KH Laser intermittent rough starting and losing power

MungoDragons · 18-02-2009, 12:08 PM

Looking for thoughts on an intermittent problem I've been having with my 1993 KH Laser for nearly 18 months now. There are two things which are happening - one is occasional (so maybe once a week or so) rough starts where I need to rev a bit to prevent the car stalling, usually the engine smooths out and settles down after a minute or so. The second is a loss of power (or hesitation might be a better word) while driving, again generally it clears itself after a bit of revving (whilst saying "oh golly" under my breath, especially if there are cars behind me). Once or twice I have noticed a puff of white smoke appear from behind just as it seems to clear itself.

Mechanic has had several attempts to fix, unfortunately has only been able to replicate the problem once in the workshop. Each time it has been to the mechanic the problem has seemed to settle down for a while though. So far have had ignition coil, ignition module, plug leads, distributor cap & rotor, coil leads replaced. Last service we thought we nailed it when I noticed the behaviour seemed worse on low fuel. The fuel pump was pulled and it had a bent strainer, possibly impeding the flow, and after replacement all seemed fine for maybe 5 or 6 months but now it's happening again. The car is 1.8litre, 5spd manual with EFI and has done approx 280,000km.

Any thoughts appreciated as it's driving me nuts.

Denis.

Peter B - CV8 · 19-02-2009, 01:55 PM

Had a similar problem in my son's old Laser (carbie version). Turned out to be a faulty vacuum modulator on the auto tranmission. The diaghram had split - allowing auto fluid to be sucked up into the inlet manifold. Got an occassional puff of white smoke as the fluid got burnt up.....
Not sure if your model has the same vacuum modulator - but it might be a starting point. New part cost is approx $50-, but make sure you get the right version - otherwise the tranmission shift quality can be impaired.

Peter B - CV8 · 09-03-2009, 03:47 PM

Denis,
Any feedback on solving the problem ???

MungoDragons · 23-03-2009, 10:12 PM

Thanks for the tip Peter (sorry for slack reply but have been away a whiles). The Laser has been running ok this past week or two but played up badly the week before. I'm going to go visit a new mechanic this week and I'll take your suggestion along although not sure my car has one being a manual transmission. Will post updates.

Cheers,
Denis

MungoDragons · 06-04-2009, 10:00 PM

OK, so tried a new mechanic today - they were able to get it to play up and suspect the problem may be the coolant temp sender. Replaced it and fingers crossed - will so how it goes over the coming week.

Denis

MungoDragons · 08-11-2009, 04:58 PM

Just following up on this - everything has been sweet since the replacement of the temp sender. Has been running outstandingly in fact and about to tick over 300K.