I bought my 1997 e350 club wagon (with the v10, e4od and factory towing package) new in 1996. I have 84k miles on it. Most of these miles have been towing a 7500# trailer around California and other Western States.

Here is my issue: Over about the past 20k miles I have noticed a serious decrease in fuel economy, some pinging and on our most recent trip the a/c would cut out when climbing the slightest grade. I know that the a/c has cut out before, but only under extreme conditions (heavy load + steep hill + high outside temp.) It's hard for me to gauge the power output because I don't usually push too hard.

I have always been good about regular maintenance, 3000 mi. oil and filter changes, 30k trans filter and fluid, cooling system service and air filter as needed.
I suspected that it was time to do some more serious maintenance.

So far I have:

installed new Motorcraft spark plugs
replaced all 3 Bosch o2 sensors
installed new fuel filter
checked for vacuum leaks
replaced pcv and vac. line (showing it's age, but not leaking)
checked fuel pressure regulator ( fuel pressure is good with no load, is a road test necessary?)
I disconnected the battery during some of these service procedures.
ran base idle relearn routine

There have been no changes in performance that I can detect and the a/c still cuts out.

What should I check next? I would appreciate any suggestions.

FTE is a great source of information. Thanks!!!

Robert

 

Not sure if this will be helpful...
We previously (Y2K) had a different type of van, when it was brand new we had this same sort of problem. It only happened when towing, don't recall if the trouble involved hills or not (too long ago).
Turned out that the van had insufficient vacuum reservoir capacity. No way to know if it was specific to our van. The dealer added an aux. reservoir somewhere and we never had trouble again.
Possibly you have developed an issue relating to vacuum storage or leakage that you haven't found?
Good luck.

Mark

 

Hello Mark,

Thanks for the info. I have searched for vacuum leaks, can't find any. For years my van used to be able to tow heavy loads up hills through the desert in the summer with the a/c running. This problem is new. Combined with the reduced fuel economy it seems like an engine problem.

 

I would check the vacuum reservoir check valves. All engines make weak vacuum when working hard. If the check valve got stuck, then the strong vacuum in the reservoir would not be maintained when the engine intake pressures go up.

https://www.ford-trucks.com/forums/1...efrosters.html

More info. This job sucks.

 

Thanks for the reply. The link that you posted is good info.

I have been checking for vacuum leaks, including the line that runs to the heater and a/c controls. No leaks.
In the link that you posted it states that the a/c blower defaults to the defrost vents. My van does this too.
My Club Wagon has the dual a/c and when the a/c cuts out nothing comes out anywhere. No air blows out of the defrost vents or the rear a/c.

I read a post on FTE about connecting a test light to the compressor clutch electrical connector to see when the clutch should be engaged.
I suspect that something is turning the a/c off to devote more power to pulling the load.
Something on my van has changed. The a/c cuts out much more often with less load than it used to. I can remember only a couple of times years ago that it cut out, and that was on long grades in hot weather.

 

I am from the 7.3L forum but you can check one thing. Your ac compressor has an electrical clutch that controls if the compressor turns or not. There are shims or a shim that maintains a gap between the coil side of the clutch and the plate of the clutch. If your clutch plate is wore and the gap is greater than .020 inches then you need to measure the actual gap. Do this with the engine NOT running. Turn the key to ON/RUN (not accessory) and turn the ac on. This will engage the clutch without the belt moving. Now with a set of feeler gauges measure the total gap between the coil and the clutch. Let's just say the measurement is .080 inches. Now with the coil engaged take the proper socket and remove the bolt in the middle of the clutch to remove the clutch coil. If the key is not on with the ac turned on......the clutch will rotate when you try to remove it. It is probably a 8 mm socket. Be careful when removing because there are shims that you do not want to misplace. Measure the shim(s). Lets say the shim is .100 inches. You need a gap of .020 inches an you have a gap of .080 inches so file the shim .060 inches so you have .040 left. Now your gap should be .020 inches. I believe ford sells a set of shims in .010 steps. I looked online at advanceauto.com but could not find any. This will help the compressor to stay pulled in and rotating but maybe your vacuum is leaking somewhere that you can not see or hear. It is possible that your actuator that shifts the vent is wore out and needs to be replaced. Do you have a vacuum drawing under your hood that shows all components? Does your vehicle have 4 wheel drive? On the 7.3L this is accomplished by a Pulse Vacuum Hub Lock Solenoid located on the firewall. Sometimes the orings wear out on it the hub. I hope this helps you. I do not know the actual gap that is required for your vehicle.
Dwayne
Forgot to add that when you put the bolt back on....use a small amount of blue loctite so it does not work it's way loose again.

 

The clutch issue does not cause the blower to stop blowing. If the vacuum gets weak while climbing hills, the diverters inside the AC unit can settle into a position that causes the blower to just spin without blowing much air.

One of your vacuum actuators (that actually control the blend door, for example) could have sprung a leak, or the check valve has failed, it would cause the symptoms you describe. Its a vacuum problem.

 

Thank you, 95e150CW! It looks like the check valve is the problem. After reading the article from the link that you posted, I thought that I might have to cut the access hole as described in the article.
While trying to find vacuum leaks one of the things that I did was to attach my vacuum pump and gauge to the vacuum line connector that is under the hood near the blower. I pulled a vacuum, waited 10 minutes and checked the gauge. No leak. However this process does not verify the function of the check valve.
My solution was to install a check valve at the connector under the hood by the blower.
Now the a/c runs like it used to. It's output is not as cold as it used to be (approx 62*F) but I think that may be a topic for another thread!
I now know that some day I may have to cut an access hole, thanks for the info about that!

Robert