Replace Vacuum Advance Carbed 88

[Va 88 Festiva]

So i've searched and can't find out an answer. My car runs good but has no power on hills in 5th gear. Checked my timing is at TDC with vacuum lines plugged and plug unhooked. After further checking I see that the vacuum advance is not working at all. It has plenty vacuum just doesn't advance. My question is do you all replace the advance? All I can find is the whole dist. Thanks in advance.

[Banana Bonanza]

Some time back I posted pics of how I repaired mine. The vac advance on mine had a ruptured diaphram. No nobody sells a replacement. But I bought one of those adjustable vac advances made for old Chev V8 off ebay for like $7 back then. Didnt take that much effort to adapt it. Had to make a bracket to mount it, and had to modify the metal arm coming out of back, I just cut the arm off the Festy vac advance and welded it on to correct length. Been running it with the adjustment maxxed out. Really improved gas mileage. Hit 50mpg a few times with 4spd transmission.

The politically correct and boring way to repair a Festiva vacuum advance is to buy a rebuilt distributor. But they are or at least were (havent priced one in some time) crazy priced IMHO.

[Va 88 Festiva]

Thanks. I see that Rockauto has them for $28 but haven't seen anyone do it so thought maybe I'd screw it up.

[FestYboy]

you may also have the lines backwards. red to the bottom.

[Va 88 Festiva]

Vacuum pulls on the top Right? Don't remember if they still have colors on the. I do know the one on top has vacuum and the bottom one vents back to the canister.

[Fordverde]

are you sure??? I tought that both have vacuum

[Banana Bonanza]

You dont need the dual vacuum can. The 323 with carb only had single vacuum. I think the dual is some sort of pollution setup. There were some older American vehicles with the dual vac too. Again they could be replaced with single one unless you live someplace with really anal pollution control nazis.

[iceracerdude]

really anal pollution control nazis.

Ha, Ha, Ha as opposed to just.

[WmWatt]

Timing check instructions say to plug top hose. I use it to plug in a hand held vacuum guage when diagnosing engine. It definitely has vacuum. Don't know about lower hose.

[BigElCat]

Here it is... from the FSM 23-02-4

The dual-diaphragm vacuum advance mechanism acts on the stator plate which is free to rotate in the distributor housing. The larger diaphragm chamber is connected to the spark port on the carburetor, just above the throttle at the idle setting. The smaller diaphragm chamber is connected to the intake manifold, below the throttle, and exerts a retarding effect to limit the response of the vacuum advance to spark port vacuum, but because of the smaller diaphragm size, does not over-ride it. The resultant advance response, in crankshaft degrees, is a complex combination based on throttle position, engine speed and engine load.

End Quote.

My vote is to restore the stock vacuum diaphragms if possible.

I will be checking mine soon, because I have the same low power symptoms. I'll be doing a compression check, too.

I'm looking for a dizzy from an '89 EFI with an auto tranny. It uses the dual-diaphragm vacuum advance, but has a better advance curve. The Festiva guys that have been around for awhile report a noticable performance improvement when this dizzy is used on a carb'd B3.

[Banana Bonanza]

Amazingly the pics are still there. Here is link to my post about using Chev vacuum advance. Remember this is aftermarket adjustable advance so you can adjust with allen wrench how quickly you want vacuum advance to advance the ignition. I maxxed it out and had no problems but if you get some ping on hard acceleration, back off a bit.

http://www.fordfestiva.com/forums/showthread.php?t=23984

[Va 88 Festiva]

I just got the last 2 Vacuum advance cans from rockauto. They are motorcraft#DD925. Hope that will help.

[zoom zoom]

I'm not familiar with "vacuum advance"

What would it be relative to on an EFI engine? My car doesn't want to pull in fifth either, I took it for granted as a 1.3L downfall. I installed a vacuum gauge a couple weeks ago and whenever I try to pull a hill in fifth it loses the battle with the vacuum gauge steady on 0. (petal floored)

[nitrofarm]

I'm not familiar with "vacuum advance"

What would it be relative to on an EFI engine? My car doesn't want to pull in fifth either, I took it for granted as a 1.3L downfall. I installed a vacuum gauge a couple weeks ago and whenever I try to pull a hill in fifth it loses the battle with the vacuum gauge steady on 0. (petal floored)

Its for carbed motors basically.The efi have the same amount of advance & retard.They just do it via the ECM. At start up you dont need/want timing advance. An "advanced" engine can be hard to start.The pistons will actually want to push "backwards" if its really advanced at start up. So before efi disty's had two forms of advance.Sometimes used in series with wach other. Counter weights in the disty & then the vaccum. Ford Duraspark distys where very nice cuz you can stick an 1/8" allen wrench in the vaccum can.This allows you to fine tune your advance via spring pressure on the internal diaphram. So I'm asumming thats what people are doing with there carbed festy's.

Soooo with all that being said,to answer your question. Sounds like your timing just might be "retarded". If your engine isnt Pinging/Rattleing like crazy in 5th gear under heavy load. Check ignition timing per shop manual. Or if you want shade tree like this.
Clean the base of your disty & engine so you can make a "reference" mark.
Mark the base & engine with sharpie/paint pen.
Loosen the two hold down bolts
move the disty @ 1/16"
tighten bolts
test drive
If its worse ie less power in 5th gear. You went the wrong way.
Try going the other way,if it helps. Keep going in small incremants till it pulls strong w/o pinging.
FYI Racers do this all the time.The just use a timing light so they know exactly how far they can go before detonation. And dont forget a motor that is "PINGING" is being abused. Never drive it that way under extended load. Hope this help,sand I'm sure people are going to add there comments.

[Banana Bonanza]

I'm not familiar with "vacuum advance"

What would it be relative to on an EFI engine? My car doesn't want to pull in fifth either, I took it for granted as a 1.3L downfall. I installed a vacuum gauge a couple weeks ago and whenever I try to pull a hill in fifth it loses the battle with the vacuum gauge steady on 0. (petal floored)

On pre-computer cars distributors had both a mechanical advance and a vacuum advance. (Well there were some with just mechanical advance, and some old Ford 6cyl had just vacuum advance) Anyway the mechanical advance mechanism let ignition fire plugs earlier the faster the rpm. The vacuum advance fired plugs sooner the stronger the vacuum. Anybody who has a vacuum gauge in their car understands that the strongest vacuum isnt always at highest rpm. So in effect a vacuum advance would respond to lower vacuum at high engine load and not advance ignition as much....

The Festy was kinda unique in that it had a computer carb and a vacuum/mechanical advance distributor. Most cars with computerized carburetors, the ignition advance was handled by the main ECM via the ignition module.

On an EFI engine ignition advance curve is going to be handled by the ECM dependent on input from various other sensors. And obviously engines with coil packs dont even have a distributor.

First thing to check is engine compression if power is down with a compression gauge. Modern engines just like Model T engine still are mechanical at heart. All plugs out and test cylinder by cylinder. Do you have low compression cylinder? If so then there is your problem. Only 3 cylinders working properly in a 4cyl engine will lower performance. But if compression is good and even, next connect a tach and disable wire to cylinder one notice any drop in rpm, then put plug one wire back and do same for cylinder two and so on. If compression is good and there is an even drop in rpm as each cylinder in turn is disabled, then move on to possible low fuel pressure and other things. If you have good compression but not even rpm drop, then could be bad plug or bad plug wire or bad distributor cap or rotor....


I know everybody wants to depend on computer throwing up trouble codes, but good mechanic doesnt just depend on that. Or at least us old timers dont want to depend just on that.