New forum member with a problem!

I bought my 2002 Dakota in 2008 after a divorce, she has been a great truck! 3.9 4x4 5-speed.

My first big problem. She was running fine, and one day just started sputtering here and there occasionally, no big deal, maybe cold or some bad gas? Then later started sputtering big time, then just quit. Nothing. Tried to start her and she seems like she's "loaded up" if you get what I'm saying, just VROOM and then nothing. Next try just spins, doesn't even try to light up. Any ideas? I'm stumped, no error codes, not much else I can check. I've been a gearhead most of my life, have old Harleys etc., can fix anything just using common sense, EXCEPT when it comes to a computer. I'm really stuck with this one, she has always been very dependable, just did a 23-hour road trip last month chasing down an old Panhead, pulled a '40 Olds from Philly to Cleveland a month before that, never a problem and never even crossed my mind about having one. HELP!

 

Hi and welcome to the forums.

Can you hear the fuel pump running? Throw a fuel pressure gauge on the rail and see what you have.

When's the last time you did cap/rotor/plugs?

 

Even with a computer, you still need to check the basics. Does it have fuel pressure? How about spark? If you can determine what's not happening, it will give you a direction to go.

 

Been a while since I did a tune-up. What kind of gauge do you need to check the fuel rail? I saw what looked like a Schraeder port, is that where I would check? Sorry, give me a good old carb any day! lol

I HAVE been able to start it, it's kind of random if I let it sit for a few days, but same end result, she stalls and then won't start back up.

 

Yes, you tap into the Schraeder valve to measure the fuel pressure. You can probably rent one from your local auto parts place, Advance Auto usually does anyways.

Don't hesitate to check or change the cap/rotor/plugs. Look at the coil too, we just had a guy with a '98 3.9 that would die and the coil was cracked.

 

Can you just use a tire pressure gauge to check, or am I missing something here? I'll check out the obvious stuff, just seems odd that she would just crap out with no warning!

 

No, you must use a gauge that's specifically set up to measure fuel pressure. There are a lot of rubbers and plastics that don't like gasoline, so something designed to work well with air isn't going to succeed with gas. The fuel pressure test gauge looks similar to a vacuum gauge with a screw on end that goes on that port that you see the schroeder valve - there will also be a long plastic tube that comes out the side of the gauge near a "button" - this is to relieve the pressure build up before you try to unscrew the gauge from the rail. Attach the gauge before you crank the engine, and shut the engine off before relieving the pressure and removing the gauge - put a cup or something at the end of the plastic hose when you press the button, you'll get a bunch of gasoline coming through there. There are lots of videos that you can get on-line that will show you exactly how to use one of these. You'll also need to get the various pressures that apply to your truck so that you can see how the pump is performing. There's the normal running pressure, the "under load" pressure (same as what you get on a kick down on the accelerator), leak down pressure time (this is how long it takes for the pressure to leak down from running pressure to some lower value - the manual will give you the 2 pressures and the time for the test), and finally, the max pressure (don't do this one if you aren't familiar with the process or if you don't have the manual explaining it all). Aside from the pump, leaks in the line, failing regulator, or clogged fuel filter can all lead to this type of behavior - then there's all the other stuff that needs to be looked at, as mentioned in the earlier posts - plugs, cap, rotor, etc.

 

OK, gonna dig in this weekend and see what I can find. What about this plenum issue I keep seeing? Think that could have anything to do with this?

 

And does anyone know if there is an online manual available for this truck? Don't have anything and would like to know acceptable fuel pressures etc.

 

It should be 49-50 psi. 49.2 actually.

You can get a manual from this link:

https://dodgeforum.com/forum/2nd-gen...-download.html

Don't use the 2002 link, it isn't for a Dakota. Use the 2001 link as your truck is almost identical. Once you download it you need to convert it to a .pdf, use Winrar to uncompress it, it's free.

With the plenum you'd normally be burning oil like crazy. A quick check is to remove the air hat, open the throttle, and look down. It should be dry.