Cold Idle and A/C vents

[alsej]

1993 Mark VIII

I have two problems and am looking for advice on how to repair.

First, the engine will not idle up when cold and

Second, A/C and/or vent air will not come out of the dashboard vents but will come out of the defroster and floor.

Any suggestions?

[pro-five-oh]

1. Buy a code scanner and pull some engine codes. The Idle Air Control Valve might be your problem, but its not worth guessing.

2. You have a vacuum leak from the engine to the rubber hose that goes into the firewall (and eventually goes into the blower motor). Find a little hose that starts at the center of the firewall and check for cracks and a tight connection to the source of vacuum. Replace the hose with generic vacuum line if necessary.

[alsej]

Thanks pro-five-oh for replying about my troubled Mark. The cold engine idle up is a problem but it is only annoying at this time. I usually go out in the morning and start the engine about 5-10 minutes before my wife leaves for work. After that it idles fine but the rpm's do drop a little when the compressor is on because of the idle up problem. Like I said, I can live with that for now.

On the other hand, the dashboard vents are really beginning to tick me off. I have removed the cover from the engine and have checked out the lines on the passenger side (RH) of the engine. There is one main vacuum coming from the top of the engine on the drivers side (LH) supplying vacuum to a 2 lines on the RH side. One goes into the car and the other goes into a cannister in the wheel well. The line and cannister do hold a suction and don't seem to be leaking. The other line goes into the back of the climate control and there is vacuum on that black line there. At that point a yellow line goes off by itself and gets lost somewhere under the dash and than the other lines go into a connector behind the glove box. Again, the black line at this connector does have vacuum.

I took a piece of vacuum hose with some small plastic connectors on each end. I inserted one connector into the black line and the other end into each of the other lines. Started the engine and here's what happened:

Max A/C- The door in the fan box opened and closed (I removed the fan and saw the door moving).

Vent- Heard movement but air was than directed to the defrost.

Panel- Same as Vent.

Floor- Air directed to floor.

Floor & Panel- Again, heard movement and got air from floor and defrost.

So you get my drift. All else works except vents. I feel sure it's a vacuum leak but don't know where else to look.

Jimmy

[pro-five-oh]

ALSEJ:

The engine problem is PROBABLY the IAC valve, as previously mentioned. The part is hidden under the intake runners, and is an absolute nightmare to get out. The part itself is $50-$70...you can clean your old one, but I'd recommend buying a new one instead.

If the blower motor can redirect air to anything besides the DEF position it probably isn't a vacuum leak. I would check the blend door motor on the blower. Do a search on this board and the Town Car board for more information.

If this car is a keeper, I'd highly recommend getting a Ford shop manual. Trust me, it will come in REAL handy. ;)

[alsej]

I've had this baby since '96 and, yes, it is a keeper. Haven't had any real serious problems and just love the damn thing. Thanks for all the advice.

[pro-five-oh]

I know the feeling. Have had my 1993 Mark since 1998 and I can safely say that they "just don't make 'em like they used to!"

Go on Ebay or www.helminc.com (http://www.helminc.com) and get yourself the shop manual. Makes life a whole lot easier!