ajbristol

Hi all, I've seen somewhere either on this or another forum some info about relay clicking from behind the dash on the passenger side (N/S) but cannot find it again !!! darn it, anyway I too have this problem now and it seems to cause lots of strange little gremlins. I also have a strange one in that I can drive the car for 5 -10 mins and it starts to miss at low rpm and will cut out if I let it... and more annoying than anything is it then refuses to start again until cooled down about 20 -30 mins. Any one who has had this prob could maybe enlighten me to how to cure or where to start please reply or refer me to the article if poss. Thanks in advance for any help.

NZ_Benz

Looking at your profile I guess you car is pre 1994? Could be a degraded wiring harness in the engine bay.

ajbristol

yes shes a 92 imported from Singapore to UK about 3 yrs back. low miles @ 55k but just got these few probs, which although are not the end of the world are dammm annoying.

NZ_Benz

Thats where my car came from too. Mine had a new wiring harness when it arrived in 2001 or the new owner here in NZ delt to it. AC core was doen too.

Phoenix

my 97 S500 has the same clicking sound of a relay form the same place.
i hear it mostly when i accelerate hard.
i was wondering what it was myself.

ajbristol

I have changed the crank position sensor today so will post at a later date to advise if this has cleared the warm start problem. Done by QAS auto's Bristol UK @ £118+vat part alone was £103inclusive from MB bristol so not worth getting hands dirty really was it.

Rod Spohn

If it still starts hard try the fuel presure regulator. I just finished tracking down the same problem. After changing the crank positioning sensor , cam sensor then finally the fuel pres. regulator. Regulator fixed it. As for the sound from behind the dash , its probably the vaccum relay for the AC. It controls the doors when you change zones ( like air from floor to dash vents) When it starts to go it makes that type of sound as it randomly changes without you moving controls. This is due to Vaccum leaking I believe. Hope this is some help.

Drive On

ajbristol

Thanks, car been fine so far until today when it started to miss fire at low rpm once over 1000 seems ok, its as if its missing on about 2 cyl so still a gremlin in there somewhere, I will change the fuel press reg just in case that was the other item on my list of suspect bits but thanks for your reply. With regard to the relay clicking from behind the passenger side of the dash I think I do have a vac leak somewhere ?? as my heater now turns its self on as it wants to and not normally when I want it to....lol, I can be driving down the road and suddenly it clicks on to automatic... either its faulty or I have a ghost who like it warm.

ajbristol

Tried car again today no problem whatsoever so maybe it was a bit flooded just sitting on choke for 5 mins. Drove about 50k no problems not a single miss.