the vacuum reservoir? the vacuum can, coffee can whatever. i know it's tied inline with the cruise control. and that there's vacuum check valve coming from the VAC source that feeds the can AND the cruise...

but i've gone through 2 cans allready from rusting out and i'm wondering if it's necessary. i'm still trying to figure out my surging problem so i need to isolate everything to only the bare essentials.

 

Yeah. it's important alright. Those damn things was the source of a stumbling problem on my '89. I replaced the metal can with a plastic version I found in a scrap yard truck.

 

any more details on where your can came from? i wanna make sure to know the correct one to grab. i guess i'm gonna have to find one.

 

Could you make one from a piece of schedule 40 plastic pipe?I would think a piece of say, 3 or 4 inch diameter schedule 40 pvc or abs pipe with a couple of caps glued to each end would work. I have drilled and tapped pvc for 1/4 and 3/8 pipe threads without any problem.I attatched a brass fitting and used teflon tape on the threads. This arrangement held 40 psi. I was doing this to solve a plumbing problem at the time.

 

It is just for pollution, with vacuum source plugged you may get an O2 sensor and EGR error and it may run little lean. More than likely you will not notice anything with it plugged.

The only items that use it are s the ACV. AIR BPV and the EGR Valve.

It has nothing to do with the cruise control, the cruise control should be from a "T" in the A/C Heating vacuum system and it has a plastic ball reservoir on the other side of the engine compartment.

The FPR and MAP sensor have their own vacuum sources.

 

I removed mine on my 94 and no problems to speak of.

 

what was the problem? I think i have a vacume problem and i cant find any leaks. what would this thing cause as far as problems from not working?
Thanks dan

 

i'm still wondering about this.^^^

 

I think he is using the round plastic ball reservoir of the A/C Heating vacuum system found on just about all Ford Trucks. I think you will find one on the other side of your engine compartment.

 

my 95 f-250 had a plastic one. I live in up state ny and it was fine when the whole truck was rusted out.
dan

 

I just noticed that on my 1995 F150 both the round plastic "Ball reservoir" of the A/C Heating vacuum system and the "Can reservoir" of the pollution system are on the same side (passenger) of the engine compartment.

 

I have one on the drivers side on my 92 f-150

 

I'll have to get a pic of the damn thing. I'm pretty sure it came off an early to mid 90's F or E series truck.. can't remember for sure. It's not circular.. more like a rectangular box with the corners all rounded off.

The problem it cured? The truck would not idle smoothly. It would hunt a lot and die and then pick back up again. Also when driving.. sometimes when you tipped into the gas from a stop it would fall on it's face and then catch and go. Other times it would stall.

 

That is the problem i am having in my 92 f-150. But it is more of a bucking when you hit the gas. I had the thing you are talking about in my 95 f-250, and my 97 f-250. The plastic box looking thing with two hoses right under the heater core hoses.

 

Sure it can be done. We used to use vacuum pumps to check suction lines on swimming pools for leaks. I don't know that Schedule 40 is really necessary. As long as it's sealed up properly, DWV pipe is much thinner walled (lighter). You'll probably want to approximate the same volume, but nothing says it has to be the same diameter either. Now, I'm a little curious here, about the problem that started this thread. It may take a while to pull enough vacuum on a larger reservoir, but a larger one for operation of all the vacuum gadgets in the dash might help. Dunno. I believe the connection on the ends of the metal VRES cans has a built in check-valve, though. I think this is the reason the inline valves disappeared. Just make sure of the plumbing before substituting it, and make sure to get all the appropriate valving back in the right place and pointed in the right direction.

My '92 has two separate metal VRES cans on it. One is dedicated to dampening for the EGR, TAB, and TAD valves. Without the reservoir, loss of vacuum in the intake (heavy throttle but not WOT for instance) would cause things to drop out for lack of vacuum, and I'd be willing to bet this would cause some pretty weird symptoms with the EEC trying to react. The other is dedicated to the cruise control. Obviously that isn't going to work very well if the vacuum drops on it. Is your cruise control factory hardware, or is it after market? The control vacuum for the louvers and stuff in the cab comes straight from the plenum with a check valve in it, then disappears through the fire wall. I have a sneaking suspicion there's a plastic reservoir hidden somewhere in the murky depths of the dashboard. Another line comes back out (white) for the fresh-air louver vacuum motor in the AC system. Before anyone says it's been modified, no it hasn't. I'm the OO on this truck.

Oh, and danny_g, check to make sure #7 and #8 spark plug wires do NOT run side by side on the left side of the engine on your 302. I didn't get any pinging whatsoever, but I had a dead miss when I started up a long hill on the interstate. This was with brand spankin new wires and plugs. I moved the wires around a bit last weekend to separate them, and this has been the largest improvement yet on performance. I've already seen at least a 20% increase in mileage on the highway, just judging from the fuel gauge and the trip odo. At light throttle and in town driving, never noticed the miss. Only on the interstate in 4th or 5th gear (M5OD). I had the severe bucking too, but found that to be greatly reduced when I replaced the plenum gasket. See my gallery if you havent read anything about the notorious leaking plenum of the 5.0L's This made a big difference too, but really didn't do much for the mileage or highway performance. It solved the nose-dives when starting off in 1st and 2nd, though, as well as the jerking at 40-45 in 5th. You too may have a combination of problems like I did, and no ONE magic thing is gonna fix it. I can't complain, though, I got well over 125K on this truck before the mileage dropped down from 22 highway / 14 city. Taking it to a dealer only exaggerated my performance problems, causing broken exhaust manifolds and sundry other problems. The plenum removal can be done in about an hour. You don't have to pull the dizzy out completely on the '92, but it helps to remove the bottom half of the dizzy shell from the shaft housing. Two screws hold it on. I didn't even disconnect the plug wires when I did it. Was my first time, and had the plenum off in about an hour. Good time to clean the throttle body thoroughly and if you can spare the downtime, have the plenum boiled out too. I didn't do it, but I've seen another recommended modification of moving the connection for the PCV hose around to the center/left side of the plenum from the back to prevent all the crank-case gasses from going straight to #8. This apparently causes some major woes with #8 if there's any significant blow-by. I took my PCV off and cranked the truck, and found I had no significant blow-by at all.