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87 lwb manche wont run

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I just bought a 87 4wd lwb auto truck that is almost rust free with 88,000 miles on it. But I can't get it running, I changed the fuel filter and check the fuel rail and it's shooting gas fine. What else should i check? It ran for a minute or two than stalled out.



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First of all keep in mind that a motor has to have three things to run. Air, Fuel and Spark. Take away any one of those and it won't run.

Has it been sitting for a long time? If so, how long?

Just because its shooting fuel doesnt mean its under enough pressure to fire the injectors. Try puttin a little gas directly into the throttle body and see if it acts like it wants to run. It'll run rough only for a couple of seconds but at least then you'll know if you have a fuel delivery problem.

It's easy enough to check for ignition spark too. Pull off one plug wires, stick a screw driver into the end of tha wire and hold tha screw driver close (1/4") to a good ground on tha motor. Meanwhile have somebody try to start tha motor. You should be able to see and hear tha spark jump from the screw driver to your ground. I assume you know not to hold or be touching the metal part of tha screw driver when you do this. Some people man up and just hold the end of plug wire with their fingers close to a ground. I personally don't like taking tha chance of getting shocked so I use tha screw driver method.

Tha lack of Air usually isnt tha problem although it couldnt hurt to check filter and tha air box for obstructions.


Hope this helps and Good luck with your new toy. Post some pix when ya git a chance.

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Also check the ballast resistor on the drivers side fender wall (has two orange wires hooked to a ceramic thingy). If it is broke the truck will stall after it starts. Mine was broke in half and stalled out after it would start. You can jumper between the wires as a quick check.

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Stalled how? Just quit like you turned off tha key or sputtered a little and then quit?

When it stalled and presumably wouldnt start again you should have done your spark and fuel test again. I'm thinkin its a fuel problem. As in your fuel pump is going out. I had the same thing happening to my E250 van. Granted it has not one, not two but three fuel pumps, it was the high pressure pump feeding the injectors that was causing the problem. don't worry, your Jeep only has one pump.

A fuel pump thats on its way out can spit and sputter making your motor run one time but not tha next. Finally it'll quit all togather.

If its your fuel pump, the addition of cleaners in tha fuel will often make an already weak pump quit working.


Here's some good info on testing the 4.0 system. http://www.lunghd.com/Tech_Articles/Fue ... ostics.htm


Hope it helps.

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