Occasional Engine surge

[RS Disposal]

2 hours ago, Freightrain said:

15# is about right.

I was having power issues years back and found my lift pump was failing.  I mounted a fuel pressure gauge out on the air cleaner so I could watch it while driving.  It would rise and fall.  Replaced pump and was a solid 15#.  

If you don't have a liquid filled gauge it will flutter due to check valves in the pump.  A liquid filled gauge will dampen the bouncing needle some.

The lift pump is where the plastic check valves are at that was mentioned to check by Terry.

truck seems to run fine around town but when I am climbing the canyon occasionally it will start to miss (more than just loosing power) and I would have to pull over and let it idle for a bit.  Then I could start back up again.  I do understand about a liquid filled gauge, but would think the gauge attached after the secondary filter would mellow the fluttering a bit.  I did notice a couple of times that the gauge did drop to zero for several seconds.  I did pull the plastic check valves and they did look ok, but don't have new to compare against.  Truck only has about 160,000 road miles (not sure about motor miles being there is a pto running a packer) but then again it is 47 yrs old and sat for about 20 yrs before being put back into service about 8 yrs ago.  Truck only really works part time anyway, but I do know stuff breakdown with age alone

[fjh]

14 hours ago, RS Disposal said:

truck seems to run fine around town but when I am climbing the canyon occasionally it will start to miss (more than just loosing power) and I would have to pull over and let it idle for a bit.  Then I could start back up again.  I do understand about a liquid filled gauge, but would think the gauge attached after the secondary filter would mellow the fluttering a bit.  I did notice a couple of times that the gauge did drop to zero for several seconds.  I did pull the plastic check valves and they did look ok, but don't have new to compare against.  Truck only has about 160,000 road miles (not sure about motor miles being there is a pto running a packer) but then again it is 47 yrs old and sat for about 20 yrs before being put back into service about 8 yrs ago.  Truck only really works part time anyway, but I do know stuff breakdown with age alone

Have you checked the tank vent?  And You can actually take the Drainback tee apart and stretch the spring to raise the pressure some 20 25 psi won't  hurt anything!  

[RS Disposal]

14 minutes ago, fjh said:

Have you checked the tank vent?  And You can actually take the Drainback tee apart and stretch the spring to raise the pressure some 20 25 psi won't  hurt anything!  

haven't actually checked the vent it self, but I did try running with the fuel cap loose. I will try the drain back tee and see if it makes any difference. Being a one man show with only one truck and this being my busy season and truck having to also work while I try to figure this out makes for some long frustrating days

[Geoff Weeks]

I had my truck have somewhat similar problem. It was the suction line from the tank to the pump. On hard pull it would draw in enough air to cause a problem, lighter work, it would tolerate the little air just fine. A new hose and the problem was fixed. 

Just something that is easy enough to try, and given the state of the other hoses on the truck, I would say is a good bet. Stratoflex etc hoses don't last forever.

[RS Disposal]

5 hours ago, Geoff Weeks said:

I had my truck have somewhat similar problem. It was the suction line from the tank to the pump. On hard pull it would draw in enough air to cause a problem, lighter work, it would tolerate the little air just fine. A new hose and the problem was fixed. 

Just something that is easy enough to try, and given the state of the other hoses on the truck, I would say is a good bet. Stratoflex etc hoses don't last forever.

thats the last hose i have to replace. Would of done this weekend but my hose place is closed on weekends and truck has to go to work tonite. It's hard to work on equipment that also has to work every day. 

 

[cruiseliner64]

59 minutes ago, RS Disposal said:

thats the last hose i have to replace. Would of done this weekend but my hose place is closed on weekends and truck has to go to work tonite. It's hard to work on equipment that also has to work every day. 

 

Feel for you bro.Mines just a hobby truck.Wish you the best...

Paul

[Geoff Weeks]

1 hour ago, RS Disposal said:

thats the last hose i have to replace. Would of done this weekend but my hose place is closed on weekends and truck has to go to work tonite. It's hard to work on equipment that also has to work every day. 

 

Just a warning, mine went from just a little problem to not being able to pull a load in less than a day. One of the 2 times in my whole time owning trucks, that mine was on "the hook".  The other was when the fuel pump "self destructed" Running just fine one moment, and dead the next. 

Got to go, can mean not making it plus a tow bill. Better to delay a partial day to address the problem, then loose 2 days when it shuts down and has to be towed in. Just a little hard won experience. Not only do you have the repair bill but you have the tow bill as well. 

[RS Disposal]

On 1/18/2026 at 4:50 PM, Geoff Weeks said:

Just a warning, mine went from just a little problem to not being able to pull a load in less than a day. One of the 2 times in my whole time owning trucks, that mine was on "the hook".  The other was when the fuel pump "self destructed" Running just fine one moment, and dead the next. 

Got to go, can mean not making it plus a tow bill. Better to delay a partial day to address the problem, then loose 2 days when it shuts down and has to be towed in. Just a little hard won experience. Not only do you have the repair bill but you have the tow bill as well. 

I totally understand your comment.  My problem about truck not running is it is a garbage truck and I service a ski resort town which in the ski season is extremely busy particularly on holidays.  non of my accounts have the space to miss a pickup day which is 4 or 5 times a week.

[Geoff Weeks]

No matter how you look at it, a planned down time will be less then a forced down time, and a whole lot cheaper too. 

Measure the hose before the truck goes out, while the truck is out have a shop make one.  Most likely will be -10 hose and fittings, but check 1st. A bit more money then buying bulk hose and reusing the reuseable fittings, but still a whole lot cheaper then being pull  in on the hook. 

 

[RS Disposal]

On 1/18/2026 at 9:52 AM, Geoff Weeks said:

I had my truck have somewhat similar problem. It was the suction line from the tank to the pump. On hard pull it would draw in enough air to cause a problem, lighter work, it would tolerate the little air just fine. A new hose and the problem was fixed. 

Just something that is easy enough to try, and given the state of the other hoses on the truck, I would say is a good bet. Stratoflex etc hoses don't last forever.

Being that the tank to primary filter hose is the last one needing replaced I decided to try a wild hair idea.  I spliced in an inline fuel pump (being the line was going to be replaced anyway so no concerns about cutting it) and powered it off a keyed accessory circuit. Powered it on and had about 20 psi at the injector pump. Started the truck and let it run for a bit watchin the fuel gauge to see if having the lift pump still in line (if indeed the pump is bad) would have any adverse effect on the fuel pressure.  Being it was a work day I had to climb canyon I decided WTH and give it a try being after about 15 minutes of fast idle the pressure seemed to stay about the same.  Climbed the canyon with no problems at all.  I do believe I felt there was a bit more power available, I did notice that the boost pressure was a little higher and the the pyrometer was a little higher (neither was crazy high). Correct me if I am wrong, but my thinking those factors would mean the engine was getting better fuel flow.

[Geoff Weeks]

Well it does seam to confirm that the suction line is the problem. It isn't a long time cure to a hose that is coming apart. I don't understand how you had the time to rig this up but don't have the time to replace the hose? 

I have been in your shoes running a single truck and trying to keep it running and my customers happy.

Am I to take it, by your statement that this was "the last hose" to be replaced, that you have addressed the other air lines?  I doubt it is the "last hose" as there are so many on a truck. Did changing out the air hoses solve your drier problem?

 I started stockpiling hose and fittings at my shop. I also got a parts truck that I could rob parts off of, either to use or to send off as cores for rebuild while my money make was still running. I am thinking things like a P/S box that required to be re machined for a seal to hold. 

If you are going to run a single truck, you HAVE to be proactive with maintenance. The guy that picks up garbage, showed up in a different truck one day, I asked if he bought a new one, he said no, it was a rental while his was in the shop. I didn't know you could rent them, but I guess around here you can. Another possibility is if you know a "competitor" who will not "stab you in the back" that could cover a pick-up for you while you do a repair. I know, this takes a lot of trust, but there are people who will help out as long as you will when they need it.

 

Running an old truck as a single operator is difficult, Often it can mean being one big breakdown from loosing it all. that is why it is so important not to have multiple small breakdowns that could be prevented. Most customers will understand that everything breaks at some point. As long as it isn't common, they will live with a temp interruption in service.

I carried brake diaphragms, various hoses, filters, throttle return springs, etc so most minor failures could be repaired right where and when they happened.

Many small business fail when they failed to plan on a breakdown. A parts truck can be a true windfall of parts if you have room to store one.     

Edited 3 hours ago by Geoff Weeks

[RS Disposal]

38 minutes ago, Geoff Weeks said:

Well it does seam to confirm that the suction line is the problem. It isn't a long time cure to a hose that is coming apart. I don't understand how you had the time to rig this up but don't have the time to replace the hose? 

I have been in your shoes running a single truck and trying to keep it running and my customers happy.

Am I to take it, by your statement that this was "the last hose" to be replaced, that you have addressed the other air lines?  I doubt it is the "last hose" as there are so many on a truck. Did changing out the air hoses solve your drier problem?

 I started stockpiling hose and fittings at my shop. I also got a parts truck that I could rob parts off of, either to use or to send off as cores for rebuild while my money make was still running. I am thinking things like a P/S box that required to be re machined for a seal to hold. 

If you are going to run a single truck, you HAVE to be proactive with maintenance. The guy that picks up garbage, showed up in a different truck one day, I asked if he bought a new one, he said no, it was a rental while his was in the shop. I didn't know you could rent them, but I guess around here you can. Another possibility is if you know a "competitor" who will not "stab you in the back" that could cover a pick-up for you while you do a repair. I know, this takes a lot of trust, but there are people who will help out as long as you will when they need it.

 

Running an old truck as a single operator is difficult, Often it can mean being one big breakdown from loosing it all. that is why it is so important not to have multiple small breakdowns that could be prevented. Most customers will understand that everything breaks at some point. As long as it isn't common, they will live with a temp interruption in service.

I carried brake diaphragms, various hoses, filters, throttle return springs, etc so most minor failures could be repaired right where and when they happened.

Many small business fail when they failed to plan on a breakdown. A parts truck can be a true windfall of parts if you have room to store one.     

Not replacing the fuel line wasn't a matter of time, It was a matter of availability of being able to have one made over the weekend.  It was the last FUEL line needing to be replaced. The inline pump isn't meant to be a long term cure.  It is just another step in my trouble shooting process. Being the line wasn't wet anywhere along it's length with pressure on it makes me think that it wasn't sucking air. Being any older truck alot of parts aren't able to be locally sourced. I do have a new lift pump on order.  My mindset is one that I need to know what was actually causing the problem and not just throw alot of parts/repairs at it in hopes that one of them fixes the problem.  Time consuming and can be frustrating I know, but just the way my mind works.

I haven't really addressed the air lines yet being the truck has no problem building air. I was just concerned about servicing the dryer.  Once I get to the dryer job the lines from the compressor to dryer and from dryer to wet tank will be replaced alone with the signal, etc lines to and from governor.  The truck is a 1979 and when my dad was running it I don't think it was maintained very well knowing that the arrangement he had with his brother (who owned a ski lodge in the resort) that every 4 or 5 yrs the truck is replaced.  The truck have never run full time even back then.  The truck then sat for 20+ yrs before I put it back to work  Mile wise it only has 160,000 miles, but it it 47 yrs old so just is not really wearing out, it is aging out.  My biggest problem has been sourcing parts as I found out with the engine breakdown 2 yrs ago. The truck only really makes any money thru the ski season (about 4 or 5 months) and then it only works two days a week for about 10 hours total, so there is not alot left over to stock pile anything more than than maintenance parts and smaller breakdowns.. I do totally understand what you are saying about a parts truck, but that search didn't go well back when I had my engine breakdown

Edited 3 hours ago by RS Disposal
additional info

[Geoff Weeks]

Looking at your air drier, it looks like all the hoses are using re-usable fittings. You could buy 25' or so of the different sizes to keep at the shop and a few mating fittings (to take the re-useable ends off the hose). That and a cut off wheel for a saw or die grinder and you an make up new hoses when stores are closed. Wheel seals, brake shoes are good to have on hand. 

Things like brakes, king-pins, tie rod ends etc can be monitored and planned for when they wear out.

What would you do if a brake treadle valve failed? A rear axle?

Do you keep a spare alternator on hand? if not what is your plan if one goes bad on a Friday night?

I am not picking on you, I am explaining what things you need to have a plan for when operating a single truck with no down time.

A truck with a manual transmission can be roll started if it has air to release the brakes, but an auto, you might want a starter on hand. 

 

[RS Disposal]

2 minutes ago, Geoff Weeks said:

Looking at your air drier, it looks like all the hoses are using re-usable fittings. You could buy 25' or so of the different sizes to keep at the shop and a few mating fittings (to take the re-useable ends off the hose). That and a cut off wheel for a saw or die grinder and you an make up new hoses when stores are closed. Wheel seals, brake shoes are good to have on hand. 

Things like brakes, king-pins, tie rod ends etc can be monitored and planned for when they wear out.

What would you do if a brake treadle valve failed? A rear axle?

Do you keep a spare alternator on hand? if not what is your plan if one goes bad on a Friday night?

I am not picking on you, I am explaining what things you need to have a plan for when operating a single truck with no down time.

A truck with a manual transmission can be roll started if it has air to release the brakes, but an auto, you might want a starter on hand. 

 

I keep brake shoes, wheel seals, alternator, starter, most air valves that are on the truck (seems I have alot of trouble with those in a really cold winter whereas the truck is stage up canyon and can see single digit or lower temps on a consistent basis). Just recently did a total rebuild of front suspension all the way from springs, steering components, brakes and wheel seals.  So I think those are good for a bit but as you say will definitely be monitored on an on going basis

The fittings on the air dryer are no reusable ones unfortunately.  But I have kicked the idea around of buying bulk hose and getting reusable fittings.

I don't feel that you are picking on me. I value all of your thoughts and insight being I know what I don't know. If I thought I knew it all I wouldn't be asking questions. I appreciate anything and all you have to say  Thank you

[Geoff Weeks]

Yes, the fittings are, I can tell by the type of end, they are not crimped on.  Pull the hose, tighten on to a fitting, to hold the inner portion, unscrew the hose end from the part attached to the  fitting ( this will be normal right hand thread). then unscrew the hose from the metal end (this will be left hand thread).  If you still have trouble understanding what I am saying, and I agree it is hard to convey in words, I can see if I can find some fittings like yours and take a picture with them apart to show what I mean. Non reuseable will be crimped on where the hose jacket goes into the fitting. 

I suspect your air system problems stem from excessive compressor cycling, and/or a defective drier. With a good drier and air system, temps well below zero are not a problem. 

[Geoff Weeks]

Here is a YouTube for mandrel type fittings, His I think are brass ends, but same as yours.

Mandrel type fittings

You can use a fitting in place of a mandrel, I prefer to put the fitting in the vise and rotate the hose  end, less chance of distorting the end you are working on. 

Many reusable fittings made today are "mandrelless" type with a second hex below the fitting hex to use to unscrew the fitting from inside the hose. They both go together the same way, but the mandrel type require something to hold the center from turning when installing/or un installing.

[RS Disposal]

1 hour ago, Geoff Weeks said:

Yes, the fittings are, I can tell by the type of end, they are not crimped on.  Pull the hose, tighten on to a fitting, to hold the inner portion, unscrew the hose end from the part attached to the  fitting ( this will be normal right hand thread). then unscrew the hose from the metal end (this will be left hand thread).  If you still have trouble understanding what I am saying, and I agree it is hard to convey in words, I can see if I can find some fittings like yours and take a picture with them apart to show what I mean. Non reuseable will be crimped on where the hose jacket goes into the fitting. 

I suspect your air system problems stem from excessive compressor cycling, and/or a defective drier. With a good drier and air system, temps well below zero are not a problem. 

I have used reusable fitting so I do understand what you are saying.  I will look closer

[Geoff Weeks]

Watch the video, he has the exact fitting that you do.