BMW 523 non start

Captain Slow IRL

1998 BMW 523 auto, non starting. When it's tried first thing in the morning, it'll pretend to start, give up, and then just keep cranking. If it's left a while, same thing.
So far I've checked:
- compression (perfect)
- spark (very strong, with plug out of head)
- fuel pressure (bang on)
Unfortunately, the (cheapo) diagnostic tester I have won't communicate so can't check any codes - eml is going out when ign turned on. After cranking it, removed the plugs - they're drenched with fuel.

Gonna check timing tomorrow (pending tools) - is there anything I'm missing? This is frustrating, the bloody thing should start. I've tried drying the plugs, clearing out the petrol from the cylinders and putting a little bit of oil down into the cylinders in case the petrol is washing the liners. It started coughing but no joy.

Anyone any suggestions?

biko

Did car start before? Has it been sitting a long time?
As you said about timing, maybe it's not igniting at the right moment.

Captain Slow IRL

A neighbour bought it as a non-runner. The seller said he came out one morning and it wouldn't start - not sure how true this story is.
I'm not sure how long the car was idle.

biko

Maybe leave the plugs out overnight to let the petrol evaporate?
Then maybe a little shot of starting fluid before you put them back tomorrow?
Try another battery, just in case?

AzureAuto

Perhaps check the coolant temperature sensor is working within spec, i.e. that the correct amount of fuel is being injected for efficient cold start.
I know you said ignition is grand, but Ive had a lot of issues with crankshaft position sensors giving up the ghost.
Secondly check the air mass meter for a 5V feed with ignition on, if the car isnt cranking for long enough to run a satisfactory self check, i wouldnt think the EML would illuminate, so you may be unaware of the problem. Try disconnecting it, car may start in LOS.
Lastly, get a diagnostic check. I have a suitable computer if you're interested PM me.

Captain Slow IRL

I got a CarmenScan today (thanks for the offer Azure) and got it plugged in - 2 faults, 1 for IAT - went into live data and it was showing 150 degrees reading. There was another fault for a circuit break in the tank vent valve. I dont think either would prevent it starting.

Coolant temp is fine on live data, was showing 18 degrees. Everything seemed to be fine - crank, cam, injectors. A new crank sensor was fitted recently.

The air-mass meter has been disconnected for most of the time - faulty ones can play havoc with the M54 engines so no harm leaving it disconnected.

Got a more accurate compression tester today - building up 11 bar on each cylinder (10-11 recommended) He left the plugs out overnight and tried putting a little oil into the cylinders to help compression - it made shapes to start but quickly gave up. Got him to take out the lambda probes, to rule out a blockage in the exhaust - very strong smell of petrol after cranking. Took the plugs, coils and wiring loom out of my car, swapped over - no joy (1 more thing ruled out)

I was hoping to check the timing but my source for the tooling told me the camshaft locking plate is missing:mad:

Slidey

Welding rod down the spark plug hole and check it is rocking on the cam.

Should give you an idea if it is close to being right. They chain driven?

daveharnett

Slidey wrote: »

They chain driven?

Yes

Slidey

Well unless the chain tensioner is banjaxed it it very unlikely to have skipped so.

Captain Slow IRL

Slidey wrote: »

Welding rod down the spark plug hole and check it is rocking on the cam.

Should give you an idea if it is close to being right. They chain driven?

I'm gonna try get the kit somewhere - if not, I'll park my car beside it and try compare it visually.

Slidey

IF there is a TDC mark on crank pulley you should be able to see it rocking on 6.

Have you checked the chain for slack? How is the oil pressure? Is it possible that the oil pressure is that poor that it is nor fit to keep the chain tight when cranking?

AzureAuto

Hmmm, that IAT would only be used for slight trim to fuelling, the tank vent solenoid as you say wouldnt have an adverse affect on starting.
(Thinking aloud now) The fact that plugs are wet indicates good fuel delivery,plugs have been dried so floodng is ruled out; new crank sensor and good compression...
Id be interested to see those timing results.

Captain Slow IRL

AzureAuto wrote: »

...................plugs have been dried so floodng is ruled out.................

No, this seems to be the problem - getting spark but plugs drenched when removed.

Slidey wrote: »

IF there is a TDC mark on crank pulley you should be able to see it rocking on 6.

Have you checked the chain for slack? How is the oil pressure? Is it possible that the oil pressure is that poor that it is nor fit to keep the chain tight when cranking?

Haven't gotten a look at the timing gear yet. Never thought about oil pressure - that'll be something else to consider. The engine in my car is identical, so hoping to get the 2 side by side and compare the cams when it's set to tdc.

I'm convinced it's the timing now - how it slipped is beyond me though. We've spark, fuel, compression, free air flow and all major sensors seem to be doing their jobs - it has to be (please god!)

gofaster_s13

First things first, if plugs got a good wetting replace them as they'll never properly dry, with new plugs try giving it a shot of easy start while cranking(easy start is a great diag tool but don't use too much), if it fires on the easy start it rules out spark problems.

Captain Slow IRL

It's a timing problem.

Took the rocker cover off today, found the exhaust off by about 90 degrees. Also found bits of metal in the head - further investigation found badly scored cam bearing. We got to reckoning there was oil starvation up top, cam seized enough to jump the timing:(

If anyone has/knows of an engine going handy, gimme a shout.

Slidey

Sell him your lump and get a 3.2 for your beasty

Captain Slow IRL

I have to get desensitized to the fuel/tax bills before I go up any more - it's a gradual process!