re. Help needed from CIS experts

Ben Swann bswann at
Fri Dec 13 00:00:53 EST 2002


Different car, similar culprit as the 4kq one I just replied on.

Check/replace that Multi-Function Temp Sending unit - the one that mounts
upside down on the bottom of the cooling neck.

Sometimes the ECU will force the code if you run diags, though not always.
 These things seem to be the most overlooked, but easiest to fix thing that
cause these sorts of problems.

Not the only possible culprit, but sure is a lot easier than fuel pressure
tests.  I don't know how cheap Rod at has them for, but
I'm sure less than the dealer.


[Anyway, my '89 200tq with MC-2 (MAC14, K24, etc) motor is giving me some
troubles.  Car has TAP chip since I
bought it (I know, I know, if I did it, I would have gone to SJM or Ned).
 However, I don't think it is related, as it didn't have these poblems

There are three symptoms I am experencing.  Please keep in mine the may all
be caused by one problem, or there may be more than one issue.

1)  Cold starts.
When started in cold ambient temps, the car will fire right away, and
immedietly die.  After doing this
about 3 time, you can keep it running with some throttle, and then after a
say 10 seconds of throttle
to keep the idle up, it will maintain idle on it's own.  However, when you
try to drive away, it will
quit unless you are VERY carefull with throttle/clutch.  It also bucks a
little until it warms up.

2)  Hot starts.  If I drive it and then park for 10min-4 hours, it will
crank but not start.  After
LOTS of cranking, it will eventually start and "clear out" with some

3)  Surging.  Sometimes while driving I notice the car is "surging" a bit.
 Feels kind of like a bad injector
on a 20v motor, only probably a bit more noticable.  The other day when it
was doing this, I looked at my
autometer boost gauge and noticed the manifold  pressure cycling up and
down about 2" at a shot.  Huh?
 What could do that?  ISV?  But that shouldn't be doing anything at 3000

So, I don't know.  I swaped in a different warm-up regulator, with no
change.  Fuel filter is relatively
new (no change).  Ohmed out the ecu coolant temp sensor up front, looked OK
but if I recall bently
shows a REALLY wide spec for this.

Any ideas?  I got to think this is fuel related (bad pump?)


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