Fuel Economy

[Andy 2]

Just wondering what kind of gas mileage I should expect out of my 88 2.6 automatic. I just had the engine rebuilt and have been monitoring the fuel economy. Right now I'm averaging around 17 miles to the imperial gallon. Most of the driving is on secondary highways at around 55 mph with a bit of in town driving(just to get to and from the highways). I don't have a heavy foot.

[recian]

You can expect low to mid 20s. My 94 2.4 auto gets about 24 hwy and that was before the rebuild. The at really restricts these trucks. If youre getting 17 id say replace the o2 sensor. Theyre what determines fuel mixture on efi trucks. If carb'd id look into carb work.

[92bluemax]

I'm getting 21 mpg combined in my 92 mm 4x4 3.0 v6,and a friend of mine is getting over 31 mpg in a d50 with the 2.4

[recian]

That sounds about right for the 5 speeds. He has an auto so itll be a bit lower.

[mllrtm79]

the few times I checked mine, it was between 20 and 22, could be better, but I don't spend a lot of time at highway speeds. I also have an 88 with 2.6 and auto trans.

[92bluemax]

Still isn't bad for a 4x4

[Andy 2]

My 88 is a 2 wd and the O2 sensor is new. Sounds like you guys are getting pretty good fuel economy especially if your quoting mileage in U.S. Gallons. I guess the conversion for me would be 14 mpg U.S. Pretty poor. I'll take your advice and have the carb looked at, that seems like the best place to start.

[pennyman1]

also watch the tach if you have one to be sure it is going into overdrive - if the sensor on the intake for temp goes bad it will never go into overdrive.

[Andy 2]

I don't have a tach but I do have an overdrive on/off button on the end of the shift arm. I pushed it while driving and it did downshift so I assume it's working. Taking the truck ta a garage today to have it looked at by an "import specialist". He's been in business for as long as I can remember so hopefully he can find whats going on.

[92bluemax]

hope you can get it figured out

[crock1990]

If the truck lacks power, check all your filters and plugs, make sure your timing is on point to

[ikeepzitclean]

hey welcome to the board Andy. hope u enjoy the forum. :)


Just wondering what kind of gas mileage I should expect out of my 88 2.6 automatic. I just had the engine rebuilt and have been monitoring the fuel economy. Right now I'm averaging around 17 miles to the imperial gallon. Most of the driving is on secondary highways at around 55 mph with a bit of in town driving(just to get to and from the highways). I don't have a heavy foot.

well its a carb'd motor as opposed to EFI (which is more efficient).. plus like others have said u got an auto tranny, which most of the time aint as efficient as a manual tranny. regardless, even tho ur motor is carb'd it should still get better MPGs than that lousy 14mpg u mentioned earlier. check ur fuel, air filters, and tire pressure. also take a look at the carb cuz it could be improperly tuned which may cause it to run rich, hence poor fuel economy.

[Andy 2]

Well as it turns out the timing was out, it was set to TDC. So we advanced it to 9 deg BTDC. We found a vacuum hose that was not connected. The plugs were over gapped so we set them to spec. The engine runs great. Something else we found was that the kick down linkage was not bolted in place on the manifold. The shop that installed the rebuilt motor forgot to reattach it. After correcting that I found that it all but refused to shift,which leads me to think that the mechanic, not realising that the linkage was off, adjusted the kick down screw to compensate. With the linkage at the loosest setting the gas pedal felt quite stiff and I couldn't get out of 2nd gear so I had to disconnect it again. The Haynes manual shows how to adjust the screw on the tranny so that's my next move.

[crock1990]

Sweet, good luck!

[92bluemax]

Well as it turns out the timing was out, it was set to TDC. So we advanced it to 9 deg BTDC. We found a vacuum hose that was not connected. The plugs were over gapped so we set them to spec. The engine runs great. Something else we found was that the kick down linkage was not bolted in place on the manifold. The shop that installed the rebuilt motor forgot to reattach it. After correcting that I found that it all but refused to shift,which leads me to think that the mechanic, not realising that the linkage was off, adjusted the kick down screw to compensate. With the linkage at the loosest setting the gas pedal felt quite stiff and I couldn't get out of 2nd gear so I had to disconnect it again. The Haynes manual shows how to adjust the screw on the tranny so that's my next move. Glad that you are getting it all worked out:thumbup::clap:

[ikeepzitclean]

Well as it turns out the timing was out, it was set to TDC. So we advanced it to 9 deg BTDC. We found a vacuum hose that was not connected. The plugs were over gapped so we set them to spec. The engine runs great. Something else we found was that the kick down linkage was not bolted in place on the manifold. The shop that installed the rebuilt motor forgot to reattach it. After correcting that I found that it all but refused to shift,which leads me to think that the mechanic, not realising that the linkage was off, adjusted the kick down screw to compensate. With the linkage at the loosest setting the gas pedal felt quite stiff and I couldn't get out of 2nd gear so I had to disconnect it again. The Haynes manual shows how to adjust the screw on the tranny so that's my next move.

glad u got to the bottom of it. btw, if u have a chance, give it a highway/city drive now and calculate ur MPGs. i'd be curious to see how much it improved ur fuel economy..

[Andy 2]

I'll do that the week after next. I'm curious to see if there's an improvement also. I spoke with one of the techs at the tranny shop we send our work trucks to. He informed me that driving a vehicle with the kickdown disconnected can damage the tranny. I didn't know this. He told me without the kickdown the tranny gets overloaded when accelerating at higher speeds, going up hills etc. It will also cause the vehicle to use more fuel. So, with that, I made an appointment to have it serviced next Wed. I wont drive it again until I take it in just to be safe.

[recian]

Wow yea that'll do it... Running an auto without a kickdown linkage or with the linkage loose is about like putting a 5-speed in 5th gear and never letting off or pushing in the clutch. Only difference is the trans takes the beating not the clutch.

[92bluemax]

Just let us know after its fixed:thumbup:

[ikeepzitclean]

I'll do that the week after next. I'm curious to see if there's an improvement also. I spoke with one of the techs at the tranny shop we send our work trucks to. He informed me that driving a vehicle with the kickdown disconnected can damage the tranny. I didn't know this. He told me without the kickdown the tranny gets overloaded when accelerating at higher speeds, going up hills etc. It will also cause the vehicle to use more fuel. So, with that, I made an appointment to have it serviced next Wed. I wont drive it again until I take it in just to be safe.

oh yeah.. thats all bad. didnt know u were driving it like that :bang:


Wow yea that'll do it... Running an auto without a kickdown linkage or with the linkage loose is about like putting a 5-speed in 5th gear and never letting off or pushing in the clutch. Only difference is the trans takes the beating not the clutch.

x2!

[Andy 2]

Well, I got the truck back from the tranny shop and the throttle control cable is fixed. Turns out the cable sheath was pulled out of the crimp connector at the tranny end. They had to drop the pan to get the cable out and were able to push the sheath back into the crimp with a lot of elbow grease. I figure the apprentice who took the intake off did so without unbolting the cable as it would take quite a bit of force to pull that cable apart. The truck drives great now, shifts up and down as it should. Now I'll start monitoring the fuel economy( which is how all this started). I only drive this truck on the days when it's dry, as they really salt the roads here in the winter, so it may take some time.

[ikeepzitclean]

Well, I got the truck back from the tranny shop and the throttle control cable is fixed. Turns out the cable sheath was pulled out of the crimp connector at the tranny end. They had to drop the pan to get the cable out and were able to push the sheath back into the crimp with a lot of elbow grease. I figure the apprentice who took the intake off did so without unbolting the cable as it would take quite a bit of force to pull that cable apart. The truck drives great now, shifts up and down as it should. Now I'll start monitoring the fuel economy( which is how all this started). I only drive this truck on the days when it's dry, as they really salt the roads here in the winter, so it may take some time.

glad they figured it out..

u would nvr have this issue w/ a manual tranny. 5 spd. swap FTW! :thumbup:

[Andy 2]

Well, I have been driving the 88 automatic on and off for a few weeks now and have calculated the MPG to around 21 (that's an imperial gal), Average city/hwy. Not bad considering it's been cold and warm up time. I was able to get a brand new cable and had it installed yesterday. I gave the tech my Haynes manual for the cable adjustment setting spec and it shifts like new again.