project 4ktq problem found but unsure of fix...
DGraber460 at aol.com
Fri Feb 10 23:41:30 EST 2006
In a message dated 2/10/2006 7:56:56 P.M. Mountain Standard Time,
stpndsmn at yahoo.com writes:
First, thanks to all who had suggestions and encouragment..
It was suggested to that I try to see if the throttle plate for the CIS was
stuck and this is actually close to what the issue is.... The throttle
plate isn't exactly stuck but it is very stiff.
I pulled the intake boot off and the turbo inlet out of the way and tried to
lift the plate by the center bolt using my small snap-on magnet which is
usually strong enough to lift large bolts and sockets, wrenches etc... Well,
the magnet actually had a difficult time staying on the bolt head and it took
a couple of tries to actually get a good connection... I'd say that it is
probably a 2-3 lb pull to lift the plate from it's resting position. The
plate will move through it's entire range but it takes some effort to move it,
more than the intake of the turbo can provide I am sure...
If I wedge the plate up a little the engine will idle and rev up until it
runs out of fuel and if I work the throttle plate and tb butterfly
simultaneously the engine will rev up and run beautifully.. but if the plate falls to
it's resting position the engine instantly dies...
I don't recall that the throttle plate on my 83 CGT was ever that stiff and
I am not sure that my 4kq is supposed to be that stiff. I doubt that the old
JT could ever have pulled a plate that stiff except at high rpm and full
throttle....So I guess the question is... is the plate supposed to be that
stiff, is it fixable, or do I need to replace it????
I have the CIS head turned URQ style with a VW rabbit intake boot and a
custom fab'd 3 inch intake tube from there to the turbo inlet... I was thinking
it was possibly a problem of too much air volume in the system but I had a
difficult time lifting the plate by hand with my fingers on the center
Thanks for all the help
project 4kq Hopefully getting very close to done...
While trouble shooting the 2 URQ's I've had, I found the FD plate very stiff
due to fuel pressure. If you relieve the pressure I would bet it will flop
rather easily. The car should maintain pressure for over 20 minutes after which
it will drop slowly for some time. If it is still stiff with no pressure
_then_ you might have an issue.
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