Cleaned tank and now won't go above 35mph

[beetleswamp]

On my quest to make my m1008 more respectable I decided to attack the gunk that was bogging things down when I got below 1/4 tank. Also had an issue with bogging when driving up medium size hills at highway speeds and hoping this would be cured as well.

Dropped the tank and put it back in, drove it to the end of the street and it died. Dropped tank and reinstalled again several times (I'm a freaking expert at doing it with a ratchet strap now) and did lots of stuff including;

replaced hoses
replaced clamps
took the cap off middle nipple on the sending unit cause it was making a vacuum
re-crimped electric lift pump leads
checked pink wire for clicky (yes)
opened water drain valve with engine running (engine stalled pretty quick)
removed fuel tank inlet screen
checked clear in-line filter for bubbles moving through (nope)
moved the tank into the bed and ran new lines
checked ip return for flow and it has occasional bubble
replaced square fuel filter
1/4" in-line filter between filer head and ip flows ok but goes to a trickle when idling
disconnected ip in-line after a stall and it sprayed fuel and air/ had lots of pressure

Now if I bleed the system before starting truck will cruise around the neighborhood at speeds less than 35 on flat ground but anything over that makes the idle unstable and gotta let off the gas or it dies.

I guess tomorrow morning I'll try and borrow my friends car and go to Hydra-Air Pacific and see what they have for spin-on filter/separators and mounts. If I leave the carter pump on it starts to leak out the back of the square filter bracket so i hope that's where the air leak is.

Been reading the threads and I think that about covers it. Is there anything I might have been overlooking?

 

[Armada]

If I leave the carter pump on it starts to leak out the back of the square filter bracket so i hope that's where the air leak is.

When it leaks from the back of the filter base it is usually from the water sensor.
Also, put the strainer sock back on the fuel sender. Diesel fuel is dirty. Do you have a filter before the electric pump? Add one if you want the electric pump to last. What is the pump rating? You need a low 3-5 psi pump. What happened to the mechanical pump? Are the lines still plumbed through it or has it been removed and a block off plate installed? Is your return line hooked to the tank? Is the fuel cap venting properly?

 

[beetleswamp]

Thanks for getting back Armada. I'd like to get this thing running proper soon so I can focus on body work and paint but with the tank riding in the bed it's looking a little too hillbilly even for me.


Do you have a filter before the electric pump?
Yes, an inline filter with a glass housing so you can see the rust build up and empty/change it when it gets full.

What is the pump rating? You need a low 3-5 psi pump.
It's a Carter pump for a civi ford or chevy truck that someone recommended here.

What happened to the mechanical pump? Are the lines still plumbed through it or has it been removed and a block off plate installed?
I left it in and disconnected/blocked off the lines a couple years ago when I installed the electric pump so it's not really doing much right now. Didn't know about the block off plate until you mentioned it. Ya think that leaving it in might mess with performance?

Is your return line hooked to the tank?
Yes. Hopefully it's draining fast enough.

Is the fuel cap venting properly?
I don't think so. Had a pretty good vacuum going on it the other day so I opened the line that goes to the second tank and if you listen close you can hear it gurgling when the pump is switched on.

 

[beetleswamp]

update

Installed the napa 4309 and 3123 filter and wow it pumps a LOT more volume than the oe box. Was working great for about 15 min until I stopped by the liquor store for a cigar and when I came back out and tried to fire it up no dice and clear in-line filter between new spin-on and the ip was dry.

Made my way back to the house and it died 2x on the way. I'm gonna be known in the neighborhood as broke-down-truck-man pretty soon.

tried a test to isolate the bubbles:
Plugged a clear glass in-line filter to the hose just before the new spin-on, turned on the electric pump, and a few bubbles were coming up kind of regular. Put that back together and then put the clear filter on the OUT side of the electric pump and no bubbles, so it looks like the leak is somewhere in between the electric pump and the spin-on. Will probably run a new hose in between them next.

Have no idea how it could suck in air on the pressure side of the pump. The pump is allowing some fuel to flow backwards to the tank so might have to change that soon anyway. This has become quite the saga. Good thing it happened when work was slow.

 

[nk14zp]

Have you checked the glass check valve on the IP?

 

[beetleswamp]

Didn't even know that existed. Will look it up right now.

 

[nk14zp]

Steel Soldiers::Military Vehicles Supersite - Search Results

 

[epitts]

Try this link
http://www.steelsoldiers.com/cucv/47346-so-i-cleaned-ip-valve-fuel-return-line.html

 

[Bob USNR]

A quick and easy method to find fuel delivery problems, in any vehicle, is to connect a pressure gauge to the fuel line that connects to the IP after any other gadgets/filters ect, in the fuel system.

1) If your fuel pressure >at the pump< is adequate during the problematic event the cause is not a supply pump or filter, it is inside the IP.

2) Also obvious is if the fuel system pressure, at the pump, goes to zero, or less, just as the problem "presents itself" there is a problem before the point where you connected the pressure gauge.

I believe that engine has the Roosa Master IP. It is not a "field serviceable" assembly. On the other hand, being an older one, a rebuilt one will probably not cost as much as some of the newer ones. If replacement of the pump appears necessary that is the time to inquire about "more power"!

On the "bubbles" issue, the fuel system is designed to purge more air bubbles than most people think, with no apparent symptoms at all. This is the reason there is a "return line."
Some people believe "ANY bubbles, at all, are big trouble". That is not the case on any diesels.

Personally I have over 25 years "under the hood" I was never "paid by the hour". When you are paid by the hour you can mess around with a single vehicle for 3 days and you still get paid the same. When you work "flat rate", as I did, you have to have methods that take you directly the problem because you get paid for the repair but not your time wasted trying to find simple problems.

FYI. When I worked for a FORD dealership they liked us to diagnose for hours because they could bill the customer (you!) all that "labor" time. I was once told "create a reason to bill each vehicle $450.00 or more... (approx 199 or you will be fired". I left shortly thereafter.

I had a customer's 1984 Ford sedan that displayed a similar failure to what you seem to be having. He had replaced the tank because it had rusted out. It ran beautifully... as long as you didn't try to drive it. The more it moved on the road the quicker it stalled. The owner had not cleaned the rust off the sender and pump assy inside the tank. The resulting powered rust particles clogged the "sock" when you tried to drive it. When the ignition was turned off the particles dropped out of the sock and all seemed ok again.
e

 

[SmokeyDod]

Just curious, what did you do in "cleaned the tank"?

 

[beetleswamp]

I dropped the tank, sucked out the fuel to a couple jerry cans with a drill pump, washed out the inside with water, put in some chain and shook it around, washed it out again, put a pint of denatured alcohol in and swished it around, let it sit in the sun for a bit, stuck my paw in the hole and mopped up the alcohol on the bottom and it was looking pretty nice in there. there was a bit of rust and water on the bottom for sure


update

Popped the glass ip return check valve cherry and man what a difference. I tried cleaning it at first and was able to blow a little air through, but still seemed super restrictive and I'm pretty sure a new IP is not too far away in my future.

Drove down the street and truck died. Checked hoses and nothing was coming out cause I wasn't paying attention and ran it out of gas. So I was stuck on the side of the road for a bit cracking the injectors and bleeding the air out, and once that was done I bombed around the neighborhood and loving the new found power. Got on the highway for a bit and so stoked to find that it had acceleration going up hill which is an issue I've had for over a year now.

Got almost all the way home and it died again all random. I think the fuel was still kind of low and it got more bubbles in there. I'm wondering if the tank screen keeps it from sucking big chunks of air when the fuel sloshes around.

Another thing I noticed is there is vacuum building in the tank. I sprayed some carb cleaner on the gas cap to clean the vents and some brown stuff came out but it was still making suction after that. The middle line on the sending unit has a short piece of hose on it and you can hear very clear gurgling where it's pulling in air.

I guess I'm going to keep driving around and see if I can get it to stall again. Hopefully that's it and I can put the tank back to the frame rails and start working on the other long overdue maintenance stuff.

 

[beetleswamp]

I believe that engine has the Roosa Master IP. It is not a "field serviceable" assembly. On the other hand, being an older one, a rebuilt one will probably not cost as much as some of the newer ones. If replacement of the pump appears necessary that is the time to inquire about "more power"!
e

Thanks for your suggestions. I am really interested in this power that you speak of. Also looking for an IP that would be more compatible with vegetable oil, since I will try that route again once I'm done catching up with the maintenance. Are you talking about the DB2?

 

[beetleswamp]

Had a date tonight and took her to a party which was fortunately not too far away. Engine started cutting out after about 5 minutes on the highway but fired right back up again after waiting a couple minutes. This happened like 3 times. After I dropped her off at home I limped to a parking lot and saw the in-line filter that is replacing the tank screen was kind of gunky so swapped the element and it fired right up and made it home no prob. Looks like it's time to hook up the pressure gauge to see what's really going on.


With the glass ball gone this thing runs noticeably louder, especially the marbles in a can part of the sound. It gets more muffled when it's about to die.

Also some of the particles that were clogging the filter were translucent. May be time to drop in a little biocide just in case.

 

[Armada]

Sounds like you need to keep more fuel in the tank.
One important thing you need to do to keep from pulling air into the fuel line, is that you need to put the sender inlet 'sock' back on. Along with stopping debri from getting ingested, up their main function is to wick the fuel. Once the sock is saturated with fuel you can slosh fuel around, as in an almost empty tank, and air will not be pulled in through it. It 'seals' with fuel and acts as a sponge.
Not that you would be effected by this because of your location, but there is also a 'wax ring' feature on the sock which is a small patch with a larger micron rating. It becomes important in colder regions where low temps will bring the fuel down to it's cloud point and it will begin 'waxing'. Think of it as water becoming slushy just before freezing solid. The larger micron rating of the wax ring will allow the 'slushy' fuel to still be wicked through the inlet sock whereas the smaller micron rating/tighter mesh portion of the sock will begin to plug and restrict flow.
Sooo, that is why it is important to have the fuel sender inlet sock/filter installed.

Try driving with your fuel cap loosened and see if that doesn't help. If so, get yourself a new cap.
Good luck.

 

[beetleswamp]

Sounds good to me. Will reinstall in the am.

Filled up the tank and noticed that it slid back in the bed a bit while I was *cough* enjoying the performance gains, and as a result the return was pinched. Saw a friend at the bus stop and gave him a ride home across town tonight to see if it would die and made the round trip without issue.

I know my ip is about to bite it but still have a smile on my face. Highway test tomorrow.

update 2.22.11
hopefully editing this post won't bump it back to the top but wanted to say this issue was solved thanks to you guys. Haven't replaced the screen yet as the glass in-line filter is actually a great way of sucking junk out of the tank. Cleaned it a couple of times after stalling probs but now she's running beautiful and has plenty more power. Will replace screen and put the tank under the bed again sometime this week. Thanks so much for all your help. Now I can get back to the 'fun' maintenance. Mahalo!