E36 328i Engine Hesitation

[spikeymikey12000]

I've posted on this before.

My 328i runs lovely but at about 1,500rpm - 1,700rpm there is a hesitation in the engine, as if its misfiring. Happens under power and when the engine revs are coming down too.

So far I have changed the air filter, mass airflow sensor and fitted a new ait intake boot. I have changed the spark plugs and tried different coils and no difference whatsoever.


My next move was to change the cam position sensor but cant get a couple of pipes out of the way to do it myself.


Any other ideas? Car has done 125k and above 1,700rpm the engine is really sweet.

[helix402]

Could need a VANOs rebuild.

[spikeymikey12000]

Really hoping it’s not that. Seems to be only across a 200 rpm rev range which makes me think not

[bearman68]

Air leaks on the inlet pipework are common on these.

[helix402]

spikeymikey12000 said:

Really hoping it’s not that. Seems to be only across a 200 rpm rev range which makes me think not

It’s not a hard job, my E46 328i M52tu used to do it after oil changes and very rarely on cold starts till I rebuilt the VANOs.

[E-bmw]

helix402 said:

spikeymikey12000 said:

Really hoping it’s not that. Seems to be only across a 200 rpm rev range which makes me think not

It’s not a hard job, my E46 328i M52tu used to do it after oil changes and very rarely on cold starts till I rebuilt the VANOs.

Don't be afraid of doing it yourself, you don't need to fully remove the Vanos unit if done with care & it can be done in around an hour easily.

[spikeymikey12000]

Is it just the seal that needs replacing?

[vsonix]

Are there any codes present or is it just coming up with no faults found? It does sound a little like a bad crankshaft sensor, but if there are no codes present then I'd be thinking either a vac leak, or maybe the MAF's feeling its age.
Is the engine standard or are there any modifications at all? Does the engine do it when it's still cold, or does the problem only appear when the car is up to temperature?

[spikeymikey12000]

I’ve changed the MAF and no change. Haven’t had the codes checked but no check control issues and no engine lights on.

There’s no difference whether the engine is hot or cold - totally standard engine with no mods

[E-bmw]

spikeymikey12000 said:

Is it just the seal that needs replacing?

2 seals IIRC, but yes.

Also IIRC it is 1500rpm that the Vanos is energised/de-energised.

[vsonix]

spikeymikey12000 said:

I’ve changed the MAF and no change. Haven’t had the codes checked but no check control issues and no engine lights on.

There’s no difference whether the engine is hot or cold - totally standard engine with no mods

There is no check engine light on a UK model E36 so not seeing one means nothing.

[BGarside]

FWIW when the cam sensor went on my E36 328i the revs bounced up and down at idle and the car tended to stall when idling out of gear coming up to lights etc, so doesn't sound like that might be your problem.

Had the VANOS seal and rattle ring replaced on mine by a local specialist, bought the kit from i6 Automotive via eBay and it wasn't expensive to get the parts fitted so don't worry too much about that.

Another possible issue is crank sensor failure, though I don't know what the symptoms of that would be. Cheap and easy to check the main intake rubber hose for splits in the corrugations though and also the small-bore hoses entering the intake system after the air mass meter.

[dmarkovina]

Any chance of hooking up INPA and getting the error codes?

Don't think it's vanos - when it's out on M52 (nonTU) you only get flatter torque curve.

Edited by dmarkovina on Monday 28th January 17:41

[vsonix]

Honestly it sounds more like crank sensor to me, especially as AFAIK the car takes readings from cam and crank sensors regardless if in open or closed loop mode.