Hey everyone, hoping someone can help point me in the right direction, just bought a 1991 318is m42 car, 144,000 miles, my issue is, that it won't start, it try's and will sometimes sputter for a few seconds (about 5) then dies, this is what I have tested so far, fuel pump, I'm getting fuel I just don't know the pressure yet, I'm getting spark at all plugs, I tried testing the cam and crank sensor, and if I did it right the crank sensor is super low ohms about 148 on pins 1 and 2, the cam sensor on 1 and 2 went over 200k, it almost sounds like the timing is way off, like it jumped a tooth on the chain, so I pulled the front of the engine off and checked everything, it looks like brand new in there, no slop, no debris, shavings anything, it would turn over nice and smooth, start to fire then almost like the cylinder was detonating halfway through the stroke, from what I've read when the crank position sensor goes out the car just turns over and will not sputter, is that correct? Is there a way to test the coil packs? What are your guys thoughts or can someone point me to the right thread? Thanks everyone!!
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If the CPSs are off (I can't recall the spec off hand) they clearly need to be replaced, although only the crank sensor will cause a no start, while cam sensor fail will not cause a no start. Also worth inspecting the vibration dampener while you are there, although I suspect that you did if you did a timing case tear down.
Timing is dead easy to verify, and if your engine is back together all you need to do is remove the valve cover to check. DIYs are plentiful, so have a look, but you essentially get the rear cam squares flush (cyl 1 lobes point up, towards each other), and the timing case arrow on the mark for TDC1.
You can also pop the top on the AFM and look for moisture damage if the car has been sitting. TPS is also worth a quick test, and you should visually check it's wiring connection.
Assume you already checked, but vacuum leaks that are bad enough can cause a no start, as can bad fuel, or a clogged air filter. You can also smell the tailpipe after cranking to see how combustion is progressing.
Doing a stomp test might yield a code or two if it hasn't been sitting without a battery since last driven.
Finally, look at your engine ground on the passenger engine mount, and if you want to test it you can take one side of a jumper cable to make an ersatz engine ground.
There's also a little one pin connector on under the firewall mounted clip on wiring cover on the passenger side that should not be connected.
Finally, if you've never seen it run it's possible that the spark plug leads are not in the correct order. If still present there is a little metal tab under the coil pack cover indicating which coil is which unless someone mixed the coil plugs (which is hard to do as they are pretty much molded in place to each coil after 20+ years).
It's either one of those things above or a dead/damaged DME (seems unlikely if spark exists), so have fun, report back and good luck. -
Hey thank you for all the info, tonight I'll look over everything you have explained! I haven't seen the car run, and it had no battery when I purchased the car, I'm almost 100 percent on the timing, I'll pick up a new cps, I did check the firing order and it is correct, now I have somewhere to go with it, it did pop out the intake last night while I was trying to fire it, and if blew some starting fluid out right under the throttle body, where the intake bolts together so I'm having a feeling I have a blown intake gasket as well, I will keep you updated as I test and replace parts! Thank you again!!!Comment
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replace the cam sensorsStrategic nw e30 commandOriginally posted by bmwm42Comment
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Re. Still trying to start
Okay, so far parts that are replaced with no improvement... yet, new cps, cam sensor, upper and lower intake gaskets, fuel pump, fuel regulator, cleaned injectors and new o-rings, all vacuum lines replaced, new fuel filter, plugs and wires, my next try will be a compression text, then a new dme, and if no avail new coil packs unless you guys think I should try something else, it still try's to fire but can't quite get there...Comment
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Check your crank trigger wheel as well. In doing so you can check timing, if they don't line up as you think they should the elastomer may have failed causing timing to be off according to the TPS, but be on mechanically.Comment
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I'll triple check that tonight, as far as I can tell it lines up dead nuts with the arrow on the timing cover arrow with the cam arrows straight up, thank you for the reply, I will let you know what I find out!!!Comment
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Do the dampeners slip or go bad in anyway?Comment
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The rubber can fail, sometimes causing the center to rotate away from alignment with the outer part. It's not common just yet, but in 5 years it probably will be.Comment
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Now I'm not to sure if the chain has been messed with before I bought the car, I bought it knowing there was issues, do you know what degree the keyway on the crank should be with the engine at tdc? Incase the trigger did slip, the timing cover had been off before, unless bmw uses Autozone Rtv to seal something like that up 😂, I just want to be sure no one re clocked the timing gears...Comment
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Couldn't say for sure what angle the keyway should be at TDC, but if I were you I'd just set the dampener/lower case on there to check against the marks.Comment
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Maybe this photo I took while I was trying to set time on my motor will help you.
From what I recall I took this with the block at tdc.
-NICKComment
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That's perfect!!! I will check tonight after work! Thanks guys!!!Comment
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I'd revisit your fuel injectors and fuel pressure. Crapped up injectors won't make the car run.Comment
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Have you checked the ecuStrategic nw e30 commandOriginally posted by bmwm42Comment
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