Fuel filter had already been changed about a month or so ago, was one of the first things I did when I got this truck on the road.

I have the throttle kicker adjustment procedure copied from somewhere (may have been this forum) saved on my computer at home.

It's like a totally different truck with the new fuel pump. No more dead spots in acceleration, much more power. It's no thrill ride by any means, it's still just a 3.9, but I had to be careful with the skinny pedal in the rain driving to work this morning, it'd break the tires loose at will on the wet roads, never did that before.

A little back story, i bought this truck off a friend for $150, he'd bought it 2 years previous from a co-worker who inherited it after his father passed. He was going to scrap it, so my friend paid him $150 for it.

My friend just used it for minor hauling and taking trash to the dump until the drivers caliper locked up solid, then he parked it for 6 months before I bought it.

It would start right up, but ran rough, so I first did a tune-up. When I pulled the plug wires from the distributor, at least 3 of the 6 just had green powder where the electrode was supposed to be. It ran SOOOO much better with new plugs, wires, rotor, and cap. I honestly don't think it'd ever had them changed.

This site has been a tremendously helpful resource.

 

Good story...always nice to hear about an old Dodge being resurrected.

 

After a week or so of running great, now it's starting to run like garbage again. Sputtering and trying to die when pulling away from stop lights, dying completely if idling for more than a couple of minutes, etc.

I was down to about 1/4 tank and thought maybe I didn't get the pump mounted all the way down in the reservoir, so I stopped on my lunch break to fill up. Didn't try to stall on the way back to work, but it DID stall out while parked with the AC running.

I turned the key off, and clicked it back to the run position, about to restart, when I noticed that my check engine light had started working. So i did the on-off-on-off-on trick to pull the codes.

13** No change in MAP output voltage from start to run
24** Throttle Position sensor signal outside acceptable range
52** Fuel system rich
55* End of error messages

The throttle position sensor one throws me a bit since the sensor is new, I'll double check that it's connected properly after work.

I'll double check the MAP sensor vacuum line as well, but last time I checked it there was good vacuum on the line, so I'm thinking my sensor may be bad, which sucks, because it's not cheap. Is there any way to test the sensor itself?

 

Since we don't have an easy way to see what the ECU sees on our 1988s, then the easiest way is by substitution.

Or, by ohming across it with a hand vacuum pump - with it connected to power, but the motor not running, you should measure a difference across the orange/red wire and chassis ground. (BTW, in the Factory Service Manual, that's on page 8W-61 for a 1988; good book when you're chasing down wiring gremlins.)

I'd then finger plug the vacuum hose and have someone start the truck; you should get manifold vacuum across the hose (may sting a bit, and if you bruise easily, may even bruise your finger!)

The TPS may be bad; if stuff didn't break when new, we wouldn't have warranties *grins*

RwP

 

Another possibility is you've got some kind of crud in the fuel lines and/or tank that's clogging your fuel filters. It goes like this; replace the screen (or inline filter) it runs good, then a little later the problem comes back. I suggest you try replacing the inline filter again, and see what happens. You may be able to get away with a couple more filter changes, otherwise you may find a tank flush is the answer. Anyway you've got little to lose trying another filter.

 

Winner winner chicken dinner! Swapped out the filter and she's running like new. Going to order a couple of spares to keep in the glove box. The tank didn't look dirty when I changed the pump, but I didn't look that thoroughly either.

 

Good deal!!!

 

Glad to hear you're back on the road!

 

Indeed, the little Dak makes a much cheaper DD than my 7.3 superduty.

 

Well that was short lived. Started running poorly again. MAP sensor has been replaced, no change. Found that the fitting on top of the sending unit had broken loose and was leaking fuel, so I pulled the bed, pulled the sending unit, and drilled it out and replaced with a metal piece. No more leaking. Replaced fuel filter again (I've got 2 more as backups), still no change. Replaced the distributor pickup coil, still no change. I'm about ready to set this thing on fire and walk away.

No engine codes, starts right up, idles for a few seconds and then the idle drops down to almost stalling before jumping back up, rinse, repeat. Put it in gear and it'll die almost immediately, if I'm quick enough hitting the throttle I can feather it and keep it running. Let off the gas completely and it's going to die.