broncobilly

All,
I have been having the same problem with my 93 W250, for the past month. The truck will sit idle (unused) for a few weeks or more. I start it up at home with no trouble. I then drive 5 miles or more to the big box store etc., and when I come out to restart the truck - it just cranks over and wont fire. Starter and battery are both fine.
This has happen to me twice, resulting in AAA towing me home. The first time I had a crank and no start issue, the check engine light came on. That ended up to be the air temp sensor (which I replaced, and knocked out the check engine light). I replace the lift pump l year ago, with a pump from NAPA. I am also using the larger block attached fuel filter (as per the sticky, which was put in about six months ago). So; I am wondering if my lift pump has now crapped out, or if I have crap in the fuel tank causing a blockage in the fuel line, or is the fuel pump going out? I guess replacing the fuel filter would also be a good idea, even through I did this about six months ago - and don't use the truck too often I always add 2 stroke oil, as well as Diesel Power Service and Marvel oil, when filling up - to deal with ULSD fuel. I am debating putting a carter electric pusher pump, as close to the tank as possible, to aid in getting fuel up to the lifter pump. The first time my truck wouldn't start and was dragged home, I placed a hydraulic jack under the rear diff, and jacked up the rear end a bit - I got in the cab and the truck started right up! So - I know I have a fuel delivery problem somewhere? The 93 is not hot rodded - no advanced fuel pump, bigger injectors etc. Any input/help is greatly appreciated!!!!

j_martin

It really ain't rocket science or anything. It just isn't getting fuel. The trick is to find out why.

When it quits, I'd crack the fuel line at the IP and crank it. If it sprays out there, crack an injector line and see if you have fuel there. If not, suspect the Fuel Shutoff Solenoid or the power to it.

If there is no fuel at the IP, try manually pumping with the lever on the lift pump. If that goes, the LP is bad. If no fuel, then find out why, plugged line or sucking air.

So if you think ahead and take along 3 end wrenches and maybe a multimeter, you should be able to noodle it out in the parking lot in about ten minutes.

I'd check the fuel filter immediately for water or debris. That should go without saying.

patdaly

The next time it won't start, open the hood and wiggle the FSS lead and see if it isn't an intermittent connection problem.

Better yet, since you are local to me, just sell that old heap to me and get it out of your hair........

Seriously, don't freak out just yet, it is probably something simple.

maybe368

I just went through a very similar problem, replaced all the usual suspects and it turned out to be the battery. It would crank pretty fast, but not stert. I am thinking that the battery had enough juice to crank it, but not enough left over to put 12 volts to the fss. When it did it to me last time, I put 12 volts to the fss from a remote battery jumper box and it started right up. put a 1250 cca die hard platinum in it when I got back and it hasn't happened since...Mark [/I]

broncobilly

Thanks JMartin, patdaly, maybe368 for the input! When I get a chance, I will try and pinpoint the problem - through the process of elimination, as per JMartin . I will start with changing out the fuel filter. I have an inclination that the Napa lifter pump took a dump : ( Hope I can locate the receipt from a year ago.

broncobilly

I had a few minutes today to look over my 93. After checking the lifter pump, as well as the fuel pump and FSS - it appears that the FSS is bad (checked with a multimeter, and cracking the fuel line after the pump). I haven't located my service manual yet : ( How difficult is it to get at and replace the fuel shutoff solenoid? I have a replacement on it's way from Geno's.

tyssniffen

I have a problem a bit like this... it acts much like air in the line. I can crank a few times (4?) and get it going. it doesn't always happen though.

and I do know that my FSS is bad. I've put in the manual kill switch... but interestingly, I don't always have to use it. I wonder if anyone woudl agree with me that perhaps when my FSS *works*, the next time I get in and try and start (days later, not minutes) is when I have this problem.

I was starting to think about oil pressure and all sorts of crap. I guess, if someone can confirm my thought that it's the FSS stuck CLOSED, then I'll just work on using the kill switch every time.

RamGuy84

FSS is a 15/16 wrench and a 5/16 to remove the top nut that hold's the wire connector on .Pull the throttle bracket off and the intake tube to give you a little more room for the wrench.

maybe368

The FSS is located too close to the pump to get a normal wrench on, so 1 good way is to use a hammer and chisel. I didn't like doing that, but it did work really well. If it happens again, the FSS in old VW Bosch pups is exactly the same and costs about a quarter of the price. You can get them on Amazon or eBay. Do a search on removing FSS and there are a couple of good threads with pics, good luck...Mark

maybe368

Most guys that convert to using the manual shutoff "gut" the FSS by taking the FSS out and removing the plunger. 1 way to test is to run 12 volts to it directly from the battery, or any 12 volt source, and see if it opens. I don't hear well, but there should be an audible click if it is opening. If the rubber tip is damaged, it may work intermittently...Mark

tyssniffen

just to continue my chiming in on this thread on a side note:

I've now been paying close attention to my similar problem - when I kill the engine with my manual kill switch, the next time I start up - no problem. if I let the diesel clean the solenoid enough that it works (shutting down the engine when you turn the key off) the next time, it sticks closed, and I struggle to start.

thus, it's totally the FSS that is causing my problem that sounds exactly like brocobilly's.

getting that thing off and replacing it is too hard for me to tackle before a number of other projects.

Tys