Strange RPM issue
Hi All,
finally decided to have a closer look at this.
After a cold start as I accelerate I get a dip in rpm where it feels like it's changing up gears too soon and it bogs down.
However...it doesn't seem to show when logging current gear and TCC.
TPS is steady or climbing at the time this happens.
I've attached a screen shot of where it happens.
Howard
YOU ONLY NEED TWO TOOLS IN LIFE - WD-40 AND DUCT TAPE. IF IT DOESN'T
MOVE AND SHOULD, USE THE WD-40. IF IT SHOULDN'T MOVE AND DOES, USE THE
DUCT TAPE.
IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.
98 K1500 'HOLDEN' Suburban.
Custom Whipple SC, Mercruiser Marine intake, 0411 PCM, 4L80E w/shift kit
Howard,
At that point, the commanded AFR goes richer, timing is reduced, throttle is more/less steady... and rpm drops...
I'm wondering if one of the OBD non-continuous monitor tests is triggered to run just at that moment...?
Joe
Yeah....I noticed that Joe.
I have tried lifting the VE table in that area but it doesn't seem to make any difference (was thinking a lean spot).
When cold...I can almost trigger it at will.
It feels like the truck bogs for a second and then the rev's come back up.
Once the truck's warm....I haven't noticed it.
Howard
YOU ONLY NEED TWO TOOLS IN LIFE - WD-40 AND DUCT TAPE. IF IT DOESN'T
MOVE AND SHOULD, USE THE WD-40. IF IT SHOULDN'T MOVE AND DOES, USE THE
DUCT TAPE.
IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.
98 K1500 'HOLDEN' Suburban.
Custom Whipple SC, Mercruiser Marine intake, 0411 PCM, 4L80E w/shift kit
I have to think about it...
Time's up Joe!
Howard
YOU ONLY NEED TWO TOOLS IN LIFE - WD-40 AND DUCT TAPE. IF IT DOESN'T
MOVE AND SHOULD, USE THE WD-40. IF IT SHOULDN'T MOVE AND DOES, USE THE
DUCT TAPE.
IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.
98 K1500 'HOLDEN' Suburban.
Custom Whipple SC, Mercruiser Marine intake, 0411 PCM, 4L80E w/shift kit
plug ur maf in and try it then.
sounds stupid, But friends car was also doing this first thing in the morning, we are yet to fix or find the problem ( only get one chance to do it a day )
but fitting the maf fixed it up.
That's strange.
I now have the MAF back in (OL MAF) and I'll check it out in the morning.
Howard
YOU ONLY NEED TWO TOOLS IN LIFE - WD-40 AND DUCT TAPE. IF IT DOESN'T
MOVE AND SHOULD, USE THE WD-40. IF IT SHOULDN'T MOVE AND DOES, USE THE
DUCT TAPE.
IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.
98 K1500 'HOLDEN' Suburban.
Custom Whipple SC, Mercruiser Marine intake, 0411 PCM, 4L80E w/shift kit
Howard, please let me know of the outcome!Originally Posted by hquick
Dave
Posting Permissions
Reply With Quote