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Power Loss in 1985 D150 318 2BBL

Power Wagon 440X4

Power Wagon 440X4

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Hey Guys,
I am stumped at what might be causing a loss in power while accelerating.
At first I thought that there may be a clog or the factory 1985 rubber hoses collapsing in the fuel system.
Replaced the carb, fuel pump, fuel filter and rear passenger fuel hoses and the hoses on top of the tank.
Still bogs down when trying to accelerate past 25MPH.
Then I tried a different ECM to see if it had a bad resistor or something might not be keeping up with the increased power demand.
Not it either.
Could a coil or distributor cut down power? It starts right up and idles fine and will rev in park with no power loss.
Its when you go down the road it bogs down when trying to accelerate. it won't even make it up a hill and dies like its starving for fuel or spark.
It might be in the tank with a broken or clogged strainer. I did blow back through the fuel line when installing the new fuel filter.
I'm dreading doing the fuel tank, so I am getting all other options off the table.
 
I would check the coil before messing with the fuel tank. Secondary coil brake down will act that way. You may also want to check the distributor reluctor air gap and shaft bushings. But this really sounds like a coil issue.
 
I had an 83 Ramcharger with the 318 that got really bad. To the point I kept it off the road. It turned out my intake manifold had gotten clogged up tight with Carbon. Build up. I found it easily after I was told what to look for. I pulled the choke off and it was packed to the top.
I don't know if that helps, but might be worth a try
 
Does not the chock well set in the exhaust cross over in the intake? Only thing carbon buildup would do is maybe prevent the choke from pulling off on time.
 
Just a thought, how much exhaust is coming out the tail pipe? Does it still have the catalytic converter? If you think it could be a problem with the sender in the tank, take a fuel can and run a hose from the pump to the can. If it runs good the problem is in the tank. If you do this though, use extreme caution with the can and how it's secured.
 
On mine the choke well was plugged solid. Also the rest of the passageways were on average far less than 50% open. It took a long time (2 to 3 hrs) to clean the damn thing out. It was as if a nee motor were in there afterwards.

7mopar said:
Does not the chock well set in the exhaust cross over in the intake? Only thing carbon buildup would do is maybe prevent the choke from pulling off on time.
Click to expand...
 
7mopar said:
Does not the chock well set in the exhaust cross over in the intake? Only thing carbon buildup would do is maybe prevent the choke from pulling off on time.
Click to expand...

Choke is working properly. I even put a clothes pin on the butterfly to see if maybe it was closing with acceleration from a weak choke thermostat. same result. It closes when cold and fully opens when warm.
 
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65 sporty said:
Just a thought, how much exhaust is coming out the tail pipe? Does it still have the catalytic converter? If you think it could be a problem with the sender in the tank, take a fuel can and run a hose from the pump to the can. If it runs good the problem is in the tank. If you do this though, use extreme caution with the can and how it's secured.
Click to expand...
It has dual exhaust with no converters.
The gas can is a great idea directly to the pump.
That's what I do when testing an engine that has sat for a long time so I don't pump old gas from the tank.
I am taking a new dist and coil out there tomorrow and trying it first. Rained hard here all day today.
 
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Hops mentioned the timing chain, I did a Ramcharger a few years back, came in as a no start. Fuel pump was bad, replaced the fuel pump and gave it back to the customer. He comes back and says it has no power.

So long story short, after spending a lot of time diagnosing a possible fuel issue I checked the timing because it seemed lazy like low timing. Sure enough it was retarded, advance the timing, power is back. I recommend he have the timing chain and gears replaced. He comes in from time to time, but he has since sold the Ramcharger.
 
Chain has been replaced. I will check slack when I am there at the distributor.
I always change the timing chain when I instal an engine because of the factory plastic coating thats usually chipping off and chain stretch. Its been a few years since I installed the engine though.
 
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Well guys it was my original thought of it being fuel related. I first put on another coil and had the same result. Then I put on a rebuilt distributor. Same result. Hooked up a gas can with a hose straight to the pump and it climbed the hill like it use to with no power loss. The distributor needed attention anyway because the inside of the cap was black.Cleaned the cap and rotor and set the timing and it ran great. Now I get to tackle the tank.
Thanks to all of you for your excellent advice. It could have been any one of those issues.
 
Fuel filter is external. I would change it before dropping the tank. Poly tanks do not rust anyway.
 
Fuel filter got changed with the new pump. The poly tank doesn't rust but the sending unit and tube does. not to mention years of sediment from 1985. Been in these tanks many times and they always have crap in the bottom of them.
The strainer is probably rotted and not stopping anything.
 
Must be where you are getting gas. These tanks are not directly vented moisture has to be getting in there some how.
 
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