2.3L ('83-'97) Need help misfire

[Ridered308]

88 2.3 XLT
Had bad problems bucking under acceleration anything over 3k rpms to the point it would shudder pretty good.

Here's what I did fuel pressure test, new fuel filter. Cap rotor wires plugs. Air filter.
Seafoam.
Nothing changed until I replaced the 13 year old battery and it would rev up and drive great with only a slight buck or hesitation here and there. What else could be causing this? Icm? TPS? Bad grounds since replacing the battery made it 90 percent better? Any advice would be great thanks!

 

[Brain75]

any codes?
how did the fuel pressure go during rpms > 3k?

 

[Ridered308]

any codes?
how did the fuel pressure go during rpms > 3k?

It would stay at 30 psi idle bump up to 30-35 psi while revving motor. When I unplugged vacuum from fuel regulator it bumped to 40

 

[Rick W]

What I know about such things will fit in a thimble, but if changing the battery made a big difference, that would seem to indicate something electrical.

Is the alternator putting out the correct voltage? Is it putting it out consistently? I believe all of the alternators have the easily removable brush set. You may have to take the alternator off to pull it out. If it’s got a lot of wear, you may be getting inconsistent voltage levels. Put in a new set. Look at the brushes length compared to a picture online.

Also look inside the hole to see if there’s wear on the rotor. When they’re new, the surface is flat. I just replaced an alternator on my 97 (320,000) and the grooves from the brushes were almost 1/8” deep. If the alternator is bad, I always suggest getting a slightly higher amperage replacement. Usually they’re only a few dollars more.

My next thought would be the coil or coils. Typically, they work or they don’t work, but in my 50 years, I have seen a couple that short across the windings, usually from abuse and dirt, grease and such. They’ll have output, but not the right output, and the voltage may go up and down.

Having said all that, I still think it’s unusual that a battery would make such a significant difference in the performance. You may want to look at whatever you might have touched or moved around the battery, by accident, that affected the performance. I have ham hock hands and Railroad ties for fingers, and I’m always pushing something out of whack when I’m working on something else. Whenever you work on anything, if something changes, always go right back to where you were working and look around.

These other guys know a lot more than me, so don’t hesitate to tickle them if you can’t figure it out.

 

[SenorNoob]

Right on Rick. Especially the bit about whatever you touched last. I almost always find my problem there.

 

[Ridered308]

What I know about such things will fit in a thimble, but if changing the battery made a big difference, that would seem to indicate something electrical.

Is the alternator putting out the correct voltage? Is it putting it out consistently? I believe all of the alternators have the easily removable brush set. You may have to take the alternator off to pull it out. If it’s got a lot of wear, you may be getting inconsistent voltage levels. Put in a new set. Look at the brushes length compared to a picture online.

Also look inside the hole to see if there’s wear on the rotor. When they’re new, the surface is flat. I just replaced an alternator on my 97 (320,000) and the grooves from the brushes were almost 1/8” deep. If the alternator is bad, I always suggest getting a slightly higher amperage replacement. Usually they’re only a few dollars more.

My next thought would be the coil or coils. Typically, they work or they don’t work, but in my 50 years, I have seen a couple that short across the windings, usually from abuse and dirt, grease and such. They’ll have output, but not the right output, and the voltage may go up and down.

Having said all that, I still think it’s unusual that a battery would make such a significant difference in the performance. You may want to look at whatever you might have touched or moved around the battery, by accident, that affected the performance. I have ham hock hands and Railroad ties for fingers, and I’m always pushing something out of whack when I’m working on something else. Whenever you work on anything, if something changes, always go right back to where you were working and look around.

These other guys know a lot more than me, so don’t hesitate to tickle them if you can’t figure it out.

Well your right the next day back to bad bucking was a fluke after the battery maybe I moved something around. I ordered icm and I'm gonna check all ground wires and vacuum hoses next

 

[Ridered308]

88 2.3 XLT
Had bad problems bucking under acceleration anything over 3k rpms to the point it would shudder pretty good.

Here's what I did fuel pressure test, new fuel filter. Cap rotor wires plugs. Air filter.
Seafoam.
Nothing changed until I replaced the 13 year old battery and it would rev up and drive great with only a slight buck or hesitation here and there. What else could be causing this? Icm? TPS? Bad grounds since replacing the battery made it 90 percent better? Any advice would be great thanks!

Ok I found out the issue!! Well mostly. Unplugged the alternator and it runs awesome! I'm so pop pumped. But now is it a bad alternator or something else. Any insight??

 

[scotts90ranger]

Alternator could be backfeeding things, haven't heard of that but with this old stuff you never know...

 

[Rick W]

If you drank so many Coca-Cola‘s that you feel pop pumped, you may want to hold the diagnosis until that high comes down.

Again, pulled the alternator and pulled the brushes out, and see how the brushes look and see if there’s a deep roof where they ride in the rotor. I don’t know where you are, but around here you can get used alternators pretty cheaply, the brushes are about 20 bucks, the whole alternator is about 75 bucks, And a higher amperage one is about 100.

 

[Ridered308]

If you drank so many Coca-Cola‘s that you feel pop pumped, you may want to hold the diagnosis until that high comes down.

Again, pulled the alternator and pulled the brushes out, and see how the brushes look and see if there’s a deep roof where they ride in the rotor. I don’t know where you are, but around here you can get used alternators pretty cheaply, the brushes are about 20 bucks, the whole alternator is about 75 bucks, And a higher amperage one is about 100.

I replaced the whole alternator and it does the same thing. I'm now thinking ignition module because I put back the old one in and it ran great for awhile. Both were autozone cheap ones. I ordered a oem motocraft one so we will see

 

[Ridered308]

UPDATE! Truck fixed! Replaced the ICM that I already replaced with a motocraft OEM one and she's running perfect!

I guess stay away from the cheap ones both the cheap ones I bought made truck run awful one worse than the other!

 

[Rick W]

Any job worth doing is worth doing twice!

 

[scotts90ranger]

Good to hear, TFI is something I try to avoid and is the sole reason I stayed with the DIS setup on my '90 turbo ranger... I'd read enough horror stories, I've only had one crank sensor issue in over 25 years...