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Topic: Blow motor...acting variable? (Read 1282 times) previous topic - next topic

Blow motor...acting variable?

I just noticed this and I know it isn't normal, but for some reason, the more I press the throttle down, the lighter the vents blow on me. WOT gives me no air out the vents but the charging systems remains at 14.6v. It isn't on and off, its actually variable to how much I push the throttle down. Why is it doing this?!

My best guess is a ground problem somewhere. Ideas? This car has more than one  gremlin eating away at it!
1988 Thunderbird Sport

Blow motor...acting variable?

Reply #1
be more specific
what are your settings when this happens.  I can assume you have the heat on and low.,, but then again, we assume nothing.

details because you could have a vac related problem.

also details on what hvac system you have.

Blow motor...acting variable?

Reply #2
Manual hvac, I have the blower on high with heat on. Either while driving or when going from a stop, the blower dies down when throttle is applied and comes back immediately when it is coasting. I would listen for the blower itself when this happens but the exhaust drone overpowers it when it gets throttle.
1988 Thunderbird Sport

Blow motor...acting variable?

Reply #3
are you sure it is the blower motor slowing down and not the vac operated door switching to defrost. that happens alot to these cars. you hit the gas and the door goes to defrost and when you let off the gas it goes back to the setting you had it on.
84 Turbo coupe 2.3T Modded with 88 upper and lower intake, 88 injectors, E6 manifold, T3-4 AR.60 turbo, 31X12X3 FMIC, Homemade MBC , Greddy knock off BPV.
4 eyes see better than 2! 
Da Bird!

FreeBird

Blow motor...acting variable?

Reply #4
Quote from: ipsd;210186
are you sure it is the blower motor slowing down and not the vac operated door switching to defrost. that happens alot to these cars. you hit the gas and the door goes to defrost and when you let off the gas it goes back to the setting you had it on.


x2
louie  :birdsmily:
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It seemed like a good idea at the time.        88TC R.I.P.      88 Sport build in progress

Blow motor...acting variable?

Reply #5
The vacuum reservoir tank is supposed to keep vacuum on the HVAC when the manifold vacuum drops.

Blow motor...acting variable?

Reply #6
I'll stick a multimeter to the blower wires to check but that sounds like the problem. Without vacuum, the vents pop back to defrost automatically? It doesn't rely on vacuum to move it? Learn something new...one of my defroster vents seems plugged up though so it isn't easy to reach over to one to feel for airflow out of them when driving. I'm really not sure whats up with that either.
1988 Thunderbird Sport

Blow motor...acting variable?

Reply #7
Quote from: Seek;210254
Without vacuum, the vents pop back to defrost automatically?


Yes

 

Blow motor...acting variable?

Reply #8
After the engine has been shut off for a minute, move the HVAC function lever. You should hear the vacuum actuated doors move.
The vacuum reservoir tank should hold vacuum after the engine is shut off.