Had the same problem with my 460 coachman spent months chasing fuel problems. Old timer looked at it within moments said you know you need new wires on thing. Solved my "fuel" problems
Yep, it happens in airplanes, and can happen in ground based vehicles too! When air travels through the carb at a high rate of speed, it will be reduced in pressure...that's what sucks the fuel in. Well, for the same reason an airplane wing icies up, your carb will too! What will eventually happen is that the air inlet gets smaller and smaller until the mixture is so unbalanced the engine won't run. It's probably computer controlled, so the ECM will compensate for it by tweaking the mixture until it cannot anymore, and the thing just shuts down.
There is a hose that goes between your air cleaner's snorkel (we called the old round air cleaner housings "dog dishes" back in high school)and the exhaust header. On GM vehicles, it was called the "thermac" system. It is designed to regulate the air temp to the intake somewhere between 70 and 100 degrees. Warm enough to prevent freezing, and evaporate the incoming fuel, but cool enough to provide good power (cooler air is more dense). Frequently the thermac hose gets discarded because it falls apart, or owners, or mechanics deem it unnecessary for whatever reason.
The reason why the truck starts right back up is because when the engine is off, it's heat transferrs up into the carb and melts the ice. Also, the reason why the truck messes up at certain times of the year is because if it's warm enough, you won't get ice obviously, and if it's cool enough, there's too little moisture in the air for icing to occur too. Here's a temp/humidity curve to show when it will occur the most...you may be able to pinpoint the weather conditions your truck was dying on you based on this:
As I try to remember my Dad's problem with the filters in the carb getting plugged I do recall he had an after market fuel tank added when he bought the truck and it had begun to deteriorate. Ultimately he shut that tank off and the crud stopped plugging the carb filter.
1st, the electric fuel pump just outside the tank went bad. As near as I can tell, Fleetwood replaced the stock tank with internal fuel pump (if that's how the '83 came?) with an aftermarket fuel tank and external fuel pump. I replaced mine with a Holley Red. Verify your fuel pump flow and pressure. I believe you need around 7 psi fuel pressure, but don't recall for sure. I don't recall what the fuel flow should be.
2nd, external fuel filter(s) in the fuel line (if equipped) as well as the filter IN the base of the carb.
3rd. Fuel flow diverter valve, AKA fuel pressure regulator, AKA a few other things. In the fuel line near the carb, diverts a portion of the fuel back to the tank. If bad, you will get fuel starvation, as it's starving the carb by dumping more fuel back to the tank than it should. Another symptom is a pressurized fuel tank. Also verified by fuel pressure and flow test at the carb, after verifying the fuel pump is working fully.
However, none of these issues should make the vehicle quit - just run very poorly, like fuel starvation or what we all used to call "vapor lock"
4th - for the engine to quit completely, you may have an issue with the oil pressure switch, which is one of the two interlocks that keep the fuel pump running; the other being the inertia switch. There is information about this on the ford-trucks site listed below.
For further reading, check out the discussion forums at www.ford-trucks.com specifically the 1980-1986 F100, F150 and Larger F-Series Trucks forum or the 1968 - Present Full Size Vans forum. There is also a CARB forum that may help.
Greg
'83 Tioga 27' Ford E-350 460
'97 Dodge 2500 CTD 4x4 in need of a TC
couple of ratty old well-loved Artic Cat sleds that the kids just can't hurt any further
Sorry I'm laughing here. It may or may not be related to my old problem, especially since my was related to a brand new 2005 Chevy Express Van. About six months after I got it, it would start pinging excessively and lose power on semi-steep, then steep grades. It took the dealer a week to figure it out. (They gave me a free rental vehicle!) It was a manufacturing error. It seems the electronic ignition computer was installed too close to the alternator and though it took the van a while to break in, eventually it got to the point where the ignition wires would interfere with the ignition computer. Once they relocated the computer the problem was solved. Maybe you have something similar where an spark plug wire or something is a tad too close to a critical component and generates a larger magnetic field at the higher RPM thus scrambling the computer.
I was having a similar problem with a truck a few years ago and it turned out to be the 'sock' filter in the fuel tank. I T'd a fuel pressure gauge into the fuel line and I could see it dropping before it died. Turn engine off or even just idle and the junk would fall off the filter, then it would be picked up again at higher RPM.
lovemedic wrote: okay...I found a filter that is where the line goes into the carb.. at least i think its a filter. It feels like a grinding stone...shaped like a cork..and is golden color. I guess thats the only thing that it could be. Ill go by the parts store tomorrow morn and get a new one and see if that fixes the problem. thanks everyone!
That's it. You can blew (by mouth) into it and see how hard it is to get air thru it. That's the 'ol timer trick.
The thing that is interesting is the fact that you said you can only start it in neutral after it dies. That would mean electrical. Are you sure you can't start it in park after it dies??
"Use it up, wear it out; make it do, or do without."
1996 Cruise Master (Pre Coachmen)
33.5 foot wide body (no slides)
460(7.5L EFI) V8,E4OD, F53
2002 Saturn SC2, Roadmaster Falcon 2 tow bar, Brake Buddy
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