88 festy surging/jerking

[brickdog2000]

I already did a search on this toppic, however it seems that everybody elses festy surg or jerk when the accelerator is applied, going up hill, or under a load, ect..... yet with my festy is does it when i am in gear and coasting, but if I am coasting and out of gear it doesnt do it. The only thing I can think of is the clutch needs to be replaced or the vehicle is going to slow for that gear. Either way it is irretating and when the jerks you can feel it. I am sure who ever is behind me can also see it too. Any advice is greatly appreciated.

[AlaskaFestivaGuy]

I used to think jerking meant clutch problems, but it's the carb! I spent a small Fortune at a professional carb shop having the carb rebuilt on my pristine 88LX to cure jerking. Now it jerks worse than ever (particularly when in gear at low power settings) and gets only 25mpg around town. My 88L jerks somewhat less (despite never having touched the carb) and gets 37-39mpg with jackrabbit starts at every stoplight.

I'm speculating that when in gear, it's pumping fuel (too much of it) into the carb, and it's burning at random times, producing jerking. When at idle (out of gear), excess fuel isn't going into the carb due to the lower rpm.

I think all the carb experts must have moved to the Old Folks Home.

None of my fuel-injected Festies ever jerk.

[Festiva Time]

Sounds like your Decel Pot isn't working. It keeps the throttle plates from snapping close when you let up on the gas pedal. Note: the Fuel-Injected motors have it, too.

Kirk

[worfdog]

My 89 when I first got it did the same thing. Turned out to be vacuum leaks in a couple of different places, mainly around the vacuum switches on the firewall to the right of the air cleaner.

[m715]

Each of mine vary to some degree, but Rasta jerks as you describe. Vacuum leaks, and resulting ABCC valve fluctuations are what I have always attributed it to.

Michael

[AlaskaFestivaGuy]

Rather than futz with all those brittle hoses, my "To Do" list includes upgrading the jerky 88LX's carb'd engine to FI. Perhaps next summer ...

[zoe60]

You can have everything else perfect and it will still do it if your O2 sensor is bad. Took me about a year to figure that out on my '89 LX. Now I'll bet it runs as well or better than anyones on here.

[brickdog2000]

Well I have one vaccum hose that is disconnected and I cant figure out where it goes. Wish i could figure out where it does go. Other than that my O2 sensor is good. The carb I really dont want to mess with unless I buy a brand new one to replace it.

[zoe60]

You can replace the accelerator pump without removing the carb. Of course, rebuilding would be the best option. Once you get it off the car, it's not really that bad. Already rebuilt ones are way expensive. Rebuild kit is 20 to 30 bucks. If you take a picture I may be able to figure out where your vacuum line goes. Mines completely original except the ignition system. If you do rebuild, be sure to mark all the hoses before removing the carb. Good luck- they are frustrating but they can be fixed.

[Pu241]

Brickdog2000, you might, as a temporary fix, plug the hose.
Till you find were it goes.
Assuming it is a vacuum hose.
I really don't know what else it could be.
Do you have a carbie trouble shooting manual which shows the vac hoses and electric diagrams?

[brickdog2000]

Pu241 The only manual I have is a haynes manual. However, on my hood is a vaccum diagram for the engine. The only issue is I dont understand it. That is my downfall as a mechanic. I cant convert diagrams to the actual parts, I like to see diagrams with pictures of the actual components so i can relate it to the vehicle.

[brickdog2000]

Never mind I took time to look at the area where the vaccum line was hanging and figured it out, BUT now my check engine light is on so I am going to see what the code is hopefully sometime this week.

[smurfstiva]

just one thing from the peanut gallery, no-brainer be sure to check the fuel filter

[brickdog2000]

Well it aint the fuel filter. I found out that my O2 sensor wire was rubbed down to bare wire. So I figured I could fix it right, after all its only a wire. Well It turns out that the wire has a seperate wire internally. this wire is wrapped with wire on the outside. Hopefully I did fix it, but just in case does anyone knows if this matters???

[TominMO]

Well I have one vaccum hose that is disconnected and I cant figure out where it goes. Wish i could figure out where it does go. Other than that my O2 sensor is good. The carb I really dont want to mess with unless I buy a brand new one to replace it.

Consider switching to a Weber. Clean engine bay, works great, don't have to deal with lotsa vacuum hoses, the O2 sensor, or changing over to EFI. Here is a link to adaptors: http://www.fordfestiva.com/forums/sh...=weber+adaptor

You can buy a used Weber on ebay and buy a rebuild kit from the place that sells the adaptors and air filters. I'm considering doing this with a used carb intake manifold just as a proof-of-concept, then selling the result (if it works).

Of course, this will only apply if you are not subject to emissions inspections where you are.