I was wondering about one other thing today. The little piece of tin. I believe its the interuptor for the distributor pickup. Is the position of that gap important. When I pulled my distributor apart, the interuptor was moving around a lil bit. I used a lil rtv silicone to hold it down but it is possible I didnt position it dead on where its supposed to be. I cant seem to find just this part anywhere. You have to buy the whole distributor around here. All you have to do to get this piece off is pull the distibutor, drive a pin out and it slides right off the shaft. I am just wondering if this is the problem or not.

 

I came across your thread this morning looking for answers. I have a 92 Dak V6 2wd. When I read your thread it sounded almost identical to the problem I have been having. 2 weeks ago mine started to intermittently run really rough and backfire at low rpm with no power. It would run fine above 2000 rpm under no load when I could get it up there. I spent last weekend going through it but could not come up with any thing. I have recently replaced the plugs, plug wires distributer cap and rotor as well as the ECM & coil when the fuel consumtion suddenly dropped from 19 mpg to 12 mpg. This did not fix the problem. I took the ECM back to the auto parts store for them to test and they said there was no way of testing it, but they have had quite a few problems with them and as it had a lifetime warranty they gave me new one. No luck, it made no difference. This morning I was about to go down the route you have been down and that was to start replacing things in a process of elimination. After reading your thread I was ready to give up!! [:@] Any way I had borrowed a high end scanner and decided I would use it to go through the whole thing. Quite a fancy piece of electronics. It could test all the relays and solonoids without removing them. I spent several hours today putting it through a barrage of tests. It also has a graphing function on it that helped me narrow down the problem. What I found was the timing was running at about 10 deg at idle and all of a sudden it would get rough and move up to 25 deg and some times to 45 deg and then cut out. The graph showed the timing to be very erratic. Any way, using the trouble shooting option on the scanner it pointed to the crankshaft sensor. It said to check the flywheel for damage or dirt as this would cause the sensor to give errors. I removed the sensor which was filthy and replaced it and it solved the problem. The timing graph is nice and smooth now with clear cut changes at rpm changes. By the way the scanner had the following specs for the fuel system. I checked these on mine and they were within these parameters. Fuel system pressure with vacum hose to fuel pressure regulator disconnected - 39.0 - 41.0 psi. With vacum hose connected - 31.0 psi. Fuel pump pressure 75 psi. Not sure if any of this will help at all, but thanks for all the posts it sure helped me. I know you have changed the crank sensor on yours but you may want to check for dirt or damage to your flywheel. Does yours run rough all the time or is it intermittent?

 

I have a brand new crank sensor on the way. The last one I got from a junk yard off a good running truck. The owner is a friend of my uncles so I didnt pay anything for it. Other then that everything else I have bought was brand new.

It runs rough all the time I guess. It starts up fine when it's cold and runs beautiful for a min or so. Then it dies off. It doesnt even run long enough to get it out of the drive way. I think I will have a look see at the flywheel tho. I am running out of options. I really need to get this truck runnin one way or another.

I'm glad this helped someone thoough.

 

I would think pretty important to your timing as they determine when the the hall effect switch turns on and I imagine this occurs at a certain cam position. If they are off some maybe the controller tries to adjust the timing and loses all signal from the distributor which should cause shutdown.

 

That kind of what I have been thinking. I think I'll just find a distributor and throw that on too.

 

Brand new crank sensor. Idled for approximately 20 mins. Then I gave it gas......it died. Started back up.......same deal. Give it gas and she dies after a couple mins. I'm buying a new distributor for it. Hopefully soon. It definitly seems like a timing thing and I just wonder about that interuptor in the dist. not being in exactly the right spot.

 

i had almost the same problem u have with my 94 3.9L what i did was i ask my mechanic about it and what he did is he went into the comp and reset it then raised the RPM amout so instead of the truck idleing around 150-300 it now idles at around 600

 

Brand spankin new distributor and timing chain now.....still no workie workie. Pulled the plugs again last night. They are covered in black soot. To much gas........? Pulled the 02 sensor, Its all covered too. Would the oxygen sensor send a signal to the puter to keep dumping fuel if its covered in soot or not reading properly causing my truck to die? When I unhook the one vacuum line and let more air in the intake it runs a lil better but not 100 percent. Still dies eventually. I hit the gas while its running and it hesitates then rpms go up. I cleaned the o2 sensor all up today and I am gonna throw it back in tonight. I guess we will see what happens.

 

Well tonight for ****s n giggles I ripped the front off my engine. Guess what I found????? The timing chain has about 7 degrees of play in it. Nice.

All this time........a lesson learned. Just because you set the damper at top dead center on number one, then line up the distributor to number one, doesnt mean the timing is always dead on.

I would indeed like to thank everyone for all their responses. They have been helpful in making me think about things that may be wrong. During this endeavor I have learned so much about these engines that I almost feel like I designed it myself.

Tomorrow I am going to the parts store after work af picking myself up a new timing chain set and slappin that in there. Im guessing that this will fix the problem. There is only supposed to be about an 1/8th inch of play at most and well 7 degrees.....thats about an inch.

I wish I would of followed my gut in the first place and saved myself a bundle of money. I have never been the greatest troubleshooter but all the neato tools I have picked up and the new dakota wing in my brain make it worth while.

At least now I shouldnt have any trouble with it for a while [sm=headbang.gif]....knock on wood...short lil prayer.....

Almost everyting under the hood is new aside from major engine componets.

No I never did go buy a new speed distance sensor.....but I really thought about it.

Well I look forward to talking to all of you in the future on here.

Thanks a bunch,
Eric

 

Eric,
Thanks for keeping us up to date on this repair. It has been a very informative thread.
Regards,
Greg