9 replies to this topic

[superfly_GTR]

Hello everyone,

Im having some pre ignition problems with my 186, it has only started happening in the last couple of months and doesnt happen everytime i turn the car off only sometimes and only for a second or two. I have also noticed that after driving and then getting back in and starting it after a short time that it seems to not want to start, it does, just not with the punch that it does when cold or when having sat for a while, i spose the best way to put it is that it doesnt go VRROOOM when you turn the key like it does when it has cooled down, it just sort of cranks over and stays at idle speed unless you pump the throttle a "couple" of times (bad throttle response)

I hope this all makes sense, any help would be great.

Cheers Matt

[superfly_GTR]

By pre ignition i mean that after you turn the car off the engine cranks over a little bit more and knocks and farts around but only for a second or two, and i should say that the car runs drives and idles fine it is only starting when warm and turning off when warm that problems arise.

Thanks Matt

[rodomo]

Pre-ignition is also known as "pinging" and relates to a rattle under acceleration, this fault is either timing, lean mixture and/or heat related - either running too hot or hot spots in combustion chamber inc. plugs. If your car is "running on" after you turn off the key this is called detonation in that another source rather than your ignition system (which is turned off) is igniting the fuel. Generally this is caused by high idle and is why later cars (VB Comm UC Tor) use an idle up solenoid to maintain idle rather than the base idle screw.
If your car turns itself off after a couple of seconds I would look at idle speed. If it keeps running and you have to stall it to stop it I would be looking at hot spots and lean running. As devils advocate mentioned retarded timing can cause hotter running and running on.
If you fix this problem you will probably fix your hard hot start problem as it sounds like flooding due to running on. Remembering that running on is not under control of ignition and that not all cylinders may have the ignition source thus flooding those cylinders.

Clear as mud?

Good luck!

RACV MAN

Edited by rodomo, 31 March 2006 - 09:17 PM.

[FastEHHolden]

Set your idle speed and set your ignition timing correctly...thats the short version.

[rodomo]

Yeah I blabbed on a bit didn't I?
But this Q comes up time and time again and the more that read and understand the less it will come up.

RACV MAN

[superfly_GTR]

Thanks for all your help guys,

Im going to try the timing and see how i go, im also in the middle of playing around with jets to get the carby to work right so this may have something to do with it as well.

Does any one have any general idea on what carby specs would be good for a medium worked 186 running a 390 holley 4bbl with vac sec? At the moment im running 52 main jets with a blanked of power valve and im having trouble with it running rich if you put your foot down to much to early, it coughs and splutters unless you back off a little bit.

Cheers Matt

[superfly_GTR]

Also i had my elec dizzy rebuilt by performance ignitions and they wrote 10-12 degrees on the little box on the side what does this mean?

Cheers Matt

[FastEHHolden]

that would the static advance they set it up for....so if you set it for 10-12 degrees is should be good....to check I would ring them.