Stalling Issue 6.9 IDIT

[tbirdfiend281]

So my truck died out on me Sunday night. Stalled out twice, once leaving the grocery store, and once in the front of my neighborhood.

I had a new fuel filter for the truck, so because its so easy to do I removed the old filter to check it, it was actually still full of fuel. Prefilled the new filter spun it on, then got the truck started again. Ran for about 10 minutes at idle then fizzled out. Tank is full to the brim. I have been having issues similar to what I have going on now at 1/4 tank and below so I am hoping and leaning towards the front tank pickup (my truck has never switched since I have owned it) being full broken off or having damage. I am to unhook the supply and return and try and see if the truck will pickup out of a 5gallon bucket sometime in the next 2 weeks. Do you guys think this is a good way to see witch fuel system I am having issues with?

The day it died I ran her about 150 miles. 2 days before that I replaced the lift pump with an airtex unit because the unit I had was leaking fuel externally. I have no external fuel leak signs currently

Can you have air intrusion with these trucks and still have the filter full cause a stall issue? I hope this truck doesnt need a high pump, I dont feel like spending that money on her.

Whats everyone think? If I do diag it to having an issue with the front tank I may elminate the multiple tanks and go to my single 38 gallon, since I have one laying around waiting to go in.

Any other diag I need to do to determine the problem or do you guys think starting with a fresh fuel supply is a good idea before anything else?

Thanks.

 

[icanfixall]

My guess is the new lift pump has failed. Do this. Remove the suction line to the new lift pump and place it in a 1 gallon can. That will tell you a couple of things. If it runs fine then you have a suction line issue back to the tanks. Could be the switching valve of a hole in a line. If it wont continue running them you new lift pump has failed. When you installed it are you sure the arm went in UNDER the cam lobe. If they are installed on top of the cam lobe they will work for a whiles but soon fail like sounds to be whats going on with you.

 

[Mulochico]

Just by an odd chance, did you change the fuel cap? (i.e., locking, etc) I changed mine and had a problem with it not letting air back into the tank as it used fuel causing a suction in the tank.

Try loosening the cap and run it. Mine created so much suction it sucked in the sides of the tank until I loosened the cap. These trucks breath thru the cap, the gassers do not is what I was told.

 

[tbirdfiend281]

Like I said I ran the truck about 150 miles. Would the lift pump arm being over the cam lobe allow it to run for that long and then start having problems? I didnt even know about the orientation of the lift pump arm, whats a good way to verify this? It was running great and then all of the sudden this problem arose, so I lean a little toward the lift pump arm not being the issue. That and this truck has had the 1/4 tank problems before the lift pump quite badly.

Anyways yes I was planning on running the truck right off the lift pump from a bucket to verify if its a problem in the fuel tank(s) and or fuel tank selector valve.

 

[laserjock]

It could be that there is crap in your selector valve if you know you have the 1/4 tank problem. Could be a venting problem or fuel pump problem too.

 

[bbjordan]

It is always a good idea to diagnose the problem. Eliminating everything before the fuel pump by pumping from an alternate fuel source is a good idea. Airtex fuel pumps do not have a good reputation with some of the members here. I have read of lots of problems with them. An electric fuel pumps is always an alternative/upgrade. http://www.oilburners.net/forums/showthread.php?24142-Carrier-Pump-Group-Buy It is something that I plan on doing.
I noticed you have a 1984. Are you still sucking fuel thru the stock Water/Fuel separator? They are known spot for air intrusion.
Low fuel pressure will cause retarded timing, which can cause stalling. Check your fuel pressure, it should be about 7 PSI.

 

[79jasper]

Highly doubt the pump gave out that quick.
Even though I preach the same as everyone else, I don't think the airtex are that bad. I've never had a problem with them.
I would almost bet a piece of shower head is clogging the line somewhere, or the selector valve got clogged.
I had to blow mine out with a air hose.

Sent from my SM-T537R4 using Tapatalk

 

[tbirdfiend281]

It is always a good idea to diagnose the problem. Eliminating everything before the fuel pump by pumping from an alternate fuel source is a good idea. Airtex fuel pumps do not have a good reputation with some of the members here. I have read of lots of problems with them. An electric fuel pumps is always an alternative/upgrade. http://www.oilburners.net/forums/showthread.php?24142-Carrier-Pump-Group-Buy It is something that I plan on doing.
I noticed you have a 1984. Are you still sucking fuel thru the stock Water/Fuel separator? They are known spot for air intrusion.
Low fuel pressure will cause retarded timing, which can cause stalling. Check your fuel pressure, it should be about 7 PSI.

I weighed doing an electric pump vs doing a stock replacement, and its hard to compete with 30 dollars and an hours time to do the pump. So thats why I am not electric yet. 200$ is a lot harder to handle then the 30 of course.

 

[tbirdfiend281]

It could be that there is crap in your selector valve if you know you have the 1/4 tank problem. Could be a venting problem or fuel pump problem too.

we shall see probably next weekend. Where are you in Maryland?

 

[tbirdfiend281]

Sorry for the multipost but no one every clarified if my 150 miles of running would have determined if the lift pump actuation arm is in the right spot? Would it haven died early then it has if its wrong or is this a possible suspect issue. The bucket of fuel test will help me determine witch end is causing problems of course, but it would be good to know, just in case I am having pump issues.

 

[laserjock]

we shall see probably next weekend. Where are you in Maryland?

Oh fairly close by... I work in Columbia...

I can't say for sure on the pump arm but I would guess it wouldn't work at all. If you replaced with one of the infamous airtex pumps, it very well may have failed that soon. Again, no first hand knowledge, just have seen several posts about it in different places.

 

[tbirdfiend281]

Well I was mainly asking icanfixall who had mentioned that it would run, but eventually die out. I think the arm is probably in the right spot, that seems like to much running to be wrong. Especially since my failure wasnt progressive, it was running great, then it just wasn't running. I hope I get some time this weekend to mess with it, but it seems like I most likely wont. Next weekend will happen for sure.

 

[tbirdfiend281]

Alright, made some progress on sunday.

First I removed the lift pump 3/8th inlet line, dropped it into a bucket. Truck started right up, idled the truck till 2 gallons of diesel was gone, reved fine, seemed ok. Moving on, went to the FTSV in the middle of the frame. removed it. Ran rubber lines to the back tank. Poured diesel I had on hand into the tank. Started right up. Idled for a while, went on a 6 mile road test, truck runs great. There is an issue with the front tank. It will come down. I am probably going to drop both tanks in one weekend, install my 38 gallon rear, repair the front tank, then brainstorm a better way to switch tanks. For now I will run on the stock rear tank, I need to wire it up so that I have a rear sending unit reading. Anyone know what wires go to what on the FTSV plug to make that happen? I have 1 orange, 2 blacks, and 2 yellow wires going into the unit.

thanks.

 

[IDIoit]

funny, i was having the same problem. only with the rear tank.
with the recent mods ive done to the truck, it was easier to delete the front tank and run a 38 gal tank in the rear,
yesterday i was using an electric fuel pump to drain the diesel and noticed that with the pump hooked up to the sending unit, the out side of the electric pump would airrate.
these tanks have vent tubes that do get cloged up, and will create a "vapor lock" issue.
as i have previously went through both sending units, extended the pick ups with fuel line, and cleaned the vents, i was still having an issue.
i took off the vent valve, and used a flashlight to see what was going on.
i found that a piece of the old strainer was blocking my fuel flow.
that must have been my issue.
too late to fix it now, ive already modded it! lol
FYI, if you are going to install the bigger tank, you will need a piece of 3" angle or other material for the rear saddle mount to the frame.

in this thread, there is a partial wiring diagram of what you need, and a request for the rest of it.
good luck, and keep us posted, im in the same exact position with the FSV!
http://www.oilburners.net/forums/showthread.php?71501-Fsv-gage-wire

 

[tbirdfiend281]

Ya thats about what I was looking for. I wasnt getting any voltage or resistance on any of the pin plugs when I was poking at them through the connector, but that may be related to my attachment pieces being to big to fit into the pins. I am going to finish it up this long weekend.