I've been having some trouble getting the truck to start. I go out and turn the key and nothing happens for anywhere from 28-45 minutes (longer times when it is colder).

At the 28-45 minute mark, the "maint reqd" light comes on and flashes and I can hear relays in the PDC start clicking (verified with a stethoscope that they are the ASD and fuel pump relays doing the clicking).

I was also hearing the IAC motor clicking.

After about 5 minutes, the "Check engine" light comes on and begins flashing in sync with the "maint reqd" light.

Eventually, the two light stop flashing and stay on constantly, at which time I can hear the fuel pump spin up and output about 24psi at fuel rail.

When I turn the key over, it will fire up and die about 3 times, but then it stays on and runs like a champ until it cools off. If I don't run it for 4-6 hours, I go through the same process, but with somewhat shorter times.

I've done some reading here and have done the following:
-Replaced ASD and fuel pump relay
-Uncovered and reworked all of the splices under the PDC
-Used meter to backprobe and verify all relay funtions
-Replaced spark plugs, wires, ignition coil and cap/rotor
-Replaced IAC motor
-Replaced battery terminals and both cables
-Replaced fuel pump/sending unit
-Ordered a new crank position sensor... should be in tomorrow morning
-Replaced fuel pressure regulator

I've also pulled the 6 following codes, in this order, with some repeating:

1/6-43
2/6-42
3/6-47
4/6-21
5/6-42
6/6-47

I am unable to clear the codes with the scanner, it just keeps trying to read. It will however read and display codes. The scanner is an Innova 3120.

I'm running out of stuff that isn't the ECM... am I missing something? Is there a way to evaluate the ECM to see if it is the problem? Would that be something a dealer could do?

Thanks in advance for your time, this thing is driving me nuts.

 

Well, after obsessing over it for four hours last night, I read something something about someone using directed heat on components to get them to work. I figured, why not?

This morning, after my wife left, I took her hair dryer, built up an insulating layer around the ECM and started the hair dryer on high blowing on the computer. I turned the ignition key and started the stopwatch to see when the clicking would start.

Four minutes and 28 seconds later, the truck started and stayed running on the first key turn.

Unfortunately, my fuel pressure gauge is reading zero. I know this isn't right because it was working fine yesterday and I left it connected the same way overnight. I' hoping when the motor warms up, the gauge will warm up and start working right.

That said, I still need to increase my fuel pressure at the rail from 24-26psi while running.

Long story short:

-I've determined a bad ECM via directed heat onto the component followed by a resolution of symptoms.
-I need to increase fuel pressure at the rail, though I think this may fix itself when (if?) I can find a new ECM.

 

Have you replaced the in-line fuel filter?

I just noticed that it's missing from the list on your first post. If it's really clogged it may be the reason why fuel pressure isn't up to par.

 

Yep, Fuel filter, oil change, lube, etc all done as part of my end-of the diving season tuneup/maintenance.

As a update, I used the hair dryer this morning for about 5 minutes and it started right up. I packed a 700w inverter and said hair dryer in truck and took off for class.

I came out of my first class and tried to get the truck to turn over, but no luck. I popped the hood, hooked up the inverter to the battery (Optima red top) and plugged in the hair dryer to let it do it's magic. Four minutes later, the clicking starts and the truck fires right up.

I called Autozone, the had a reman computer in stock with a lifetime warranty. I bought it, put it in right there in the parking lot and the truck fired right up. It sat through most of the day at the office and started right up when I drove home 45 minutes ago.

I guess I'll find out in the morning if it starts after sitting overnight in some cooler weather.



I still need to recheck the fuel pressure at the rail now that it has a new computer.

 

Look forward to hearing what the outcome is. We have been battling for a long time with our '92 Dak that will not start when the temp goes down to freezing. Otherwise it starts and runs perfect. Good idea to try the heat on the computer!

 

In the interest of full disclosure, I think I found the heat idea somewhere around this forum or maybe on another Dakota specific forum.

I think that poster was using a heat gun though. I opted for a hair dryer for three reasons:
1. My heat gun is at work in my tool box.
2. My wife's hair dryer was left unattended, what with her having left for work and all.
3. I didn't want to put a heat gun that close to the ECM and have it work TOO well, melting a bunch of stuff that I'd rather not melt.

So, I just built a nest around the ECM with an old blanket and put the dryer in with the air intake sticking out into fresh air. It still only took five minutes of air.

As an update, I went out first thing this morning and tried to start the truck. I turned the key and waited until the fuel pump stopped spooling up, then turned the key off and on again and waited for the fuel pump to spool up again. I turned the off and on three times before the fuel pump had pressurized the circuit enough to not have to spool up.

The truck started on the first crank in less than 3 seconds.

I'm calling this one good. Now, I need to determine the cause of the low fuel pressure readings.

 

Glad the Dak fired up for you, hope you find the low fuel pressure issue.

 

Just wanted to touch base with you cd, its cold up here in Ontario this morning and the Dak would not start so we decided to try your hair dryer trick, In about 4 to 5 minutes it started right up. Just called Rock Auto to order a computer. Thanks for the heads up about the heat.

 

I am told that ECM needs to be programmed for each individual vehicle. Is that not true ?

 

Read about this hairdryer trick on the other thread, and thought I'd comment.

More than likely what's happening is you have a cracked cold solder joint on the PCM and the hair dryer/heat is temporarily reflowing that joint and increasing conductivity. I don't know anything about the physical body of the PCM, but before you buy another one, if you're handy with a solder gun, crack the PCM case and reflow the pin connections on the harness with a solder gun. You'll probably be good to go.