surging at idle

[andy_k]

Our 1989 230TE auto has rediscovered an old problem which we thought was cured.

At idle the engine seems to surge between normal revs of about 650 to anything up to 1200 rpm. It was doing this before the last full service (2000 miles ago) which included new fuel filter, plugs etc but the mechanic couldn't get it to happen and it hasn't done it since.

Symptoms - all of these are based on the car sitting in neutral

1, as soon as the engine starts it ticks over at 650 rpm then jumps to anything between 1000 and 1200 before settling down to 650 again, this cycle keeps repeating

2, after sitting in traffic for a while and the engine temp rising until the fan kicks in it lessens to almost nothing - probably flicking up to about 750/800rpm.

3, as soon as the engine temp is lowered it reverts to jumping between 650 and 1000 rpm

4, it seems worse on hot days - just before the last service we had a hot spell and now it's started doing it again whilst the weather is hot. however it still does it at night when the outside temperature has dropped.

Any ideas folks?


Thanks in anticipation

Andy

 

[andy_k]

BTTT



Andy

 

[piestore]

idle

Hi

Air mass metre is favourite butt try cleaning the throttle body first.

 

[Kinky]

Andy,

I'm getting exactly the same problems as you.

Only happens occasionally - and I can't find any consistency as to when/why it happens.

K

 

[andy_k]

interesting thing here - we headed over to the GTG at the weekend, 200 mile round trip with a good run back down the motorway at speeds that were "sensible" and within the law (well that's my story and I'm sticking to it) - the uneven idle? gone!!!!!! the car is running as sweet as can be and idle speed is a rock solid 650 rpm

Guess that's what they call an irish Service

any guesses?

Andy

 

[Kinky]

Hummm .....

Don't mention the GTG to me - a bit of a sore point.

I won't go into details here, suffice to say I gave up and went to SGT instead and ended up with a free bottle of wine for test driving the new 156 which I then drank on Sunday night and got a little bit trolleyed.

Cracking stuff though - not your usual cheapo dealer plonk.

K

 

[mjtray]

Surging

Kinky,

I also have an E280 that suffered badly from surging......if I had to stop at the lights with the car in gear, it would start surging badly, so much so, that I would have to put it into neutral.

Once clear of traffic or lights etc, you would'nt notice a problem.

I took the car to John Griffiths in Caversham and they cleaned out the throttle body, which had a load of carbon build up in it. Once done, the car has never suffered from surging again.

Hope this is of help

 

[Kinky]

Caversham eh?

Not too far from home/work

Would you recommend Griffiths?

I ask as I absolutely swear by Purslows in Basingstoke. But I'd be very interested in getting some quotes for some 'possible' work (of which by the sounds of it the throttle body would be 1).

I'm sold with Andy up near Birmingham (just not conveniently around the corner).

K

 

[mjtray]

Kinky,

I used to get my Year 2000 E220CDi serviced at Purslows and will not have a word said against them.....excellent service.

Having got rid of the 220 due to a change in jobs, I purchased my 1993 E280 and have had it serviced by Giffiths, thinking that servicing costs would be lower and that they would be better for older Mercs than Purslows. They are also really convienient being just a mile away from home. In general I have been pleased with them, however, on the last service, I think I was taken for a ride, my car was worked on by a younger mechanic and he messed up a coolant change which resulted in an air lock and my car boiling over........they did change the coolant again free of charge, but thats not the point, it should have been done correctly the first time. I also think I got stung on the bill. It also looks like two of the older and wiser mechanics have moved on (?)....I'll see if this is the case the next time the car comes up for service.

If they have moved on I think I'll try Star Motors (0118-9462750)....a friend of mine, who hates garages at the best of times, has used them for years and swears by them.

In terms of your 280, I would almost guarantee its the throttle body that needs a clean......I would ring up Star, Griffiths and Purslows, and see how much they will charge to do the job.

Good luck, if you see a Black L reg 280 with 8 hole alloys swanning about Caversham, that'll be me!

Cheers