Lean bank due to lifter issue?
05-03-2009, 05:56 PM
#1
Lean bank due to lifter issue? Has anyone experienced this. Been trouble shooting unburnt fuel firing in the exhaust & noted that bank 2 is adding alot of fuel. While turning the engine over w/ the starter, everything looked OK w/rocker movement.
Have checked everything except removing the head to replace lifters. There is a lifter tick. Rockers are OK, pushrods OK, spring heights OK, valves appear to be OK...leak down test is next prior to removing head, but am not expecting an issue (it likely wouldn't be causing the lean condition if there were a pressure problem). Intake vacuum is not connected to either valve cover or the valley nipple.
It must be the lifters or a lifter. Please comment, thanks.
Have checked everything except removing the head to replace lifters. There is a lifter tick. Rockers are OK, pushrods OK, spring heights OK, valves appear to be OK...leak down test is next prior to removing head, but am not expecting an issue (it likely wouldn't be causing the lean condition if there were a pressure problem). Intake vacuum is not connected to either valve cover or the valley nipple.
It must be the lifters or a lifter. Please comment, thanks.
05-04-2009, 02:06 PM
#2
If there is a serious compression issue then you may have a dead (or near dead) hole....which in a round-about way will crank alot of fuel into your exhaust.
Is there an LTerm/STerm split between the banks? Or one bank indicating much leaner then the other?
If there is a serious tick that coincided with fuel getting into the exhaust, then I would put my money on a compression or leak down test.
Is there an LTerm/STerm split between the banks? Or one bank indicating much leaner then the other?
If there is a serious tick that coincided with fuel getting into the exhaust, then I would put my money on a compression or leak down test.
05-05-2009, 06:13 AM
#6
A wire inside the injector weather seal had become disconnected. Couldn't see it because it was inside the weather seal. When I went to re-install the injector clips after checking injectors w/ a 12v power source, saw that the wire had come out of the seal enough to notice that it was no longer attatched to its' pin conector. Checked the spark plug & sure enough, it had signs of heat (no fuel). So, the non-fueling injector had created a lean cylinder of which caused the fuel trims to add gobs of fuel in that bank. The problem was corrected, once the wire was re-attatched & the injector began sending fuel again.
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05-05-2009, 08:40 AM
#9
Just checked the missfire diagnostics. Prior to buying tuning software, the previous tuner told me that he dampened the missfire detection due to the cam. Actually, he completely dissabled missfire detection by entering 32... into each cell. This explains why there was no missfire detected. I am now searching the EFILve tune repository for a tune w/ dampened, but not dissabled missfire file. Live & learn....I guess 
05-05-2009, 11:09 AM
#10
Yeah i wondered about that....I know even gm's stock tuning won't show a missfire with a MIL unless its a dead miss and often. I just found that out, I had a plug that was partially fouled and was missfiring but the computer just ignored it. Finally got so bad i just started pulling plugs.
05-05-2009, 02:40 PM
#11
Thought I had it fixed & the rich fueling remained. Ran a log side by side w/ the tune file & found that the 7.5.5 upgrade software is doubling the ECT temp in the ECT vs MAP OL fueling table. So, @ 65*C it registers 130*C. As a result the fuel trims start throwing gobs of fuel @ it & even more once it thinks it has reached engine protection temperature. Basically, there were 2 issues, the injector wire & the software.
The F9 table & the F10 dashboard both show 65*C when the ECT vs MAP is using 130*C. Either I've missed something or there is a software issue w/ the 7.5.5 upgrade. This was the additional cause of the bang in the exhaust. Problem happened again today which led to the side by side comparision.
So, now I've ruined @ least (1) 02 sensor & who knows how many more plugs.
The F9 table & the F10 dashboard both show 65*C when the ECT vs MAP is using 130*C. Either I've missed something or there is a software issue w/ the 7.5.5 upgrade. This was the additional cause of the bang in the exhaust. Problem happened again today which led to the side by side comparision.
So, now I've ruined @ least (1) 02 sensor & who knows how many more plugs.
