Need to pick some brains. Stall issue.

**r1chm** · 25-07-2019,12:49 PM

Hello

2007 Passat B6 2.0 TDI (automatic, BKP engine)

I am experiencing an issue where the car is stalling/engine turning itself off intermittently. When approaching a junction, on three separate occasions yesterday, it briefly starts to "struggle" and then simply stalls (no lurching or anything, just a quiet death). It has happened when the engine is hot and cold/warming up.

After the stall, it might start again straight away, other times I have to keep turning the engine over for 5-6 seconds and feathering the throttle until it starts again, sometimes 5 or 6 attempts. Once it's started again, it generally revs freely and if I manually turn off the engine it starts again right away (hot or cold).

Sometimes at idle it is a bit "lumpy" (but still revs alright) and other times its as smooth as you like.

Yesterday it stalled itself whilst idling, and in recent weeks has sometimes stalled as I begin to drive away (just after its taken the EPB off and begins to move), but again it is intermittent. When it is running fine, it pulls well, no smoke, no other known issues at all.

EML did not come on, but a scan revealed error code P0321 (passive) which I gather from Googling can be a whole raft of things? People seem to suggest fuel pump/filter, crank sensor or cam sensor, or possibly an injector. Given that there are no other fault codes, nothing specific to a misfire on cylinder X, I believe it is fairly safe to rule out a faulty injector?

I think am leaning more toward a faulty/dying fuel pump, but before I throw money at the car I was hoping someone could confirm my suspicions or suggest other things to look at.

I have an OBDeleven but don't know how to use it properly, if any "live monitoring" is required.

Thanks for any help.

Rich

**Crasher** · 25-07-2019,04:14 PM

16705 (P0321)000801 - Engine Speed Sensor (G28): Implausible Signal

Classic crank speed sensor failure, an absolute PITA to change on a BKP, you have to remove the oil filter bracket (new bolts and gasket are a must) and you will need a long ball ended 5mm hex (Allen) key and the key needs to be new and sharp if you round out the head of the screw, it is box and clutch/flywheel off.

Damage the oil seal and you are in a world of hurt, the chap across the road from us once did one and he rounded out the bolt so he used a blow torch to heat up the screw, the seal holder is plastic... If it has to be replaced the sump has to come off and the seal must be indexed to the crank using an installation tool with the engine locked at TDC.

**r1chm** · 25-07-2019,04:26 PM

...that was my least favourite answer. Lol. I had heard how bad they were to change.

Is there a way to test the sensor in situ before going to the hassle of removing it?

Thanks

**Crasher** · 25-07-2019,05:12 PM

Do you own an oscilloscope? You could use OBD11 to observe the live data and watch the rpm signal is graph mode, when the problem occurs you will see the signal drop BUT that could be indicative of a problem elsewhere just making the RPM drop, the only accurate test is to watch the output signal on an oscilloscope.

**r1chm** · 25-07-2019,09:38 PM

I don't have one I'm afraid.

On the flip side, is there an easy way to check the fuel pump on these cars to rule that out?

**Crasher** · 25-07-2019,10:26 PM

Which one, there are six.... there is an electric lift pump in the tank, an engine driven mid pressure on the end of the head and each injector is a pump. Why would you worry about fuel delivery when the engines computer is picking up a bad signal from the engine speed sensor?

**r1chm** · 26-07-2019,09:34 AM

Ah right, didn't understand that your initial reply was a certainty. I thought it was your advice on the culprit from the possibilities listed which all appear to cause the P0321 code (according to Google) and was interested in still checking fuel delivery to rule that out before messing and trying to change that sensor.

I'll get one ordered and see if it does the trick. Given your warning re rounding out the allen socket, I presume these bolts can be stuck really well so i'll soak it in PO and hope for the best!

Thanks