Eric,
I have little experience with the 164. I do have good experience with
Bosch fuel injection.
The first thing that comes to mind is the coolant temp sensor. AND if
rocking the engine changes the idle then I would suspect wiring more
than the sensor itself.
My approach would be to make sure that rocking the engine is not
changing the throttle position. If so a look at engine mounts is in
order. You may not need to look too hard. If not then I would closely
examine the wiring harness at the sensor. Further, I would check the
resistance at the sensor, connector off and then do the same at the
other end of the wiring harness (likely in the ECU connector) connector
on. I would also "jiggle" the harness along its path back to the
connector to see if you can get a wildly different reading. Where you
find the reading changing, you will find your problem. If not then I
would follow the factory troubleshooting guide relative to the sensor
and pay close attention to any testing relative to grounds.
I have seen idle increase to 1500+ RPM with a bad sensor. I have also
seen it do so erratically.
Regards,
Scott Shure
'85 GTV-6
Saabs with different Bosch systems
Date: Sat, 21 Jan 2012 22:30:53 -0500
From: Eric<[email protected]>
Subject: [alfa] 164 issue - John Hertzman's car is behaving strangely
I've been seeking help on 'another network' as it were. In that world, it
seems to be expected that a man named Steve who lives Virginia will solve any
and all 164 problems. I like Steve but he seems to be a busy chap.
So I'll present this issue here to the huge lurker population which was proven
last month (or was it in November?). Perhaps someone may have some insights on
an odd problem I'm having...
[The following is pasted from a post I made to the AlfaBB or somesuch. The
"lack-of-codes" issue mentioned in PP1 is exactly that: push the square button
in the manner defined by Fred DeMeteo and nothing happens...no slow flash, no
codes, nothing. The button switch has been tested OK, the CEL lights up along
with the rest of the lights when the "TEST" button is pressed, and the
'service connector' on the passenger side has been tried.]
The lack-of-codes issue is tabled in favor of the actual problem where the
engine 'surges' -- revs up while idling. (To the extent that you need to be
sure that you're applying full brakes if you're in gear.)
This is the weird part: if I pull the engine forwards (towards the nose), the
idle drops to 'barely running'. If I push the engine rearward, it revs.
Sometimes it seems to do the opposite.
This is an early '91. No rubber between the plenum and right (rear) valve
cover. While the car is 20 years old, it has only 64K miles on it. The problem
is most obvious when just started or when cold.
I've poked, prodded and disassembled most of the air intake system (to include
the oil separator, idle stabilizer and main air intake). It all looks good --
no cracks or sloppy connections.
Spark is good too. I've reseated all the plug wires on both ends plus the
coil.
If this were a 105 car, the geometry between the chassis and the engine with
regard to the accelerator pedal or choke might be an issue. But the 164 uses
modern cables which aren't affected by the engine position.
Has anyone seen anything like this?
[End of AlfaBB post.]
My experience has been that the Digesti give a bit more thought to things
before answering. Please take your time, think about experiences, phone a
friend, etc. I would very much appreciate your observations.
Thank you in advance,
- - Eric Hambleton, Marietta, GA
Current stable: 1991 164 base - 1976 Spider - 1984 Cadillac Coupe De Vile (3rd
generation owner - Grandpa bought it new in Naples, FL) - 2009 Mazda RX8 R3
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