1988 Dodge Dakota Sport 3.9, Im having trouble with the truck stalling on me, it starts after setting for a bit, but generally it dies as its warming up before I go to work, runs three to five minutes and dies , usually starts up again after 15-20 minutes but will stall on you a block away from home. Things I've checked and done are checked for bad grounds, replaced fuel filter, bench tested ignition coil, verified power to ignition coil is present while turning engine over, I've checked for voltage at the harness for idle contol valve it's a 4 pin connection and with key in on position not running, I have no voltage on none of the pins, so Im not sure if I'm testing it right, at one point i tried testing it when I did get the truck running by unplugging the harness to idle Control and it went into a fast idle plugged it back in and it died, that was probably a bad idea to do but it did start again after setting for a bit, Im at a loss here folks, maybe the ignition switch intermittently faulting out, please help, im walking to work Again. How do I check the fuel pump, I do hear it kick on when key is put to the on position right before I crank it over. Thanks in advance.

 

Step 0 - Pick up a copy of the Factory Service Manual; paper or disk; Ebay, Bishko ( www.autobooksbishko.com ), or wherever fine books are sold (also places like Books-A-Million).

Now. Sounds like you have a vacuum leak. I'd be checking all the vacuum lines (and yes, looking on the motor, you'll first want to grab a fifth of Everclear ... or some Sterno! ... to get the horror out of your mind. Don't. You'll just have to look at it and destroy more brain cells later) for vacuum leaks.

Ignition switch is one possibility, but I'd wait until after the first few steps before I swapped it since I've never gotten mine set just right (I can start the truck, or I can have ACC, but not both. So I'm missing ACC. Le sigh.)

RwP

 

I wanted to add to my thread about a harness connection under the hood on driver side next to some relays, in that row of relays there's one that's supposed to be emergency shutdown relay, well that relay is missing and harness just laying there with a little bit of black tape wrapped around the clip, keep in mind that this truck I've had only a few months and I bought it apparently with this relay missing, could that unhooked connection have been jumpered to fool computer into thinking it was hooked up and whatever jumper fell out, I guess the question Should Be will the truck run Without this relay, and how do I test my theory....of course after doing what RalphP suggested on vacuum leaks. Thanks RalphP.

 

Heh. Easiest is to check the color of the wires into that socket that's supposed to be there, and seeing if it IS the ASD that's missing.

The ASD socket is on the second page of the attached PDF; the wiring back to the SDI and the ECU is on the first page.

RwP

 

I've went through and checked vacuum lines, so what I've done so far is verify spark at the coil, I've not only bench tested the coil, but tested coil in the truck by pulling sparksplug from #1 cylinder and layed it on a good ground and recorded the test with my phone while cranking it over... it sparked a nice healthy color, so I reinstalled plug and the truck ran at idlei for 3 minutes then stallled /died again so at that point I wanted to see if I was loosing spark at this point right after it died and sure enough, No Spark, I've looked inside distributor cap not seeing anything to corroded, but did, a light cleaning anyway I didn't go down past the plate the rotor is setting on, because I don't know what to test under there in the distributor, please help, I'd also like to add that the key cylinder in the steering column was replaced by previous owner, and it never, had any accessories with key turned in the back position, how do I check to see if I'm loosing ignition power, something else that seems odd is the truck would never crank over since I've bought it if the steering wheel was tilted all the way up, I Must lower the steering wheel to a lower level for it to crank over...(pinched wire maybe). Please Help.

 

First off, locate the factory service manual.

Second - there's no ignition wires to pinch in the column for starting it; there is, however, a linkage to the switch at the bottom of the steering column.

That screams that the switch is out of adjustment; I'd adjust it some (takes a security torx bit, I THINK a #25 but am not sure!) and get it right first.

Do note that your dimmer switch is held in by one of the same bolts; you may have to adjust it also when you're done.

Losing spark. Triple check the wiring at the ECU; clean and reseat all your grounds.

Also, triple check ALL splices in the wiring harness.

See if, when it stalls and you get no spark, if you bypass the ASD, will it work.

RwP

 

RwP, how do I bypass the emergency shutdown relay, unplug it, or does a jumper have to be stuck between a couple the connections in plug of the harness, thanks.

 

You take a jumper and put it where the relay switch contacts would have been; that is, if you take a view of the bottom of the relay like this:



Note: Your relay may not have the very center tab. That's fine.

Jump that bottom tab position to the top tab position. Or using the numbers on the relay, jump 87 to 30.

That will act like the ASD relay is on all the time.

Remove the jumper after testing.

Nice part is, it's symmetrical along that line; won't matter if you're looking at the socket or the relay.

You can also check the 85 and 86 contacts (the two on the right and left) and see if there's 12V on one, and if the other goes to GND for 2 seconds after the ignition is turned on.

RwP

 

RwP, I want to thank you for all your help and guidance, I jumpered the ASD relay as you specified, and I could hear fuel pump engage , and I cranked it over and sure enough it started right up, I removed the jumper after testing, and ordered a new relay. The starang thing is that I bench tested that relay using a 12v battery and a voltage meter that when set to ohms makes a audible sound so I applied power the contactor closed and I got the continuity chime from the voltage meter, I am no expert but that damn thing seemed to check out fine, can you enlighten me some more, your jumper after all worked, but in return testing this relay has confused me as to whether it's actually bad, can these relays worked if I hold my mouth just right or do you suspect something else I should try, I replacing the relay no matter what because $14 seems kind if inexpensive. I pulled this relay in question out of it's case because I wanted to inspect the thing, Thanks bud for more of your help.

ESD Relay

 

Could be a bad relay, could be bad wiring to the 85 and 86 contacts (the coil), could be a bad signal from the ECU to turn it on.

At that point, it's time to prod the right and left side with the ignition on; one should be at 12V. If neither is, then trace both wires back to the SMEC. The diagram I posted earlier shows the contacts. With the relay OUT, one set of wires off the SMEC should be at 12V. With it IN, both should measure 12V at the SMEC due to having continuity through the coil.

I'd also disconnect the battery, turn the lights on for about 2 or 3 minutes (to make sure the caps in the SMEC are drained!), and then remove and reinstall both the SMEC connectors 3 or 4 times; if the contacts have oxidized, that'll polish them up.

If the remove and replace fixes it, then it's time to disconnect one more time, spray with contact cleaner, then use some dielectric grease to keep it from oxidizing any more.

RwP