e34 idle help

[piquet]

got a problem with my e34 525i.Car drives fine,except for one creeping problem with the idle.car will die off each time I stop it at lights etc when in N position.doesnt matter if the a/c is running or not,the idle will drop to about 500rpm and then just flame out.starting it again is not a problem eachtime.Have replaced the idle valve,done a full diagnostic(no fault shown),checked all hoses for leaks.My mechanic suspects it could be the ecu.anyone can help?

 

[pussy]

hehehheeee.. welcome to the e34 gremlins... give me time to think, then i will help you out..

regards.

 

[Bmmad318i]

Could it be the Air flow meter??? Or the throttle valve need some cleaning??

 

[flash]

hehehheeee.. welcome to the e34 gremlins... give me time to think, then i will help you out..

regards.

Yeah, don't remind me of the damn gremlins. Had that same problem, resolved it and try it came back to haunt me ! Then, I have checked and changed some parts i.e. hoses, ICV, MAF, etc, etc. Still crappy idling. One day, engine started to misfire, running on 5 cylinders. Seems one ignition coil was on the brink all along, it blew and took out my ECU at the same time. Changed all coils and ECU, NOT CHEAP! Damn. After that change, idling was perfect, spot on, but for 2 or 3 months only. Now, off and on, got crappy idling. Still better than before though. Fed-up already.

By the way, mine is M50 engine.

 

[pussy]

piquet..is your car auto... i think so...
okay, step by step..
is your speedometer eratic, meaning it moves up/down some times or all the times ? if so, please check your connection plug, maybe dirty, at the speed sensor at the rear of the axle(diff)..clean it up..then it should be okay..if not, then your meter clusteris kong..
that's all for the moment..

 

[pussy]

cyne.. the M50B25TU settings are fixed, all controlled by the sensors and ecu.. you cant' even tune the Co2 mixture..

 

[taabster]

wat about check the distributor cap and rotor arm for wear ah? + the temperature sensor. I had that with my E30, and after i sand down the contact point its all good now....but not sure about E34...hehehe

 

[piquet]

sorry,my car is auto yr 95,m50b25tu ( single vanos)
guys,I dont have an erratic idling problem, but will meter cluster cause the eng to die off.?.throttle valve cleaned already.car 'tuning' done too.The ignition system is fine too and just replaced my plugs but still not fixed.really got to be careful at the t/lights,malu la sometimes with friends sigh
btw, i go to mspeed

 

[pussy]

piquet, i ask you for erratic speedometer.. when you are runing...not erratic idle...

oh, check your air tempreture sensor...

 

[rainman55]

sorry,my car is auto yr 95,m50b25tu ( single vanos)
guys,I dont have an erratic idling problem, but will meter cluster cause the eng to die off.?.throttle valve cleaned already.car 'tuning' done too.The ignition system is fine too and just replaced my plugs but still not fixed.really got to be careful at the t/lights,malu la sometimes with friends sigh
btw, i go to mspeed

I've had that recently on my E34 (M50B20) after I replaced the airflow meter with the original BMW part. Since then, it's been checking ICV, changing ignition coil, adjusting throttle valve until one day, I was cleaning engine bay and found the fuel inlet to the throttle a little wet. So sent it to the mechanic, checked and changed the inlet hose. Since then, it's been smooth most of the time. With the occasional erratic idle that stabilises in seconds.

 

[piquet]

hi guys,still cant fix this idle problem. if it is the ecu that is faulty and i know 2nd hand ecu is not cheap, and i have been thinking of chipping my car 4 sometime now,is it worth looking at.?.dunno if i make any sense here......
came accross a website on ebay that sells eprom( An EPROM, or erasable programmable read-only memory, is a type of computer memory chipchips) chips,rgds

 

[XXX]

i also had idling gremlins for a while thought it was ECU after unichip also same problem but recently after changing timing belt it disappeared ask mech why, he said maybe the tension of the timing belt was not properly tensioned....so maybe its worth checking it out.

 

[wan520i]

piquet,

what air filter are you using? original paper filter ? or other performance filter?

XXX,

M50B25tu use timing chain, no timing belt. Is there a chain tensioner there?

 

[XXX]

well I suppose the chain and belt does the same job...so thre is no harm checking it...whether there is a tensioner or not Im not sure but I suppose there should be.

 

[viewfinder]

My experience was occasional erratic idle for ~2 seconds after a cold start in early morning. Never happen when it's hot.

Didn't manage to find the problem until one day the car cannot start when it's cold. Found out that the fuel pump fuse (very old) was almost blown. Then I realized that during cold the fuse was basically causing open circuit and when hot the metal expanded and the circuit was connected. After replacing the fuse, the short erratic idle has never happened again.

I was told by mechanic that the AFM housing (plastic) could also cause erratic idle if the housing has cracked. Apparently the crack may be at the bottom that we cannot see unless you put a mirror or remove the AFM housing for inspection.

 

[piquet]

xxx,will check out the timing chain . hopefully tht is it
wan, I am using standard paper filter(just replaced abt 3 months ago)
viewfinder, my fuel pump is new and I think the fuse is ok too.afm replaced also and my mechs last resort is to replace the ecu.the thing with my car is that the low idle problem(engine dying off at D) is more evident at higher temps ie after a long run.
p/s anyone recommend a ecu replacement for my problem? Thanks guys,really appreciate yr assistance

 

[piquet]

Idle problem fixed(so far 2 weeks).Changed my batt recently and the ECU must have reset when i disconnected the old batt,idles at around 600 now.

 

[longan]

damn lucky u piquet..
me also facing the problem..
changed so far
1. 2nd hand MAF (M50B25 using MAF rite?? heheh)
2. new fuel pump
3. servicing in intake section..

idling still erratic.. hi low hi low.. (between 700-900)...
but that day accidentally vacuum hoses broken the idle stable!!!!
fixed back the hoses.. the problem come back.. now live with the problematic idling... dunno when to do overall check