[Haynes]

Like the title says my completely factory 86 w150 318 is giving me a lot of trouble. The truck starts amazing, idles great and after it idles a bit i can rev the motor in park and the truck reacts just fine. However, when in gear when i get on the gas it just won't move. The first 1/6 of the throttle moves the truck like normal, however any amount of throttle after that just leaves the truck bogging down till i relieve the throttle to that first 1/6 range. The truck a couple weeks ago would run great for about ten miles but then cut off and refuse to restart and then have the symptoms i just stated if it did start. I inherited the truck from my step father and needless to say it hasn't seen many miles in the last ten years. What i have done so far to attempt to fix the issues is as follows:
1) replace fuel filter (old one was nasty, but haven't seen much improvement)
2) disconnect egr (guy at work said it could help, but who knows)
3) disconnected the two lines that run from the carbon filter thing mounted on the bottom passenger side of the engine bay (read somewhere those can rupture and release all sorts of junk in the carb after it has been running ~10 mins or so)

Im finally frustrated enough to come ask for help :4-dontknow:.... suggestions on where to go from here would be greatly appreciated

 

[ramvan2500]

Like the title says my completely factory 86 w150 318 is giving me a lot of trouble. The truck starts amazing, idles great and after it idles a bit i can rev the motor in park and the truck reacts just fine. However, when in gear when i get on the gas it just won't move. The first 1/6 of the throttle moves the truck like normal, however any amount of throttle after that just leaves the truck bogging down till i relieve the throttle to that first 1/6 range. The truck a couple weeks ago would run great for about ten miles but then cut off and refuse to restart and then have the symptoms i just stated if it did start. I inherited the truck from my step father and needless to say it hasn't seen many miles in the last ten years. What i have done so far to attempt to fix the issues is as follows:
1) replace fuel filter (old one was nasty, but haven't seen much improvement)
2) disconnect egr (guy at work said it could help, but who knows)
3) disconnected the two lines that run from the carbon filter thing mounted on the bottom passenger side of the engine bay (read somewhere those can rupture and release all sorts of junk in the carb after it has been running ~10 mins or so)

Im finally frustrated enough to come ask for help :4-dontknow:.... suggestions on where to go from here would be greatly appreciated

It sounds like it could be the fuel pump, I would check into that.
If it's carb'd then it can maybe be a clogged jet or the float can be sticking.

 

[Haynes]

I'm thinking it is carb related like a main jet since it only seems to affect higher demands in fuel. however, wouldn't that cause the motor to run poorly in park as well or will it still rev because it is virtually under no load??

 

[ramvan2500]

I'm thinking it is carb related like a main jet since it only seems to affect higher demands in fuel. however, wouldn't that cause the motor to run poorly in park as well or will it still rev because it is virtually under no load??

thats a good question... which what makes me kindof think maybe the fuel pump isn't delivering the proper volume. odd... well whats cleaning a jet take maybe an hour or two. just make sure you remove the dam carb cause if you drop that jet in the intake you're #[email protected]%ed!

 

[Haynes]

I think a piece is missing, see attached....

i think a piece to the actual carb is missing. sorry for the lack of technical terms but this has interested me.... the truck runs decent at first most of the time (when the choke is activated) however when it warms up it runs like shit. i noticed when press the throttle nothing on the throttle kick side moves the air restricter plate thing. so for example, full throttle and 1/4 throttle have the same amount of air coming in via the intake to the carb (metal plate doesn't move). Also, the lever towards the front of the vehicle has a straight rod running up to it in one hole, but there is a hole next to it empty. I can't find a factory picture of this carb so i took the liberty of taking some pics.... am i crazy or am i truly missing a piece??

 

[Gen1dak]

Everything mentioned could cause your issues. You should also consider a tired, dry-rotted vacuum line.

 

[ramvan2500]

i think a piece to the actual carb is missing. sorry for the lack of technical terms but this has interested me.... the truck runs decent at first most of the time (when the choke is activated) however when it warms up it runs like shit. i noticed when press the throttle nothing on the throttle kick side moves the air restricter plate thing. so for example, full throttle and 1/4 throttle have the same amount of air coming in via the intake to the carb (metal plate doesn't move). Also, the lever towards the front of the vehicle has a straight rod running up to it in one hole, but there is a hole next to it empty. I can't find a factory picture of this carb so i took the liberty of taking some pics.... am i crazy or am i truly missing a piece??

I think you should rebuild or replace that carb now, it's getting quite old. I agree with Gen below, but if their is a broken vacuum line somewhere then your idle speed would be higher then normal, try connecting a vacuum gauge and check it.

 

[Gen1dak]

Yes and no. If there's enough of a vacuum leak the idle speed will increase. However, say the ole truck for some reason is idling higher than usual. Hmmm, lemme just give that idle screw adjuster a twist. There, that's better. Now the problem seems to have been fixed. The previous user may have limped along for quite a while with nothing more than the thought that it just doesn't run quite as good as before and mileage has dropped a little.
Or, maybe the vacuum lines have been mixed up over time and are now improperly routed. My dad had one RC that he was driving, and it was a pig. I drove it for a while and started digging into it. The exhaust would water your eyes. I got in there and while all the vacuum hoses were plugged into something, a couple were cracked and the routing was wrong. I isolated a few things like the charcoal cannister, and got things properly routed. The biggie was the vacuum line from the distributor. Anyway, just doing that moved mileage from 8mpg to 12, and suddenly it'd get out of it's own way. That can cause all sorts of issues without causing an increase in idle speed. It looks like an overall clean sweep is in order. I don't doubt there's crud in the carb. With ethanol in the gas now, there's no telling what's broken loose in there.