Does anyone have experience with the AC stalling the engine.

 

Can you keep it running with your foot on the gas? If so, most vehicles have a idle rpm boost of some kind when the ac is turned on. Carbs have a solenoid that hits the throttle lever, and efi does it electronically with the IAC motor. Apparently one of these is not working.

 

The engine does not stall when the ac comes on. It idles a little rough though, like there's a vacuum leak or a dirty injector. It dies after it is driven a little while and then stopped in drive, like at a stop light. You'll be sitting for 10-15 seconds and it starts to stumble then stalls out. If you catch it in time, it can be put into neutral to prevent shut-down.

 

actually that happened to me twice today. i was at a stop light with the AC on, then when i put my foot on the gas, it stalled

 

Is it carb or efi?

 

It is FI. Have had codes checked (no errors), replaced idle positioning sensor, and cleaned air by-pass valve. It runs much better, but intermittingly still shutsdown at stops that are longer than 10-15 seconds.

Thanks for checking in

 

If you have a 302 make sure after the engine is warmed up you have an idle rpm of:

Automatic tranny in drive, 675rpm or less
Manual tranny in neutral, 775rpm or less.

If the idle rpm is higher than these figures, they say the first thing to do is to disconnect the battery positive terminal, then re-connect and try again. If the idle speed is still to high after that, turn the idle stop screw back till you get 600 rpm on an automatic, or 700 rpm on a manual, and then turn the screw back one-half turn more to get the throttle set right.

 

Yes, I do have experience with that. My '90 (I'm lurking, sorry) does the same thing. It only happens with I'm coming to a medium-hard stop, as soon as I put the clutch in, the engine stalls. It will also do it sometimes if I pop it out of gear when it gets down to idling speed without using the clutch.

I'm assuming I need a new compressor, or maybe it just needs to be lubed, but it hasn't been a real big problem yet.

 

There is an air bypass valve on the side of the FI throttle body. The Haynes manual calls it an air bypass valve; the parts store calls it an idle air control valve or idle control unit. Are these the same parts? How would the engine idle be affected by a malfunctioning one of these? Does anyone know what it controls? Please, give what-if scenario's.

Thanks

 

BigNish

I will almost bet that you have a system with an accumulator/receiver and a Clutch Pressure Cycle Switch on the Accumulator. If so, the cycle switch is probably bad. In addition to controlling the clutch cycling on the compressor the switch also sends a signal to the ECA (another term for computer) letting it know that the air conditioner is running. The ECA will then adjust the idle speed by increasing it and eliminating stall out when you stop or make sharp turns.

 

That is a good possibility. I did replace it in April.

 

I have no idea what the problem could be, but I figured if there was something wrong with the compressor, the belt would start squealing. Wouldn't you think the belt would give up before the engine would?

 

To Franklin2


I replaced the IAC (Idle Air Control Valve) as you had recommended.
The idle stalling stopped. You made a believer out of me.

Thanks

 

Spoke to soon, it died again today. Time to take it in.