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JoelC707
Premium Member
join:2002-07-09
Lanett, AL

JoelC707

Premium Member

1992 Dakota, random no-start

I have a 1992 Dodge Dakota 3.9L V6. It's got a whopping 90K miles on it (really). I've recently done a tuneup on it (plugs, wires, cap and rotor) and various oil changes have been done to it as well.

On 1/27 I took the kids to school in the morning (let the truck warm up first, was kinda cold here) and had no issues going there, but on the way back it shut off on me twice. I barely noticed it honestly and it restarted on it's own immediately. I drove it again an hour or so later taking someone to work and didn't have any issues.

Then a couple of hours after that I drove it again to pick up that person from work. As soon as I got to his place of work it shut off again and caused me to have to actually restart it myself (it started right up). I got out on the road and not even a block away it shut off again and would not restart again.

It has done this many times before and sometimes spraying starting fluid (or something flammable) into the throttle body will cause it to "catch" and start running. This led me to think it was a fuel issue, though I have not gone into the tank to check out the pump. Lately nothing flammable has caused it to start which leads me to think it's electrical or ignition related.

I've listened for the fuel pump to run when turning the key on and it runs every time (leaking down maybe). I pushed the schrader valve on the port and got fuel but I don't know if it's the proper pressure.

Anyone able to help me diagnose this so I can get the thing fixed? No check engine lights on and I've done the on/off key thing and there's no codes stored.

Cho Baka
MVM
join:2000-11-23
there

Cho Baka

MVM

Monitor fuel pressure and spark when it is failing to start.
JoelC707
Premium Member
join:2002-07-09
Lanett, AL

JoelC707

Premium Member

Don't have a pressure gauge handy, will this one work? »www.autozone.com/autozon ··· 174_0_0_. Only problem is, it's not predictable when it's going to happen. It was a month or so before this event that it did it last, and prior to that was weeks if not a month or so. I'm leery of taking it out anywhere, even around town for fear of getting stuck.

I forgot to mention this in the OP but it almost seems to be heat related. I let it sit on the side of the road overnight (a truck I could tow with wasn't available until that night) and the next morning it started right up and drove home with no issues. I also noticed the tach wasn't showing any movement when attempting to start it the afternoon it did this but the next morning it did show RPMs as it was cranking. May be nothing because I wasn't totally paying attention to the tach but that too is leading me to think maybe ignition related.

Cho Baka
MVM
join:2000-11-23
there

Cho Baka to JoelC707

MVM

to JoelC707
I am not sure what fittings your truck has, but the answer is a maybe.
I wouldn't want to leave it installed for a month.

I'd probably wait until next time and pull a spark plug wire and check for spark when the problem happens. Alternately, you can also try gently wiggling connectors and seeing if you can trigger the stall.

Hopefully a Chrysler guy will check in with something more specific.
JoelC707
Premium Member
join:2002-07-09
Lanett, AL

JoelC707

Premium Member

I picked that one because it's one of the two in stock at my local store (haven't checked other stores nor have I checked other parts houses) and it's the one with the threaded schrader valve connection. Though obviously I don't know if it's the right size.

I wouldn't leave it hooked up that long either. I didn't think about trying to induce a stall but it should locate the probable source immediately. I'll have to try that and see where that leads. Thanks!
JoelC707

JoelC707

Premium Member

Did some digging, I wonder if it could be the crank sensor: »dodgeram.info/Engine-Gas ··· t-11.htm. I don't recall seeing an 11 flash when I pulled the codes last (12 and 55 are always there) but it was a couple of months ago when I last pulled the codes. I could have also easily mistook the expected 12 code for 11 but I don't know for sure.
JoelC707

JoelC707

Premium Member

Well it's not the crank sensor. I ran the test procedure shown on that link. I get a few ohms on the ground line so it's good. I got ~8.5V on the source and with the truck running and the connector back-probed, it fluctuated between about 1.5V and 4.xV. Granted it may still be flaky, but it seems to check out OK.

Cho Baka
MVM
join:2000-11-23
there

Cho Baka

MVM

Keep in mind that the 'good' test will only be valid if the truck is exhibiting the problem.

If the truck is running normally now, then you can test the suspect component until the cows come home, and still get nowhere.

EDIT: a few ohms on the ground, depending on how it was measured, isn't necessarily good.
JoelC707
Premium Member
join:2002-07-09
Lanett, AL

JoelC707

Premium Member

True, and I know where the connector is and can easily access it top side to probe it when it does this. I just have to keep a multimeter in the truck with me. The ohm test was done with the black wire backprobed in the connector and the other end of the meter's circuit on the intake for ground. So yeah, it's still relying on chassis wiring to get back to the battery. If I could have reached the battery negative terminal it might have been less but it was out of reach.
JoelC707

JoelC707

Premium Member

Just thought I'd give an update to the thread. We haven't driven it much lately so I haven't had a chance to really continue any diagnosis. That said, we did discover an inline fuel filter on the frame rail. Twas just a basic hose clamp filter so we figured it couldn't hurt to pull off and check. It was basically completely clogged so a new one got put on. Given the condition of that, I'm curious about the condition of the pump and inside of the tank. We're hoping to start driving it more regularly now and see what we can get out of it so I'll hopefully keep this thread updated as time goes on.

aurgathor
join:2002-12-01
Lynnwood, WA

aurgathor

Member

Well, a clogged fuel filter can certainly cause random stops. Depending on when it was changed, that may be an indicator of some foreign substance/contaminated gasoline in the fuel tank.

You can remove the fuel tank and take a look, and possibly clean it out, if needed.

Alternatively, if possible, you can pack 5 gallons of gasoline on longer trip or when the tank is almost empty, and wait until the fuel runs out, and that hopefully removes most of the contaminated gasoline from the tank. You need to stop at the first sign of the engine not getting gasoline (don't want to run the fuel pump dry too long) and probably you want to keep a spare fuel filter handy.
JoelC707
Premium Member
join:2002-07-09
Lanett, AL

JoelC707

Premium Member

Presumably it was the factory fuel filter. I'm so used to newer vehicles that only have the filter built on to the pump that I didn't expect to find an inline filter. I mean it does only have 80K miles on it but there's still 22 years of use though.

It has been running closer to empty a lot lately (rarely does it get filled past 1/4 or maybe 1/2 tank) so there's a good chance that any trash/sediment at the bottom of the tank has been pushed through and it's simply doing it's job which has caused this issue to finally rear it's ugly head.

How hard is it to drop the tank versus pull the bed? I know the weight of the fuel and all but it's generally empty right now. Mainly I'm concerned because I just put a very full and heavy tool box on the bed. Sure I can remove it but if dropping the tank isn't that difficult I may take the path of least resistance lol.
Trimox
join:2012-09-24
Anywhere

Trimox

Member

Pulling the bed is always easier as long as you have access to 3 friends or tractor.

Six bolts unplug taillights and filler neck. Bribe 3 friend with a case of beer and it is a snap.

Took me 1 hour to change 96 chevy (8' bed yours will be much lighter) fuel pump but I did have a tractor. I have dropped 4 tanks in cars and trucks but would never again drop one on a truck much easier to remove the bed.
JoelC707
Premium Member
join:2002-07-09
Lanett, AL

JoelC707

Premium Member

Yeah, three of us have lifted the bed off a 2005 chevy (was a crew cab that had the extra short 5 foot or so bed). It was somewhat heavy but nothing we couldn't lift. The dakota does have an 8 foot bed but I'm thinking it should be easy enough to remove.

My main worry is that heavy tool box. It's movable by two people but it's damn heavy, probably as heavy as the bed itself. That's why I was asking, wondering if it would be easier to drop the tank or remove the equivalent of two beds. Guess from the perspective of the fuel lines, removing the bed is easier still.

aurgathor
join:2002-12-01
Lynnwood, WA

aurgathor

Member

I had to drop the fuel tank twice on my Bronco (fuel pump failures) -- the first time it took almost 2 days because I couldn't disconnect the quick disconnect line that was coming out of the fuel tank (there was some dirt in it) so after a day of cussing and cursing I ended up disconnecting the line at the fuel filter, and drag the tank out with a piece of fuel line attached.

Next time the fuel pump failed right after a fillup (33 gallons in the tank!! ) so even though the quick disconnect lines were no longer an issue (wrapped electrical tape around them last to prevent dirt getting in there) I had to get rid of most of the gasoline because I wasn't comfortable with removing a full tank.
JoelC707
Premium Member
join:2002-07-09
Lanett, AL

JoelC707

Premium Member

Yeah, not with another 250+ pounds in it lol.

OK I have good news and bad news. It was driven earlier today and got about 10-15 miles from the house before it started acting up. From what I'm told (I wasn't in the vehicle) it was mainly acting up around 45+ and at low speeds while attempting to turn. Not exactly sure that correlation, engine load maybe?

They got it back here under it's own power. It did cut off on them several times but it always fired right back up. It's last time acting up was backing it into the driveway (that was the low speed turn I mentioned). I went out and checked to see if it would crank - it wont. Ran in and got my meter and checked the crank sensor. It's getting 8.xxV to ground and the sense wire was NOT fluctuating during crank like it's supposed to.

Looks like I have my culprit. How hard is it to change that sensor and what else should I look at or do while I'm in there? Looks like the wires disappear under the distributor cap somewhere. I'm assuming I have to pull that? It's way in the back at the firewall which makes things even harder.
Trimox
join:2012-09-24
Anywhere

Trimox

Member

This could be your problem.

»www.fixya.com/cars/t1032 ··· 92_dodge

92 was the first year for the "crank sensor", hall effect pickup or distributor pickup plate, whatever you want to call it could be your problem.
JoelC707
Premium Member
join:2002-07-09
Lanett, AL

JoelC707

Premium Member

That's nearly identical to the issue I'm having. I'll bet I could go out there right now and it'd crank up just fine. That sensor is the one I tested earlier today and it failed it's test. So it looks like it's just under the cap/rotor. That's easy enough to get to (I just did a tuneup replacing all those items a couple of months ago).
Trimox
join:2012-09-24
Anywhere

Trimox

Member

Its the same theory behind a failed ignition switch. They work fine cool but thermal expansion makes a loss of electrical contact. Any electrical component can have the same effect for future reference.
JoelC707
Premium Member
join:2002-07-09
Lanett, AL

JoelC707

Premium Member

OK, so I goofed. Apparently what I was testing that I thought was the crank sensor was actually the cam? sensor inside the distributor under the cap/rotor. Apparently it uses the same hall effects sensor method so it should test the same way which in theory means it's still a valid test. Though I can't seem to find that sensor, only the entire distributor; googling reveals the sensor should just lift out without needing to pull the entire distributor.

I did take it out driving today around the neighborhood and it failed on me again. I did not have anything with me to test with (and no one to help do the test as he was back at home waiting on the inevitable call to come tow me back). First, it stalled and immediately restarted on it's own after taking off following a slow down for a turning vehicle in front of me.

I'm trying to get back home at this point so I turn down the street toward my house (still about a mile away at this point). I'm going down a hill and it stalls and will not restart. I just coast and keep trying to restart it. It finally catches and I get enough power to get me back up the hill but it dies seconds later and I barely coast around the stop sign into the neighborhood where it refused to restart.

As I'm sitting there waiting on my friend to come get me (couple blocks away at this point) I am trying to restart it and I noticed something. Remember how I mentioned I thought the tach WASN'T working when it would do this? Well it's confirmed, the tach did not move while attempting to start it. Every time it has successfully started, it did move.

As I was being towed back I was attempting to restart it still and I managed to get it to restart and was able to drive it back under it's own power (just a couple houses worth). It's currently idling out in the driveway hoping it stalls again.

Here's my theory. Since the tach was not working during the failed start attempts I'm thinking it may still be the crank sensor that's failed (or something that tells it what RPM it's running at, presumably that would be the crank sensor). Could the cam sensor (or whatever is under the cap/rotor) cause this issue too?
JoelC707

JoelC707

Premium Member

Looks like I have my answer. I finally managed to have it driven and die for an extended period. I was not present but I had them disconnect the battery to clear the computer memory and then try cranking it (after reconnecting the battery of course). It didn't start right away but it did finally start after a few attempts.

I did this knowing the checking algorithm around the crank sensor will NOT set the code if the computer has seen it run in the past (the only way for it to set a code is to clear the memory and try cranking it then). And I now have a code 11 showing when I pull the codes indicating likely crank sensor failure.

Wiring harness looks fine (not melted or anything but it is in a hard to reach spot (sitting on top of the bell housing) so I'm not sure I can easily perform the wiring tests. It's only $50 and like many of the other sensors on the truck, I suspect it could probably stand to be replaced by now after nearly 25 years of service LOL.