E30 Zone

Heya. I have a bit of a problem, the car won't start.
It turns over and just at the point where you'd expect it to idle nicely, it stalls immediately. Because of when it stalls, it seems the battery and starter etc are ok as it does fire up, but just doesn't continue to run.

I'm thinking it could be something electrical, but I've no idea where to start. The only thing that we done different recently was to remove the battery and put it in another car just to see if it that size would fit in it. It's a new battery and I'd started and moved it minutes before we took it out and there was no problems then. It wasn't until I went to go to work the next day that I found out it wouldn't start (thought it was the cold but won't start no matter what time of day I try)
It has an M50 engine in it and the battery is in the boot, so couldn't have knocked anything while tinkering

Is there anything I can check? (I don't have home start recovery, and its booked in for mot during the week so I need it ready to drive then)

Thanks in advance

Idle Control Valve leaps to mind,has it's electrical plug been disturbed by swapping the battery?

Which E30 do you have?

The wiki has an exellent trouble-shooter to enable you to work through the car's systems in a methodical manner,no doubt the grrrmachine will be along shortly with a link to it,that's way above my computer skills!

You mean this one, Malc?

http://www.e30zone.net/e30zonewiki/inde ... oubleshoot

By the sounds of it there's either a gaping big air leak or, as you say, the Idle Control Valve has been disturbed.

The battery is in the boot as I've got an M50 lump in it

Thanks for that link, I'll look through it now. Bear in mind my mechanical knowledge is limited and I shall have to hassle the other half to help me

Oh right, non-E30 engine That guide's really only written for standard engines, since M5x engines have a whole other level of electronic stuff going on, which I'm clueless about.

Stupid me kinda forgot to include that bit of important info.

Ah,now we can try to help.

I also have an M50'd touring and had a similar issue a few weeks back.I found that the ICV(idle control valve I mentioned above)had dis-connected it's self from the inlet manifold,snag is,it's under the inlet manifold and can only be reached by having a grope from the front of the engine,what you are feeling for is a round cylinder that should be connected to a pair of hoses,not flapping about in the breeze.One end should have an electrical connection to it.

Mine happened to dis-connect it's self when it decided to backfire rather than start,then would only run with lots of throttle and smoke!

Just put the ignition on and it sounds like the ICV is buzzing, so I'd have thought that means it is connected fine. Just tried starting it again and revving it hoping it would continue to run but it still stalls.

ICV is connected properly. Found a stray pipe that comes from the top of the engine, breather pipe maybe? Everything else seems to be tight in place.

Does sound like an air leak somewhere on the inlet side,but at least you have eliminated the most obvious cause.
Throttle cable is seated correctly?
MAF connected properly(air flow and electrics)?
No splits appeared in the inlet bellows between the t/b and the MAF?
Brake servo feed pipe OK?

Is there a chance that disconnecting the battery has triggered an immobiliser, such as an EWS system?

I shall check through those bits tomorrow when it's daylight. I fitted a new MAF not too long ago, aswell as new pipes to go into it, so there shouldn't be any leaks in that area.

i did come across the mention of EWS but it seems that is on 93 models onwards, and my engine is from a 91 E34.

Thanks for your help so far guys, really appreciate it.

EWS fault will allow the engine to crank but not start,similar to a failed CPS or fuel pump.

This one is starting but failing to idle,I think!

Let us know how you get on,OP.

Vanos is from 92 onwards, I think, and this motor came from a 91 car.

It's a non-vanos

Thanks, I shall get them tested ASAP.
I'd rather test as many things as I can at home, rather than trying to tow it to a garage and pay someone else to eliminate things.

Nice diagram, that will be handy, thanks

I'd be putting the fuel pump itself high on the list of suspects.

Took it to a garage to be looked at and they can't find anything on it.
It sparks fine and the fuel system is running ok and nothing is showing up on a diagnostics test. Our mechanic is pretty stumped on it, so we now need to find more of a specialist to have a look at it.

After much head scratching, turns out it was the new MAF sensor that was fitted end of last year. I had the old unit in the boot so that was fitted just to test the theory, and the car started straight away. Still runs a bit rough, but I've been told that could be due to fuel in the oil as I don't use the car that much, so it's getting an oil change when the mot gets done next week, see if that makes a difference.

Thanks for your help

It may be worth cleaning the old MAF with the appropriate cleaner, to remove any crud as they are very sensitive to oil and dirt build-up.

Speedtouch wrote:It may be worth cleaning the old MAF with carb cleaner or similar, to remove any crud as they are very sensitive to oil and dirt build-up.

Im sure the carb cleaner is not maf sensor safe?

This indeed appears to be the case - post duly edited.