pulse width at idle

Chris Morriss crsm at oroboros.demon.co.uk
Mon Nov 23 20:33:44 GMT 1998


In message <c=US%a=_%p=ASC%l=MONTY-981122234148Z-3862 at marge.asc.com.au>,
"West, David" <djwest at subcorp.com.au> writes
>Hello all,
>
>I have a sick 3 litre turbo car that is badly missing and pluming crap 
>out the exhaust.
>
>New plugs go black in seconds
>
>All sensors and compressions check out fine except for the power 
>transistor.
>
>I think that the computer is dumping way to much fuel into the engine 
>which is causing it to miss, smoke and almost not run or the power 
>transistor is not operating correctly and the plugs aren't firing.
>
>Q) A blown turbo dumping oil into the intake system should be evident 
>with oil throughout the intake manifold - is this correct?
>
>Q) I measured injector pulse width with a cheap duty cycle multimeter 
>and get 2% @ 1000 rpm. I think that this equates to about 1.2 ms - is 
>this about the right pulse width for idle?
>
>Thanks
>
>David West
>
>
>
>
It's possible that the injector drive transistor is leaky, and there's
always some current flowing causing the injectors to be held slightly on
when they should be off.  That will make them dribble fuel into the
manifold all the time.  A correct width pulse might still be there.  You
would need to check with a 'scope to see if they were turning fully off.
-- 
Chris Morriss



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