Hi all,

I have a 1990 F250 7.3l IDI, (4x4 Supercab longbed). After a recent trip, the truck started to lose prime. I would try and start, and she would turn over, catch, and then stall. I would have to crank for 30 seconds or so, and then she would start right up and run normally.

I suspected that part of the problem might be poor diesel (the last place I filled up seemed a little dodgy), so I filled up the tanks and put in some redline diesel adative (1/2 bottle in each tank). Now she won't start at all :-<

I drained the fuel filter - but to be honest, I'm not sure I can tell the difference between "clean diesel", "water contaminated diesel" or "gas contaminated diesel". The fuel definately smelled like the redline stuff I put in yesterday.

I noticed that there was air and a little fuel bubbling out of one of the connectors on the top - see the attached picture. Can someone please tell me what this is, and how to remove it? I tried lifting and rotating, but it didn't want to budge, and I don't want to break it. I suspect I have some kind of pressure leak here, and that is why I am losing prime



Any other suggestions welcome. I have the batteries charging, so once they are topped up (which takes a *long* time - small charger, big batteries!), I'll see if she starts up.

Oh, one other thing. My "Water in fuel" indicator doesn't come on when I turn on the ignition. The images I saw had a water sensor at the bottom of the fuel filter, but I just have a Napa filter with a plastic drain plug at the bottom. Where does the sensor live?

Thanks,
Chris.

 

The connector circled in red is for the fuel heater. If you are seeing fuel bubbles from there tha is where you ar getting the air intrusion. It is sealed by o-rings which are accessed by removing the fuel filter from the head, removing the head from the mounting bracket and removing the "pipe" the filter screws on to,to remove the fuel heater. Just pry the wire connector off of the stud carefully. If the filter you have on there now a one piece it is probably one tha fits without a water sensor. The OEM filter is a two piece one ie a filter that screws on the head with an aluminum cap that screws on the bottom. The water sensor lived in this cap. NAPA make an one piece filter with the water drain and the water sensor on it too, but I can't recall the number of the filter. Hope this helps. Tom

 

Thanks Tom, thats very helpful. I tracked down a part number, Napa FIL3617 for the filter with sensor port and drain plug, and FIL3417 (the one I have), which just has the drain plug. I guess the sensor is long-gone, so I will have to go and figure out where it should plug in, and track down a new sensor as well.

Thanks for the tips, looks like a bit of dismantling is in order... The good news is that I bled off some air/bubbly diesel from the shrader valve, cranked her over, and she started right up. As they say, "if it ain't broke, don't fix it. If it's just a bit broke, then put off fixing it until you can't avoid it any longer"

Thanks,
Chris.

 

By the way, I found this great thread with all the details:

https://www.ford-trucks.com/forums/8...ns-w-pics.html

 

So, on with the show, I got the fuel heater o-rings replaced, filled the new filter with ATF, and off she went. After about 5 minutes at idle - she died again :-< Holding the shrader in, she is blowing a lot of air, so I suspect that there is air getting into the lines upstream of the filter. I also noticed a fuel leak under the truck, which isn't coming from any of the parts I just replaced. I suspect that the problem lies in the lift pump or plumbing, so on to the next step...

Chris.

 

I got ready to test the fuel pump, and wouldn't you know, the truck started right up. The pump seemed to be putting out plenty of fuel, but it did seem to be quite aerated. I thought that perhaps I had a problem in the tank pickup, because she only seemed to stall when running of the rear tank. I played around for the next few days, but she was still unreliable, stalling occasionaly, and needing re-priming.

Anyway, pumps are pretty cheap, so I bought a new Bosch Fuel Pump (lift pump? Transfer Pump?), and installed it today. When I pulled the old pump off, diesel started running out of the breather hole on top - I am assuming that is certain proof that the pump diaphragm was bad! I didn't do anything special when installing the new pump, I didn't see how I was ever going to check the cam location, so I just took a chance - everything turned out fine. She fired right up, and idled for 10 minutes with no problems. A quick drive around the block, and no issues, so fingers crossed the fuel pump was the problem! I kind of wish the pump had just died altogether, that would have been easier to diagnose, but I guess to give her her due, she did get me home each time she started stalling...

Cheers,
Chris.

 

Glad you found your air problem make sure it did not put any diesel in your oil pan sometimes when the diaphram ruptures it dilutes the oil with diesel.

 

Thanks for the tip - I think an oil-change is probably next on the list...

By the way, while we're chatting here - I also replaced the rubber line that goes between the metal fuel line and the pump (with multi-fuel hose) - Is it normal for that line to be a loop? I had a hard time installing the new line without having it contact the body somewhere...

Chris.

 

Not sure about the loop but if it can contact anything I would insulate it to keep it from rubbing anything.

 

A good move there is a piece of 1/2" heater hose between the fuel line and anything it touches.

If the fuel line is off, you can just slide it over the line, or you can split the heater hose, wrap it around the line and use zip ties to secure it.

Also while you are under there, look at each of the metal clips that secure the metal line to the frame and cross member from the lift pump back to the fuel selector valve.
They are a good place for rust to eat pinholes in the metal fuel line, which will also let air in when the engine is running.

 

If my fuel pump diaphragm is also bad like the above guy's, would it make for hard starts, but run perfect and start perfect when warm? Im only having issues in the morning when cold, and I just put on new return lines.

thanks!

 

Shane with air intrusion at or above the pump they will usually start easy then stall first thing in the morning then hard to restart. Is this what yours is doing

 

exactly, It fires right away, then dies and is very hard to restart. That was before I put the return line kit in last night. This morning, It was firing a bit right away, but still had to crank for a lil bit before she took off. Once It started, It did idle just a bit rough for a lil bit. all other starts during the day today it started instanly when i touched the key.

It was 20F this morning, and was not plugged in.

 

Sounds like you have your air intrusion problem solved, hard to say but you may have a bad gp or 2.
Are you running any fuel additive.

 

Just replaced all eight GP's with beru's. No fuel additive. GP cycle seems to be about right, with one second bursts after the initial cycle.

If there is no air getting in, shouldn't it fire right up and run smooth?

Whats the best way to go about tightening the eight lines coming out of the IP? Seems maybe have to take off the top ones to get to the lower ones. The bottom few appear a bit wet. Are there O-rings, or are they just a flare fitting?

thanks for your continued help.

Do you have any tips for my cruise not working? The truck is building vacuum it seems, Could the diaphragm inside the cruise (canister) be bad?