RE: Fouled plug, injector problem - exhaust manifold crack?

["Jeff Greenfield" <alfaguy@xxxxxxxxxx>]

Ok, so you have compression and it sounds like the #4 injector is firing.
Most likely, if you hear it 'clicking' it is working properly.

It is possible to swap the injectors around, but it is a fair amount of work
... you need to remove the entire fuel rail, remove the two injectors by
cutting the short hose(s), and reinstall by replacing the hose(s) with the
proper high pressure fuel hose. (I think the consensus on the list is that
this is 7.5mm ID) Don't loose the small cupped washers as they help to
retain the hose on the barb.

A few other thoughts before you go through all this work.

Try swapping the plug wires around between 3 and 4. The #3 wire should be
just long enough to reach #4, it is possible that the wire is breaking down
under load.

Have you checked the cap? Remove it and examine it closely for a crack or
any signs of carbon trace(s). You could have a misfire causing the problem.
If in doubt, replace the cap they are not that expensive.

Try disconnecting the brake booster and plugging the hose. If the brake
booster is leaking, it would cause a vacuum leak that could affect #4.
Although I'm pretty sure that this would only be the case with a Spica car,
as the vacuum port for the booster comes off #4 on the earlier cars. On the
Bosch cars, the vacuum port is on the plenum, so it should not effect only
#4.

If all else fails, check the valve clearances ... I once had a car that
exhibited similar symptoms (running poorly, poor idle, appeared to have one
dead cylinder, everything else checked out so I replaced the suspect
injector, no difference). Anyway, the short of this was that although the
compression was good, the valve clearance on that cylinder was way too tight
so the valve never completely closed.

HTH,

Jeff

-----Original Message-----
From: Robert Abatecola [mailto:robert@domain.elided]
Sent: Sunday, April 27, 2003 8:53 PM
To: Jeff Greenfield; alfa-digest@domain.elided
Subject: RE: Fouled plug, injector problem - exhaust manifold crack?

There's one more item that bothers me about the problem with my
Spider.  I put my stethoscope against the #4 injector and I can hear
it clicking away as it should.  It sounds about the same as the rest.
If I unplug it, it stops.  So the injector sounds like it is
activating.

Just another data point in my diagnostics.


  -Robert Abatecola, San Jose, CA
   1985 GTV6
   1987 Spider Quadrifoglio


At 3:56 PM -0700 4/27/03, Robert Abatecola wrote:
>Jeff and everyone else,
>
>Thanks for the pointers.  I swapped plugs between #3 and #4.  The
>problem stayed with #4.  I also checked for spark using a grounded
>spare plug.  Spark checked out okay.  I installed a new plug on #4
>(Bosch Platinum is all I could find locally).  Again, the problem
>did not change.
>
>Is it possible (and easy) to test the injector connection?  What
>should I do next?  Order a new injector?  :-)
>
>
>  -Robert Abatecola, San Jose, CA
>   1985 GTV6
>   1987 Spider Quadrifoglio
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