Diesel runs lumpy when hot

chopper007 · Jan 29, 2015

Hi All, stuck in traffic last night ( due to snow.. but without any snow.. go figure)
anyhow.. car started running lumpy when at idle after about an hr..
i say 'hot' but the engine wasn't running 'hot'..
it was just that i'd been stop start in traffic for an hr..
took me 2 hrs to get home.. and was the same all the way..

didn't get any worse or stall or anything..

any thoughts ?

Datatek · Jan 29, 2015

Year of car & engine type would help.

chopper007 · Jan 29, 2015

Oops sorry.
1999 dse manual
Its the 2.5 bmw straight 6 diesel.
It had a 'power box ' on it which ive unplugged today to see if it makes any difference Although not sure when it will next be out running for over. 2 hrs etc

Datatek · Jan 29, 2015

chopper007 said:
Oops sorry.
1999 dse manual
Its the 2.5 bmw straight 6 diesel.
It had a 'power box ' on it which ive unplugged today to see if it makes any difference Although not sure when it will next be out running for over. 2 hrs etc

Is the EGR still operational? Probably worth looking at diagnostics but it could be an injector, CPS or any number of things.

chopper007 · Jan 29, 2015

Hmm. Ok. Have no idea Egr wise, not very mechanical savy am afraid, so dont know if it
Had it removed or not. But seams to run just fine when im running to the shops etc, a 20 tun eachway.
But sat in traffic not moving was like it had a cylinder missing or something. So just thought id ask in case there was something easy i can check etc

Datatek · Jan 29, 2015

chopper007 said:
Hmm. Ok. Have no idea Egr wise, not very mechanical savy am afraid, so dont know if it
Had it removed or not. But seams to run just fine when im running to the shops etc, a 20 tun eachway.
But sat in traffic not moving was like it had a cylinder missing or something. So just thought id ask in case there was something easy i can check etc

Look on the end of the inlet manifold and you will find the EGR, there is a vacuum pipe from it that goes to a valve on the bulkhead behind the EAS box. Pull the tube off (if it's there) and block it with an M5 screw.
They run better with the EGR disabled, so nothing to lose. Probably will not make a any difference to your problem.
As I said, really need diagnostics.
Wammers may have a better idea.

chopper007 · Jan 29, 2015

Ok cool. Will take a look tomorrow! I can def manage that !!
Ha ha

wammers · Jan 29, 2015

Datatek said:
Look on the end of the inlet manifold and you will find the EGR, there is a vacuum pipe from it that goes to a valve on the bulkhead behind the EAS box. Pull the tube off (if it's there) and block it with an M5 screw.
They run better with the EGR disabled, so nothing to lose. Probably will not make a any difference to your problem.
As I said, really need diagnostics.
Wammers may have a better idea.

Worth a try if EGR valve is sticking open or coming on when it shouldn't. It should never open at idle. Diag is way forwards as Keith says.

kds · Jan 30, 2015

Does it only do it on tickover engine hot? does it go away if you blip the throttle for few seconds then starts again ? If its a yes then my guess would be DMF, mines doing the same again !! Fitted new DMF and clutch about 5 years ago, it can wait a bit longer to change it.

chopper007 · Jan 30, 2015

DMF ? No i tried blipping, but didnt help any. Only seams to do it when stood for a long time in traffic.
As i say. It never stalls, but you can see the rev counter dipp etc

wammers · Jan 30, 2015

If there is an absence of fault codes on diag. DMF is a good shout.

Diesel runs lumpy when hot

chopper007

Active Member

Datatek

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chopper007

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Datatek

Well-Known Member

chopper007

Active Member

Datatek

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chopper007

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wammers

No longer with us, RIP

kds

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chopper007

Active Member

wammers

No longer with us, RIP

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