I was reading on the fuel cutoff switch or Solenoid, and was also told that it is what could be causing the hard start. Someone told me to pour water over the switch area and it works every time and starts right up. Is this something that can be changed out pretty easy? This only seems to happen when it is hot out ( Of course I am in Phoenix AZ so lately it has been 110 for the last week) After sitting overnight it will usually start right up no problem. I just hate having to make sure to have a bottle of water handy to pour on the switch to cool it down so it will start right up. Any help would be great.
Thanks
Nick


1992 F350 4x4 7.3 IDI
235,870 miles

 

What you ar describing is tipical of a dieing injector pump. The internals of the pump are getting worn, and when the pump is hot, it cant get the correct pressure to the injectors. When you pour water over the pump shrinks the housing a little making the internals fit a little tighter, thus increasing the fuel pressure to the injectors. Shriinking the housing to much can cause the internals to sease, and shear off the shaft in the pump. I would start looking for a rebuilt pump, or a shop that can rebuild yours.

 

You know I was afraid that was the case but someone said that it could just be the fuel cutoff switch I will start looking to see what I can find around. Any hints on what I should look for in a person to do this? Or is it simple enough that I could do this in an afternoon?

 

There are several good threads on here detailing how to remove and replace a pump. Uhaul had them on sale through ebay for a good deal, I'm not sure if they still do.

One more thing to check that might point towards the fuel cutoff switch. When hot, play around with the wire to the fuel shutoff solenoid. Its one of the two on the drivers side top of the pump. I think the rearmost one, but I'm having a brainfart right now.
If it clicks when you disconnect/reconnect the wire, its probably not the fuel shutoff and more likely a bad pump. If it doesn't click when hot. But will click when cold, then its possible its just the fuel shut off.

If you do go to replace just the fuel shutoff solenoid, be careful!! Installing it wrong will lead to a runaway situation and quite possibly blow the engine. There are good instructions (with pictures) somewhere describing how things have to sit.

 

Great thanks that is what someone was telling me since it is only when it is hot out and by putting some water on it from a water bottle you can go in and just start it right up. I was reading on here there was a nice pic of the top of the injector pump and wiring and that was getting me to thinking. I will try that and see if I hear a clicking or not.

 

Any update on this? I'm in the same boat - engine shut off while driving and can't get in to start now. No clicking at the fuel shut off solenoid, but it is receiving power.

 

Jumper a wire from the battery to the fuel shut off solenoid. If it doesn't click, the solenoid is shot and needs to be replaced.
You can also check the resistance from the terminal on the pump to the body of the pump (which is grounded). I'm not sure what resistance the solenoid should read, but you should get continuity there (aka the meter beeps if it has that feature, or shows some resistance). If its not showing anything, sounds like the solenoid burnt out while you were driving, and then the truck died.

 

Well mine ended up it was the rotor head on the Injection pump, I had it replaced with a rebuilt pump and not had the hard start issues and lots more power out of it. All in all it was 675.00 out the door and had it done in just over an hour. He has them on Ebay Hector with Injectors, and Diesel Injsection Services. He worked 10 yrs for Southwest Diesel and now has his own shop 5 years.

 

Anyone know what kind of pressure I should see on the low pressure mechanical pump that feeds the fuel filter ? I only get around 5 psi (at the inlet to the filter) and volume output of 16oz in 30 sec when cranking. Engine cranks but will not start and found fuel filter almost out of fuel. Filled up the filter and got engine to start, but will stall again after a few minutes and found filter almost empty again. Is the engine more fuel than the low pressure pump can supply? Also on the fuel cutoff solenoid I noticed the voltage is 10.5 with the wire connected and 12 volt at the connector disconnected and measured 4 ohms for the solenoid - is this OK?

 

5PSI is fine; anything over 0 is good for the pump. Chances are, you are sucking air somewhere into the fuel system.
That's the only reason for the filter getting emptied while running.

Before going to anything else, add 5 gallons of diesel to *both* tanks. If this fixes it, you know where the problem lies.

 

When I was checking the volume output for the line going into the filter there was no air just fuel coming out

 

How old is the filter? It could be clogged up, so you're getting fuel to the filter fine, but the pump is having trouble pushing it through the filter.
Make sense?

 

If so, the filter light would come on, and the filter wouldn't empty itself.
when the engine is running, the IP can actually draw a vacuum on the fuel line by itself(it has a small sliding-vane pump inside it)

 

agreed. it does not sound like a filter problem. sounds more like a fuel supply problem.

 

Fuel filter is new and feeder pump is working Checked passage is clear going through filter housing, so why does the filter empty and not stay full