Fuel problem puzzle

The place to discuss problems and routine maintenance questions and tips. This is for topics that are specifically diesel-related.
User avatar
science
Regular Member
Posts: 158
Joined: Mon Oct 24, 2011 4:22 pm
Location: Greensboro, NC

Fuel problem puzzle

Postby science » Sun Feb 10, 2019 2:05 pm

Hey folks,
I'm troubleshooting a problem with one of my pup's (this has been the winter of problems, first the entire coolant system, then the brake system, now the fuel system).

When starting early in the morning the truck will start and run, but at the 1st stop sign (about 0.5 mile) the truck will idle super low and die. I have to come to stops while keeps the rpm's up. When going again the truck will have poor power and act as if the clutch isn't fully engaged or is starved for fuel.

The problem is getting worse but at first I narrowed down the problem to (a) fuel system or (b) clutch problem.

I've eliminated the idea of a clutch problem because the problem goes away once the engine warms.

Moving ahead with the fuel system problem, I've checked lines and replaced the fuel filter. I always use a diesel additive for lubrication (sans sulpher diesel) The problem persists and is worse in colder temps.

I'm thinking it's a failing IP. Has anyone else had this issue?
1981 Chevy Luv 2.2L Diesel -- on grease
1982 Isuzu P'up 2.2L Diesel

User avatar
puttputtinpup
Regular Member
Posts: 10544
Joined: Sat Oct 08, 2005 5:18 am
Location: Winston Salem, NC

Re: Fuel problem puzzle

Postby puttputtinpup » Sun Feb 10, 2019 2:21 pm

I was gonna suggest fuel filter but i see you already covered that. The white pup and my Imark both did that on me once when I had been buying bad fuel from a place in Virginia. I had a lot of water in my filters and the low temps that winter turned it into a slush.

Perhaps the screens in the banjo bolts (input and return) need cleaning?. See the link in my signature for copies of the TSBs for this.

User avatar
science
Regular Member
Posts: 158
Joined: Mon Oct 24, 2011 4:22 pm
Location: Greensboro, NC

Re: Fuel problem puzzle

Postby science » Sun Feb 10, 2019 2:25 pm

Great idea. Also a good idea to change up fuel sources. I'll try it, it'll be easier than the IP!
1981 Chevy Luv 2.2L Diesel -- on grease
1982 Isuzu P'up 2.2L Diesel

User avatar
puttputtinpup
Regular Member
Posts: 10544
Joined: Sat Oct 08, 2005 5:18 am
Location: Winston Salem, NC

Re: Fuel problem puzzle

Postby puttputtinpup » Sun Feb 10, 2019 2:34 pm

science wrote:Great idea. Also a good idea to change up fuel sources. I'll try it, it'll be easier than the IP!

We're talking about the Luv here, right?

dorf
Regular Member
Posts: 353
Joined: Sun Jul 17, 2011 1:03 pm
Location: N. Central Arkansas 81 LUV 4x4

Re: Fuel problem puzzle

Postby dorf » Sun Feb 10, 2019 2:47 pm

Fuel hoses sucking air....worn out fuel hoses....bad clamps.......all of the above

Plus leaking fuel filter water seperator o ring on filter bottom

User avatar
Halden
Regular Member
Posts: 2776
Joined: Thu Mar 29, 2012 5:20 pm
Location: Everertt, WA
Isuzu vehicle(s): 1983 Diesel LS Long Bed 4x4

Re: Fuel problem puzzle

Postby Halden » Sun Feb 10, 2019 3:28 pm

I second Andy. You probably have slush/ice in your filter. Your problem sounds just like one I had years ago except it didn't go away when warmed up. My system was completely gummed up with rust and junk. Did you check your filter when you changed it? Dump the contents into a jar and take a look.

Unless you are located where it's cold enough for fuel to gel ditch the additive. Your pump is going to be just fine so long as it has good clean fuel... If this ULS fuel was a problem thousands of trucks would have been stranded at the dawn of ULSD...

Also. Which truck is this problem on? The truck on grease?
It's not pronounced "Ih-soo-zoo", it's pronounced "It-screws-you"
83 LS Long Bed Diesel
64 Chevy C20 w/ 283 & 4 speed.
05 Sonata with a standard
At work: 2000 Blue Bird TC2000 w/ 5.9

User avatar
science
Regular Member
Posts: 158
Joined: Mon Oct 24, 2011 4:22 pm
Location: Greensboro, NC

Re: Fuel problem puzzle

Postby science » Sun Feb 10, 2019 6:46 pm

puttputtinpup wrote:
science wrote:Great idea. Also a good idea to change up fuel sources. I'll try it, it'll be easier than the IP!

We're talking about the Luv here, right?


No it's the PUP
1981 Chevy Luv 2.2L Diesel -- on grease
1982 Isuzu P'up 2.2L Diesel

User avatar
science
Regular Member
Posts: 158
Joined: Mon Oct 24, 2011 4:22 pm
Location: Greensboro, NC

Re: Fuel problem puzzle

Postby science » Sun Feb 10, 2019 6:51 pm

Halden wrote:I second Andy. You probably have slush/ice in your filter. Your problem sounds just like one I had years ago except it didn't go away when warmed up. My system was completely gummed up with rust and junk. Did you check your filter when you changed it? Dump the contents into a jar and take a look.

Unless you are located where it's cold enough for fuel to gel ditch the additive. Your pump is going to be just fine so long as it has good clean fuel... If this ULS fuel was a problem thousands of trucks would have been stranded at the dawn of ULSD...

Also. Which truck is this problem on? The truck on grease?


Good idea. The old filter was done, element looked black. But the fuel I dumped out of if didn't look horrible.

The additive is for fuel lubricity. In '82 diesel still had sulpher in it, which acts like a lubricant. I'd prefer to use a little biodiesel but I haven't been able to find any around the Piedmont of NC. Thus I use lucas diesel additive. It's not needed for gelling.

The truck in question does not have a grease system on it, it's puttputtingputt's old truck.
1981 Chevy Luv 2.2L Diesel -- on grease
1982 Isuzu P'up 2.2L Diesel

User avatar
Halden
Regular Member
Posts: 2776
Joined: Thu Mar 29, 2012 5:20 pm
Location: Everertt, WA
Isuzu vehicle(s): 1983 Diesel LS Long Bed 4x4

Re: Fuel problem puzzle

Postby Halden » Mon Feb 11, 2019 12:45 am

Unless what you dumped out of the filter looks like what you put in, it might be worth draining the tank and seeing what comes out. Of course if you have a full tank this is easier said than done. And if you can shine a light in the tank once empty and see if you can get a glimpse. Seeing in a crusties or schmoo?

As far as a fuel additives... Diesel sold in the US has to meet certain requirements which is done through testing. They have to meet standards from the ASTM and blah blah...Additives are put in the fuel before it gets to a fuel station in order to become more slippery after being hydrodesulfurized... That's the last I'll touch on that. I've put my two cents in. Not sure if I am off my high horse yet or not... :roll: hehheh really I'm just trying to save you money. But you're not using two stroke oil which is a step in the right direction!!
It's not pronounced "Ih-soo-zoo", it's pronounced "It-screws-you"
83 LS Long Bed Diesel
64 Chevy C20 w/ 283 & 4 speed.
05 Sonata with a standard
At work: 2000 Blue Bird TC2000 w/ 5.9

User avatar
puttputtinpup
Regular Member
Posts: 10544
Joined: Sat Oct 08, 2005 5:18 am
Location: Winston Salem, NC

Re: Fuel problem puzzle

Postby puttputtinpup » Mon Feb 11, 2019 6:16 am

After cleaning out the banjo bolt screens and pinholes, I'd take the fuel cutoff solenoid out and be sure it's not gummed up, possibly not opening all the way.?.?
I'd probably take both fuel lines loose from the firewall and blow back to the tank (w fuel cap off) and make sure there's no obstrution.

I changed those fuel lines some years ago, but wouldn't running any biodiesel through them degrade the rubber? I never ran that stuff in it, but some suggest using Viton hoses for that...right?

There is a big plug inbthe bottom of the tank that you could put a pan under and drain off whatever water and sludge might be in there. Might get messy though.

User avatar
science
Regular Member
Posts: 158
Joined: Mon Oct 24, 2011 4:22 pm
Location: Greensboro, NC

Re: Fuel problem puzzle

Postby science » Mon Feb 11, 2019 9:29 am

Halden wrote:Not sure if I am off my high horse yet or not... :roll: hehheh really I'm just trying to save you money. But you're not using two stroke oil which is a step in the right direction!!


Haha, I understand!
1981 Chevy Luv 2.2L Diesel -- on grease
1982 Isuzu P'up 2.2L Diesel

User avatar
science
Regular Member
Posts: 158
Joined: Mon Oct 24, 2011 4:22 pm
Location: Greensboro, NC

Re: Fuel problem puzzle

Postby science » Mon Feb 11, 2019 9:32 am

puttputtinpup wrote:After cleaning out the banjo bolt screens and pinholes, I'd take the fuel cutoff solenoid out and be sure it's not gummed up, possibly not opening all the way.?.?
I'd probably take both fuel lines loose from the firewall and blow back to the tank (w fuel cap off) and make sure there's no obstrution.

I changed those fuel lines some years ago, but wouldn't running any biodiesel through them degrade the rubber? I never ran that stuff in it, but some suggest using Viton hoses for that...right?

There is a big plug inbthe bottom of the tank that you could put a pan under and drain off whatever water and sludge might be in there. Might get messy though.


BIodiesel doesn't degrade the soft fuel lines that are sold these days. It mainly dissolves natural rubber lines found in older vehicles. Anywho, I've never found any bio while I've had this truck, so it's never seen it.

I understand what you're saying about gumming, however I can drive from GSO to W-S, going 60 or 65 the whole way, with no problems. When I come to a stop at the exit ramp, the idle gets low and the engine acts starved for fuel.
1981 Chevy Luv 2.2L Diesel -- on grease
1982 Isuzu P'up 2.2L Diesel

User avatar
puttputtinpup
Regular Member
Posts: 10544
Joined: Sat Oct 08, 2005 5:18 am
Location: Winston Salem, NC

Re: Fuel problem puzzle

Postby puttputtinpup » Mon Feb 11, 2019 2:31 pm

Oh, okay. I though it wouldn't stay running at all. Then check the idle stop bolt on the injector pump and see if it got loose and backed off. Should be a 10mm head bolt w a jam nut on it. If it gone, (hope not) swipe one off one of the other pumps. It used to idle a bit low in the winter anyway til it warmed up.

User avatar
science
Regular Member
Posts: 158
Joined: Mon Oct 24, 2011 4:22 pm
Location: Greensboro, NC

Re: Fuel problem puzzle

Postby science » Mon Feb 11, 2019 5:04 pm

puttputtinpup wrote:Then check the idle stop bolt on the injector pump and see if it got loose and backed off.


Idle bolt is there, and good and tight. I'm going to do a little more diagnosing but I'll let ya'll know if I learn anything. Thanks!
1981 Chevy Luv 2.2L Diesel -- on grease
1982 Isuzu P'up 2.2L Diesel

User avatar
Halden
Regular Member
Posts: 2776
Joined: Thu Mar 29, 2012 5:20 pm
Location: Everertt, WA
Isuzu vehicle(s): 1983 Diesel LS Long Bed 4x4

Re: Fuel problem puzzle

Postby Halden » Wed Feb 13, 2019 10:13 am

science wrote:I'm going to do a little more diagnosing but I'll let ya'll know if I learn anything


Please keep us posted, once the issue is diagnosed/fixed. It's a great reference for if the issue pops up for someone else.
It's not pronounced "Ih-soo-zoo", it's pronounced "It-screws-you"
83 LS Long Bed Diesel
64 Chevy C20 w/ 283 & 4 speed.
05 Sonata with a standard
At work: 2000 Blue Bird TC2000 w/ 5.9