| Author | Message | ||
| John Wardell (Hitherandyarn)
Registered Member Username: Hitherandyarn Post Number: 3 Registered: 1-2007 Posted From: 148.64.187.28 Rating: N/A |
I have a 1976 MCI 8 with an Detroit 8V71, non-turboed. Adventure 1: With the engine running, the Fuel Pressure Switch leaks from a point where the curved washer behind the mounting nut meets the plastic case of the switch. I haven't removed the switch, but, it looks like the plastic is warped and not fully seated against the washer. Is this repairable? If not, where do I get another switch? The markings on it are Nason SP-1B-1F. Adventure 2: The non-ground wire on the back of the switch is broken off at the switch terminal. The only lose wire (banded with tag #56) I've found comes out of a metal tube wire harness along the right side engine rail. That wire is 6" short of making the connection to the Pressure Switch terminal. Where should I be looking for the wire that connects to the terminal and completes the circuit for the switch? Adventure 3: Everything I've read so far says the engine should not start without a functioning Fuel Pressure Switch. My engine starts just fine and the switch is not connected. What am I missing and what else should I be looking for? Thanks for any advice you can offer, John | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1505 Registered: 12-2000 Posted From: 76.71.101.5  Rating: N/A |
If we're talking about the same thing, the fuel pressure switch is to prevent the starter from being accidentally engaged when the engine is running. It is also critical to the operation of the emergency run bypass if you have the auto shut-down features functioning for hot engine and low oil pressure. You have to hold the starter button in to keep the engine running to move it from the disappointing place it chose to stop. The fuel pressure switch will have cut out the starter once good fuel pressure was reached. Someone may have just cut the wires off.... and you just go buy a new one, nothing to repair. happy coaching! buswarrior | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 972 Registered: 12-2000 Posted From: 71.54.29.215  Rating: N/A |
Make sure you get a heavy duty replacement. When ours started leaking, I went to a local parts place and purchased a replacement (I think it calls for about a 6-9 PSI NC). Anyway, the replacement was only about 1/2 the size of the original and only lasted a few months. The contacts in the smaller switch were not large enough to handle the load. This switch completes the coil circuit from the starter relay in the rear panel to ground. They must have wired the relay coil wire directly to ground instead of going through the pressure switch. Jack | ||
| Bill Gerrie (Bill_gerrie)
Registered Member Username: Bill_gerrie Post Number: 230 Registered: 3-2006 Posted From: 216.198.139.38 Rating: N/A |
The replacement switch I used was a Carquest #CPS 80467. It is a NC switch 10psi. It is adjustable to 5 - 15 psi by removing the rubber plug in the end and using an allen key to turn the plug slowly. I think these switches are a Stewart Warner product. |