I have 1.6 liter '87 E30 BMW 316 with Pierburg 1B2 carburetor and LPG conversion. It has only 30000 miles on the clock, and was not in use for 7 years (but was started and let at idle for ~20 min every month).
I started to use it now, and all worked perfect for 1000 miles, but now engine is shaking at idle. Not constantly, but every 10 or 15 sec and not in regular intervals. I adjusted valve clearances, changer sparkplugs, checked all vacuum hoses and vacuum operated devices (at carburetor and distributor). Carburetor was cleared (some ultrasound clean) in carb shop, and i changed rubber flange at the bottom of the carb. All looks OK, but shake is there.
I went to BMW dealership, and they could not do anything about it.
On cold starts rpm is to low ~1000 rpm. But when I switch at LPG it goes up at normal ~1700 rpm and then goes down as it warmes up.
Now to my question. How do find why is it shaking? It is the same on both LPG and petrol. Could it be ignition. I had a lot of advice's to bin Pierburg and get a Weber carburetor, but I would fee very stupid to find (after spending a lot of money) that it's ignition problem.
Any advice's/ideas?
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check the engine and gearbox mountings. After 20 years they may have softened or separated..
madf
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>>It is the same on both LPG and petrol
That would make me look *very* carefully at the ignition system.
Number_Cruncher
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"It has only 30000 miles on the clock, and was not in use for 7 years (but was started and let at idle for ~20 min every month)."
I would look carefully at a new engine.
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TourVanMan TM < Ex RF >
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"It has only 30000 miles on the clock, and was not in use for 7 years (but was started and let at idle for ~20 min every month)." I would look carefully at a new engine. ------------------------------ TourVanMan TM < Ex RF >
Not the most helpful answer to a genuine request for diagnosis/advice by the OP...........
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Maybe not, but its possibly the right answer. This will not be healthy mechanicals - its not had the best of life experiences.
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TourVanMan TM < Ex RF >
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>>That would make me look *very* carefully at the ignition system.
I would agree with that,doesnt sound like mechanical fault to me!
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Steve
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>>That would make me look *very* carefully at the ignition system. I would agree with that,doesnt sound like mechanical fault to me!
And how do you do that? Ignition was set at BMW dealer's. How do I find out what went wrong? Just changing parts hoping to change right one sounds stupid.
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When you say the ignition was set, do you mean that they adjusted the ignition timing?
If so, that falls short of a full check on the ignition system.
Most reasonable garages will have the facility to measure the operating voltages in both sides of the ignition system, and can track down faults.
However, there is quite a bit you can do for yourself, especially if you have a multimeter available. You need to measure the resistance of all the plug leads, and the coil king lead. Also, the primary and secondary resistance of the coil.
In some cases, you can see the ignition HT leaking out if you open the bonnet at night - you shouldn't be able to see any sparks.
I agree with your comment about changing parts - it is, on average, cheaper to diagnose a faulty part than to simply change things out.
Number_Cruncher
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When you say the ignition was set, do you mean that they adjusted the ignition timing?
Yes, that's what meant.
If so, that falls short of a full check on the ignition system. Most reasonable garages will have the facility to measure the operating voltages in both sides of the ignition system, and can track down faults. However, there is quite a bit you can do for yourself, especially if you have a multimeter available. You need to measure the resistance of all the plug leads, and the coil king lead. Also, the primary and secondary resistance of the coil.
I will do that. I have Bentley and Haynes manual for E30, and multimer, so I will check everything that I can.
In some cases, you can see the ignition HT leaking out if you open the bonnet at night - you shouldn't be able to see any sparks.
I do not think that I have HT leads leak as I did some work around carburetor and I tested it with my hand. I felt nothing, so I think that HT leads are OK. But I will check it at night.
I agree with your comment about changing parts - it is, on average, cheaper to diagnose a faulty part than to simply change things out.
I suspect that I will find everything to be OK, as it was the case with carburetor, but I still have engine that shakes.
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