Twice now out of the last three or four times I've driven my V6 '87 Dakota it's cut off on the road without warning; no bucking or jumping like it's out of gas or a bad fuel pump, it just shuts off like I turned the key off. I live in Atlanta, where it's been incredibly hot and humid lately, so I think it's probably vapor lock, but is there anything to do to prevent it? Is there anything else to look at? I feel like I can't trust it at all right now, so it's worthless until I figure out what's going on.

The first time it happened, I was on my way back home from delivering a motorcycle (about a 45 mile round trip) and, like I said, it was hot and humid. It cut off at the very end of the trip and wouldn't start like it wasn't getting any gas. I was lucky enough to end up at a gas station close to home, so I walked home, got some starter fluid, and after a few shots it started up and drove normally. The second time it happened was today, I drove about ten miles to pick up some supplies, drove another 25 or so to a jobsite, all fine, and then the truck sat all day (still hot and humid). I stopped to get gas a few miles from the jobsite on my way back home, then after leaving the gas station it died again less than a half-mile up the road. It wouldn't start, again like it just wasn't getting gas, but I'd only driven less than five miles at that point with a stop in between. I touched the gas line and filter right where they go into the fuel pump at the block, and they were warm to the touch, but not hot. After being stranded for over an hour, a friend showed up with some starting fluid, and, again, after a few shots it started up and ran fine and I made it back home the remaining thirty miles or so. Needless to say I'll be carrying starting fluid with me from now on (and hoping that it doesn't explode sitting in the hot cab), but if there's anything else I can do or check I'm all ears.

 

The 87 uses the electronic feedback carburater and the ESC.

I'd start with the normal problems on any vehicle that's 33 years old - disconnect the negative battery cable, then disconnect/reconnect the connections on the ESC and the carburator both. Do that about 3 or 4 times, then reconnect the battery and see what it does.

You can also try the key dance and see if your POWER LOSS light blinks codes.

I have no idea how well that will work for you, but it won't hurt to try them.

Oh, and don't forget to check the fuel filter under the cab. It's an odd ball - https://www.rockauto.com/en/catalog/...el+filter,6200 .

(I'd go for the regular Wix from that list.)

RwP

 

I'm not sure what you mean by "the key dance", can you elaborate? I get what you're saying, but I don't know the specific incantation. I also didn't know there was another fuel filter under the cab...I replaced the one just downstream of the fuel pump by the block, but if there's another inline that could very well be the problem (or a big part of it). Now that I think about it, just in case we're talking about different things, mine has the mechanical fuel pump mounted on the block, not the electronic pump in the tank. Is there still another filter inline?

 

I double checked the parts diagram downloaded from the FAQ link here, and you're probably right; just the one by the mechanical pump.

Sorry; I made an assumption due to its design.

For the key dance, it's on/off/on/off/on within about 5 seconds, and then wait for the light blinks so you can read the codes.

I don't know for sure the ESC will oblige there, though; you may be out of luck on that.

RwP

 

A fuel delivery issue will generally sputter and bog when it's about to die. If it's like turning the key off, I'd look at electrical. Two things come to mind. The coil could be failing, although that's not a common problem. The other is your brain box failing from the heat. I worked on an '87 Diplomat once that had a pesky problem like that. I put a baggie full of ice on the box and where it wouldn't hit a lick before, it fired right up when it cooled down. Considering the age of your truck, that's the first thing I would look at. Make sure it has a good ground and replace the ballast resistor as a matter of routine.

 

ol' grouch brings up a point.

You MAY have a failing ignition switch ALSO!

Switch is at the bottom of the column, switched by a rod from the ignition lock where the key goes.

I'd be checking that also.

(Due to age, it may be worth while swapping for your cousin and mine, Justin Case.)

RwP

 

I had considered electrical, but the reason I thought it was vapor lock is that after it died it would just spin like it wasn't getting any gas, but with starting fluid it would fire pretty roughly a couple of times and then start and run normally. Could that actually help get it over the hump if it's electrical?

I just did some looking and ECMs are both more widely available and cheaper than I expected ($150 or less), so it may be worth swapping it out anyway. I assume there's not really a way to test it, other than something like ol' grouch said of trying to cool it down after it cuts out, which I'm not too keen on. Regarding the ballast resistor, some quick Googling makes me think they went away and were actually replaced by the ECM in these trucks, is that correct?

 

You either have a ballast resistor or you don't. It's be a long white thing on the firewall about 3 inches long with a wire connection on each end. If you have fuel injection, I don't think you'd have one. If you have a weak spark, starting fluid is easier to fire than gasoline, that's why it's called starting fluid. On your brain box, AutoZone used to be able to test them. They also just happen to have new ones if you need one. Isn't that handy? Seriously, that's why they test for free. They used to be able to test coils too. Those fail so rarely, it's often after you replace everything else you check the coil. You're right there and they have it at hand so that's where you'll buy it. It's been years since I bought one. I think they were $30 back then, but that may be 15-20 years ago. It'll spin if you don't have ignition. The only time you'll notice a difference in the way an engine cranks over is if the battery is weak, it will crank slow or, if it's flooded, it will really spin fast due to no compression.

 

Thanks. It looks like if I'm willing to wait on Rock Auto's crazy shipping policies (I've been frustrated by them more than once) I can get a coil, remanufactured ECM, and ignition switch for good measure and still be < $200. It's not my daily driver, so waiting for parts isn't the end of the world. I'm pretty sure I don't have a ballast resistor, but I'll doublecheck (and check the ground).

 

87 does not use a resistor...... I put a carter rotary pump on mine. Then ran a fuel line from the pump to the carb. No regulator is needed, it only builds 6lbs pressure.
IMO if it is dead and spraying starter fluid in it, then it hits..... Its not an ignition problem.
My limited understanding of the feed back carb is, the computer used an o2 sensor.... and the carb has an electric power valve. (known for trouble) Upon internet advice, I disconnected the power valve wiring, and it seems to run fine.
On the electronic side, another known problem is the dist. pick up...... Mine has gone bad twice.
Edit to add, there is no ignition control module..... Just the computer on the passenger fender.