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leadman · 06-29-2019, 01:57 PM

The a/c on our Adventurer would stop blowing out the dash vents and default to defrost sometimes. I investigated and found that the source from the engine to the vacuum accumulator under the hood had a rubber hose with a loose end at the accumulator. Fixed that, still a/c intermittent, continued checking. The vac line from the accumulator ran to a canister by the right front tire. Have not identified this as was needing to get on with repairs to leave on the trip. The end at the canister has a short section of rubber hose connecting the hard plastic line to the canister. Hard to see as it is on the front side but is was mush. Replaced it. Traced out the vac. lines leaving the canister and they go to the dash a/c/ heat selector, fuel pressure regulator and the egr valve. There are one or 2 vac switches also. Fixed hoses as needed. A/c/heat selector was lazy so replaced it and all is good now.
On our trip last week from Az to Mich. the engine ran better than ever with increased power AND fuel mileage! Since the source of the vac is on the intake horn the engine may have been running lean.
I drove 2,170 miles and averaged 6.8 mpg. I drove faster than normal, up to 75 mph this year vs last year when I drove around 62 mph and got 5.4 mpg.
We were towing the same vehicle on the same tow dolly also.

Can't say this is definitely due to fixing the vac leaks or the increased rpm at faster speed but it may pay owners of similar rigs to check these vac lines.

TeJay · 06-30-2019, 07:40 AM

leadman, Great catch sir!!!

As an automotive teacher for 35 years that is another area during my career that was stressed and was a standard service procedure.

Vacuum lines of old were always rubber and time plus gases being passed inside some of those hoses especially on the crankcase breather system (PCV) deteriorated from the inside. Standard procedure was to service vacuum lines and hoses after a certain time frame and replace.

Were I in need of an older vehicle and purchased one I'd replace all rubber vacuum lines or rubber connecting hoses to the hard plastic lines which do last longer and all flexible rubber brake hoses. The brake hoses should be replaced about every 10 years or sooner.

bstrong · 07-03-2019, 03:51 PM

Leadman

Thank You for your post. I have been chasing a vacuum leak (rough idle) for a while now and low and behold You nailed it at the canister in front of the passengers side front wheel. It was that pesky 90 degree bend that is out of sight. It had almost disintegrated. Replaced it and all is smooth once again.
Thanks again

leadman · 07-04-2019, 12:25 AM

bstrong, Wow, I was hoping someone could use the info I posted and you made my day by letting me know it worked!

Waiter21 · 07-04-2019, 07:44 AM

This is what the accumulator looks like on my 1999. This is looking forward from the passenger side front wheel well..

Very bad location as its exposed to road spray, salt, chemicals, rocks getting kicked up, etc.. Note the starter relay is above this..

The red tube in these photos is pressure for my air bags, not vacuum line.

C-Leigh Racing · 07-04-2019, 10:45 AM

Thats a special starter switch also Waiter, not regular like a normal Ford. I was having starting problems, replaced the engine starter & problem was still there. Come to find out that starter switch was bad. Well, at least it has a new starter & switch that should last a while.
Neil

leadman · 07-04-2019, 11:51 AM

Waiter21, same location as mine but a little different. The vac lines are more on the end with the front one not easily visible.

getitdone451 · 08-13-2019, 12:11 PM

Thanks Leadman, I just had the same experience with my 2001 Hurricane concerning the A/C. I suspected the same thing (the vacuum lines) when I would start pushing over 60 MPH the A/C would just stop and if you slowed down or idled the A/C would come back on.
Good Catch I will now take the time to check out the Vac lines.

Was on the road in Neb, Co, Utah, Wyoming, So. Dakota, Mo. and Kansas during the the whole month of July.

Jeasen · 08-30-2019, 09:11 AM

I saw this post the other day and decided to replace some of the vacuum lines on my 2001 Itasca Sunrise on the F53 chasis because I was having the same AC issue. After replacing several of the rubber vacuum lines I decided to check the vacuum system with a Mityvac pump. I started at the intake manifold where the black plastic line connects to the intake manifold and found that the vacuum line system would not hold any vacuum. I then started checking each vacuum line separately including the vacuum storage tank. All tested good until I got to the white hard plastic line going to the Gasoline Vapor Recovery System Solenoid that sits on the inside of the motor compartment just opposite of the gas pedal. The white hard plastic line checks good that runs from the vacuum storage tank to the to the Gasoline Vapor Recovery System Solenoid but the solenoid itself will not hold any vacuum. Does this mean that the solenoid is bad? I have no other issues that I can tell with the fuel system.

Jeasen · 08-30-2019, 10:42 AM

I just went out and pulled off the 5/16" vacuum line that runs from the intake manifold to the Vapor Canister Purge valve and connected my vacuum pump and the valve holds vacuum with the key in the off position.

I have read several tests for the purge valve and they only deal with the 5/16" vacuum line. I did not find one that deals with the 1/8" white plastic line that is causing my problem. Anyone know if the 1/8" white plastic line going to the purge valve should hold vacuum. I would think so but I read a thread from another member that replaced his purge valve and it still did not hold vacuum on the 1/8" white plastic line. Why would Ford connect a vacuum line to a vacuum leak? Does anyone know what this connection does? I thank everyone in advance for your help with this.

Bob_C · 08-30-2019, 11:04 AM

Quote:

Originally Posted by Jeasen

I just went out and pulled off the 5/16" vacuum line that runs from the intake manifold to the Vapor Canister Purge valve and connected my vacuum pump and the valve holds vacuum with the key in the off position.

I have read several tests for the purge valve and they only deal with the 5/16" vacuum line. I did not find one that deals with the 1/8" white plastic line that is causing my problem. Anyone know if the 1/8" white plastic line going to the purge valve should hold vacuum. I would think so but I read a thread from another member that replaced his purge valve and it still did not hold vacuum on the 1/8" white plastic line. Why would Ford connect a vacuum line to a vacuum leak? Does anyone know what this connection does? I thank everyone in advance for your help with this.

Can you check for power there?

Mark_T · 07-22-2020, 12:50 PM

Did you ever solve this?

Thanks

Quote:

Originally Posted by Jeasen

I just went out and pulled off the 5/16" vacuum line that runs from the intake manifold to the Vapor Canister Purge valve and connected my vacuum pump and the valve holds vacuum with the key in the off position.

I have read several tests for the purge valve and they only deal with the 5/16" vacuum line. I did not find one that deals with the 1/8" white plastic line that is causing my problem. Anyone know if the 1/8" white plastic line going to the purge valve should hold vacuum. I would think so but I read a thread from another member that replaced his purge valve and it still did not hold vacuum on the 1/8" white plastic line. Why would Ford connect a vacuum line to a vacuum leak? Does anyone know what this connection does? I thank everyone in advance for your help with this.

Jeasen · 07-23-2020, 08:55 AM

No I did not solve the problem. I was not able to find an answer to the vacuum leak at the 1/8" white line so I just plugged off the white line. Nothing changed in regards to how the motor runs and no more vacuum leak. I know this is not right but I thought it was the right solution at the time.

Mark_T · 07-23-2020, 01:27 PM

I have a ford F53 1999 V10. It has had a loping idle for quite some time. It run good off idle. I have smoke tested it, no leaks, replaced the epr valve (didn't help) and finally traced to the vapor purge valve. If I cap the 1/8 vacuum line the idle settles down and stops hunting. Also it feels like there is always some vacuum on the 5/8 line (hose that goes to charcoal canisters).

I also have the thought that this is a intentional leak and the pcm is programmed to account for it. As an engine get older it leaks more and by plugging this leak it get closer the correct air/fuel mixure. The fuel trims should show this.

It is an after market valve. I ordered a new motorcraft valve (somebody is real proud of this valve by the cost). When I get it I'm going to check and se

a. if the 1/8 vacuum line will hold vacuum.
b. if the vapor lines are normally open (no power, no vacuum).
c. test what happens when 12 power is applied.
d. what happened when 12v power and vacuum from the 1/8 line is applied.
e. compare the old and new valve.

I have looked all over the internet and I am unable to find the purpose of the 1/8 vacuum line. My guesses are it

a. inhibits the valve from opening at high vacuum when the pcm command it.
b. If the valve is opened by removing power, the vacuum may hold the valve open.

I will post the results of what I find.

Any comments are welcome, specially if I am missing something.