PSpirine
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| posted on 23/4/10 at 03:59 PM |
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BMW engine won't start
I've got a M43 (318ti) engine that had a failed gasket (bought like that - never heard it running). I changed the gasket, put it all back
together, but the bastard won't start.
It cranks well, and makes a boomy pop once in a blue moon.
Definitely getting petrol (plugs flood very quickly since it won't fire). I've taken out a plug and tested it and it sparks VERY
intensely, so it's getting fuel + spark.
What the hell else could be wrong? I tried spraying some Easy-start into the intake, but it hardly did anything.
It sounds like it wants to catch, but doesn't.
Spark plug leads are all numbered and in the correct order (1 at front, 4 at rear).
I've got two thoughts:
1) I put the cams/cam sprockets back incorrectly. They won't be massively out as they were marked before taking the cams off, and the sprockets
were ziptied to the chain and each other so they're in time. The only thing that could've happened is if the cam is slightly out (as the
sprocket-cam fixing is adjustable), but this wouldn't be more than a couple of degrees. I can dismiss majorly incorrect reassembly on the
grounds that it would've hit the valves on the piston if it was way out (i.e. cam 180 degrees out).
2) Bad fuel. I've heard that unleaded can 'go off' but I've never experienced it even with cars that hve been standing for
about 8 months. By my estimates the last time this BMW engine ran was approx 14 months go. Could it have gone off THAT badly that it won't even
catch? If so, why doesn't easy start help? (I'm squirting it in, then going in and cranking as I don't have telescopic arms to reach
the ignition key from the engine bay).
I'm just struggling to find what else to check as it SHOULD be running but isn't!
Pavs
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jossey
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| posted on 23/4/10 at 04:06 PM |
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ermmmmm
bmw engines are a pain when taken out.
here is a few things to try.
lining up of the cams is a maybe i guess.
the next thing is the ecu looking for the key immobilser .... thats an issue with alot of bought engines.
have you bought the diagnostic tool for the engine? that would check what maybe the problem
bad fuel is unlikely to be an issue. you can test the fuel by putting the spark plug with ht lead in a metal container with maybe a 3rd of a cup of
fuel in it. if the fuel goes up it is working. best not to try this indoors.
last thing is try spray WD40 into the ports where the sparkplugs are and fit the plugs and try that.
i have a e60 engine which was a nightmare to start. turned out to be immobiliser issue. but the bmw forum suggested the above.
see if that works.
dave
Thanks
David Johnson
Building my tiger avon slowly but surely.
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Guinness
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| posted on 23/4/10 at 04:07 PM |
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Check the compression.
You are getting two out of the three things you need to make bangs.
Mike
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55ant
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| posted on 23/4/10 at 04:10 PM |
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ignition timing could be out by 180 degrees?
away from cars, now cycling and building TT bikes
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dlatch
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| posted on 23/4/10 at 04:24 PM |
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check ecu for fault codes
if the crank or cam sensor is playing up its not gonna start
[Edited on 23/4/10 by dlatch]
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PSpirine
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| posted on 23/4/10 at 04:39 PM |
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Thanks for the responses guys, the engine is still in the 318ti car so has all the wiring connected etc.
Re: Immobiliser, Crank sensor - if either of these were at fault (or disconnected) then the ECU cuts fuel and spark (I know this because I was getting
no fuel and no spark because I forgot to plug back the crank sensor connector when putting the engine back together). Therefore I doubt it's
this.
When cranking, dash doesn't show Check Engine light.
Regarding spark, I'm not sure how it could be 180 degrees out, as it's a coilpack that is clearly labelled 1-2-3-4 and the HT leads going
from it are labelled respectively.
Is it worth taking the cam cover off and turning it over by hand to make sure I haven't put a cam in 180 degrees out? I would've assumed
this would've been evident due to valve-piston interference..
How much would cam timing need to be out to prevent it from even roughly starting?
Thanks
Pavel
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zoom
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| posted on 23/4/10 at 05:29 PM |
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I think you need to do a compression test first.
mycar
mybuildsite
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britishtrident
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| posted on 23/4/10 at 07:04 PM |
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quote:
Originally posted by 55ant
ignition timing could be out by 180 degrees?
That would be my bet --- the pop once in while is a big pointer to this. swap leads 1 onto #4 and 4 onto #1 2 onto #3 and 3 onto #2.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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PSpirine
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| posted on 23/4/10 at 08:04 PM |
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I already tried reversing the ignition leads, to no avail (plus I'm certain that's not the problem as when reversing them, plug #3
doesn't reach the spark plug hole without a stretch).
Will try get hold of a compression tester and check that!
Cheers everyone
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