w124 e220 idling issues

[daibill]

Hi there,
My 96 e220 coupe has developed it's first real issue with me.. Last week it would start fine drive fine but with an occasional "miss". Had a look under the bonnet and could see some sparking by the maf sensor plug. Foolishly I moved the wire causing a short and the ovp blew.
Got a replacement ovp and in the interim cut back the insulation about 12 inches and made good the cables with heatshrink.
OVP came today and have fitted it. Car starts and idles but can randomly cut out. There is also a strong smell of petrol vapour but I cannot see any fuel leaks..
Have I fried the MAF? Any advice gratefully received.

 

[RichardF]

Try unplugging the MAF. Do these suffer from engine harness issues?

 

[RichardF]

Forgot to say. Read your codes before spending on parts.

 

[carat 3.6]

Do these suffer from engine harness issues?

They do indeed.

 

[optimusprime]

Its like every thoing , some do and some dont .

 

[Ian B Walker]

I would expect that you have done some damage to the ecu. BTW reading codes on these is VERY limited.

 

[daibill]

Ok bit Of an update. Got a genuine Bosch maf on the weekend and fitted it... Idle is now under control, does not cut out but can still wander a bit until warm., you can see the throttle body moving to compensate..

There is still a smell of petrol though that I cannot seem to track down. Sometimes i can smell it at the rear, sometimes the front...related?

Oh a somebody knocked the badge off the front last night...

 

[carat 3.6]

you can see the throttle body moving to compensate..

Loom issue.

 

[RichardF]

It'd be worth checking the purge valve, it sorted a rough idle for me.

W124 E280 Surging - Page 2 - Mercedes-Benz Owners' Forums

Pull the pipe off the valve that goes to the inlet and cover the end with your thumb. See if the idle improves.

Incidentally the "sparking by the MAF sensor plug sounds odd" I didn't think these devices carried enough power to visibly see a spark.