slow acceleration, horrible gas mileage

[blue83ranger]

Truck is a 1986 Ranger super cab, 4x4, 2.9 bored 30 over, C4, 4 inch lift, 31 inch MT and the computer from my '88, it has the stock 3:73's and at warm idle my vac gauge reads 19-21. It always seems to start and run pretty good, except sometimes i can notice at idle a very slight shake.
Even before the lift, tires, and transmission (had A4LD) it never got up to speed very good and the mileage was just barely better. Now it gets 12-13. I checked for codes a few weeks ago and I'm pretty sure i got them fixed. I'll try to recheck them to make sure. Although I know i still have 2 codes that says something about the fuel pump ground. Which i hear is because an '86 isn't wired for that. and i have a code for the transmission because the c4 isn't wired like the A4LD. is there anyway just having a code can make it get bad mileage regardless of what it is?
The dist. has less than 1000 miles on it. I think it's set at 13-14 (I'll recheck that too) the plugs, wires, cap, and rotor are in great shape and relatively new. It also has a new fuel filter, map sensor, tps sensor, vss, oxygen sensor, coolant temp sensor, air filter, flow matched stock sized injectors. and all the wheels spin freely. and for some reason it doesn't take much throttle when accelerating to make my vac. gauge read pretty low (5 or less) and i had the same gauge on my '88 and i was happy with its acceleration and it read about 10 with the same size engine. So, any suggestions? I know i have to recheck for codes and recheck my timing. anything else?

 

[BRUTUS_T_HOG]

get a timing light and check what your total advance is. can you check fuel pressure?

 

[blue83ranger]

we have a timing light and fuel pressure tester. I checked the pressure maybe like 7 years ago but i'll check it again.

 

[blue83ranger]

Ok here's some more info. as far as codes go i got a KOEO 89 which is the converter clutch solenoid and 95 which is a fault in the fuel pump ground. Continuous memory codes are 29 which is vehicle speed sensor low (which is weird because i just put a new one on and my cruise control does work, and i did clear the codes since i replaced it) and 95. KOER codes none. and the fuel pressure with engine not running is 39psi, and with it running 34psi, and if i slowly rev it up it stays at 34psi but if i snap the throttle it goes down to 29 then up to 40 then levels out at 34 again. and if i turn the key on let it get up to 40 and turn the key off it stays at 40 for 16 minutes (read 37). and the timing, with the spout removed, is set at 14* I'll probably change that, as the tag says to set it at 10*. I also checked it with the spout connected and at idle it wasn't reading on any of the numbers stamped on the pulley. it was about 1/4 inch away from that deep grove in the pulley that's just past the numbers and when i rev it up till it stops advancing it gets to about 3/4 past that groove.

 

[Big Jim M]

Hers's a tip

Ok here's some more info. as far as codes go i got a KOEO 89 which is the converter clutch solenoid and 95 which is a fault in the fuel pump ground. Continuous memory codes are 29 which is vehicle speed sensor low (which is weird because i just put a new one on and my cruise control does work, and i did clear the codes since i replaced it) and 95. KOER codes none. and the fuel pressure with engine not running is 39psi, and with it running 34psi, and if i slowly rev it up it stays at 34psi but if i snap the throttle it goes down to 29 then up to 40 then levels out at 34 again. and if i turn the key on let it get up to 40 and turn the key off it stays at 40 for 16 minutes (read 37). and the timing, with the spout removed, is set at 14* I'll probably change that, as the tag says to set it at 10*. I also checked it with the spout connected and at idle it wasn't reading on any of the numbers stamped on the pulley. it was about 1/4 inch away from that deep grove in the pulley that's just past the numbers and when i rev it up till it stops advancing it gets to about 3/4 past that groove.

What I like to do to see the timing.. I measure the outside circumference of the balancer with a soft measureing tape. That measurement equals 360 degrees. Then I divide by 10% which will in effect be 36* of timing. Then I make a mark with a file and paint that mark with white paint.. Then I look at the timing at 2400/3000 rpm. The mark I just made should be very near the pointer when all the timing is in at those rpm.
Normal maximun timing should be between 36 and 40* when it is all in.
It's a good way to know if your springs and vacuum advance is working as designed.
Big JIm

 

[blue83ranger]

I reset my timing to 10* and checked it again with the spout in, and at idle it's at 26* and fully advanced it's under 40* for sure. and i'm not sure if you just meant in general or not but 2.9's don't have vac advances or springs in the dist.

 

[Big Jim M]

Yep!

I reset my timing to 10* and checked it again with the spout in, and at idle it's at 26* and fully advanced it's under 40* for sure. and i'm not sure if you just meant in general or not but 2.9's don't have vac advances or springs in the dist.

I did mean in general. If the computer is doing it all by itself there is little one can do cept to set the timing where the computer thinks it is and then allow the computer to do it's job.
Big JIm

 

[blue83ranger]

so, nothing really jumps out at you as to what my problem could be? Did my fuel pressure seem right to you? I wouldn't really think it should drop like it does but i guess if the injectors are letting more fuel in the pressure would go down.

 

[Duane867]

Does the converter clutch over ride solenoid act a little like a lock up solenoid ?
If so I would say that's your source of seriously crappy gas mileage, and possibly lack of power.

 

[blue83ranger]

That code is because the plug for it isn't hooked up. I swaped out the A4LD for a C4.

I did find a possible cause though. I rechecked how well the wheels spin with them jacked up. and my passengers side rear wheel goes easy then alittle harder. Turns out my axle was bent. (truck had been rolled by the previous owner) Today i got it swaped for a straight one and put in a new bearing because the old axle would move up and down just a slight amount. I guess i'll know how much drag i had once i drive it and run a tank through and check my mileage. But i need to go pick up some brake parts first. I'll let everyone know if there is or isn't a difference.

 

[blue83ranger]

well, the axle wasn't the problem. I ran a few tanks through and get 12-13 mpg every time and didn't notice any more power. So, does anyone have ANY thoughts on what I should check now? I'm up for checking anything.