Ivan Arcuri (201.52.239.27) - Wed Aug 20 21:00:04 2008

Hi!

I live in Brazil, and I have a 1995 ford Taurus 3.0. The mileage is near 63k mi (101, 000 km).

Since I purshased the car (february 2008), I have the following problem: When I turn on A/C, the idle suddenly goes down, near 500 RPM. When it happens, the A/C turns off (automatically) and the idle comes back to ~760 when in gear, or ~ 1000 when in "P" or "N". When the idle comes back to normal rate, the A/C is turned on, and again the problem repeats. So, the A/C turns on, off, on, off, but just when the engine is idling. If Iīm driving, and turn the A/C on, it works well.

I have already tested the A/C system, the refrigerant pressure, the fuses in both boxes (near the battery, and near the parking brake), and itīs all right. I have also taked off, cleaned, and checked the idle bypass (near the throttle body), and it seems OK!!!

My mechanic advised me that the idle is a litle high when in "P" or "N". It should stay at 750, and not 1000. When in "D", the idle goes to 750~760.

IF THE IDLE BYPASS IS OK, WHAT CAN DO IDLE GOES WRONG??

Thans,

Reply #1 Eric Anderson (76.28.246.100) - Sat Sep 20 23:57:53 2008

Is your electric fan coming on when you turn on the A/C? It should be, and if it is not your system could be rapidly overpressurizing with the high pressure switch shutting off the compressor. At speed that won't happen because you are getting air through the condensor.

Don't know what to say about the idle speeds.

Good luck.

Reply #2 Ivan Arcuri (189.120.30.6) - Thu Oct 9 18:18:48 2008

Yes, the electric fan is comming on when the A/C is turned on... and the electric fan keep working for 2~3 mintes after the A/C is turned off, then, stops.

I guess the Idle Bypass is not working well, because the idle is not going down to 750 RPM when in "P" or "N". The engine should idle at 750~760 RPM, when hot, in any gear position (P, R, N, D or L), the main problem is itīs very hard to find another idle bypass... Fordīs dealers doesnīt have parts for Taurus, Iīll have to find it in some "import" stores.

Thanks

Reply #3 Ivan Arcuri (189.120.30.6) - Sun Dec 21 06:18:01 2008

I foud!

The problem wasnīt the Idle Bypass, but the throttle position sensor. I think the last mechanic didnīt screwed it very well, so the sensor was out of position. Very, very easy! I put the sensor on the right place, and put a couple of new screws. Done! Now, the idle speed is ner 760 RPM with or without the A/C.

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