R129 500 engine intermittent hesitancy ?

[dellyend1]

Dear All,

Firstly hello I've just picked up my SL500 1993 and driven back a 110 miles which was a joy. The car is great, other for one small concern.

After I have driven approx. 50 miles , the engine started intermittently hesitating ( a bit like bad fuel going through the system) . It would then disappear for 2o mins and then happen again. If I booted the accelerator it did not misfire but just lurched into life.

I initially thought it might just be crap in the fuel as the car has been standing around for the winter or maybe some crud in the filter. Failing that I am thinking HT leads which after an hours driving are producing a small misfire ?

Any help would be gratefully received.

Many Thanks

Jeremy

[HumbleJim]

dellyend1 said:

Dear All,

Firstly hello I've just picked up my SL500 1993 and driven back a 110 miles which was a joy. The car is great, other for one small concern.

After I have driven approx. 50 miles , the engine started intermittently hesitating ( a bit like bad fuel going through the system) . It would then disappear for 2o mins and then happen again. If I booted the accelerator it did not misfire but just lurched into life.

I initially thought it might just be crap in the fuel as the car has been standing around for the winter or maybe some crud in the filter. Failing that I am thinking HT leads which after an hours driving are producing a small misfire ?

Any help would be gratefully received.

Many Thanks

Jeremy

I have no idea, but since having my SL320 R129 these guys have been helpfull in pointing me in the right direction. The knowledge on the forum is outstanding.

http://forums.mercedesclub.org.uk/

[Xtriple129]

When my SL 500 did this, it was the MAF thing. As it deteriorated the idle got really lumpy as well.

[BlueMR2]

Worth checking the wiring loom on a car of that age.

[GregE240]

Distributor caps and / or rotors

[RiccardoG]

There you go, 4 replies each one with a different possibility!

Did you buy this car in London (only asking as I was recently looking at a blue 1993 SL500)?

[TEKNOPUG]

RiccardoG said:

There you go, 4 replies each one with a different possibility!

Work through them in order of price

[Seeker UK]

GregE240 said:

Distributor caps and / or rotors

Worth a check but AIUI is more of a problem on the M119 engine, not the M113 engine which the OP's car has.

[Mercky]

Seeker UK said:

Worth a check but AIUI is more of a problem on the M119 engine, not the M113 engine which the OP's car has.

The OP'S car has the MII9 engine not the M113(It would be very hard to check caps and rotors on an M113...)

From previous experience,I would replace the caps and rotors if they look anything less than perfect.

Edited by Mercky on Tuesday 11th February 22:06

[Pentoman]

Also at this point I think it's worth noting that surprisingly the M119 came with KE-jetronic in early versions and... something more high-tech (LH-jetronic?) on later versions. Completely different methods of metering the fuel and air, so each engine could be different. Think the switch was around 1992-1993 time.

If I could be bothered I would think up a way that you can tell the difference.

Oh yes - toilet lid in the intake = KE-jetronic

This stuff takes me back...

Good luck

[Howitzer]

GregE240 said:

Distributor caps and / or rotors

I would at least have these checked. M119s are very hard on Caps and Rotors for some reason.

Dave!