bad engine cut out under certain conditions.

[jimsat]

Good evening gentlemen. Ok here's the deal. my ram d-50 5speed 2.6 1988 truck has been cutting out badly under certain conditions. When I am driving on fairly level ground it winds out nicely in each gear, however if I have to accelerate quickly going up a hill or an on ramp it can really cut out badly in second and third gear. Very irritating and dangerous. Mikuni carb. Truck sat unused for several years before I bought it. Is this a makuni thing and a reason people go to the webber carbs? Any council would be appreciated.

[tortron]

Could just be a fuel blockage or an issue with the pick up pipe in the tank, so lack of fuel on certain angles and hard acceleration. I would then check that the carb float is sitting correctly

[geezer101]

Could be a bad carb (most likely) - fuel float might be dead or needle and seat are jammed. Could also be a weird fault with the fuel cut solenoid (the thingy with the thick black wire with the white stripe on the carb). If your fuel filter appears to be clean then you can cross off a blockage from a contaminated tank. Try taking the top off the carb and look at the needle and seat + the float. If the carb appears to be o.k. you might need to look at the fuel pump. They can get tired and struggle to maintain fuel pressure. The main reason people swap to the factory carb for a Weber is simplicity. The Weber is a lot more forgiving to work on. The Mikuni has a complicated wax pellet choke that can fail, the secondary throat vacuum actuator fails from age/wear and the carb is not great for performance. It's CFM is restrictive and will make an engine fall flat around the 4500-5000 rpm mark.

[pennyman1]

check the vacuum hoses, especially the ones going into the box on the driver's inner fender - the hoses split and cause a massive leak which throws off the computer for the carb.

[jimsat]

thanks much. I will follow up on your suggestion.

[jimsat]

thanks geezer101.

[geezer101]

Good luck, hope you nail it :)

[jimsat]

One other question regarding vacuum lines. Are the original vacuum lines color coded with different colored stripes? If lines are original they all should be replaced I assume. 30 years old almost.

[pennyman1]

no, and if they were, after 30 years they won't be. Just go to our manual section for the 1988 truck vacuum diagram, and change them out one at a time.