I'm puzzled by this. 1986 D-150 /6 225 Manual tranny. When I bought the truck it ran rough and when I connected the vacuum hoses at the carb it would die immediately. - carb was just garbage. I replace the carb., fuel filter, fuel pump, fuel line from pump to carb. I had to return the first two Tomco carbs I got from OReilly because fuel was getting to the carb. but not filling the bowl. Third carb. is a rebuilt Campion from Advance. The truck starts up just fine and runs like a beast, until it warms up, then it stumbles, stalls and dies, like its starving for fuel. I check it when it dies and have someone turn over the engine and disconnect the fuel line from the carb and its getting fuel just fine. Then I checked the spark, it was weak coming out of the coil so I replaced the ignition coil, dist. cap, plugs and cables. Now I have a strong blue spark but it still stalls after warming up and seems to do so only when under a load, like going up a hill. This truck has no ignition module it has an (ESA) Electronic Spark Advance computer mounted in the drivers side wheel well behind the battery. Any ideas, distributor, voltage regulator, fuel tank sending unit, ESA?

Let me ponder that for a while.....

Does your fuel line wrap around the front of the engine, and pass near the exhaust manifold, or does your new fuel line go straight up from the pump and over the valve cover to the carb?

-S/6

_________________
The "Silver Bullet"
87 Ram D150

When I purchase the truck the fuel line was as follows: Rubber hose from pump goes upward and meets a metal fuel line, then runs through a clamp on
the valve cover, then to the carb. I have replaced the metal fuel line and shaped it to the form of the old one. Should I replace it again and route it differently? Boiling gas?

If the line is already routed over the valve cover, boiling gas should not be an issue. (Which you correctly assumed I ws getting at. ) It can be an issue when the fuel line is routed in front of the engine, and passes too close to the exhaust manifold.

Craig is very knowledgable about the '80's era trucks with the ESA computer, hopefully he will have some other ideas. I took the 'easy' route, and got rid of my computer completely.

-S/6

The reason this is stumping me is that I can't figure out if it's a fuel or spark problem. When it stalls I can crank the engine and disconnect the fuel line from the carb and see that fuel IS being delivered to the carb. and what are the chances that I got a bad carb. three times. I can also check for spark when it stalls and dies and it appears to getting sufficient spark also. This is driving me crazy. I can't afford to just keep throwing $$$$ at it and not fixing it. At this rate I'll have a whole new truck just by carelessly attempting to resolve a fuel/spark problem. I did find a Fuel Tank Sending Unit at the local dealership, but it's over $100 and I don't want to just throw $$ away.

Some blind guesses to check (free) until someone with some better ideas speaks up:

Disconnect and plug the vacuum line to the EGR valve.

Check the pickup-reluctor air gap in the dist (there should be two of them). Set to .008" with a non-magnetic feeler gauge (I have also seen the air gap spec at .006".....depending on year)

Check the dist pickup(s) resistance at the dist connector. Should be between 150-900 ohms.

As you say you are now getting good spark, I doubt the dist pickups are a problem, but it never hurts to check. Once warmed up, they may be getting warm enough to open the gap far enough to lose spark.

Check the carb float level.

That is the factory routing of the fuel line over the valve cover on these trucks.
Ummmm...... Rubber hose from pump goes up to metal line that goes over valve cover???? Where is your fuel filter? There is supposed to be a fuel filter in there. Very short rubber line connects fuel filter to line from fuel pump and other end to steel line to carburetor. The correct fuel filter also has a third connection for a 1/4" hose. This line leads back to the fuel tank. There is a orfice built into the correct fuel filter that bleeds off any vapors through this fuel line back to the fuel tank.
Maybe this is your problem? No vapor return line and you are getting vapor lock when the engine gets hot?
Check it out and let us know.

Hey, all good ideas Super6. Now I'll add my two cents worth to this.

I too was going to suggest disconnecting the EGR valve but even if some malfunction caused it to stay wide open you would not really notice it at heavy throttle and engine above 2000 RPM such as driving up a hill.

That pick-up coil in the distributor could be the problem (also see my other post about fuel filter and vapor return line). I had a problem with the pickup coil in my truck some years ago. My truck is an automatic transmission and uses TWO pickup coils. The manual tranny trucks only use one pickup coil. Anyway... my truck had always ran fine until one day out of town it made a sudden lurch and jerk, then continued to run but with much reduced performance into town. Hours later when I restarted it, it ran fine until a few miles down the road it repeated the same thing. It consistantly did this.... ran fine from cold and jerked after reaching a certain temperature, then ran with reduced performance.
The problem was the "run" pickup coil. It developed an open circuit after it warmed up. When the auto trans setup with TWO pickup coils has a failure with the "run" pickup coil, the ESA computer automatically switches over to running off the "start" pickup coil and goes into a "limp mode" operation. I drove it this way for a week while waiting for a new pickup coil assembly to come in at the local Chrysler dealer. They call it a "plate" or something like that in the parts book. Suprisingly the OEM part from Chrysler was the same price or cheaper than from some place like NAPA so I bought the OEM one instead of taking a chance with some misfit aftermarket part.

There certainly could be a problem with your pickup coil in that it is making a weak signal after it warms up and causing your engine to stall.
. Also check all wiring connections to be sure they are clean and tight inside. A bit of corrosion in a connection can cause endless troubles too.

This long distance trobleshooting is not easy. If I was there in person then I may have a different perspective on things. Good luck finding the problem.

Correction---in my post above when stating the spec'd resistance for the magnetic pickup, I meant to type DIST connector, not carb connector. (

Craig, why do the manual trans trucks only have a single pickup? (this is news to me )

-S/6

Thanks for your suggestions. I took the truck to my local garage last night . It's about 5 miles from my house and the truck stalled and died three times before I made it there. They're gonna start by blowing out the fuel line from the pump to the tank, that'll prolly blow the sock (filter) off the sending unit but may fix the problem if its being caused from the sending unit inlet/outlet hose getting clogged or something. Then we'll go from there. I thought about the distibutor, which does have a single plate pickup, but wouldn't I have a consistent miss if my problem was in the distributor? Just asking...you guys are the experts. I'm a noob when it comes to this stuff, I work on computers for a living.

The guys at the garage hooked an ait hose up to the fuel line runing from the tank to the fuel pump and blew out the line. They said they drove it about 20-25 miles no probs. The cost was 1 hrs. labor @ $45.00. I could've done it myself if I had a compressor. I guess now I will still need to flush the tank and replace the Fuel Tank Sending Unit sometime in the near future.

Get a new fuel-sock, AND a inline filter.
Just to be sure.

So all the crud that was in the line is now in the tank---and if the sock survived, all that crud is trapped in the sock, waiting to be pulled back into the line.....

Glad your problem is fixed, but I would drop that tank for cleaning (replacement if necessary) sooner rather than later, or you could end up right back where you started.

-S/6

I believe the sock was prolly blown off, but I have an in-line filter. Does that mean my fuel guage will be slightly off now, and until I get it fixed I shouldn't let it drop below 1/4 tank.? Fuel Tank Sending unit is $106 at the Chrysler dealership. Any idea as to where to get just the sock?