Need Help for MOT?

[Brian Mac]

Hi all
Im new to this forum and an owner of a 1991 190E which is in fairly good order for its year. The car is soon to go through its MOT.

My problem is i got an oil leak repaired, and got the engine bay power washed
the car starts ok and runs quite well but on occassions wont idle under about 1500rpm, so was wondering if anyone could help please ???

The car ran faultlessly before this happened

 

[turbopete]

hello and welcome Brian. thats really a difficult one as the problem will most probably be in finding where the fault is, not what the fault is! most mechanics would say to avoid getting water or steam under the bonnet like the plague as there are so many electrical switches and sensors and contacts etc. i would start by checking the obvious things like spark plugs, ht leads etc and then i would start checking all the plugs onto the various engine sensors, switches etc for any signs of corrosion (green usually) oil or water in/on any contacts and wiring, clean using electrical switch and contact cleaner (from most parts factors) and that should, hopefully cure the problem!

tip for everyone: if you need contact cleaner but cant get hold of any, i found a good substitute is brake cleaner!

 

[television]

I did not know how to answer this one when I first read it, I would check that all of the vacuum pipes are still a good fit

 

[Brian Mac]

Thanks for the quick reply guys,
there goes my night sittin in front of the telly with a couple of beers,
will try what you suggested and let you know thanks.
Brian.

 

[bigasotonuk]

hello and welcome Brian. thats really a difficult one as the problem will most probably be in finding where the fault is, not what the fault is! most mechanics would say to avoid getting water or steam under the bonnet like the plague as there are so many electrical switches and sensors and contacts etc. i would start by checking the obvious things like spark plugs, ht leads etc and then i would start checking all the plugs onto the various engine sensors, switches etc for any signs of corrosion (green usually) oil or water in/on any contacts and wiring, clean using electrical switch and contact cleaner (from most parts factors) and that should, hopefully cure the problem!

tip for everyone: if you need contact cleaner but cant get hold of any, i found a good substitute is brake cleaner!

Does,nt the solvent in Brake cleaner melt plastics? which most electrics/electronics are predominatly constructed of.

 

[rf065]

On a previous car of mine which had the engine bay steam cleaned, it suffered a few electrical gremlins which were only cured after I found there were a couple of electrical earths in the engine bay that required cleaning up. Very simple to fix, very hard to diagnose.

Russ

 

[meanie]

Hi all
Im new to this forum and an owner of a 1991 190E which is in fairly good order for its year. The car is soon to go through its MOT.

My problem is i got an oil leak repaired, and got the engine bay power washed
the car starts ok and runs quite well but on occassions wont idle under about 1500rpm, so was wondering if anyone could help please ???

The car ran faultlessly before this happened

When you say that it won't idle under 1500rpm,do you mean that you have to hold it at 1500,or that it decides to idle at 1500?
If it's the former,does the dizzy cap still have the black protective shroud (looks a bit like fingerless gloves!) on.If so remove the cap,turn it upside down & carefully cut the brass tabs & slide it off.Water gets under this & causes it arc across the top.