88 dakota fuel question

Need some help diagnosing my '88 Dakota, which hasn't been starting. I thought there were two problems, but now I'm not so sure. I checked and it does have spark. I do have to go get new contacts for the starter as they are worn and it doesn't connect and crank reliably right now. I had suspected the fuel pump, since it does have spark, but after my diagnosis today, I'm not so sure. I'm honestly not all that familiar with the Dodge fuel system.

Its a 3.9 and looks to have some sort of TBI set up on it with two nozzles that squirt down the primary and secondary throttle plates. There are two fuel lines that come up the front of the engine and back along the intake manifold towards the rear of the carb. There is a smaller rubber hose that connects one of them to the passenger side of the carb, and a larger one that connects to the rear of the carb at about 11:00 (while standing in front of the truck). When I disconnected the hoses, a small amount of gas came out of each one of them. More from the larger hose. When I turn on the ignition, fuel comes out of the larger hose for a second or two. I'd say an ounce or two in that time. Nothing comes out the smaller hose.

What's normal on this vehicle? How much gas should pump when the ignition is switched on to prime the carb? Is the second line an overflow/return to the tank? If so, then perhaps the truck will start right up once I replace the starter contacts.

Reply to
bruce
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You need a fuel pressure gauge to check it.  

Is the second line an

There is a "supply" line and a "return" line.

Reply to
twisted

s the truck will start

I guess one out of two questions answered isn't bad. So now I know that there is a supply and return line.

Is there anyone who can tell me what the fuel pressure should be like on the 3.9 TBI? Having done lots of work on VW, where the fuel pressure is high and all the lines are braided and have banjo fittings because the pressure is measured in 10s to 150 psi, I"m presuming that the pressure in this application is rather lower because there are simple rubber lines with screw clamps on them. Is the pressure 5 psi? 10? 15?

Reply to
bruce

The fuel pressure spec is; 13.5 PSI -15.5 PSI

Reply to
aarcuda69062

Hold your finger under the injector and have a pal crank the engine. If your finger stinks like gas, move on.

Fuel compression and spark is all you need... HTH Ben

Reply to
ben91932

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