Question
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Followup To
Question -
The tach works fine most of the time, however every now and then when sitting at a stop light the tach will go from reading 700rpm to zero, once the car gets going again the tach reads fine.
Also the car stumbles and the transmission won't shift right some of the time, I ran the codes and got a 17 - engine running too cool for too long and am going to replace the thermostat.. Is there another sensor I should be on the look out for and would that intermittent tach cuase the stumbling?
Answer -
Hi Tommy,
The tach runs off the sensor(s) in the distributor which also time and synch the fuel injector(s) so if it stumbled exactly when the tack drops I would speculate that the sensor is getting weak. If not then they are unrelated. So watch for a code 11 (and/or 54 if you have the V-6) which are the one(s) for those sensors. There is a tach module on the instrument cluster at the edge of the tack gauge that can wear out so that is another possibility if the tach gives up but the engine still runs.
On the temps, I would verify that it is indeed warming up too slowly. Does that jive with the temp gauge on the dash being slow to reach normal range? If not, then it might instead be the coolant temp sensor. It should read between 7 and 13,000 ohms when cold, and declinein resistance slowly to 700 to 1,000 ohms at 200F. If you don't know where the sensor is tell me which engine you have. If that all checks out then a stuck open thermostat may indeed be your problem.
Roland
responce-
Roland, I replaced the thermostat, when I pulled it out, it fell apart into a few peices, spring was sprung. Installed the new thermostat, car now gets up to operating temp and seems to run fine, transmission is shifting good, tach is still acting up though, but you suggested what I suspected which was "There is a tach module on the instrument cluster at the edge of the tack gauge that can wear out so that is another possibility if the tach gives up but the engine still runs." So I consider that matter closed, I do have another question if you don't mind.
The AC system, fully charged, compressor engages, but won't blow cold air. Accumulator lines and canister never get cold, if I disconnect the low pressure switches the compressor clutch disengages like it should, where should I begin to search for the problem?
AnswerHi Tommy,
If the A/C compressor is doing its job yet you get no cooling effect I would wonder whether there might be a problem with the refrigerant handling aspects, perhaps the expansion valve. But I have little or no experience with that "side" of AC systems. It appears that the electrical is o.k. So all I would do under this circumstance is go to an AC shop.
Roland
