E30 Zone

I've just bought an 1987 325i cabriolet which has an intermittent cutting out problem. It only seems to do it when it gets up to running temperature. Person I bought it from thinks it may be an issue with the alarm what's fitted but not in use. Just wondered if anybody else has had the same problem and if so what was it ?

First thing to check is Fuel and Spark.....

I have intermittent cutting out problem too. Mine is 318i with M40B18 engine.

Always happens when driving. The engine doesn't die, just losses power momentarily (a fraction of a second).

I notice the fuel flow gauge drops to zero when this happens. Possibly fuel filter blockage or the fuel pump is on its way out?

IF it's cutting out when hot, I'd be checking the crank position sensor.
These can break down with age and cause misfires, and cause the engine to cut out as the ECU looses it's reference point.

It can be checked using a resistance check on a multi meter between the pins, if it's out of the specified range of 540 ohms +/- 10%, its probably more than likely blown and malfunctioning.

More info here: http://84.45.115.78/e30zonewiki/index.p ... ion_Sensor

Thanks for the tip. The cut outs seem to happen mostly in hot weather or after a long drive (250+ km).

I located the CPS, next to a toothed pulley, in front of the engine. It has pretty long cable and the plug is hidden under the intake manifold. It is well covered in black grease/gunk so possibly still the original one from 1989.

My 323i was doing the same. I recently found a small leak in the heater hose that was squirting coolant at the distributor. Inspection showed some had got in. I replaced all of the radiator hoses today, and fitted new jubilee clips. I also cleaned up the inside of the dizzy cap(old style, side mounted),Does anyone know if the coolant hitting the distributor could be the cause?

I'm having the same problem but mine is doing it even when it's warming up. When up to temp and in put my foot down it cuts power off for a split second. Is this a cps problem aswell?

The CPS connection is found just under the service plug for resetting the dash lights as per the arrow.



When up to temp, the cutting out can be caused by a faulty CPS sensor as heat causes them to break down internally.

Do early (1984) 323i have a CPS?

Silferfang, my engine is 4 cyl M40.

Now the newbie question: where do I find the ECU?

I looked in the engine bay but didn't see it. I checked the glovebox and took out the plastic cover on the top of the glovebox, there's a black plastic box there, not a metal ECU box and didn't seem to have a big electrical socket or thick wiring loom.

Damn it is not the coolant squirting on the dizzy causing the cut out. All new pipes, cleaned up dizzy , no leaks, but still the occasional cut out. Mainly on corners!!!!

mackley wrote:I've just bought an 1987 325i cabriolet which has an intermittent cutting out problem. It only seems to do it when it gets up to running temperature.

DME relay! If yours is the pre 9/87 engine with the two speed sensors on the flywheel (look at the gearbox bellhousing on the passenger side) then this is very likely the problem.
There are two relays together on the inner wing (passenger side near the air box) and it's the one with five pins. At this stage it's worth replacing both this and the four pin fuel pump relay next to it.

DME relay is easily checked out by removing it and fitting two short wire links to its base, linking together pin 30 and both 87s. If the car runs properly with these links in place, then the relay is probably the problem. If the fault returns when the links are removed and the relay refitted, then it is almost certainly the problem.
Don't forget to remove the links when you park the car, or you'll return to a flat battery.

Would this apply to a 1984 323i?

xavier wrote:Would this apply to a 1984 323i?

Sort of - on these the tall seven pin fuel pump relay goes tits up. It controls the injectors as well.

Andyboy wrote:

xavier wrote:Would this apply to a 1984 323i?

Sort of - on these the tall seven pin fuel pump relay goes tits up. It controls the injectors as well.

Wiring diagram for an '84 318i is in our wiki, which is fairly close to that of your 323i.
Same applies to the 7 pin combined relay - connect 30 to both 87s and it's bypassed.

I've removed the alarm and it still does it and the relays on the inner wing have been replaced. It is loosing all power to the fuel pump. The car dies at this point then will re start after a min or two then die after another min or so driving.

New or used DME relay?

Mackley, please answer the question about what the instruments do when it cuts out. See the third post in the thread.

This will help with diagnosis.

Thanks
Ben

I bought a DME relay from sytners Leicester £11.
My car was randomly cutting out, rev counter droping straight away.
I did the test bulb from the + of the coil to an earth and it stayed lit when the fault happened.
£11 DME relay seems to have sorted it, not missed a beat since fitted

When the car cuts out the rev counter drops and the ignition lights come. The temp gauge has a mind of its own as goes up into the red at times but the car if deffently not overheating and if you hit the top of the dash it drops back to half way.

Forgot to say also the car has new dme relay fitted.