1987 F350 460 will not start after sitting 2 days

[hpfiend]

Hey all-

We have an 87 F350 that if it sits 2 days or more requires to be started with starting fluid- we are thinking the fuel is draining down and the oil pressure sensor wont allow the fuel pump to run to restore it until it starts a few times on starting fluid.

We are thinking of adding a checkvalve to the supply line to the carburettor?

Any other ideas? Is it easier to just bypass the oil pressure switch?

Thanks,
Andrew

 

[5.0Flareside]

how are you starting it? are you attempting to start it by pumping the gas peddle or no?

 

[hpfiend]

Yes- we pump the gas pedal before and while trying to start it... we have also checked the fuel pumps for pressure and volume, put a new power valve, accelerator pump, most gaskets, o-rings etc in the carb from a rebuild kit.

 

[5.0Flareside]

have you checked your rotary button and distributor cap? plug wires?

 

[hpfiend]

All new- we just went over the top half of the engine completely as we had an exhaust leak that turned out to be a few manifold bolts broken off in the head, which turned into removing the head, intake, carb, etc and having them drilled out and helicoils put in. The distributor we broke getting out as it was seized to the block and so we got an advance auto special reman- we then had a serious down on power issue which after eliminating most of the emissions vacuum equipment and replaced the plug wires and plugs and ignition box, no luck- it ended up being dirt in the carburettor so a rebuild and some gumout did the trick. It still wont start properly and didn't before we started all of this work- it has done it since my dad bought it and it only has 36K miles. He did buy it used back in 89 or 90

 

[1985 Ford F-150]

How is the condition of the fuel and fuel filter?

 

[5.0Flareside]

thats what my next question was gonna be was the fuel and fuel filter.

 

[hpfiend]

Fuel is fresh- the filter on the carb is brand new is there another somewhere?

 

[5.0Flareside]

no. not unless it was put on there by a previous owner. which is possible but not likely. im honestly stumped by this.

 

[1985 Ford F-150]

Should be another along the frame rail somewhere. When ya got the gas how long had it been since the tanker came to the station?

 

[hpfiend]

Not sure about how long the tanker had been there as I did not think to ask but we have ran numerous tanks of gas through it and always have the same problem- this has been going on for years.

Does anyone know how to disable the oil pressure switch? We have the service manuals and we think we just need to ground it out but havent had time to check or try it.

Thanks,
Andrew

 

[flareside_thunder]

You could unplug the switch.....one wire is all it is.....if you're going to do a checkvalve get a primer bulb like you use on a boat and put it inline. I know guys that do it on diesels. However, if your fuel is leaking back down it's a good possibility of a bad mechanical fuel pump.