E38 Intermittant engine stall and mid range rev hiccup issue????

[sirjamesh]

HI Guys,

Firstly Ive checked all the forums i can find, spent days on Google, Bing etc to no avail so please dont think I'm wasting anyones time - but i really am at a loss now....

Desperate help needed - I have a problem where intermittantly my engine will just die at idle (traffic lights, junctions etc) or it will stutter/hiccup mid rev range whilst driving for about 4 seconds - 90% of the the time it will restart on the 1st key turn but will occasionally take a few cranks to fire and almost certainly feel like its fuel starved....

Ive checked, rechecked and cleaned MAF and disconnected MAF and re road tested - still with fault....
Ive had full live diagnostics with only a camshaft sensor being highlighted - changed that - now no fault appears on the computer but driving the car still has the same intermittant faults...
Ive changed fuel pump, fuel filter, fuel pump relays...etc no success....
Air filter is new, ive disconnected all ICV, MAF, VANOS and throttle sensors at the same time and the problem still exists when roadtested....
Ive checked all pipes for air loss,cracks, petrol loss etc again to no avail....
The car has now done 158,000 miles but still drives (and looks) like new, its drives absolutely 100% most of the time - no hesitation, no flat spots - perfect idle, perfect starts, perfect cooling, good fuel economy(for a 7 anyway), its been serviced by BMWUK for life and 99% of the time drives like new however at least once every journey (and usually when hot) it will reveal these two intermittant faults.....

Im thinking now spark plugs, boots, coil packs or Lambda sensors but i'm running out of cash and wondered if anyone has any ideas?????????

Please please please help

Cheers James

[epmedia]

Inspect the coil packs and sparkplug insulators for spark leaks. Clean them all with something: alcohol, or new paintbrush. Spark plugs go bad too.
So, change spark plugs and inspect packs and insulators at the same time.
Robert

[jthomsit]

Vacume leak from one of the rubber boots around the MAFs? One of mine had begun to perish. Addmittidly it doesn't seem to have solved my stalling but has eliminated the rought idle, could be intermittantly droping the revs enough at idle to expose another fault and cause a stall.

[elpescador47]

HI Guys,

Firstly Ive checked all the forums i can find, spent days on Google, Bing etc to no avail so please dont think I'm wasting anyones time - but i really am at a loss now....

Desperate help needed - I have a problem where intermittantly my engine will just die at idle (traffic lights, junctions etc) or it will stutter/hiccup mid rev range whilst driving for about 4 seconds - 90% of the the time it will restart on the 1st key turn but will occasionally take a few cranks to fire and almost certainly feel like its fuel starved....

Ive checked, rechecked and cleaned MAF and disconnected MAF and re road tested - still with fault....
Ive had full live diagnostics with only a camshaft sensor being highlighted - changed that - now no fault appears on the computer but driving the car still has the same intermittant faults...
Ive changed fuel pump, fuel filter, fuel pump relays...etc no success....
Air filter is new, ive disconnected all ICV, MAF, VANOS and throttle sensors at the same time and the problem still exists when roadtested....
Ive checked all pipes for air loss,cracks, petrol loss etc again to no avail....
The car has now done 158,000 miles but still drives (and looks) like new, its drives absolutely 100% most of the time - no hesitation, no flat spots - perfect idle, perfect starts, perfect cooling, good fuel economy(for a 7 anyway), its been serviced by BMWUK for life and 99% of the time drives like new however at least once every journey (and usually when hot) it will reveal these two intermittant faults.....

Im thinking now spark plugs, boots, coil packs or Lambda sensors but i'm running out of cash and wondered if anyone has any ideas?????????

Please please please help

Cheers James
James,

I have a 1989 325i with 280,000 miles on it that is doing the exact same thing. Did you ever discover the problem? I haven't done as much trouble shooting as you did, and hoping to avoid it. Any help would be appreciated.

Thanks,
Stu

[Edwin NL]

Welcome here, sure the MAF is good? CPS sensor acting up?

[kg018]

my car is doing the same thing as well, my new MAF is on the way and i will let you know if that works.