Possibly different '89 200qt power issues

[Joshua Van Tol]

Have a look at the fuel pump relay. It supplies power through a
seperate circuit to the frequency valve. Having that circuit go open
(and it can happen) causes the car to run lean, and this will cause
poor idling, and stumbling throughout the rpm range.
On Wednesday, December 11, 2002, at 04:44  AM,
Mike_Buckham at ptk.pioneer.co.uk wrote:

> Hi everybody.
>
> I've just joined this group because I've just got myself an '89 200qt
> Avant
> to replace my older '86 100q Avant (which I am storing for spares). I
> am
> having an intermittent power problem which seems to occur about 80% of
> the
> time. When the fault is not there, the engine is sweet and there's
> plenty
> of power. When the fault is in, the engine still has some power, but a
> LOT
> less, and it also struggles to idle. Also, I've noticed that if you
> pump
> down the accelerator and hold it, the revs rise initially and then drop
> down quite a bit. You have to keep pumping the accelerator to keep the
> revs
> up. This symptom may be related to the engine temperature though.
>
> The problem comes and goes throughout a journey and so I believe it to
> be
> an intermittent connection to the ECU from or to one of the sensors or
> valves in the engine. The trouble is that I can't track the b*gger
> down.
> Can anyone give me a suggestion as to where to look based on this
> information?
>
> My car doesn't have an engine check light wired in (I believe this is
> normal for UK spec cars of this age) so I was also wondering if anyone
> could tell me which ECU connections to wire a light to. This way I can
> hopefully read some ECU diagnostics. It has the Hitachi MAC-12D ECU.
> Can
> anyone tell me how many diagnostics I can read from this ECU? I
> believe I
> activate them using the fuse connection in the fuel pump relay.
>
> Finally (for now), I just read the email from Ben Swann ("re. More '89
> 200q
> power problems") which indicated that the multi-function temp sensor
> could
> affect the engine performance. I know that this is faulty on my car
> because
> my coolant gauge doesn't work and I have traced the wiring back to that
> sensor with no breaks. I have already acquired a replacement sensor
> from a
> scrappy but haven't fitted it yet. Is there a chance that this will
> cure my
> intermittent engine power problems?
>
> Cheers, Mike.
> '89 200qt Avant.
> Reading, UK.
>
>