Another fuel issue

Duckworthe

Member
329
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San Diego, Ca
Ok so my truck runs like a top. I check everything over before every start up. This engine fires up fast every time. Now for the fueling issue......I had an issue back about 4 months ago where I started the truck and it stumbled and stalled. Acted like there was air in the line. I primed the system and built up pressure and restarted the truck. It sputtered some then came up to idle and ran great. I found that after letting truck sit for about 12 hours or more it would act like this. I prime the bulb and it is soft. I keep pushing it and it gets hard. If I keep pushing it I can hear the fuel returning to the tank. So about 2 months ago I replaced the fuel lines and the Racor primer/fuel/water housing with a new unit. I get the truck running and drive it around and all is good. The next day I start the truck and same story, sputtering and primer soft. I end up replacing the primer housing again and also refab new lines with better fittings just to make sure that isn't the issue. I used quality fittings and parker push-lock hose. so I know I don't have a bad fuel line. I called Racor tech line and talk to them. Their story is this, quote "The primer housing is new but could be sitting on the shelf for 10 years as we don't really sell these to often. We recommend anyone with the 3116 to place a check valve in line at the tank." end quote. Ok... so I don't think I have two bad primer housings but do put in the check valve. get the truck running and then leave the truck non running for about 2 months. Now it is time to go to the Expo. I start the truck and get sputter but no stall and then prime the line while it is running and it comes to idle and runs great. I should add here that when it is stumbling it also has white smoke out exhaust until it comes to idle. It takes about 2 min for the truck to come to a clean strong idle. Now for some back ground info- I can turn the truck off for anywhere from an hour to 6 hours and it fires right up, I don't know the precise time it takes for it to have the issue, basically just over night or 12 hours. I checked the oil and there is no Antifreeze in it. I check the exhaust and it doesn't smell like antifreeze or is wet.

Now to yesterday. I take the truck to a shop and ask them to check it out as I just don't have the time and want it fixed. They tell me that they found the issue. Quote "the issue is that the injectors have copper seals under them and they need to be replaced because the cylinder pressure is blowing back up the line and pushing the fuel back through the system. This requires the head be removed and machined. We can't do the work because we don't have the tools to do the 3116. The tools are about $2000. dollars." end quote. I told them that once it gets to idle it isn't acting like it has fuel issues. I don't understand that. Wouldn't it have fuel issues while running also? I am going to pick it up today and take it home. I know that those copper seals can be an issue but I really don't think it is MY issue here.

Here is my next step, I will get some fittings and hook a vacuum pump to the lines from the tank forward and see if I loose pressure over time. Next- hook fuel pump in line and pressure the system and look for leaks and also see if a lift pump makes the issue go away. I am open to any and all suggestions here. I don't have an issue paying for a repair if that's what it needs, but I don't think this is a pull the engine apart repair at this point. feel free to give me a text or call if you have thoughts on this and I will also check here throughout the day.
Thank you,
Eric 619-952-4337
 

Suprman

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You can check and make sure your fuel tank vent isnt clogged. I havent seen an issue like you describe but the shops diagnosis sounds a bit odd to me. The 3116 injectors sit in a cup that has a coolant channel around the sides. If the cup wasnt seated properly and you would see combustion pressure, and some coolant blown up along with it, in the valve train. Seen that. Cant fix it because it takes 2000 dollars worth of cat tools and someone who knows how to do it though. If it was a cummins I could make the tool with a bolt and socket.
 

Duckworthe

Member
329
12
18
Location
San Diego, Ca
Update- I picked up the truck yesterday from the shop that I chose to trouble shoot it. Here is the quote of the issues that they described that was wrong with the truck. Quote "checked fuel system and found compression in return side of fuel system, possible bad o rings or split injector copper." end quote. They told me they couldn't do the repair as they didn't have the tools any longer. I asked them how they tested the system and they said that they put a pressure gauge in the return line and a sight glass. look for air and pressure on the gauge. I left wondering if it really was this and stopped buy other shops and they said , because it runs fine all times besides after sitting over night they all doubted that it was the copper seats that the injectors sit in. As I have no coolant in my oil or fuel in my oil. Now as for the o rings.....could they be dried out? sure! this thing sat for years. The other possibility is that I have an injector sticking and it is dripping fuel into the cylinder. Once it gets through the excess fuel in the cylinder it cleans up and runs fine. Could explain the white smoke after sitting over night at start up. Again, it has full power, no stumbles, no black or white smoke when it gets up to idle and when in any driving situation. They all recommended this option- 1. get truck up to operating temp. shut off and remove the spin on fuel filter. pour dye into the filter and reinstall and run engine for about 3 minutes. Shut off engine and remove the valve cover. With black light look at each injector and see if any dye is visible around the injectors. If so that is the one/ ones that are the problem. They don't think I am having an air leak, they think the line pressure is down because the fuel is either leaking into the cylinder or around the injector. While the dye is in the fuel, it will go through the whole system and you can also check all of the hoses and fittings after. As far as the copper cups are concerned, all the other shops think that is a far off chance of an issue. What I was told it takes the following- it is better to remove the head, disassemble the head and remove all the injectors and rack. Remove the copper cups and ream the ports where the copper cups go. Replace with new coppers and reinstall the components. Finish by reinstalling the head and test. Some say you can do it with the head on but you risk shavings into the cylinders. I also want to make sure that everyone knows that my water fuel separator is always full of fuel. Some of the questions were if the filter was being sucked dry after sitting. Mine does not have that issue.
Here is my plan- 1. take the weekend off to go Overlanding in the FJ80. 2. When I get back Tuesday and after work start this whole process! I want to thank everyone who called and replied to this issue. I will keep you all in the loop as to the progress and the outcome as I move forward. I have found that I am not the only one dealing with this issue here. I have also found out that not a lot of shops have the tools to work on the 3116 anymore. I located the one guy in Santee Ca. by pure luck and word of mouth. If I need them, and they also do a good job I will share the name. But I don't really know if they are good or bad at this point.
Have a great weekend!
Eric 619-952-4337
 

coachgeo

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That’s what I would think also!
where is the fuel pump on the 3116? is fuel all pulled from tank via suction from the IP? Sounds like strategic placement(s) of pint can with fuel+ die ... might can help diagnose if one makes sure the die is fully clear of things before trying a different place for pint can to feed things.

Hows your oil level? does it smell diesel-ly? Maybe send a sample of oil to blackstone ?
 

Awesomeness

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Are the sputtering and white smoke related to the losing prime? Both my 3116's sputter and white smoke some when I start, but don't lose prime.
 

scottmandu

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Texas
where is the fuel pump on the 3116? is fuel all pulled from tank via suction from the IP? Sounds like strategic placement(s) of pint can with fuel+ die ... might can help diagnose if one makes sure the die is fully clear of things before trying a different place for pint can to feed things.
Fuel is pulled from the tank by the pump/governor assembly. The 3116 doesn't have a typical injection pump, each injector is it's own pump.
 

Bigoutfit

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I am no expert, but this situation sounds similar to my 1998 M1078. It would barely start, sputter, smoke and miss fire then clear up then run fine, until it would sit for a few hours , then it would repeat the symptoms. After reading everything I could find on this site and other sites I finally ran across a video from a company called Hot Shot's Secrets Stiction Eliminator. (I have no affiliation). Their product is designed to lubricate the injectors and eliminate "Stiction" which causes the injector to continue to drip fuel after shut off and cause a "air in the lines effect" I found it at our local Napa and tried it and sure enough it stopped the issue in a few hours of driving. I no longer have the problem( 8 months so far) I recently spoke to a local Cat service tech who is highly regarded and he has a 50 gallon barrel of their product and uses it for that problem all of the time. I Hope this helps. here is their site: www.hotshotsecret.com
 
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Duckworthe

Member
329
12
18
Location
San Diego, Ca
Just a quick update on my fuel issue. I talked to many on the forum about my issue and possible concerns and fixes. Well here is what I am trying before opening the engine. I decided to take the "snake oil" route first. I know, I know, these never work! But wait.....has this one actually worked?! I used a product called "Hot Shot Secret", from here on I will call it (HSS). in my oil and my fuel system. it was recommended by someone here on the forum. It says that it "Fixes 9 out of 10 injectors". I changed my oil and there wasn't a smell of Diesel in it, (No I didn't send it of for analysis). So I put my new oil in and the correct amount of HSS. I then put in the HSS Fuel additive. I primed the fuel and pushed it through the fuel system and heard it returning to the fuel tank. I started the truck and let it run for a bit and then shut it down. It was hard to start and once running it seemed fine as always. I went back yesterday and started the truck. It fired up and had no issues even after sitting over night. No white smoke and only a little stumble! I then drove it about 16 miles total and shut it off. I will go back out tomorrow and try again to see if it is actually better. But I think at this point it might be better. I am cautiously optimistic. After I get back out to it, I will report the finding. Side note- I put HSS fuel treatment in my other hauler that has 3126 as it had a slight "miss" when driving it every now and then. We drove it out to the races pulling the car hauler and it didn't seem have the miss anymore. Again, I will wait to tell you its all fixed, As that is not confirmed yet in my eyes. Time will tell. Update to follow.
Eric
 

Pointman0853

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Eric,

I've had few fuel issues lately as well, after my solenoid replacement and now running it empty. My studies of the 3116 CAT fuel system indicate a few check valves, that if clogged or stuck open could possibly cause the loss of prime problem.

I plan to go at mine again this afternoon. I will also try some HSS just in case I have something stuck as well. I also plan to pull the little screen on the pump intake and make sure there isn't some funk stuck in there just as a precaution.

Finger crossed...

Pointman
 

Pointman0853

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Gardnerville, NV
Not to hijack Eric's thread, but will put this here in the hopes it may help someone in a similar situation:

So... after further attempts to prime my fuel system and start the truck, I gave up and removed the Fuel/Water separator and found this..

Separator bowl 060518.jpg

A fairly large amount of aluminum metal shavings in the bowl. Based on the fact that the system will not prime, I will assume the pump is toast. I found a new one and a filter online for less than $50.00 US, so they are on their way. Hopefully this will solve the problem. It may be that this was not caused by running the tank low as I found a loose fitting on the pump housing from the tank indicating it may have been sucking air. This fitting could have been left loose as we were diagnosing the solenoid problem down in Alamo on the OE18 trip. All the exercise the pump has gotten in the last month could have killed it and the shavings are just a symptom of this part being 'shot'.

Pointman
 

Awesomeness

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I will assume the pump is toast. I found a new one and a filter online for less than $50.00 US, so they are on their way. ... I found a loose fitting on the pump housing from the tank indicating it may have been sucking air.
What fuel pump are you talking about? These trucks don't really have a fuel pump in the conventional sense of the term. Fuel come up out of the tank, through the governor, and into the injectors... that's it (besides the filter and water separator).
 

Pointman0853

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Awesomeness,

Sorry If I was not clear on this. In the 3116, fuel comes up from the tank to the Fuel/Water separator on its way to the governor. The bracket which holds the spin-on filter and drain bowl includes a 'hand pump' for priming the system.

The part, as described on the popular on-line auction site, is "Base 3/8" NPT 1-14" Spin On Mount Hand Priming Pump Diesel Fuel Filter Mounting".

Priming pump.jpg

Pointman
[FONT=&quot]Base 3/8" NPT 1-14" Spin On Mount Hand Priming Pump Diesel Fuel Filter Mounting[/FONT]
 
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