I have seen that as well. Check to see if there is a good ground connection where the temp sensor screws into the head. With some corrosion and acidic coolant, especially if there is a grounding ring between the sensor and the head, the ring gets corroded.
> Date: Sat, 28 Jan 2012 17:56:05 -0500 > From: [email protected] > To: [email protected] > Subject: [alfa] RE: 164 issue - John Hertzman's car is behaving strangely > > 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 > -- > to be removed from alfa, see http://www.digest.net/bin/digest-subs.cgi > or email "unsubscribe alfa" to [email protected] -- to be removed from alfa, see http://www.digest.net/bin/digest-subs.cgi or email "unsubscribe alfa" to [email protected]
