warm engine difficult to start

hi

I own a 350 slc with m116-V8 engine.
cold engine starts without any problem when I turn the ignition key.
the warm engine will not start at the first attempt.
only If I rev up the engine before turning off will the engine start when it is warm in the first attempt.
in the bosch d-jet manual it is recommended that the warm engine should be started by partial pressing of gas pedal but this does not work either.
what could be the problem and what is the remedy.

when I get off the car my clothes smell gas and burnt exhaust.
the wall in the garage where I park my car has a black spot created by the exhaust. the last time when my engine specialist made the final adjustments he kept the CO levels higher than that is recommended i the bosch d- jet manual. he said that this way engine would rev up better. (?) could this have anything to do with this. what would you recommed

Hi Juan,
nice to hear from you again.

You left jetronic.org 18 months ago with the same problem: jetronic.org/de/forum/introduction-vorst...roblem?start=40#8514 .

Did you check out the hints Volker and I gave to you there?

We don't really know: Does the car run rich or lean?
You write, it stinks from gasoline and exhaust.

This would mean, it runs rich.

But, this car has no catalysator and HAS another smell than new ones. Driving on the road behind a classic car means inhalating this special smell...

Yes, and classic car leave spots on walls... Maybe this is all normal, maybe the car runs rich.

Back to your problem.
I remember you had your TPS rebuilded, your MPS revised at Bosch, your ECU changed.
Where the other components checked, too: the injectors (maybe they drop), the cold start valve (maybe it leaks)?
What about the fuel pressure? Does the pressure stay almost constant or does the pressure leave in a few seconds?
Do the spark plugs look black, brown, white or crusted....?

You wrote, your workshop did adjust the CO higher than recommended.
Do they know this adjustment is active only at idle, not in normal driving?
And - could they adjust the CO to the normal level or did this fail?

We need more information from you.

Regards
Norbert

Hi Juan,

and additionally if your clothes smell exhaust, you must have a leakage on your exhaust and your chassis so that the smell can come inside. A black spot on the wall from exhaust of a starting car is normal. Cold start enrichment form cold start valve and ECU will let the engine first run very rich. But that should come down quickly.

You could come with your car to Antakya in August. I will be on a wedding then. But yes I know it is too far from Istanbul.

And yes you still need to measure fuel pressure and how qucikly it drops after switching off engine.

Hi Norbert,

I know that the car is running with a rich mix.
I took my car to TUV inspection last year.
Beforehand I asked my engine mechanic to adjust the CO values for exhaust test. He adjusted it a bit higher.

I also know that the AAV needs repair.

injectors were all replaced with new old stock.
fuel pressure is around 2,0 bar. Was measured several times.
in the beginning the car had the wrong fuel pump
I found the right one in the US and brought it to Turkey.

When ECU was defective I used to have black spark plugs and they were replaced mamy times. I suppose it shows that the car is running with rich mix.

the CO level could be adjusted to the normal level but later the mechanic set it higher he said this way engine would accelerate much better

I will try once I get the avv back from repair

thx again
juan

nordfisch wrote: Hi Juan,
nice to hear from you again.

You left jetronic.org 18 months ago with the same problem: jetronic.org/de/forum/introduction-vorst...roblem?start=40#8514 .

Did you check out the hints Volker and I gave to you there?

We don't really know: Does the car run rich or lean?
You write, it stinks from gasoline and exhaust.

This would mean, it runs rich.

But, this car has no catalysator and HAS another smell than new ones. Driving on the road behind a classic car means inhalating this special smell...

Yes, and classic car leave spots on walls... Maybe this is all normal, maybe the car runs rich.

Back to your problem.
I remember you had your TPS rebuilded, your MPS revised at Bosch, your ECU changed.
Where the other components checked, too: the injectors (maybe they drop), the cold start valve (maybe it leaks)?
What about the fuel pressure? Does the pressure stay almost constant or does the pressure leave in a few seconds?
Do the spark plugs look black, brown, white or crusted....?

You wrote, your workshop did adjust the CO higher than recommended.
Do they know this adjustment is active only at idle, not in normal driving?
And - could they adjust the CO to the normal level or did this fail?

We need more information from you.

Regards
Norbert

Hi Juan,
could you please look for the color of the injectors?

This could be essential...

Regards
Norbert

They are yellow 0280150034

Hi Juan,
the injectors are the correct ones.

Did you measure the vacuum level at idle? What about the vacuum line towards the MPS?

A loss of vacuum <vacuum leak> would signalize the MPS a higher demand for fuel.

Regards
Norbert