Subject: [alfa] re re re no more than 5000 rpm

[RonHorowitz <RonHorowitz@xxxxxxxxxxxxxx>]

Kind of jumping into the middle of this thread, so apologies if this is
redundant or eroneous.... Still, if it helps:

> I am curious, however as to why the pressure goes up from some
>30 psi to about 45 psi as I rev the engine up.

Perhaps you have 14PSI or so difference in manifold vacuum?

>Is there some signal to
>the pressure regulator or pump that tells it to increase pressure as
>rpm's go up?

I'm not sure which fuel injection system you have, but the relative
pressure across the injectors is what's regulated rather than the pressure
in the fuel rail per se.

>It has been suggested that the problem may be electrical in
>nature--that somehow the drain on the electrical system goes up as the
>rpm's do and therefore we lose spark. How would I check that?

Maybe. Put a scope on the ignition and see if the voltage is dropping. The
trace tells you what's going on. Adbvance is OK?

>Any other suggestions????????

I'm kind of jumping in, but put a scope on one of the fuel injectors and
see if the duty cycle is increasing with RPM or if thre's anyhing funky
going on. Got good grounds everywhere?

I'm not a specialist on the late model injection, I've never worked on a
164 if that's what you've got (sorry, jumping in the middle...) but if you
have a knock sensor and a bad rod bearing, it's conceivable that _could_ do
it.

Also, if it's not fuel and it's not spark, it _could_ be the valves
floating, though that's pretty doubtful. I suppose I should go back and
read the other posts, but you could check the exhaust for damage and check
the cat to make sure it's not plugged up....
--
to be removed from alfa, see /bin/digest-subs.cgi
or email "unsubscribe alfa" to majordomo@domain.elided