Heater plugs - 1994 cavalier 17td. - coldstart
I have a 1994 cavalier 17td. it has been having cold start problems so I checked all the heater plugs were OK but discovered that although the indicator light on the dashboard was coming on for appros 10 secs the plugs themselves were staying on for a couple of minutes after the engine had started. (This was established by wiring a light up direct from the plug feed)which remained lit after the dashboard light had gone out.

What actually controls the time that plugs stay on ? it appears at the moment to be the engine heating up.
Heater plugs - Screwloose

Yes; that sounds about right. "Post-start" heating helps to reduce smoke etc. when the combustion chambers are still cold. It's controlled by the glow-plug relay, probably in conjuction with a coolant temp sensor.

To fix your cold starting problems; check and re-shim your [closed-up] tappet clearances. A very common Cavalier/Isuzu diesel classic!
Heater plugs - coldstart
I have enquired about getting valves adjusted but have been informed that they are hydraulic therefore no need to adjust.

Another suggestion for starting problem is that the fuel is draining back overnight through a faulty/worn fuel filter and is taking a lot of pulling through on a morning. The fact that its cold as well doesn,t help.

Will replace filter next week and let you know.

Thanks for your input
Heater plugs - Dynamic Dave
I have enquired about getting valves adjusted but have been informed
that they are hydraulic therefore no need to adjust.

Whoever told you that is talking rubbish. They occasionally need re-shimming.

All inlets should be 0.15mm and exhausts should be 0.25mm
Heater plugs - Richard J
It's definitely valve clearances. If you have access to a surface grinding machine, it's a fairly straightforward d.i.y job. Take off the cam cover. You won't require a new gasket as there is a fitted neoprene seal. Turn the engine over by hand (unscrewing the glow plugs will help) and check clearances as per manual. They will probably all be less than specified. You can make a tool to lever down the cam buckets and remove the shim from it's recess. If available, grind off the amount required to make the correct gap. If grinding facility unavailable, you can buy new shims to suit from you friendly Vaux dealer. You should be able to 'mix & match' some of the shims.


n.b A surface grinder is a precision engineering machine and every engineer's workshop in the world will have one.

Ask Honest John

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