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+--- Thread: OM606A start probs when above 85C... (/showthread.php?tid=8370)
OM606A start probs when above 85C... - TBMY - 06-26-2020
Hi!
There is something fishy going on...
OM606A, kkk14, DP7.5mm, egr removed, ca 275hp, 300.000km
Starts fine when cold, also in -15C in winter, so compression should be ok.
Ok idle running, normal nailing. Goes good as long as I dont stop it.
When warmed up to ca 85C, it can crank forever, some puffing in exhaust.
No blinking on red/green rear mirror leds during cranking.
When it stands still long enough to cool down to 60-70C it starts again.
I started to analyse problem. I had lots of bubbles in plastic tubing, due to fuel breathing valve was stuck.
Getting vakuum i fuel tank that pulled fuel back to tank when motor stopped.
Changed breathing valve, all o-rings, bypassed fuel heater; no more bubbles.
Changed crank position sensor, just in case.
Changed dieselfilter.
Changed starter, since old was worn out.
Maybe temp related, but not sure.
No error messages in Star.
What can it be??
Cheers, Tom
RE: OM606A start probs when above 85C... - TwoMuchBoost - 06-26-2020
If you’re talking a mechanical 7.5mm pump and not EDC 7.5mm, the crank sensor does nothing but run tachometer and run electronic idle speed regulation(which you also don’t even need). Definitely chase after those air bubbles and figure out where they’re coming from. Air is compressible and retards timing effectively and reduces fuel quantity injected.
You could have no crank signal, no glow plugs, hell.... no battery power even; and on a hot 85*C engine you could roll it over it should fire right off if injection is working correctly.
RE: OM606A start probs when above 85C... - TBMY - 06-26-2020
Thanks for input! I forgot to mention its a EDC pump.
I will chase some more bubbles!!
:-)
RE: OM606A start probs when above 85C... - TwoMuchBoost - 06-26-2020
I should have guessed it was EDC when you said "error messages in STAR" haha. The crank signal is much more important for those pumps and they do tend to act up/fail most often on a hot engine. Since you have that already ruled out with a new sensor, chasing the air you're finding is still a good path with the lack any codes and small puffs of smoke coming from the exhaust; sounds starved for fuel.
It's not losing/consuming any coolant is it?
RE: OM606A start probs when above 85C... - TBMY - 06-27-2020
No problem with coolant missing, thankfully, but I did see some air pockets in the plastic tubing around diesel filter/pump after standing still. Think I will change the shut-off valve too, thats only whats left to change I think.
Faulty temp sensor on block or the two temp sensors on coolant tube or inlet airtemp sensor should not be able to cause this problem I guess?
RE: OM606A start probs when above 85C... - AlanMcR - 06-27-2020
The lack of red/green is weird, but I'd still guess that the K40 is a possible fault. I presume that the red/green leds do light up with the remote is used to lock/unlock the doors?
Replace the K40 with a known good one. In theory, a bad K40 will stop the engine once the relay gets warm. But it could be that it is only failing when the stopped engine heat-soaks it.
RE: OM606A start probs when above 85C... - TBMY - 06-27-2020
Yes, the leds light up red when locking and green when unlock by remote.
K40 is a good tip
Will look into that as well!
RE: OM606A start probs when above 85C... - TBMY - 07-01-2020
Hmm. Changed diesel-shut-off-valve (black plastic) and K40 relay. No air bubbles at all now, even when standing still for a while. Still problems starting when hot. Must be a electrical problem, steering of EDC pump? Typical ground points or wires to check?
RE: OM606A start probs when above 85C... - AlanMcR - 07-04-2020
Do you know anyone with the STAR system? With that you can get actual sensor values, including whether the ECU is seeing the CPS sensor signal. No CPS signal (for any reason, including wiring) = "engine not turning" = "no fuel".
RE: OM606A start probs when above 85C... - TBMY - 07-07-2020
I have Star, but still learning how to use it. I will look into your tip! Thanks!!
RE: OM606A start probs when above 85C... - TBMY - 07-09-2020
Went over ALL grounding points, brushed and cleaned them and spades on wires. Problems gone!
RE: OM606A start probs when above 85C... - AlanMcR - 07-10-2020
Awesome!