Diagnosing a HVAC vacuum issue on a Ford F53

dougrainer wrote:

JaxDad wrote:
Glad you found the actual problem instead of just throwing silly wasted parts at it.

So much for the “ONLY” solution........

The main reason I won’t go to the stealerships is for exactly that reason, there’s no THINKING about the problem and finding the solution, it’s just throwing parts at it because a book or computer said to do that.

Thankfully the only place where such foolishness does NOT exist is in aviation, which given the price of parts is a VERY good thing.

According to the description the OP made, Heavy acceleration, The problem was the vacuum was used up......

Doug

And yet the OP’s post actually said;

Mike Schriber wrote:
It actually seems to be doing it now under low throttle steady state conditions as well. Obviously a vacuum issue but I'm not finding any obvious leaks.

Mike

BTW, my problem stealerships is NOT ‘trust’, it’s the SA and guys in the shop who just throw parts at things because they walk up to the vehicle with a preconceived ‘knowledge’ of what the problem MUST be instead of actually diagnosing the problem and fixing THAT.

In this case a 12 volt electric vacuum pump would have done ZERO unless it happened to be spliced in where the leak was by complete fluke.

There’s no savings in doing a job ‘fast’ if the problem isn’t fixed or an expensive ‘repair’ that was NOT needed is done instead of the repair.

I found my vacuum leak in about ONE minute using a propane bottle, my repair also ‘cost’ me about 2 feet of rubber vacuum tube, maybe a dollar.

Can you sell and install a 12 volt vacuum pump for ONE dollar?

dougrainer wrote:

JaxDad wrote:
Glad you found the actual problem instead of just throwing silly wasted parts at it.

So much for the “ONLY” solution........

The main reason I won’t go to the stealerships is for exactly that reason, there’s no THINKING about the problem and finding the solution, it’s just throwing parts at it because a book or computer said to do that.

Thankfully the only place where such foolishness does NOT exist is in aviation, which given the price of parts is a VERY good thing.

According to the description the OP made, Heavy acceleration, The problem was the vacuum was used up, which IS a common problem on Ford Chassis vacuum supply. The difference is YOU don't trust dealerships, that is fine. But you come to me and then you pay me $150 an hour to find a supposed vacuum leak, then I find some leak and fix it $300 later. Then you come back and tell me the problem still happens on full acceleration, you then pay me MORE. So, a customer comes to me and based on MY EXPERIANCE, I charge him $150 install plus the $75 for the Vacuum pump and at $225, he is fixed EVEN IF HE HAS A SMALL VACUUM LEAK. The 12 volt pump will overcome any supposed vacuum leak. Lets wait and see if the OP's problem is fixed on heavy acceleration. Doug

Doug, your thinking on how to "diagnose and fix" IS exactly the way most all "dealerships" approach repairs now days.

It IS quick and fast and the dealership EARNS the money in a hurry.

They don't have REAL troubleshooting and diagnostics training which leads to mickeymouse fixes and just throwing parts at it.

All the time not fixing the real problem, only masking the problem and often ADDING NEW PROBLEMS.

Yeah, I am angry with how repairs went with one of my vehicles, cost me nearly $4K, ten trips later and they NEVER fixed the problem.

I ended up doing Internet searches and FOUND the fix, a can of carb cleaner and a rag.. Instead I ended up paying for new fuel pump, new filter, new plugs, new cat.. Then down the road because of other problems I ended up having to change all the O2 sensors which were damaged and finally the other cat which because the dealer didn't fix but add other problems..

Yeah, $4K and dozens of trips to dealer, lost use of that vehicle for months, couldn't depend on it...

JaxDad wrote:
Take a small propane torch and unscrew the head leaving just the valve and pipe, then slip a piece of tubing over the end of the pipe. With the engine idling and the valve on the torch open (but not lit obviously) run the end of tube along every vacuum tube in the HVC system.

When you get to the vacuum leak the engine will inhale the propane and the extra ‘fuel’ will cause the engine to speed up a little, when you pull it away it goes back down again.

It makes finding vacuum leaks super easy.

I've been around the auto repair industry over 55 years and just learned another trick to add to my repertoire. Thanks for posting.
With this trick, I'll bet even Doug will consider looking for leaks.

Richard

JaxDad wrote:
Glad you found the actual problem instead of just throwing silly wasted parts at it.

So much for the “ONLY” solution........

The main reason I won’t go to the stealerships is for exactly that reason, there’s no THINKING about the problem and finding the solution, it’s just throwing parts at it because a book or computer said to do that.

Thankfully the only place where such foolishness does NOT exist is in aviation, which given the price of parts is a VERY good thing.

According to the description the OP made, Heavy acceleration, The problem was the vacuum was used up, which IS a common problem on Ford Chassis vacuum supply. The difference is YOU don't trust dealerships, that is fine. But you come to me and then you pay me $150 an hour to find a supposed vacuum leak, then I find some leak and fix it $300 later. Then you come back and tell me the problem still happens on full acceleration, you then pay me MORE. So, a customer comes to me and based on MY EXPERIANCE, I charge him $150 install plus the $75 for the Vacuum pump and at $225, he is fixed EVEN IF HE HAS A SMALL VACUUM LEAK. The 12 volt pump will overcome any supposed vacuum leak. Lets wait and see if the OP's problem is fixed on heavy acceleration. Doug

Glad you found the actual problem instead of just throwing silly wasted parts at it.

So much for the “ONLY” solution........

The main reason I won’t go to the stealerships is for exactly that reason, there’s no THINKING about the problem and finding the solution, it’s just throwing parts at it because a book or computer said to do that.

Thankfully the only place where such foolishness does NOT exist is in aviation, which given the price of parts is a VERY good thing.

Found it!

I ignored the critical axiom, test like you fly. It only was leaking in recirculation mode and I wasn't testing it that way (because it was cold and I had the heat on) even though that's how I usually have it set. Found several leaks in the hose "under" the hood leading to that baffle. Easy fix with some tubing I had lying around from a previous repair.

Thanks for the feedback!

Mike

For some reason the resevoir is not holding vacuum. There can be a leak just about anyplace but I would look where ever some kind of work has been done.
I once fixed this sympton on a car that had a battery changed. They pinched the vacuum line under the edge of the battery and it took a couple of years for it to rub though.

This is a common problem on Ford Class A chassis going back over 20 years. The ONLY sure fix is to install a 12 volt vacuum pump and plug the vacuum line from the engine. You will have people tell you to test this and test that and add another accumulator, and check all the vacuum lines and motors on the dash evap system. The plain fact is, the aftermarket Dash AC systems on Ford Class A's have inherent vacuum leaks and cannot overcome the engine going to zero vacuum on full acceleration or climbing hills. You can do a search for this problem on this forum and see all the silly things people are told to do, when the plain fact is, you need the 12 volt pump. I speak from over 38 years and still working on Motorhome Dash systems and YES, I have installed a few of the 12 volt pumps, even years ago when the Coach Maker paid for the pump installation when the RV's were under warranty. Doug


https://www.amazon.com/APDTY-015325-Vacuum-Pump-Supplemental/dp/B00BVQZSKO

I have heard of adding a vacuum pump to run the dash.

Take a small propane torch and unscrew the head leaving just the valve and pipe, then slip a piece of tubing over the end of the pipe. With the engine idling and the valve on the torch open (but not lit obviously) run the end of tube along every vacuum tube in the HVC system.

When you get to the vacuum leak the engine will inhale the propane and the extra ‘fuel’ will cause the engine to speed up a little, when you pull it away it goes back down again.

It makes finding vacuum leaks super easy.