this is a f-250 with a 351W and 2bl carb with automatic . I just picked it up Sat off a car lot. I spent 20 minutes test driving and another 20 minutes or so running the engine looking for leaks and watching oil pressure and generally listening for bad noises, after getting it home I spent over 30 minutes in the school parking lot letting my duaghter get the feel of driving a large vehicle. In all this time never a hesitation or a stumble. it does idle a bit low ,no tach but sounds like it is around 6-700 maybe a bit lower, but has started on the first crank every time. I also know that the fuel selection valve has been bypassed with only the front tank in service, unknown why but when I operate the selector switch with the engine off and key in run I can here the valve shift or atleast try to shift.

today on the way to the parts store ,to get door locks,going downhill on a bumpy street, the engine stuttered twice, then as I turned into the parking lot and hit a pretty good bump. it cut off totally, I tried several times to restart and it just cranked and cranked. got out and spent about 5 minutes under the hood looking for possible wires loose on dist,coil etc. got back in and it cranked right up with no issues and and ran fine leaving and going back home. BTW parts store is a 5 minute trip. So I am looking for your thought on things to check. Things already on my list

possibly crap in the tank/broken fuel intake foot.

fuel filter partially clogged or a large chunk that is moving around.

loose/bad connection on dist or coil or other part of the ignition system. (althought the dist and all the plug wires appear nearly new)

I am assuming that this engine has the mechanical pump since it is a 3 port selector valve and is carb vs injected thus the best of my understanding does not have electrc boosters in the tanks, right so no low oil cutoff or inertial switch.

could the mechanical fuel pump mounting be loose and cause this?
looking for other items to check


Getting back to the bypassed selector valve , could I use air to test for proper operation hook to the out put and check that air only comes out one inlet or the other based on selector switch position.

I was thinking I try using a inspection scope to look at the inside of the back tank to make sure it is not totally gross then mount a filter between it and the selector valve just in case and get that tank back in operation after looking for leaks of course.

 

Could be the ignition control module mounted on the drivers side fender, what year?

 

it a 1983 , but it looks like there has been some modifications done...



also this morning after it has sat in the parking lot at work overnight, it was hard to start , after it started it died in the aisle of the parking lot, spent an hour trying to restart, it started a few times and died after just a few seconds. Finally got someone to give me a push to get the truck out of the aisle and off to the side and was going to get a ride home. after we pushed it I cranked it one last time and the SOB started up and ran just fine. during that hour I wiggled every ignition and coil wire I could find ,prayed cursed ,screamed. I have to work again tonight and then I am off for two days. I plan to grab a can of starting fluid on the way to work, so if it dies or does not want to start I can maybe determine if it is a spark issue or a fuel issue. The way it restarted as soon as we pushed and jostled it around I amm wondering if something is blocking the pick up tube in the tank.

 

Quote:

Originally Posted by larryn

The way it restarted as soon as we pushed and jostled it around I amm wondering if something is blocking the pick up tube in the tank.

In general, fuel delivery issues like you're describing result in a delayed type
of reaction. A blockage in the tank will not be noticed at the engine until all
the fuel already in the carb (and possibly the fuel line running the length of
the vehicle depending on the problem) has been burned off, at which time the
engine will sputter & gasp for a few seconds until it dies.

Electrical & ignition problems sometimes manifest themselves with all-of-
a-sudden-type of behavior; for example, after driving over a speed bump
results in the engine suddenly "shutting off."

I'll suggest you get your ignition module checked, many auto parts stores can
perform that service for you for free, what you describe is sometimes a
classic symptom of a dying DSII box.

 

I know you said that you checked every connection in the ignition circuit ...

but I got a feeling you are gonna find the problem in one of the connectors ... either at the box or at the distributor.

Its the "hitting a bump" part that makes me think I would start looking for a spotty or high resistance, green and corroded connection.

 

When I bought my truck (also an 83 F250, 351W) it did pretty much exactly the same thing, although only once while in motion.
But sitting at an idle it would reliably cut-out & not restart for a few minutes; then when it did start, it would run perfectly.
It became more frequent, & was a headache at lights or an intersection wondering if you would get through.

The problem was the connector to the distributor - I was wriggling wires once while it idled & this caused a cut-out. Then wriggling the same wiring would usually let it restart. The connector looked fine & was full of dielectric grease, but was faulty; we cut it out & soldered the wiring - end of problem.

I never did figure out why it was OK at higher rpm, but it never recurred.

 

Well it appears like the winner is , electrical. on the way to work last night I stopped adn bought a haynes manual for the ever elusive wiring diagrams. I also picked up a can of starting fluid. Came out this morning she started up just and drove just fine with the normal grumpiness of a cold old lady of age drove the 4 miles home. Of course after 4 miles she was just starting to warm up , after parking I popped the hood adn started looking over the ignition wiring and jiggling a few wires and connectors and ended up killing the engine.

While tracing out wiring and looking closely at connections and comparing diagrams to actual wiring it became obvious that the wiring does not match 83 configurations at all, it appears to be a duraspark II ignition system best I can tell in the brief time I spent looking, there is a six wire two connector ignition module mounted on the front fender well the connectors are 4 wire adn 2 wire, there is no signs of any emmissions sensors and the brain box under the seat is disconnected ( not that it makes a difference since the wires have all been hacked out just below the floor ). after i get some sleep I am going to get out the multimeter adn a spark plug and do some trouble shooting, on the ignition system. I am thinkin that I will find the problem at the coil connection or in one of the splices that were made to match up the installed oem wiring to the engine that was put in as a replacement.

I also found a small fuel seepage leak where a PO did not think hose clamps were needed. BTW in case anyone is interested I did trying to get her to fire over with starting fluid also after she died and had no luck, so although I am not sure of the exact location of the problem on the bright side I will not be crawling unser the truck to drop and inspect the tanks like I thought I may have to doo.

 

Sounds like an easy enough fix. Good luck with her, hopefully your daughter likes it.

 

well the coil connection was not making good connection, I popped out the terminals from the connector housing and cleaned them real good I also looked into the splices for the wires to the distributer pick up connection and those will have to be redone to ensure reliability. also clamped the fuel line hose where the PO bypassed the selector valve