E30 Zone

Hi, I have a new to me 320i (1988) face lift model. Totally original with the standard 6Cyl. Car has done 105k miles (approx 1k a year for the last few years).

When running, runs sweetly apart from a slight hesitation moving off idle (New TPS on order). The car appears to need a good full service/cambelt etc as most of the components are possibly original (I think the lead set is original).

Fault - occasionally it wont start, checked coil, green wire - Fine
Checked and cleaned rotor arm / dizzy cap - fine (but will be replaced)
No spark seen when tested, but it does start sometimes making it tricky to diagnose (it is intermittent) - When running it doesnt cut out.
When it doesnt start - I have pulled all plugs; they are wet with fuel. If I pull the fuel pump relay - crank it over a few times, then put it back in again - it will fire up.

To me, the resultant is a flooded engine running too rich on start up, but I think that is the result of something else.

It could be the following - I wonder if anyone here backs up or could recommend some weighting..

1) Main relay / Fuel relay dodgy - Moving or pulling it knocks it back into shape
2) FPR - leaky diaphragm, fuel being pulled over to intake manifold when cooling down making it too rich when you start.
3) Fuel injectors - leaking and allowing fuel to leak past when the engine is off
4) AFM - wiper track dirty so fuelling is off (unlikely as i hear the TPS switch when I touch the throttle) - running open loop when starting / cold and not reading AFM
5) multiplug under intake side where the injectors plug in
6) CPS - I will test using the bentley manual method next time it wont fire (probably this morning).

It has a bit of a lumpy idle for a day or so after it wont start suggesting there could be crap in the injectors / fuel?

I have ordered all the parts for a full service and I will do that when they get here - full ignitition service inc. leads and new plugs.

There appears to be no relay in the lambda sensor heater position - I assume this was for the US rather than UK where they want the emissions on close loop as soon as possible?

Any advice on whether the options above are likely culprits or am I looking in the wrong place?

I would start by checking all the earths (brown wires) are good, including the engine-to-body earth strap. Also use a multimeter to measure the resistance of the HT leads, which should be between 6-10 kilohms.

Try starting the car in the dark and look for any stray arcing from the ignition system.

Which ECU do you have? The later 0 261 200 380/381 version was known to blow diodes in the idle control circuit.

Thanks - Will undo all earth points, check and clean up when I service it this week. I might see how much a pair of relays (DME + Fuel) is and throw them in too

Relays are easily tested without throwing money at the car by temporarily removing them, and plugging wire links into their sockets, linking pin 30 and 87s.
Do you have a relay clipped onto the outside of the fusebox casing?

I only have 2 relays under the black plastic hood by the suspension turret. The lambda heater relay is missing (I think they are only on US spec cars). No other relays (I think you are thinking of the cold start relay? - )

Some 320i purchasers found that their cars suffered from overfuelling when starting from cold, and BMW responded to this by the utter bodge of fitting a relay, operated at the same time as the starter motor which switched a resistor into circuit, making the ECU think the engine was hotter than it rally was.
Lambda sensor heater relay is only fitted on cars with emissions equipment, including a cat. in the exhaust. This was optional on UK cars until 08/1992, but there are UK cars out there where the emissions package was fitted before this date. After 08/1992, all UK E30s have the lambda relay fitted.

Looking back at your OP: If the ignition leads are the original ones, and undamaged, don't change them. They don't deteriorate.
Hesitation moving off idle, is more likely to be a badly adjusted TPS than a faulty one.
If the car has done 105k miles on the original injectors, they are overdue for a rebuild. See 'injectortune' in our traders' section. Rebuilt injectors may be the solution to all your symptoms.
Multiplug under the inlet manifold should be checked out for corrosion under the rubber boots as a matter of course, and the nick made in the rubber of the lower boot, as per TIS, if not already done, but problems here normally cause poor hot running, not poor starting.

Thanks for the info - I have thought the injectors could do with a refurb - there is old oil/goo around there - probably when it drips out through the tps over time. I will take the TB off thisweekend and clean it up. I have the new TPS now to fit and fettle.

Didnt start again today so went out there - Definately a spark, used a new plug on the rocker cover and saw the plug spark- Also checked the coil - Primary 0.7Ohms (Bentley suggests 0.5), secondary 5500 Ohms (again manual suggests 5000). Looks like coil could be ok as there doesnt appear to be shorts to the windings even though the values are a bit higher - perhaps ageing dielectrics in the can. Found where the alarm had been cut in to the coil primary lead - shame they cut the original pin 15 wire (ignition) short so if I wanted to bypass the alarm/immob I would still need a break / connector in the line. I can solder and heat shrink an extension as the original terminals on the oil have hardened up a bit. (Will do some time in the future when the alarm finally gives up the ghost)

Pulled the fuel pump relay - car started almost immediately without the relay in then died as the fuel rail dropped in pressure. Put relay back in then it ran - roughly at first but then got better as per the original post.

I bridged the relay with some wire and could hear fuel pump running (or something running from the back of the car). I will check relay out on the bench (I have a bench top PSU) but if relays aren't too expensive I may just put a new one in. (I assume these have inbuilt flyback diodes to protect the DME).

Have ordered all the service parts - dizzy cap / leads / rotor - although the lead set received was the wrong one (for an earlier engine) so need to exchange them.

I agree that the injectors /Fuel Press Reg are the next port of call once serviced.

On a different topic, the previous owner didn't leave the alloy wheel key. - I am thinking of just going down to the tyre place and seeing if they have a bolt extractor (I have a kit myself but only really do it on smaller bolts (mainly on old motorbikes)and am worried of wrecking the wheels. Need to get them off so I can do the brakes. Anyone had this problem and solved it by a simpler means?

If the engine won't start, and there hasn't been any catastrophic mechanical failure, then the problem must be either lack of spark, no, or too little fuel, or too much fuel.

Pulled the fuel pump relay - car started almost immediately without the relay in then died as the fuel rail dropped in pressure. Put relay back in then it ran - roughly at first but then got better as per the original post.

This shows that the fuel pump works, but it could have only worked when you were testing for sparks - when it failed to start before you tested for sparks, the fuel pump may have failed to run. As they begin to fail, they often refuse to start on the reduced voltage that it gets when the starter motor is running.
Is there any sign of it firing at all on the first couple of turns of the starter motor on the occasions it won't start? If there is, then the pump is a prime suspect.
If the ignition leads are original, and have no obvious physical deterioration, then I strongly recommend that you don't change them. They are of much higher quality than those fitted to lesser makes at the time, and are not a service item. Aftermarket replacements are likely to be of inferior performance, even the so called top quality ones.
Which version of the alloy wheel locking bolts do you have (assuming genuine BMW)? The key operated type are easily dealt with by a hammer and large flat bladed screwdriver. A quick smack across the front with these and the outer shell will drop off, leaving a conventional hex. bolt. The internal splined version can be removed by an internal coarse reverse threaded socket, which is readily available on ebay, or your BMW dealer can supply the externally splined 'key'.

Getting closer to it now - I think we are nearly there.

Didnt start again today, this time I disconnected the fuel pipe and return from the FPR and plumbed into a coke bottle, turned the engine over and fuel squirted into the bottle suggesting the fuel delivery was ok.

Previous poster said about taking the injectors out so I set about it- Bently manual says it will take about 30 mins - for me it took 3 hrs but I got them all out and they all look pretty dirty - The inlet manifold probably contains loads of oil crap as the bottom of the injectors were all caked in gunge. I may take the manifold off and clean it out too (depending on how much further dismantling there is!

Anyway - sending injectors out to be refurbished as they are out and take a look and the flow patterns.

Tried to take the injector harness out and it was stuck on the multiplug under the manifold. Took about 2 hours of swearing to get it undone, but in the end I had to cut the injector loom as the plug was mashed. The reason why - it was full of water and completely corroded out. All the pins had corrosion and they had bonded together.

I will get a set of waterproof automotive plug and socket sets and make up a new harness. But I think combined with the dirty injectors and a bad electrical connection the collective here may have got towards the solution.

I will let you know when I rebuild it what happens - but thanks anyway so far.

chainslack wrote:
I will get a set of waterproof automotive plug and socket sets and make up a new harness.

It was full of water because a modification instruction issued by BMW years ago hadn't been carried out.
You will find that corrosion has travelled some distance up inside the insulation of the wires to the plug and socket, so considerable lengths of new wire will have to be spliced in to replace it. Pre facelift looms didn't have this problematic plug and socket, and it's unnecessary on post facelift ones, so I'd recommend just splicing in the wires without including a plug and socket of any kind.

Pretty remarkable it ever started at all, by the sounds of it...

I have loosened locking wheel nuts using an old socket which is slightly undersized compared to the outer diameter of the wheel nut.
I just get a big hammer and give it a good few hits to get the socket over the wheel nut.
Its a bit brutal but it has worked in the past.

Update: I had James refurbish the injectors (Injectortune on here) ,re wired the C191 connector, replaced the crank case breather hose (made a nick in it when replacing the injector harness). Car now starts on the button and has a perfect idle (750rpm).

The injectors were all a little low (162ml/min rather than 165 - one injector was 158 which James thinks could be the cause of the idle irregularity.

Only taken the car for two runs since the works and both times runs really well (much better than before). Just need to confirm it starts every time to confirm there is nothing else that is being masked!

Thanks all for the help.

Hmmm - Spoke too soon.

Struggled to start, although did go on 5th turn of the key without any removal of relays so things are getting better.

Starts fine when warm, just when laid up over night it isnt too useful.

I will take the plugs out and replace them this weekend and continue my servicing. I will also try to take a look at the fuel filter in case it is clogged. I will see if I can get the ECU checks done too, to see if the blue plug is passing the correct readings to the ecu (there could be other faulty wiring elsewhere in the loom)