M102 engine: cold running problem

PaulAA

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Afternoon All

Newby here, new to the forum and new to MB ownership. I've just bought a 1990 230TE, good overall condition, supremely comfortable and it won me over with the relaxed, effortless 200km drive from the vendor to the car's new home.

So, full service done as soon as it arrived, brake pads, discs, front springs and all tyres replaced. All filters and fluids changed, new dissy cap and arm, new plugs. Engine bay a bit grubby, but the wiring harness looks to be intact.

Everything looks good, except for cold starting, when the engine hunts a little at tickover and then repeatedly 'misses' under load. I went back to the mechanic who did the service and he adjusted pressures on the KE Jetronic, replaced the boot under the throttle body and assured me that the problem was either cured... or electrical... Unfortunately, it is not cured. Once warm, all is good and the engine runs smoothly.I've searched the forum, but haven't found the conditions I'm describing - can anybody help? Any thoughts?

Engine is the M102.982 - does this fall into the category of failing engine looms?

Thanks

Paul
 

grober

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Sounds as if you have a problem with the warm up idle regulator assuming the car starts OK. There are two types to bypass the throttle butterfly- the early one based on a heated bimetal strip the other a motorised valve
 

optimusprime

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Paul this is a hard one . I would never let any one play with my injection system . Now if the OVP relay is faulty then the ECU wont have power to enhancments . Like power up the cold start injector , the engine temerature sensor, and warm up regulator ..etc
 

Will

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First things first - did the car have this problem before the service? :)
 

optimusprime

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Good question there Will Paul ..You replaced most of the ht system why not the plug leads [none resister type plugs and leads ] . Every time i have thad my engine missing its been a plug lead every time .
 
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PaulAA

PaulAA

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Chaps, thank you for your responses and apologies for the slow feedback... long weekend away.

The car was a little hesitant from cold when I bought it, but seems to be a lot worse since the service, which was done more or less as soon as I got it back to Warsaw. Yes, I replaced everything in the ht system except the leads, but only because they look to be practically new Bosch leads.

To be specific, the car starts either on the first or second turn of the key and idles reasonably smoothly. It only begins to show the problem when the throttle is pressed, as if it has been provoked.

Good call on the OVP relay - I will get it tested... or replaced. They are about 30 quid here.

Graeme, I'm not sure I can identify the warm up idle regulator. Could you give me a bit more detail? I assume it isn't the idle air valve..?

I've not tested the coolant temperature sensor or the O2 sensor - could either of these be the cause of poor running when cold?

Thanks

Paul
 

optimusprime

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Paul I dont think you going down the right path but - .It is not unknown for the WUR to go wrong and fail and seize up . And often the rivets holding them to gether can be drilled out to service the WUR thats its name by the way .There is a service kit to do it yourself - Google for a repair company who will rebuild it for you bbb122d1-4dfe-48f2-bf1d-8a7f0dcc307b_k+jet+warmup+reg.jpg for you .See picture of WUR . I can find you a picture of its location on the engine if you dont know where it is .
 
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PaulAA

PaulAA

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That's very helpful - thanks. I've searched on the engine itself and in partial tear-down pictures on the web, but I can't identify its location. If you could post a location, preferably on the m102.982 engine, that would be great.

Thanks

Paul
 

optimusprime

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This isa picture of the WUR you need to remove the air box to see more of the engine . I searched for a picture of it in its location but cant find one .
POP.jpg
 
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PaulAA

PaulAA

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Under the air filter box - check.

Thanks

BTW, probably thirty years ago, I designed the original scheme for the KRM building, next to what was then the BR station.

Paul
 

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Check the coolant thermostat . Probably stick open.
 
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PaulAA

PaulAA

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Graeme

Definitely. Thanks for the link - question is, does the KE Jetronic also have the WUR? The car's daily driver, my son, is away on a trip with it, so I won't be able to check myself until they return tomorrow.

Paul
 

grober

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The KE does not have a WUR ---- post starting enrichment is achieved by the electro hydraulic pressure regulator. see page 17 onwards
 

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