Idle issue when you put the heat on

[cmg540]

So sitting at the bus stop waiting for the kiddo I finally decided to turn on the heat. When I did the explorer sounded like it was going to stall out, I grabbed the phone and shot a video of the tach. Unfortunately it did not catch the sound of the motor almost stalling out. This goes on for a few minutes then straightens right out. It almost sounds as if it's trying to start something and its to much of a load on the motor.

 

[grrtrainman]

Usually, when you turn on the defroster or defogger, the compressor comes on to act like a dehumidifier. That would put an additional load on the engine. BUT, you only put on the HEATER.
Hmmmmmm ???

 

[cmg540]

Usually, when you turn on the defroster or defogger, the compressor comes on to act like a dehumidifier. That would put an additional load on the engine. BUT, you only put on the HEATER.
Hmmmmmm ???

I have used the defogger without any issue's, this just struck me as odd.

 

[GWA1]

Time for a trip to the dealer.......

 

[VinceL]

That's odd...

 

[GWA1]

I believe when you put a load on an idling engine, whether mechanical or electrical, rpm dips alittle for a split second then the do-hicky tells the gizmo to increase rpm to compensate.
So it must be something in the hizenburg idler circuit.

 

[GWA1]

Isn't the a/c on when defroster is on to supply dehumidified air to clear windshield quicker?

 

[gorecp]

I have a similar issue to yours. Only my idle doesn't drop it surges from 750 to about 1100 for the duration that the heater is on. Rear defrost makes no difference either. Its baffling to say the least.

Update:

This happens only when floor/ windshield and the windshield only settings are chosen. Floor or panel settings there are no surges.

 

[peterk9]

I have a similar issue to yours. Only my idle doesn't drop it surges from 750 to about 1100 for the duration that the heater is on. Rear defrost makes no difference either. Its baffling to say the least.

Update:

This happens only when floor/ windshield and the windshield only settings are chosen. Floor or panel settings there are no surges.

Welcome to the Forum gorecp.:wavey:
Is this on your '97 XLT?

Peter

 

[peterk9]

I believe when you put a load on an idling engine, whether mechanical or electrical, rpm dips alittle for a split second then the do-hicky tells the gizmo to increase rpm to compensate.
So it must be something in the hizenburg idler circuit.

I guess my hizenburg idler circuit must be okay. My tach was reading an idle speed of approx 600rpm in the driveway. When I turned on the heat and when I turned on the A/C and Max A/C, the needle didn't budge at all.
I normally always have the Climate set to Auto so I don't need to adjust heat/cool.

Peter