Rover 75 1.8 intermittent engine cutting out

[gliderdoctor]

Hi all

Been lurking here for several years and got lots of useful info from all you experts, thanks a lot, but a bit stuck with this one.

Went to pick up the kids last week (about 20mins drive) (1.8 non-turbo, auto) engine started fine, but on setting off, every few seconds the engine would cut for about 1 second, then carry on. A few seconds later, it would do it again. I almost turned back and went home, but after about a mile, it cleared and was fine, no issues for the rest of the journey.

On coming home 10 mins later though, it was doing the same cutting out for about a second every few seconds. then it would be fine for a few minutes, then do it again.

It seems an intermittent electrical issue, because every time it cuts out the rev counter immediately drops just as if it has been turned off for a second, then comes back as normal, just as though a wire somewhere is broken but touching and making contact most, but not all the time.

Doesn't seem to have much of an issue starting hot or cold, although it does have to crank over a few times occasionally before it fires.

Any ideas you 1.8 or electrical experts?

Many thanks
Dave

[suzublu]

First I would check for fuel filter separation. I'll leave the electronic stuff for the experts 😎

Sent from my SM-A326B using Tapatalk

[gliderdoctor]

Thanks Suzublu

I will have a look at the filter under the rear seat on Monday. I haven't done that already as I have made the assumption (perhaps incorrectly) that the issue is electrical in some form or other, as the instant the engine cuts, the rev counter needle just drops as though it is turned off, and a second later when the engine catches again, the rev counter needle goes immediately back up to where it should be.

I will look at the filter though, just to perhaps eliminate that as the source of the problem.

Thanks
Dave

[dave lincs]

I think it is very unlikely to be the fuel filter as usually if it is the filter it wont start, I would be looking at the wiring that goes to the crankshaft sensor and the connectors on the bottom of the under bonnet fusebox

Dave

[gliderdoctor]

Thanks Dave

Where is the crank sensor? is it obvious? I assume it has an electrical connector of some sort on it that may be loose or or the wiring chaffed somewhere. also I will have a look at the underbonnet fusebox for loose connectors, etc.

Thanks
Dave

PS What does the crank sensor actually do once the engine is running? I understand the crank and cam sensors inform the ECU of the crank and cam positions for the timing, etc, for engine starting, but what do they actually do once the engine is running?

[SD1too]

Hi Dave,

I can answer your questions using RAVE (I don't have a 1.8).

Originally Posted by gliderdoctor

Where is the crank sensor?

It's mounted on the front of the gearbox housing in line with the flywheel.

Originally Posted by gliderdoctor

What does the crank sensor actually do once the engine is running?

It enables the ECM to control ignition and fuel injector period and timing. If the signal is missing, the engine will stop running.

Originally Posted by gliderdoctor

I understand the crank and cam sensors inform the ECU of the crank and cam positions for the timing, etc, for engine starting, but what do they actually do once the engine is running?

The camshaft position sensor (CMP) is also required by the ECM to complement the data from the crankshaft position sensor. If its signal is missing the engine will still run but with a reduction in performance and driveability.

By the way, your profile says that you have a diesel. If it's out of date, can you change it please?

Simon