Bucking during acceleration

[creyes1994]

My 1993 GL Automatic has recently started having some drivability issues. The problems started last Monday night. I was driving on the highway and the engine died with no warning. I got out on the side of the road and checked to see if any hoses were disconnected. Since 18 wheelers were passing by very quickly, I didn't want to stay outside for too long.

While I waited for an hour for the tow truck, I had a chance to do little checks here and there while inside the car. When I cranked the car, and it would just crank without sputtering. I could hear the fuel pump relay clicking. Well when I got home, I ordered a fuel pump of eBay. It was a $40 3-door aspire fuel pump that appeared to have never been used. The next day, I looked under the hood, planning to test the car with starting fluid, and noticed that the wire from the primary ignition to the distributor was disconnected. I reattached the wire and the car started right up.

I went driving for a bit and it wasn't until I had driven the car for a while did I encounter a new problem. The car started dying again. This time, I was able to get off the highway. I opened the hood and saw that the wire fell off again. I reattached it but noticed that it was loose. I went home and grabbed another ignition wire from my 1988 LX 5 speed.

That fixed the issue, but then a new one started. After driving for a while, the car started to buck slightly. It felt like it was running out of fuel. I pulled into a parking lot and checked the wire but this time it was secure. I went home and the bucking went away.

That night, the unused pump with sending unit came in and I installed it. After starting the car up, while it started quickly, the bucking was more noticeable. I filled the car up with gas and the bucking stopped.

Yesterday, I was in a rush and the car was performing okay until the evening. Last night, the bucking returned and has gotten progressively worse. I haven't driven the car far enough for it to run out of gas. When barely pressing the accelerator, the RPM would only slightly drop and come back up, indicating that the car was hesitating a little. A harder press on the accelerator would bring a longer and more severe hesitation which has gotten worse. At this point, I'm not sure what else to check.

[Studebaker]

Replace that ing. wire with a longer one / new one. The wire that comes in the kit is to short. I grab a longer one from the pick in pull.

[WmWatt]

Bucking is an ignition problem. Spark not firing properly.

[creyes1994]

I'm starting to think that the problem is something electrical based. It starts as a light hesitation and gets worse the longer you drive. If you briefly turn off the car and restart it, it goes away slightly, but comes right back. I uploaded a video of the problem on Youtube.

https://www.youtube.com/watch?v=H_4GsWPT4tw&feature=youtu.be

From 0:00 - 0:04: idle
From 0:05 - 0:10: 1/4 to 1/2 throttle
From 0:11 - 0:14: full throttle
From 0:15 - 0:15: quick release and quick full throttle

[WmWatt]

Look inside the top of the coil and distributor ignition wire connections for corrosion which you can clean with the twisted end of a rag. I would not use abraisives because contacts are platinum plated on some products and removign the platinum ruins the component. I ruined a distributor cap by cleaning the contacts with sandpaper.. You can also pull back the boot on both ends of the ignition wire and crimp the ends smaller fro better connection. To get the boot to slide on the wire put some WD-40 or other light oil on the wire.

I'd wipe down all the ignition wires as well as the distrbutor cap. I do that on my car as part of the annual tuneup. The Festiva has a weak Mitsubishi ignition system so I try to keep it clean.

[Studebaker]

In the dark look for arcing in the engine compartment.

[creyes1994]

I'll try that tonight after work. If there is no improvement after cleaning the contacts and checking for arcing in the dark, how likely would the case be for a failing ignition coil, distributor, ECU, or vane air flow meter?

[WmWatt]

When I wrote that bucking is an ignition problem I was referring to a particular engine behaviour, which is most often seen when the engine fires when it is turned off, called preignition. That's a spark issue, not fuel. However you report the symptoms vary with acceleration and level of fuel in the tank so maybe what you are experiencing is not bucking but coughing or some other symptom maybe alone or maybe in conjunction with bucking. I don't want to misdriect you because we are using the same name for two different things. Therefore I would not give up on the fuel angle and you might want to check for dirty fuel filtre, or other restriction in the fuel feed.

[Tyler77]

I had a similar problem with a friends vehicle, it would start up good and run good/accelerate when cold but when it warmed up then the bucking started when you accelerated.
It was actually just the Maf that needed cleaning, something as simple as the intake.

I would check out the whole air intake system, all the tubes, Intake - Vacuum lines check for any cracks or any where air shouldnt be getting in or out.
I know the festivas have a Vane air flow meter which you cant clean, but if you disconect the intake hose you could check that the plate which opens for the air to pass through moves nice and freely

Ive also seen problems with egr valves stuck open, to test if that may it you can disconect where the egr tube mounts to the intake and block it off with a piece of tin bolted in between, then go for a drive and see if the problems still there

[creyes1994]

It seems to be something related to acceleration. The car is acting like it's not getting enough fuel but it does seem to have power and it's not misfiring.

https://youtu.be/5o_gUbLDwEA

This is a video that I recorded yesterday night. I apologize in advance it's not a good recording as I didn't want to have an accident call recording but close to halfway and towards the end of the video you see how the car acts.

[creyes1994]

It was the fuel pump. I replaced the fuel pump thinking it was bad with a remanufactured 3-door aspire sending unit assembly, but I guess the pump, though new, was just bad. The car seemed to go back to normal after I had put the old pump on, which is also for an Aspire. The original pump had failed, or rather the Festiva sending unit. At the time, I had a choice between an 89 EFI Festiva fuel pump (which I then learned that 89 was a transition year with unique parts) or a bunch of Aspire fuel pumps. So I took the Aspire pump and wired it in to the Festiva harness.

[creyes1994]

Here's another update. After driving for 20 minutes of combined highway and city driving, the car started to hesitate. This is with the 1st Aspire fuel pump and a Festiva fuel strainer. I drove to my friend's workplace and left the car there for a while. I bought a new fuel pump and used the new strainer from the first pump, which I will find a picture of. The car ran even worse with the new fuel pump. The only way I could make it home was to put the car in neutral while driving, turn it off for 20 to 40 seconds, restart it, and then put it back into drive. It will drive with power for 30 to 45 seconds before losing power, and now it dies when the accelerator is pressed. Could it be that the fuel strainer from the aspire, which is new, is not compatible with the Festiva fuel tank?

Update - 10:21 PM CST - I think it was a strainer issue. I installed the proper strainer, new from Oreilly auto parts, and the car seems to be driving normal, for now.

[WmWatt]

This might help...

https://fordfestiva.com/forums/forum/maintenance/repair-help-forum/1244288-solving-fuel-sock

[creyes1994]

The pump I got came with that fat looking fuel sock I was able to drive the car 50 miles with the right one so it looks like it was the fuel sock all along.

[WmWatt]

Excellent!