pre ignition, if thats what it is???

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Anonymous

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hey guys, again
minor problem with my sister 1.6l escort....
you wouldda all experienced this before im sure, ive just gotta try explain it so u know what i mean....

well sumone once refered it too me as pre ignition... dunno if thats rite tho.
ok. when car is switched off it likes to continue to....well...... sorta keep firing, and doesnt stop instantly... its just gotten bad tonite... like a good couple a seconds before it finally stops...... oh and then it lets out a nice loud.. pfffffft from the carby i guess..... ideas????? timing????

all help apreciated as usual :wink:

-matt-
 
Matt.
I havent got a technical name for what you are describing, but the same thing you described happened to the XF about 12 months...here goes.

*takes a deep breath*

Driving to hospital to pick up my g/f and the car seemed to be idling/revving overally high (like 1300rpm opposed to the norm of 800rpm). I was a tad confused, although it was quite funny stopping at the lights and the people in the cars next to me giving me odd looks..
Anyways, i get to the hospital and turn the ignition off, but the car chugs/stutters and trys to keep running, it them expells a loud pshhht noise (as you described).
My intial thought was to changed my underwear as soon as possible.. :oops:

After the final shock of it, i put it down to the car running extremly "rich" and overfueling from the hi-idle/revs it was receiving during the journey. And the extra un-burnt fuel was igniting once the engine had been switched off. A strong petrol smell was evident.

Anyways, the next day i found the problem. The latch/lever (near carby)on the throttle cable was getting stuck at a certain point causing the excessive revs, and over-fuelling which in turn caused the stutter after turning the car off.

I adjusted the cable/latch and i now have no dramas..

It maybe a different problem in your scenario but, worth a thought?!

cheers
-Mike.
 
The technical name is ' dieseling'

Maybe caused by idle speed, timing, excessive engine temp.
 
I used to have this problem a bit on a car with points ignition.

When was the last time you checked your point gap or your timing?

When the little nylon wears on the points they tend top close up which changes the ignition timing. The smaller point gap means they close sooner and hence the timing is advanced.

Advanced timing can cause preignition and run on that you have.

If the timing is causing it then the engine will be runing very doughy down low in the revs also. If you leave it go too long the points will close up completely and it won't start.

When you put new points in make sure grease the cam lobe in the distibutor to stop the nylon bush from wearing.
 
Matt,
sounds like you are stuck with an escort from the early eighties.
They had a big problem with dieseling.
If the idle speed was slow enough to stop it the it would idle badly. Fast enough to idle smoothly and it would not shut off.
Many people got used to stalling the bloody things when they wanted to stop them.
But this doesnt help you.
Check the tune and make sure that all is 100% ok. Adjust the idle speed to spot on the recommended idle speed and try lowering it a bit and see what happens.
If its an auto you probably will have to put up with it running on/dieselling.
A fix from ford back then was to fit a filtered valve the allows fresh air with no fuel on key switch off.
Probably very difficult to locate the valve and system now.
Noel.
 
wow, you were all pretty much spot on with ur assumptions... mike what you said seems to be exactly what was happenin... and noel, yeh 1980 4spd manual..... but its no problem anymore,...... while i was at werk today my mum and sister just took it str8 to the mechanic to have it fixed!!! personally ii woulda rathered saved my muney and tried to fix by myself first, but ohwell, wasnt my muny.......... cheers for all tha comments!
 
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