4.2L pinging--finally got a lean code
#1
![Default](/forum/images/icons/icon1.gif)
Probably the only time I'll be happy to see the CEL in this car... popped a P0174 finally. Been dealing with a pinging issue on this engine since last summer, had the dealer do the PCM flash already which didn't help, did a Techron treatment, nothing seemed to change the light throttle ping.
So I have a "bank 2 lean" condition. Pulled the freeze frame data, find it a bit odd that it only threw a P0174 because the fuel trims are as follows:
LTFT1 18.8
STFT1 -1.6%
LTFT2 18.8
STFT2 -2.3
(other data -- fault occurred at 68 mph, 1778 rpm, 5.9 lbs/min MAF, 51 psi fuel pressure, 185F ECT, and 19F intake temp, 26% throttle.)
Seems with BOTH banks running 18% LTFT, I have a lean condition for the entire engine, yet it didn't throw a bank 1 code. I will try watching the STFT while I spray some solvent around the intake gaskets and throttle body to check for vac leaks. Any specific areas I should check when I'm searning for leaks? I've seen a few old posts about intake manifold leaks. ARe the gaskets a common failure?
The other aspect of this is that just in August I had CEL for the MAF being out of range. I cleaned the MAF (had a lot of dirt on the sensor) and it hasn't returned yet, but I'm wondering if the MAF is just due to be replaced at this point. Is looking at a MAF flow table while running the engine through rpm ranges an acceptable check for this? I assume that the PCM has enough sensors to realize that it's actually running lean, and not an out of cal MAF based on rpm and MAP values.
Thanks for any advice,
-Michael
So I have a "bank 2 lean" condition. Pulled the freeze frame data, find it a bit odd that it only threw a P0174 because the fuel trims are as follows:
LTFT1 18.8
STFT1 -1.6%
LTFT2 18.8
STFT2 -2.3
(other data -- fault occurred at 68 mph, 1778 rpm, 5.9 lbs/min MAF, 51 psi fuel pressure, 185F ECT, and 19F intake temp, 26% throttle.)
Seems with BOTH banks running 18% LTFT, I have a lean condition for the entire engine, yet it didn't throw a bank 1 code. I will try watching the STFT while I spray some solvent around the intake gaskets and throttle body to check for vac leaks. Any specific areas I should check when I'm searning for leaks? I've seen a few old posts about intake manifold leaks. ARe the gaskets a common failure?
The other aspect of this is that just in August I had CEL for the MAF being out of range. I cleaned the MAF (had a lot of dirt on the sensor) and it hasn't returned yet, but I'm wondering if the MAF is just due to be replaced at this point. Is looking at a MAF flow table while running the engine through rpm ranges an acceptable check for this? I assume that the PCM has enough sensors to realize that it's actually running lean, and not an out of cal MAF based on rpm and MAP values.
Thanks for any advice,
-Michael
Thread
Thread Starter
Forum
Replies
Last Post
OkieTim
S-Type / S type R Supercharged V8 ( X200 )
3
09-08-2015 04:48 PM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)