Son's truck 1990 F350 Crew 2wd (salvage truck) hypermax,3.5 exhaust,and intake w/e4od & transpak.

Stalls when slowing down. Air at Shraeder valve. Bleed it between cranks. Crank 4-5 times (several minutes between cranks) it will start up and drive normally for 3-5 miles. Starts to starve as I slow to turn or stop, then stalls. Original tees, Os, injectors and returns except for crossover that came w/ Hypermax. Fairly new lift & vaccum pumps and new front poly tank. Starts good in morning. White smoke present. Newish GPs. Has a leak (for last 7 years) at the front of IP cover, looks like fuel.

Thought low sulfur was the culprit cause forgot my DieselKleen on last fill up but been running about a third of tank w/ DieselKleen and 1/2 quart of ATF to try to lube IP. Changed fuel filter w/no joy. Haven't pulled off governor cover yet to look for bad black stuff. Ideas anyone?

 

Seems you have selected NOT to get PMs or emails.........SO

I have the TSB where you can correctly remove the IP cover...... You state there is a leak there already... not sure if that would add to the problem. Check the fuel pressure from the lift pump......

Do a pressure and flow test of the fuel pump at the Schrader valve on the filter header (FSS- fuel shutoff solenoid disconnected on IP). Remove the tire valve core and hook a hose and pressure guage on it should see 4-6 psi when cranking. Then do a fuel quantity test same place, should see 1/3 pint in 10 seconds of engine cranking, route fuel to a suitable container with a hose.


If you want the TSB info click on my name and email me or PM me your email addy. I will be off line after 0700 in the morning and gone all day.

Pete

 

papahud,
Welcome to FTE and the IDI diesel forum.

 

PLC7.3 still setting things up to recv. email and PM.

 

Did flow test pump 7-8 oz in 10 sec. The fuel pressure tester needle didn't move at all. I know it was working cause it would bleed off diesel through the clear tube. Put it on my Sub just to make sure it was working. Seemed to be quite a bit of air bubbles coming thru the bleed off tube. I know these idi don't produce alot off pressure but the needle wouldn't move at any rpm.

 

also how do I recv PM and emails?

 

Any ideas yet?

 

You need to have 25 posts before you can recieve PMs.

 

I believe your sucking air in at the fuel tank or fuel line connection. Mine was sucking air at the manual fuel selector switch by the drivers seat and door for the 3 fuel tank,(if you have one) I have also heard on these forums that the plastic pickups in the fuel tanks go bad and start sucking air in there. Mine when i am at 1/4 tank left and come to a stop, the engine will want to stall and it is probably the plastic pickup.

One last thing, first you can see if you are sucking at idle by going to parts store and buying a $2.00 clear plastic in line filter. Put it inline between the fuel tanks and the engine. I put mine in after the selector switch. Run the truck and see if you continue to get air bubbles in the filter. If you do not get air and it purges out all the air bubbles then you can drive the truck, then when it dies look to see how much air is in the filter. If there is air in the filter, your problem is in the fuel tank, lines or selector switch.

Also, just for your information, That clear fuel filter will also help you find other issues. I used to have my fuel filter light come on all the time saying to change my fuel filter. I would change the fuel filter and it would still come on. I even changed the lift pump. It would get to the point where the truck would just die. So thats when I first bought the clear fuel filter to watch fuel flow. When I stuck in inline between the fuel pump and tanks, To my suprise, the filters clear plastic housing was sucked in touching the filter eliment inside indicating there was a large vaccum. Come to find out, a pice of small gravel from my 3rd fuel tank got stuck in the manual selector switch nipple that goes to the motor. A little off topic but that $2 filter is a good diagnstic tool. Yall have a great day!!!

 

Never hurts to have another filter. Would that explain not having any fuel pressure but still flowing fine on fuel flow test?

 

Could the IP pull enough to give a false read on the flow test but still have no fuel pressure from a bad lift pump? Or does this sound more like air?

 

Well, Your post says when you slow down to turn, you have to blead air at the shreader valve so to me it sounds more like an air issue. My new lift pump only put out about 3 psi cranking so you wont have much pressure to test for and you can watch the fuel flow through the filter.(althought plc7.3 method is probably more accuarte) It will flow quiet fast through the filter expecially when you rev it up. (mine did anyway. I would still check for air by the way I mentioned in my last post.

Also, a bad lift pump can also suck air from a bad diafram and the housing crimp comming apart. Had one at work that just wouldn't idle and had little power because of air from the lift pump. NOT TO CONFUSE YOU, BUT IT CAN ALSO BE A SOURCE. Usually you can tell a bad lift pump if it is leaking fuel unless the diafram is bad and its leaking in the crank case

You can see if the lift pump is producing air by checking with the clear fuel filter before and after the lift pump. If you only get air after the fuel pump, then that is your source but if you get air before it, then your problem is in the fuel tanks, lines or selector switch.

One question, does yours have an electric fuel pump under the drivers seat. Someone installed one in mine before I bought it. I don't think it was factory but it may have been an option by the conversion company. Just curious.

 

It appears I have plastic fuel lines. How did you install your clear filter and where in the line. I've read to use plastic line to look for bubbles. You know where you can to tie that in after the filter head to check for air in returns.
I don't have an electric but I'm about ready to.

 

You do not have to do the test engine running........ use the starter only for the fuel test and see what you get.

Just a warning cutting the fuel lines is bad news it requires a special joiner to repair it correctly. Also the cheesy filters do not allow sufficient fluid to feed our IPs. Clear hose at the lift pump pigtail and at the #1 return line to filter header and at the IP return to #2 injector. Remember if you disturb the orings/caps they may leak. Sent email did you get it.......

 

Sorry, I do not have any plastic lines. I figured an older one wouldn't either but I guess I learned something. Like plc7.3 said, I wouldn't cut it. No offence but As for the little plastic filter, It is still inline in mine and flows plenty of fuel. Had it in for over 10,000 miles and will still puff black smoke on hard acceleration like it did when i took it out. No fuel flow reduction and will work fine as a test tool. I keep a spare in the glove box. Infact, mine had that cheesy fuel filter (although it was metel and not plastic) before my electric fuel pump and looked to had been there for a long time. I keep it in there because my 3rd tank has alot of debrie and the main fuel filter cost $20 a pop. Yes they will plug up quick with dirty fuel but a clean one will will flow more fuel than this engine will ever use. Your fuel filter light should come on if there is too much restirction in the fuel filter like mine does. any way, I hope you have better luck with that fuel issue than I had with my turbo install today!!!! it didn't work. Have a great day