85 Ranger - where to start under the hood

[RobbieD]

I am curious if you have ever checked your fuel mileage?

Just roughly, around 14-15 MPG. But I didn't spend a lot time trying to get the carb dialed in. I just set the timing, adjusted the mixture screws for the best idle, and have pretty much just been daily driving it since then (@ 160 miles a week). During the last 13 years I have changed the plugs, wires, cap and rotor at least once, but as long as it runs decently, and gets acceptable mileage, I just drive it.

 

[kimcrwbr1]

First you need to get the distributor and module either duraspark or four wire GM module. Start from the computer behind the passenger side kick panel. Remove all the computer harness all the way back to the grey 8 wire connector by the ignition coil. You only need to cut a couple wires at the grey connector to remove the computer harness just strip the harness apart from the alternator and keep oil pressure, water temp and alternator wires intact. Just use the original ignition coil with stock plugs. Get a block off plate for the EGR. I always wondered if just putting in the #42 main jets in the stock carb would work. Put a couple needle holes in the bleed solenoid diaphram on the back of the carb. If it blows black smoke on startups you can replace the valve guide seals without pulling the heads just a little time consuming.

 

[kimcrwbr1]

Just roughly, around 14-15 MPG. But I didn't spend a lot time trying to get the carb dialed in. I just set the timing, adjusted the mixture screws for the best idle, and have pretty much just been daily driving it since then (@ 160 miles a week). During the last 13 years I have changed the plugs, wires, cap and rotor at least once, but as long as it runs decently, and gets acceptable mileage, I just drive it.

Dude get some #42 main jets I still get around 18mpg I found if you just turn the needles out three turns from lightly seated and leave it alone.

 

[kimcrwbr1]

Would the carburetor from the ignition system donor vehicle work?

Look for a late 70s pinto, mustang II or capri with the 2.8 and it should have all three distributor harness and ignition as well as the carb.

 

[franklin2]

Just roughly, around 14-15 MPG. But I didn't spend a lot time trying to get the carb dialed in. I just set the timing, adjusted the mixture screws for the best idle, and have pretty much just been daily driving it since then (@ 160 miles a week). During the last 13 years I have changed the plugs, wires, cap and rotor at least once, but as long as it runs decently, and gets acceptable mileage, I just drive it.

That's what I was doing, no complaints. If you are going to use the original computer carb, you do have to re-wire the choke to the alternator, and also fiddle with the fast idle cam on the choke. The computer carb only has one high idle step on it. So you will initially get a high idle when it's first started, but just a few minutes later it will drop off that high idle step and go straight to the regular idle, the computer system used to take over after that. So I had some stalling issues on a cold morning.

What I did was take a dremel type grinder, and ground another step into the cam so I had a intermediate speed and it helped the stalling issue.

I too could not get over 15 mpg. I also had a bad fuel smell after I cut the engine off which I thought was carb related, but turned out to be a very small fuel leak from the fuel filter. But that spurred me to try a china knock-off carb from ebay. It runs even better than it did before, and I get 20 mpg easy. If you drive it alot, that can pay for the new carb fairly quickly.

I drive approx 300 miles in 2 weeks. 300 divided by 15mpg equals 20 gallons used. 300 divided by 20mpg equals 15 gallons used. 5 gallons saved at say $2.50/gallon is $12.50 saved per 2 weeks. The carb I bought cost just over $100. 100 divided by 12.50 equals 8. 8-2 week periods payed for this carb.

 

[RobbieD]

Dude get some #42 main jets I still get around 18mpg I found if you just turn the needles out three turns from lightly seated and leave it alone.

Thanks for the advice on trying the main jet change.

I drive approx 300 miles in 2 weeks. 300 divided by 15mpg equals 20 gallons used. 300 divided by 20mpg equals 15 gallons used. 5 gallons saved at say $2.50/gallon is $12.50 saved per 2 weeks. The carb I bought cost just over $100. 100 divided by 12.50 equals 8. 8-2 week periods payed for this carb.

Haha! I count pennies, too, and yes, it would make sense to to keep tweaking it. With me, it's mainly a matter of time, and priorities. Since December, when I added another '94 Explorer Sport to the fleet, my '84 became my backup daily driver, although it's still the primary trash hauler and Home Depot truck. So as long as it runs good and is dependable, it's just not a priority.

 

[franklin2]

Thanks for the advice on trying the main jet change.



Haha! I count pennies, too, and yes, it would make sense to to keep tweaking it. With me, it's mainly a matter of time, and priorities. Since December, when I added another '94 Explorer Sport to the fleet, my '84 became my backup daily driver, although it's still the primary trash hauler and Home Depot truck. So as long as it runs good and is dependable, it's just not a priority.

I agree with you. I thought about messing with the stock carb. I even thought about getting a 12v repeat timer, so I could make the solenoid "click" like it did with the computer. Hook a DVOM to the old oxygen sensor, and then play with the timer to change the cycle of the carb solenoid to change the fuel mixture.

But like you said, time is a priority. I went ahead and took a risk and bought the complete new "normal" carb.

 

[KimB]

I Duraspark swapped several 2.8s years ago...easy process on 83/84, 85 is slightly different. One little quirk I ran into with the Duraspark coil was that I had to add a ballast resistor, that coil only need like 8v and a full 12v from your battery will overheat it. That's the nice thing about using a GM HEI module and your TFI coil, you don't need to buy all that crap...just the HEI module and some wire.

If you can find a good junkyard carb, that would be ideal... preferable over a Chinese one... but either will work. The carb you have now can be used, if I remember right you have to build a metering block for it though, similar to this: http://www.cardomain.com/ridepost/3816516/1986-ford-ranger-regular-cab/

One other thing, if you look for distributors for say a '78 Mustang II, there are three options: single vacuum, double vacuum, or Bosch. You don't really want the Bosch one, it uses a funky cap and the wires to fit it are kinda hard to find as well.

which gm hei module did you use? That actually sounds quite appealing, since I am lazy.

 

[franklin2]

which gm hei module did you use? That actually sounds quite appealing, since I am lazy.

Buy one for a 1979 monte carlo with a 305 v8. There are many many different models and engines that used that module, but that is a old engine I used to have and it had the module in it. That is the module I used on my 2.8 conversion. Make sure you get a piece of thick aluminum to mount it to so it will be a heatsink for the module.

 

[franklin2]

Here's a picture of my HEI module on my 1984 BII. I had this nice heatsink laying around so I used it.

2.8 hei conversion by D Franklin, on Flickr

 

[Shran]

Yeah that module was used from the mid 70's up to at least the mid 80's... pretty safe to say any GM product with a gas V8 under the hood probably has one except maybe some of the Cadillacs.

 

[KimB]

Here's a picture of my HEI module on my 1984 BII. I had this nice heatsink laying around so I used it.

2.8 hei conversion by D Franklin, on Flickr

The wiring on my 85 looks different than in your picture. Im not actually sure how this is supposed to be wired.

 

[dvdswan]

Here's a picture of my HEI module on my 1984 BII. I had this nice heatsink laying around so I used it.

2.8 hei conversion by D Franklin, on Flickr

Couple of suggestions for you...

Butt connectors and wire tie connectors do not belong in the engine compartment. Its just a matter of time before the elements get to them then your have real troubles. Also, on the module there should be something like a dielectric grease under it to protect it. When you buy a module a little tube comes with it.

 

[Curious Hound]

Couple of suggestions for you...

Butt connectors and wire tie connectors do not belong in the engine compartment. Its just a matter of time before the elements get to them then your have real troubles. Also, on the module there should be something like a dielectric grease under it to protect it. When you buy a module a little tube comes with it.

That's a heat conducting grease between module and heat sink. Some people say it's not necessary. But it does improve heat conduction and therefore, should prolong life of the module due to better cooling.

 

[dvdswan]

That's a heat conducting grease between module and heat sink. Some people say it's not necessary. But it does improve heat conduction and therefore, should prolong life of the module due to better cooling.

Yep, I found that out when I was a kid, didn't put the grease under it and the module and it lasted about 2 months in my 76 blazer.