1974 280 SE Cold start issue. D Jetronic

[carl888]

Hi Lance,

Thanks for the tip.  Have replaced the gauze filter and performed a flow and pressure test on the pump, all good.  Same with the MAP sensor too.  Not only does it check out fine, but substituting another doesn't resolve the issue.

I think the problem must be fuel related however.  I start the car from cold and let it run for say 3 seconds and switch it off.  Should I come back and hour later (When the engine can't possibly be warm) the engine fires straight up.  Same when it's hot.  However after an hour, it's a PIG.  It does always start though!

It's just got to the stage where I have no option but just replace items.  I really cannot live with it the way it is.  It's breaking my spirit.

       

[Lance]

In hindsight most likely nothing to do with the MAP sensor.
You need Dr Djet, search oldtimer.tips on the net. Join up, he seems very knowledgeable and ready to help. It is a German site but he will reply to questions in good English.

[Lance]

Not the AAV valve is it? Does it start better with a bit of throttle?
Also, the non return valve in the fuel pump not working.
For mine to start easily from cold, I turn the ignition on twice then start with a small amount of throttle.

[carl888]

It's bizarre Lance!

Throttle, or no throttle, makes no difference.

My cold idle is 1,200 RPM.  Curious, what is everyone elses?

I see you're in Melbourne, Have a look at the post about a January meeting in "The Org" 

[carl888]

Thanks for the other tips Lance.

[Lance]

I see you're in Melbourne, Have a look at the post about a January meeting in "The Org" 

But I only have W116-2 (W114 )

[Lance]

If the cold idle is 1,200 then the AAV is working, try posting on oldtimer.tips.

[carl888]

I see you're in Melbourne, Have a look at the post about a January meeting in "The Org" 

But I only have W116-2 (W114 )

Well, no body is perfect!

[carl888]

If the cold idle is 1,200 then the AAV is working, try posting on oldtimer.tips.

OK, thanks Lance

[Lance]

https://oldtimer.tips/en/
Or just search dr djet

[carl888]

Hello W116s.

Looks like I fixed the long running 280 SE D-Jetronic starting issue.  I can't say exactly what I did however!

Update here on the D-Jetronic forum:

https://oldtimer.tips/en/forum2/jetronic/328-starting-issue-1974-280-se?start=40#6293

[gf]

Hooray!!!!!!!! Hmmmm. All that suspense waiting for the answer to the cause. It's like missing the last episode of a good series