds.


Typical causes for this code include:

1) O2 sensor defective or contaminated (if incorrect RTV sealant or too much RTV is used, this may happen)
2) Leaking fuel injectors
3) Fuel pressure too high
4) EMI interference from poor plug wires
5) Evaporative Emission system defect
6) TPS and/or EGR problem
7) MAF sensor reading higher airflow than is actually present

Kinda makes sense to me. Anyhow, hope this helps...

ID

PS:
Russ...what do you think??

Bingo, any of those and more could trip either code. But as we've seen above, the sensor's case is cracked as well. Check the sensor's resistance and replace as required.