"Rev Hang Slows My Roll" (RevHang)
04/28/2014 at 21:34 • Filed to: None
0
7|
"Rev Hang Slows My Roll" (RevHang)
04/28/2014 at 21:34 • Filed to: None | 0
| 7 |
(pic is not my car btw!)
I've done a lot of work on the E30 since i got it and i was able to drive it to the gas station for a fill up today, which feels like a major accomplishment. one problem im having is a rough idle which comes and goes. When i tap the gas quickly the car almost stalls and when i rev it up and release the throttle, the revs drop below idle before catching and returning to normal. Any ideas what could cause this?
The car has:
new plugs, new fuelpump and filter, new throttle position sensor, new coolant temp sensor, new intake boot, and i cleaned out the idle control valve among other things.
Nick, Drives a Cobalt LT
> Rev Hang Slows My Roll
04/28/2014 at 21:37 |
|
Map or MAF?
Sounds like a fueling or air or measurement issue....
Did these have O2 sensors? Coudl that be causing an issue?
Jake, Yes, wearing khakis
> Rev Hang Slows My Roll
04/28/2014 at 21:41 |
|
Have you checked for vacuum leaks around the intake manifold?
If not, an easy way to check is to take a spray of some sort that is flammable, such as brake cleaner or wd-40 and spray it around where the intake manifold meets the heads and also around where the plenum meets the manifold. If the revs jump when you do this then you have a vacuum leak where you sprayed and had this reaction.
Aaron James
> Rev Hang Slows My Roll
04/28/2014 at 21:43 |
|
Leaking intake or faulty Idle Air Control Valve.
wbizarre - OEM fetishist
> Rev Hang Slows My Roll
04/28/2014 at 21:47 |
|
Huh, I have the same issue with my e30. It happens pretty rarely so it's not top-of-mind for me, but yea, revs drop below idle before returning to normal. Sometimes it floats up and down until I come to a complete stop(approaching a stoplight) and then evens out. The vacuum leak suggestions seem to make sense.
|
Rev Hang Slows My Roll
> Nick, Drives a Cobalt LT
04/28/2014 at 22:31 |
|
there is an o2 sensor, but the ecu doesent look at it until car is at temp. these symptoms happen cold or hot.
rotundapig
> Rev Hang Slows My Roll
04/28/2014 at 22:35 |
|
My E30 never had any issues, except for what you are describing. I tried everything I could think of and eventually ended up taking to a local BMW specialist (I never take my car to the mechanic, and it pains me to admit this), he adjusted the valves and cleaned the injectors and it returned to its flawless self.
ixismore
> Jake, Yes, wearing khakis
04/29/2014 at 08:30 |
|
This, my M20 E30 had a intake boot that wasn't completely on the throttle. This caused a leak, crappy idle, etc. We found out through oil samples indicating too much silicon (sand) in the oil. Also check for cracks on the boot itself. Its kinda wavy so take it off to check.
(And the problem with the intake boot was AFTER we replaced it. My fault entirely, but an easy to do mistake!)