i have a 90 f350 4x4.
first problem i have is lately i've noticed it i park facing uphill, even if it's hardly even a hill, then try to start after my truck sits for awhile it will start up, rev up and die like it's out of diesel. I think everytime that has happend my tank has been below 1/4 to 1/8 tank. Any ideas? I am going to go to my father in laws next time i fill the tank and park in his driveway (it's somewhat steep) and then see if i still have the issue. But any other ideas of what is going on would be nice.

Second problem is that sometimes when i go to start the truck my stereo resets like i disconnected power, but it still has enough juice to crank and start? wtf? i'm lost on this. I cleaned my battery connections and still same problem.


Third problem is since i've had the stalling issue i've notcied that my batteries arn't what the used to be. could my alt. be not giving what it should or is there an external or internal regulator that could be ****ting on me? How can i test the alt, and or regulator? And would this issue be contributing to my second problem?



thanks for any help, I'm really needing my truck to be reliable and am low on $$ so any help and ideas. Thanks again

 

1st issue... which tank gives you the problem? front? rear? both?

2nd issue how old are your batteries? when they are not fully charged or not to long from dying they will act up the reason your starter still cranks is because all the joose from the battery is going to the starter and not petty things like radio lights and such thus the need for large cable... that being said a new fully charged battery should send power to the starter and still have some to spare so that doesnt happen with your radio also could be a volt regulator but im not as familiar with diagnosing it or symptoms

3rd issue as far as testing the alt. put a volt meter on the battery take a reading when the truck is not running then start the truck and check the battery again it should read iirc in the 15, like i say im pretty sure im sure if im wrong someone will correct me. this is just a quick way to test the alt.

 

i think it's happened on both tanks. can't be sure though.

the radio resets before i even crank the starter. but it only happens sometimes.

how do i test the amps on my alt

 

this pretty common.
the pcikup screen brakes off and falls into the tank.the result is fuel can no longer be picked up.
parking on a hill like that,of course make the problem look worse as the fuel is lower in the middle,where the pickup is.
you'll need to fix it.
most guys use a section of hose,and a cut V in the end,so it doesn't get sucked to the bottom of the tank.
you'll need to drop the tanks or lift the bed to fix it.
not a fun job either way.
you could just use the top of fuel tanks only.just fill both tanks,and switch when they reach half way.
you don't want to risk running out of fuel,cus its hard on things.the fuel is used not only for burning,but cooling and lubricating the ip and injectors.
plus it's hard on the starter to crank and crank,to prime the system again.
it should be fixed ideally.if not,then just use 1/2 tank so you don't risk the issue again.

 

With your truck starting and then dieing, do you have to crank on it for a while to restart? If so you have an air intrusion problem. When parking facing uphill you are increasing the difference in height from the fuel filter to the fuel level in the tank, creating more suction on the fuel in the return lines trying to get back to the tanks. As Dave S gives as an example putting your finger over the top end of a drinking straw with the straw in a full glass of water, you can pull the straw out of the glass and the water will stay in the straw until you lift your finger from the end of the straw. The return system on these old engines works on the same principle.

 

so a little confused on how to fix this, is there any way you can get a little more detailed. thanks alot

 

The most common place for air intrusion is the return lines. The oring get hard from the hot fuel flowing threw them, and if disturbed will allow air to get in. You need to get an injector install kit,and replace the lines in between the injectors, the plastic caps and the orings under the caps that mount on the injectors. The cheapest place to get one is on line threw here FORD 6.9 7.3 DIESEL INJECTOR RETURN LINE KIT 6.9L 7.3L - eBay (item 150449611406 end time Dec-25-10 13:45:04 PST). Or any god parts house can get one but for more money. Remove the steel injector line frome the injector and carefull move it to the side. Remove one side return lines as a unit, and make the new one to match. Remove the old orings from the injectors, lube the new orings liberly with vasoline or motor oil and roll them on the injectors, then replace the caps and hoes you made as a unit,pushing the caps down onto the injectors. You should feel the cap click into place. Reinstall the injector lines, and you are done with that side, then do the same to the other side. You should be able to do this in 2 hours.

 

about 3 yrs ago or so i noticed my injector lines were leaking diesel so i took it in to a shop and they replaced all that stuff. I'll take a look at it though.
so the fuel line in the tank, is it a solid line that comes from the bottom or top of the tank? any exploded views or pics would be aprreciated. thanks.

 

If they used regular Buna o-rings it likely needs done again. When it's sat overnight, crack your fuel filter, and see if it's full or not.....if not, you have an air leak.

 

i took it as if he's only seeing the problem when the fuel level was 1/4 or less?

i guess the wise thing do is like greywynd suggests and also put some fuel (1/2 full or more) in one of the tanks and see if it still does it.

 

The fuel line in the tank is metal from the top to about 3/4 of the way to the bottom. It then has a rubber showerhead looking strainer on the bottom portion. As the rubber ages it will crack allowing the shower head to fall off, and the truck running out of fuel with around a quarter of a tank of fuel still in the tank. The easy cure for this problem is to use a piece of fuel hose with a V cut in the free end and the otherend clamped to the end of the steel line, replacing the shower head. If you are not experencing running out of fuel with a quarter tank showing on the gauge this probably is not your problem.
It does not take to much to make the return lines start letting air in. Bumping one of the caps can sometime let this happen.

 

great thanks for the info. I'll try to dig into it this week. i'll keep ya posted

 

I have the same issue. Only ever happens when fuel level is 1/4 on the front tank. Last time it happened I had just driven up a very steep incline to get to a customers home. I had just under a 1/2 tank but when I tried to restart after 3 hours it stalled. I switched tanks and cranked till it started.

As its getting colder here now I will go for the easy solution and fill up when tanks are half full.

Im wondering if the filters will need to be checked more often now if the strainer in the tank(s) are gone?