87 Mustang heater problems

[wingzero_ac19x]

I just replaced my tps due to a crazy idle...fixed the idle and dead spot in pedal, but whenever I turn on the heater, the car bogs down really bad and nearly cuts itself off....It has done this since I got the car....if I push the accelerator, it will catch itself and run, but still wants to bog down when idling for the whole time the heater is on......any ideas?

 

[Keasbey]

vacuum leak in the heater system?

 

[white1989]

Hmm...just when the heater valve is open?

Or is it when you turn on the defogger/blower?

 

[wingzero_ac19x]

It stumbles just a bit on all settings, but what really drains it is when it is set to vent, and the blower is turned to wide open, the car will cut itself off if I dont push the accelerator..

 

[rd]

My first guess would be that there is a vacuum hose off or a leak in the hoses or vacuum door motors. Plug the vac source at the intake and drive it. If it fixed it, you found it.

There are no valves in the heater system. Hot water circulates throught the heater core full time. The controls just direct the air through the heater core or ac evaporator, etc as they are set.

The other possiblility, a long shot, is an electrical problem causing the ignition to loose power or something.

 

[ratrapp2]

you may have a bad connection in the instrument cluster.i was replacing my speedo head in my 88 lx friday afternoon at work.i didn't get it finished so i was going to drive it home with the cluster out of it.about 2 miles down the road i turn on the heater and the car bogs down awfully bad.i turn the heater off the car picks back up.i limp it to my grandma's house,she's closer than my house.i plug up the cluster and it still bogged down.i wriggled the connector a little bit and it quit.just a thought because you'd have to have one real big vacuum leak to kill the car like that.

 

[wingzero_ac19x]

Hey...I know its gonna sound crazy....but that instrument cluster deal sounds right. I say that because my fuel guage doesnt connect right at the cluster, you have to hit it a couple times for it to register....I took the cluster out and the connecting points are worn down to the plastic film of the back of the cluster.... I dont really understand why this would affect the heater, unless they somehow ran off the same fire wire. I have also noticed when I turn the heater on, my volts guage plummets down for a sec. So who knows, maybe it is in the cluster....