Community Forums

harmonybrew · 11-09-2019, 10:22 AM

Hello all,

On my 99 Bounder, V10, 6.8L, F53 Chassis, I am having a problem where it won't start if it sits a few days. Otherwise, it starts fine.

If it has been more than a few days, I have to turn it over for quite some time before it starts. Then it can be turned off and restarted pretty much immediately.

I have changed the fuel filter. I have switched out the fuel pump fuse. Neither has helped.

Any ideas other than the fuel pump. This is the one job that I don't want to do myself. Could there be any other causes?

Thanks in advance,

Marcus

twinboat · 11-09-2019, 10:49 AM

Two things come to mind, cold start enrichment is bad. Will it start 8 hours after you had it running ?

Try turning the key on and off 3 or4 times before turning it to start. If that helps, the fuel is leaking back to the tank. Every time you turn the key on, the fuel pump runs for a short time.

ransil · 11-09-2019, 11:35 AM

Check fuel pressure at idle and load also shutdown bleed off time.
Harbor freight sells a cheap one that will do what you need, auto parts stores loan them too with a deposit

GypsyR · 11-09-2019, 12:22 PM

May be something completely different but I've noticed this on my much older Ford chassis. In my case know what, but not why. Most fuel injected vehicles cycle the the in-tank fuel pump on for about two seconds as soon as you turn the ignition key on. About every EFI gasoline engine Ford I can think of does this. Mine does not. I proved it while doing some fuel troubleshooting. How has got me though. All I can think of is that feature was turned off in the computer programming or something. I can't imagine why someone would do that though. I haven't pursued it yet though. Once I get around to reading the computer's data stream maybe it will indicate an ignition feed missing or something.

Fuel pressure bleeds down over time, that's why the two second fuel pump thing. It may be something in your system is bleeding down excessively though. lacking any evidence of external fuel leaking my prime suspect would be the in-tank pump itself. Bad part is that it might be the first sign of a failing fuel pump.

TeJay · 11-10-2019, 04:59 AM

You have gotten some good ideas BUT what are we trying to determine? Lets put it in simpler diagnostic terms. When the engine has set for several hours cranks and won't start what is missing fuel or ignition?

Yes try things but isn't it better to know for sure there's no fuel or no spark before you try things???

It's basic diagnostic procedures. An engine will run if it has compression, fuel and spark. Your compression is not likely to come and go but fuel and spark will.

GypsyR · 11-10-2019, 10:44 AM

Since ignition generally only comes and goes as described in extraordinary circumstances and fuel issues matching the complaint are VERY common one could consider it most expedient to focus on the fuel system. Occam's razor.
Though it's very much slower, the "no stone left unturned" investigative approach certainly has value most people asking for help with such an issue seem to prefer a tighter focus.

harmonybrew · 11-10-2019, 10:52 AM

Quote:

Originally Posted by twinboat

Two things come to mind, cold start enrichment is bad. Will it start 8 hours after you had it running ?

Try turning the key on and off 3 or4 times before turning it to start. If that helps, the fuel is leaking back to the tank. Every time you turn the key on, the fuel pump runs for a short time.

I learned this trick when the problem first started, and it worked a couple times. I thought it would get me through until February when I would be in a place where I could replace the fuel pump myself (after being very sure that the fuel pump is indeed the problem). But, this trick failed to work within a week. Also, it used to be that the only time I would have this problem is if the vehicle set for 4 or 5 days. Now it might only have to sit for 12 hours and I am back having to start it over and over.

I took me quite a while to get her running today. I did notice that after she started, the smell of gas in the exhaust was stronger than it was before this problem started happening.

Thanks

harmonybrew · 11-10-2019, 10:56 AM

Quote:

Originally Posted by ransil

Check fuel pressure at idle and load also shutdown bleed off time.
Harbor freight sells a cheap one that will do what you need, auto parts stores loan them too with a deposit

I have a fuel pressure tester kit. I tested when it wasn't starting and determined there was no fuel pressure. Since when it start it seems to run okay, I did not test it while running. I will do this for any knowledge it might bring. How do you test shutdown bleed-off time? I can imagine you time from the when you turn it off until when it reaches 0?

Thanks

harmonybrew · 11-10-2019, 11:07 AM

Quote:

Originally Posted by GypsyR

May be something completely different but I've noticed this on my much older Ford chassis. In my case know what, but not why. Most fuel injected vehicles cycle the the in-tank fuel pump on for about two seconds as soon as you turn the ignition key on. About every EFI gasoline engine Ford I can think of does this. Mine does not. I proved it while doing some fuel troubleshooting. How has got me though. All I can think of is that feature was turned off in the computer programming or something. I can't imagine why someone would do that though. I haven't pursued it yet though. Once I get around to reading the computer's data stream maybe it will indicate an ignition feed missing or something.

Fuel pressure bleeds down over time, that's why the two second fuel pump thing. It may be something in your system is bleeding down excessively though. lacking any evidence of external fuel leaking my prime suspect would be the in-tank pump itself. Bad part is that it might be the first sign of a failing fuel pump.

I agree with all this. I am trying to make sure it is not the fuel pump, so that if I can't prove this, then I will feel comfortable with the cost and work involved in putting one in. Making sure that it is not the computer is one thing I would like to do. This is a tougher nut to crack than proving the pump isn't working - I think. I have heard of this problem ending up being the computer. I think it is never a fun journey getting to that conclusion.

Thanks

harmonybrew · 11-10-2019, 11:13 AM

Quote:

Originally Posted by TeJay

You have gotten some good ideas BUT what are we trying to determine? Lets put it in simpler diagnostic terms. When the engine has set for several hours cranks and won't start what is missing fuel or ignition?

Yes try things but isn't it better to know for sure there's no fuel or no spark before you try things???

It's basic diagnostic procedures. An engine will run if it has compression, fuel and spark. Your compression is not likely to come and go but fuel and spark will.

I get this simple equation, and i think this is what makes mechanics fun.

I haven't checked spark. Maybe I should. I thought that spark was out because of the fact that once I get it running it will start on command as often as I like. The only time it won't is after sitting for - what started out as days. Now I am probably going to go back and do things like check fuel pressure, spark, etc... Just to make sure it is not 'fuel pump' before I go ahead with this work. It would be a bummer to put in a new pump and still have the problem.

Thanks

harmonybrew · 11-10-2019, 11:43 AM

Quote:

Originally Posted by GypsyR

Since ignition generally only comes and goes as described in extraordinary circumstances and fuel issues matching the complaint are VERY common one could consider it most expedient to focus on the fuel system. Occam's razor.
Though it's very much slower, the "no stone left unturned" investigative approach certainly has value most people asking for help with such an issue seem to prefer a tighter focus.

You forgot the 'poor man's MO' - start with whatever costs the least. That is why i tested the fuse and replaced the fuel filter first(it had already been 10,000 miles).

Also, a thrifty man works his butt off not to replace parts that don't need replacing. So, here I am - testing, talking, testing, talking - until I break down and do something pricey. If duck tape could fix this, it would!

Thanks

Jim_HiTek · 11-10-2019, 11:50 AM

If you do narrow it down to a bad check valve in the fuel pump, note that you can add a check valve or even an external fuel pump very near the tank. Much less difficult than dropping the tank. Probably less expensive then an in-the-tank pump too, unless they sell millions of them because they fail so often.

There is one thing on those chassis' though that I've read quite a bit...fuel hoses developing air leaks. This allows air to enter the hose. Usually happens to the hose that's right on top of the fuel tank. Doh! Means you'd still have to drop the tank. But not as far as if you replaced the fuel pump, I read it's fairly easy with a tranni hoist. That is if the tank is pretty much empty.

Good luck.

tiffy2000 · 11-10-2019, 01:14 PM

I read a post where someone added a external inline electric fuel pump right where the fuel filter sits in the frame rails, said it works for him. He tried to use the type of fittings that Ford uses but gave up on that and used high pressure rubber fuel lines and hose clamps.

TeJay · 11-10-2019, 03:45 PM

Marcus,

I made the diagnostic point because if you don't believe spark is the problem you don't check it and might do the fuel things and get bit. NEVER make the assumption. Check for spark when it won't start. Yes spark can be intermittent just like fuel.

What about the sluggish fuel pump in the tank?? When it won't start immediately smack the bottom of the fuel tank several times with a dead blow hammer and try it again. If it starts then it's a sluggish fuel pump and it needs changed.