99 Winne Chieftain 33B fuel pump troubleshooting

[Elexwiz]

Good day. I bought my MH one year ago in April 2013. The PO told me that the check valve on the fuel pump is bad and it will take several attempts to start after sitting for more than a few weeks.

What I found is that this only occurs when it's really cold (avg 30 degrees or below). I live in the Virginia Beach area and we had a colder than average winter. I found that I had to run the fuel pump (key on for 5 secs, then off) 3 or 4 times AND still start the gennie and use the AUX START button before the engine would finally start up. This does NOT happen when the temp is above 40 degrees. She can sit for over a month and will start right up, no questions asked.

When NOT towing my Jeep I have no issues. When towing my Jeep long distances (+100 miles) my SES light comes on throwing the P0171 and P0174 codes (too lean on banks 1 and 2).

After research and reading I've decided to replace the fuel pump and fuel filter so I ordered and received both parts. Let me say that I'm a quite capable mechanic. There isn't much that I can't do in my own driveway. I've dropped other fuel tanks and replaced a fuel pumps, but on jeeps, trucks, and cars, never on a MH. My issue is that I have to remove my rear jacks in order to drop my tank. The jacks share the same rear cross-member as the fuel tank. I can't find any info online. Are there any special considerations I should be aware of? Will the jack hydraulic lines need to be disconnected? Better yet, is there a hatch in the floor above the fuel tank? I would gladly peel back carpet if there is.

Thank you for your help and advice.

[TeJay]

Chances are very good that you will not have a hatch cover to remove the fuel pump. After all that makes way to much sense.

If you can gain access to what you need to by just lowering the jacks without removing the hoses you sure won't hurt anything.
If you can get the tank loose so it can be dropped or at least lower one end and gain access to the top of the tank where the fuel pump is located that might work.

If you've done this before it would be a vary good idea to remove most all fuel before starting. 5 or 6 gallons in a big tank sloshing around will create a lot of issues as you try to remove it.

There are a number of guys that have access to a lot of pictures for the F-53 chassis. I'm sure they will be commenting before to long. There might actually be some Ford manuals on these forums.

Good luck with this one. We had a 1999 F-53 as well but I never had to replace a fuel pump.

TeJay

[Elexwiz]

Thanks TeJay. Also let me say that I tested the fuel pressure and I'm only at 28 lbs at idle, with a brand new Motorcraft fuel filter. She jumps to 32 when I step on the gas. I haven't bothered taking it for a ride with the pressure gauge hooked up because 28 lbs at idle is way too low anyway. I know the fuel pump needs to be replaced.

[Jagtech]

I was able to cut an access hatch in the floor under the rear bed, to access the fuel pump. Sure makes changing the pump or hoses a lot easier; no need to find storage for 50 gallons of gas, no crawling around in the dirt under the rear of the rig, no heavy lifting. And I can have that pump out in less than 30 minutes if necessary! But this is possible on only certain coaches. I was fortunate; there was nothing directly under the bed, so I carefully located the exact position of the pump, and cut an 11" square hatch opening in the floor. But I don't have basement storeage or anything else under the rear bed, so it was quite easy to do. I attached a flange to the edges of the floor piece that had been removed, and screwed it back down. Can't even see it, as its under the carpet. Absolutely no regrets.

[TeJay]

Elexwiz,
You are absolutely correct on the fuel pressure 28 PSI at idle is a little low.

Hey maybe jagtech has your fuel pump access in hand.

TeJay

[Elexwiz]

I'm going to look at cutting an access panel. Jagtech, would you post some pictures of your work?

[subford]

Originally Posted by Elexwiz

Thanks TeJay. Also let me say that I tested the fuel pressure and I'm only at 28 lbs at idle, with a brand new Motorcraft fuel filter. She jumps to 32 when I step on the gas. I haven't bothered taking it for a ride with the pressure gauge hooked up because 28 lbs at idle is way too low anyway. I know the fuel pump needs to be replaced.

This does not sound right. If the fuel pump can put out 32psi when you put your foot on the gas then it would put out 32 at idle.

This sounds to me more like a bad fuel pressure regulator or you do not have the fuel pressure gauge hooked up very well.
I would do some more checking before replacing the fuel pump. Sounds to me like the fuel pump may be OK.

[Elexwiz]

I thought the fuel pressure regulator was part of the pump assembly. Does the 99 F53 have a separate regulator?

[subford]

Originally Posted by Elexwiz

I thought the fuel pressure regulator was part of the pump assembly. Does the 99 F53 have a separate regulator?

Yes it does.
According to the 1999 Ford shop manual the 6.8L engine has a Fuel Pressure regulator mounted on the fuel rail of the engine.

[Elexwiz]

Thank you. I'm going to start troubleshooting as soon as I get home.

[Elexwiz]

I found a bad vacuum line last summer that wasn't closing my A/C recirc door. The vacuum line will be the first thing I check. Thanks!

[olfart]

Althou my '98 Chieftain has a 460 V8 - the fuel pressure reg is on the left side of the engine fuel rail - with a vacuum line attached to the top of it. They do sale an adjustable fuel regulator - in case you wanted to tweak the fuel pressure. But that needs to be done with care. The stock fuel pressure reg is non-adjustable.

[subford]

The fuel Pressure regulator looks like it is at the back of the engine:


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[Elexwiz]

Thanks all! I will let you know what I find. And I'm not looking at adjustable regulators, just the stock one is fine.