Idle stutter - nothing left to replace!

Post Wed Dec 02, 2015 6:39 pm

Tiny idle stutter on my M42 318is. Have tried everything over the years but still not quite right (e.g. new AFM, welded manifold, new gaskets, ICV, blah, blah, blah).

Even defeated Park Lane Classics.

Will I just live with it, or is there something obvious I'm missing?

Post Wed Dec 02, 2015 7:52 pm

when was the last time the injectors were overhauled?

Post Wed Dec 02, 2015 8:04 pm

How do I do that?

Post Wed Dec 02, 2015 8:10 pm

Unless you tell us exactly what blah, blah, blah is, we can't possibly answer this question.
It already seems that it doesn't include one of the most obvious suspects.

Post Thu Dec 03, 2015 1:32 pm

Ok, point taken.

So...

New AFM, new ICV, new valve cover gaskets and bolts, new spark plugs, new oil filler cap, ALL under bonnet hoses replaced inc. intake boot (by Park Lane, the robbing bastards), welded manifold (Park Lane, still robbing bastards), new exhaust, new filters. Possibly some other stuff I can't recall right now.

So what is the obvious suspect? A sensor somewhere ? Or injectors?

Post Thu Dec 03, 2015 1:54 pm

aimlessrock wrote:when was the last time the injectors were overhauled?

These are absolutely fundamental to mixture strength. Reduced flow or poor spray pattern will lead to a weak mixture, and with no feedback loop on most E30s to monitor and correct it, weak it will stay.

Post Thu Dec 03, 2015 2:49 pm

Ok. So how do I get them out and send them?

Post Thu Dec 03, 2015 10:30 pm

the wiki is your friend, see the below link.

http://www.e30zone.net/e30zonewiki/inde ... _injectors

remove them all and contact Injectortune (like below) and get them professionally overhauled and balanced...they cost about a £10.00 per injector.

http://www.e30zone.net/modules.php?name ... c&t=152878

whilst your at it and have removed the injectors change the fuel filter for good measure.

Post Sat Feb 27, 2016 1:01 am

Can I jump in here I have a wild Idle that is propelling the car when in gear.

The car has had a new fuel filter a replacement intake boot new plugs then I took off all the clipon sensors and cleaned them with term cleaner - this is maybe the last time it ran correctly.

I was 20 mins into a drive and it started bouncing like is was steadily on and off teh power for 2 seconds on 2 seconds off.

Now its running High - aggresively so and then doing the drawing/hunting.

Any idea's its an m20b25

Paul

Tried a smoke test today which I was guessing how to do tomorrow morning I plan to light a smoke pellet on tinfoil in the bottom of the airbox - someone stop me if this is a disaster of an idea lol

Post Sat Feb 27, 2016 1:02 pm

Not sure what you mean by "clipon sensors".

I would start with the basics.

Thoroughly check for air leaks on the intake side. I do this by running the engine and spraying fag lighter gas round the intake. If the revs increase there is a leak.

Check that the idle adjustment screw hasn't been changed from the factory setting. It should be sealed with paint. If it is not sealed check that the throttle flap is only just cracked open when resting on the stop. The easiest way to check this is to remove the throttle body.

Check that the TPS is functioning and adjusted correctly: http://www.e30zone.net/e30zonewiki/inde ... ion_Switch
It must click as soon as the throttle starts to move but must also click shut again when the throttle is released.

Check that the blue sensor is functioning correctly: http://www.e30zone.net/e30zonewiki/inde ... or#Testing

Check that the ICV is clean and is moving freely: http://www.e30zone.net/e30zonewiki/index.php/ICV#ICV

Ben