E30 engine issues

[cdfeto 0]

Ok.

I will start from the beginning:

I purchased my E30 (2 door manual 83 323i) a couple of months ago knowing there was a few engines issues as it was smoking quite heavily, after a bit of advice I determined that the valve guide seals were worn/old and were therefore allowing excessive amounts of oil to be burned.

I didn't get on to replacing these straight away ... and after a long drive with a car full of passengers and some highways speeds, the car started stuttering quite heavily, enough to lose power completely for a second or two at a time. This issue sort of came and went until one evening it stuttered so much that it backfired and ripped my muffler apart. Which I blamed on the oil seals leading to fouled plugs.

So I decided to finally replace these seals and ended up removing the head, lapping valves, replacing the head bolts and all disturbed gaskets, adjusting rocker clearances and chucking new plugs in there.

After all of that the car ran quite well. Although it did seem to use too much fuel and it always smelt a bit rich ...

The other issue I encountered soon after was a stutter and the engine dying on me when I did a few very steep hills starts, after a bit of researched I came to the conclusion that it must have a boost pump in the fuel tank (as well as the main pump) which was intermittent or not working at all which would only really affect the fuel delivery at low levels or at awkward tank angles. So here is my first question: does/could my car run two fuel pumps?

The stuttered never came back after insuring I always had plenty of fuel in the tank.

Until last Friday when I was driving back home on the motorway and the car stuttered a few times, once again losing power and proceeding to once again blow my muffler (which was already weakened by the first blow).

After more research I decided to replace all vacuum hoses, which after a test drive didn't seem to fix anything.

I then replaced the ignition harness and fuel filter (old one was only about a year or two old) and the problem seemed to have disappeared, until today where I got a couple of stutters on the way home (very negligible compared to previous situations).

But a new problem has now surfaced since these two fixes: the idle is very high at about 1600 at the start and dropping to 1200 as the car is driven, and it fluctuates quite a bit between say 1100 and 1200.

So the current issues being a very intermittent and infrequent stutter, and a high idle.

Any ideas would be greatly appreciated!

[elmarco 56]

Water in the fuel tank? Dirty fuel filter?

[Allanw 1051]

Dizzy Cap?

If it's blowing your muffler, you probably have fuel making it past a cylinder (no/poor spark) and being ignited in the exhaust. If you have moisture in the dizzy cap or a dodgy lead.plug etc, that will do it.

The high revs at idle ccould be a temp sensor, or the Idle Control Valve (ICV) needs cleaning or replacing.

[Etwenty1 45]

Check throttle switch, i had a stutter like that on my M10 after a HG change. Switch was full of with degreaser/mayo maybe from when the inlet manifold was inverted, and not functioning. Would starve under throttle then come back as revs dropped.

On mine the basic proceedure was manually opening the throttle (engine off ign on) and listening for the click as it just opens. There is a further test involving a DMM and reading the pins under the switch that you can google but mine had no click so was easy.

I believe the click on (open) means the ICV is off, click off (closed) means ICV is controlling idle.

[gmccormack 0]

A 83 will be a single pump car, at least my 84 323 was.

[cdfeto 0]

Water in the fuel tank? Dirty fuel filter?

I think that could well be an issue, at least part of the problem. I opened the original filter and it was covered in black "dirt", I've never inspected one before but I'm pretty sure it shouldn't be that filthy after two years (approx age of filter). And the stuttering almost stopped after it was changed (although the ignition harness was done at the same time).

Dizzy Cap?

If it's blowing your muffler, you probably have fuel making it past a cylinder (no/poor spark) and being ignited in the exhaust. If you have moisture in the dizzy cap or a dodgy lead.plug etc, that will do it.

The high revs at idle ccould be a temp sensor, or the Idle Control Valve (ICV) needs cleaning or replacing.

I don't think it's ignition related because if it was I it would be backfiring every time it stuttered? Which it does not do, apart from the first incident.

What temp sensor are you referring to?

Where is there ICV?

Here is a picture of my engine bay.

Check throttle switch, i had a stutter like that on my M10 after a HG change. Switch was full of with degreaser/mayo maybe from when the inlet manifold was inverted, and not functioning. Would starve under throttle then come back as revs dropped.

On mine the basic proceedure was manually opening the throttle (engine off ign on) and listening for the click as it just opens. There is a further test involving a DMM and reading the pins under the switch that you can google but mine had no click so was easy.

I believe the click on (open) means the ICV is off, click off (closed) means ICV is controlling idle.

Where is this switch? I have done the throttle opening test and could hear any clicks. Does the M20 have the same system?

A 83 will be a single pump car, at least my 84 323 was.

Ok ... that still leaves the stuttering and engine dying when parked at very steep angles problem unsolved! Maybe this is another consequence of the dirty fuel tank?

Also, this vacuum diaphragm seems awfully exposed and damaged (diaphragm split), what's its purpose?

And lastly, there is an unused connector alongside the fuel rail at the thermostatic valve housing end, any ideas where it should/could go?

Thanks again!

[Etwenty1 45]

And the stuttering almost stopped after it was changed (although the ignition harness was done at the same time).

If you can't determine the fault through testing try to replace only one component at a time

Where is this switch? I have done the throttle opening test and couldn't hear any clicks. Does the M20 have the same system?

Yes it is on the underside of the throttle body - google BMW M20 TPS.

Ok ... that still leaves the stuttering and engine dying when parked at very steep angles problem unsolved! Maybe this is another consequence of the dirty fuel tank?

Also, this vacuum diaphragm seems awfully exposed and damaged (diaphragm split), what's its purpose?

And lastly, there is an unused connector alongside the fuel rail at the thermostatic valve housing end, any ideas where it should/could go?

I have my m20 apart at the moment, will have a look tonight.

Edited April 3, 2013 by etwenty1

[Etwenty1 45]

And lastly, there is an unused connector alongside the fuel rail at the thermostatic valve housing end, any ideas where it should/could go?

I have my m20 apart at the moment, will have a look tonight.

sorry your 323i is a bit different. its a blade connector so temp sensor or oil level/pressure sensor?

[cdfeto 0]

I finally found my TPS, after almost giving up on the disassembly of the unit, as it was so well glued together I discovered this:

Uploaded with ImageShack.us

Which I guess would explain the poor idling?

I cleaned the hell out of it and put it all back together, and after a week's worth of driving I can't really say it's completely fixed it. The idle drops to a lower and more reasonable RPM but it still has spikes and periods where it will just sit high. What should be my idle speed?

Also, the intake manifold seemed to have a nice oil lining which was a bit of a scare, but would explain how the oil made it's way down into the sensor?

How much oil could/should be in the intake manifold for a car of that age: 83 and kms: 155000?

(I will do a compression check as soon as I can to determine valve/guide and barrel/ring conditions.)

[Etwenty1 45]

Wow thats oily, i would have replaced it, Did you get the reinstall right? The slotted holes allow some rotation so it clicks off at no throttle.you can hear it. Try to borrow an icv that definately works 100% and swap it to see if any diff, you can do same with afm. i think there is agood sticky for e30 idle probs....

Edited April 13, 2013 by etwenty1

[louistan3 1]

Wow thats oily, i would have replaced it, Did you get the reinstall right? The slotted holes allow some rotation so it clicks off at no throttle.you can hear it. Try to borrow an icv that definately works 100% and swap it to see if any diff, you can do same with afm. i think there is agood sticky for e30 idle probs....

Do you have a link for the sticky? I'm having some small issues as well for cold idle and that sticky might point me in the right direction.

@cdfeto: does yours idle low when cold? Mine almost never starts on first go and stutters on cold starts basically have a low idle and i'd have to hold the accelerator a little to get it to maintain roughly around 1k RPM for a about 30 seconds before it can hold the idle.