Date: Fri, 28 Sep 2007 03:24:15 +0200 From: Jorgen Moquist <jorgen.moquistnospams.p.a.m.mailbox.swipnet.se> Subject: Re: Intermittent engine vibration
Charles C. wrote: > Doug Schwarz wrote: >> In article <46F56DDF.6F9C565Cnospamail.com>, >> Eeyore <rabbitsfriendsandrelationsnospamail.com> wrote: >> >>> Sometimes things just fail unexpectedly. >>> >>> Plugs can develop degraded insualtion for example. >>> >>> I had a Vauxhall once that behaved a bit like your Saab. The problem turned >>> out >>> to be a hairline crack in the distributor cap. >>> >>> Graham >> Thanks, again, for your comments. >> >> Today I replaced the coil, distributor cap, rotor and all HT wires. The >> spark plugs themselves were replaced at 95k miles (currently at 113k >> miles so that's 18k miles ago). No change in symptoms. Well, at least >> now I know what is *not* causing the vibration. >> >> As an aside, the rotor was very hard to remove. I literally had to saw >> and crush it to get it off and then lightly file the shaft to remove all >> the bits that were still stuck on. Weird. >> >> Any other suggestions anyone? Charles suggested leaking vacuum hoses -- >> how would I check those? Could an engine mount fail intermittently? > > What you are looking for is a possible misfire. > > One way of checking for leaking hoses (sucking rather than blowing) is - > I am told - to have the engine at idling speed, and spray carburettor > cleaner liquid (gas) to the various hoses and connectors. > > If you work slowly round the engine, if you find a leaking (sucking) > point, the revs of the engine will increase. > > Another possible cause of vibration would be a misfire caused by a > leaking head gasket. If (I guess) the misfire is bad enough for you to > notice the vibration then you should be able to notice a luck of pulling > power. It could also differ between a cold and hot engine, and > certainly under the heavier loads. > >> For those just tuning in: I have a 1995 900S with an intermittent engine >> vibration. It doesn't matter whether the car is moving or stationary >> and it seems to peak in amplitude at about 3200 rpm. >> > > Engine mount. Would have been my next suggestion ... but it should be a > lot more obvious or different with the car in motion. Accelerating or > decelerating would move the engine and change the vibration. > > ===================== > > Engine timing out? > Anyone? How does the timing work on this model (sorry my knowledge is as > far as early c900s). Does it have points in the distributor or > electronic gadgetry? > > Charles > OT: had an Mitsubishi -91 Colt GTI 1.8L 16V ( pre GDI engine ). once one ignition wire was bad, runned very bad around 2000-2200rpm. no problem running under or over 2000rpm. /jorgen
