Truck surges when warming up?

ramdough

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Location
Austin, Texas
Truck:

1999 m1083 A1 3126 serpentine re-certified in 2009

Symptoms:

On start up if left in low idle, the engine surges in a rhythmic way. In high idle I do not notice it. In gear, the truck lunges with each surge.

Once the truck is really warmed up (30 minute drive), no more surges.

What I have done so far:

Assumed air leak in fuel system. I have new fuel hoses. I checked to make sure the ends were tight. I have a new ish fuel filter (500 miles on it). I checked the bowl for cracks or leaks. I pressed the primer button to see if it leaked or got hard once it pressurized (with engine off). I have not found any obvious issues.

Before I replace the filter base with primer button…. Any suggestions? I hate throwing parts at problems.

I also thought of buying injector lubricant additive for the fuel tank (friend recommended).

Thanks in advance for any suggestions!


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Green Mountain Boys

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Vermont
I had the same symptoms on my 1998 New Holland LX885 skid steer. It turned out to be caused by a lack of lubricity due to the low sulfur diesel fuel. I added Opti Lube and it solved the problem right away. I would try that first since it is cheap, easy and won't hurt anything.
 

Ronmar

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Put a gauge on the primary fuel pressure test point. Should be 25 at idle up to 60 at RPM. If the primary pressure is stable while it’s surging, then it is probably not fuel related. Got anyone in your area with a compatible scanner. It could be the High pressure oil regulation scheme is acting up(Reg valve, pump or pressure sensor). A cat scan would tell this tale:)
 

ramdough

Well-known member
988
578
93
Location
Austin, Texas
I had the same symptoms on my 1998 New Holland LX885 skid steer. It turned out to be caused by a lack of lubricity due to the low sulfur diesel fuel. I added Opti Lube and it solved the problem right away. I would try that first since it is cheap, easy and won't hurt anything.
Thanks for the suggestion.

I will give this a shot.

The truck did run really smooth for about 400+ miles, so this is a new issue. That would make me a little skeptical about lubrication….. but, I don’t think it can hurt. Plus, it may do the truck some good.


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ramdough

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Location
Austin, Texas
You can put a clear line between the water seperator to your lift pump to see if air is running through. I used vinyl hose but there is better materials you can use. My truck was loosing prime so it would run poorly till the air was purged out. If I cycled the primer pump before each start I don’t have any troubles.
Thanks for the suggestion. I am not losing prime at all and the trucks starts pretty easily. I will add this to one of my debugging steps.


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ramdough

Well-known member
988
578
93
Location
Austin, Texas
Put a gauge on the primary fuel pressure test point. Should be 25 at idle up to 60 at RPM. If the primary pressure is stable while it’s surging, then it is probably not fuel related. Got anyone in your area with a compatible scanner. It could be the High pressure oil regulation scheme is acting up(Reg valve, pump or pressure sensor). A cat scan would tell this tale:)
Can the Cat reader see fuel pressure?

The closest friend I have with a scanner is 3 hours away. Do you have a suggestion for one of the cheaper scanners? I have seen a bunch of cheap Chinese versions, but I don’t want to buy until I know which one people are having good luck with. Would love to see everything.

Would the wtec be able to see anything, or is this likely not code worthy?


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Ronmar

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The ECU doesn't monitor lift/baseline fuel pressure. You can do it with a cheap mechanical oil pressure gauge kit and one 1/4M-1/8F npt adapter. I have one hooked up in one of my fuel system videos on utube. I squeeze the poly line to take the pulsations out for a stable reading.

I am not sure what scanners are compatible with the cat ECU. I have not had a reason to research it…

I don’t think the WTEC stores anything engine related…

your nearest Cat dealer should be able to do it…
 

Green Mountain Boys

Active member
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Location
Vermont
Thanks for the suggestion.

I will give this a shot.

The truck did run really smooth for about 400+ miles, so this is a new issue. That would make me a little skeptical about lubrication….. but, I don’t think it can hurt. Plus, it may do the truck some good.
I was also skeptical about lubrication since my skid steer ran perfectly for thousands of hours. Then one day it started surging like you described. After checking for air leaks and finding none. A mechanic listened to the machine idling and told me it would be solved with Opti-Lube and he was 100% correct.
 

ramdough

Well-known member
988
578
93
Location
Austin, Texas
I find alot of older fuel feed lines from tank to primary filter get little cracks and you get a little air. Wont loose prime unless it sits for a long time though. And I have seen tank vents clogged by bugs building nests or dirt.
My fuel lines are brand new from [mention]fuzzytoaster [/mention] so I trust them to be good.

The truck has been garage kept, so bugs is not as likely but I will pull the cap off and blow through it to see what happens.

Thanks for the feedback.


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ramdough

Well-known member
988
578
93
Location
Austin, Texas
I was also skeptical about lubrication since my skid steer ran perfectly for thousands of hours. Then one day it started surging like you described. After checking for air leaks and finding none. A mechanic listened to the machine idling and told me it would be solved with Opti-Lube and he was 100% correct.
I will give that a shot….. if nothing else, the engine may like it.

Did you find you had to add it every tank or just occasionally?


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ramdough

Well-known member
988
578
93
Location
Austin, Texas
The ECU doesn't monitor lift/baseline fuel pressure. You can do it with a cheap mechanical oil pressure gauge kit and one 1/4M-1/8F npt adapter. I have one hooked up in one of my fuel system videos on utube. I squeeze the poly line to take the pulsations out for a stable reading.

I am not sure what scanners are compatible with the cat ECU. I have not had a reason to research it…

I don’t think the WTEC stores anything engine related…

your nearest Cat dealer should be able to do it…
I will look for your video. Thanks!


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Green Mountain Boys

Active member
93
161
33
Location
Vermont
I will give that a shot….. if nothing else, the engine may like it.

Did you find you had to add it every tank or just occasionally?
I use it every tank at the higher rate they recommend. Something like 1 or 2 ounces per 10 gallons. The first tank full my mechanic told me to use it at 4 or 5 times the highest recommended rate.
 

Ronmar

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Location
Port angeles wa
Along the lines of lubricity, this has been an issue with the HEUI system on the lube oil side As well. The spool valves that control the flow of high pressure engine oil into the injector need to open and close precisely. This has been a known issue with power stroke owners(Ford licensed HEUI from Cat) and there are some stiction additives on the market to help the engine oil be a little more compatible with the close tolerance spool valve injectors… Where are you at in relation to your last oil change?
 

ramdough

Well-known member
988
578
93
Location
Austin, Texas
Along the lines of lubricity, this has been an issue with the HEUI system on the lube oil side As well. The spool valves that control the flow of high pressure engine oil into the injector need to open and close precisely. This has been a known issue with power stroke owners(Ford licensed HEUI from Cat) and there are some stiction additives on the market to help the engine oil be a little more compatible with the close tolerance spool valve injectors… Where are you at in relation to your last oil change?
500 miles maybe and 1.5 years…. Barely turning darker


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ramdough

Well-known member
988
578
93
Location
Austin, Texas
Gonna try this.

View attachment 853527

I also bought a brand new primer/filter base. The price was right, so I bought it. We will see if that fixes anything.

I will update with my results.
Ok, just closing the loop.

Maybe this will help others.

Day after I posted last, I added the fuel additive. I let the tank sit since then. I probably was a little heavy on the dose since my tank was not full and my gauge is not working…. So I guessed add rounded up.

I did nothing else…..

I started the engine up today first time since adding additive. It sounded clanketty (technical term) and surged a bit for maybe 10-15 minutes.

Drove it around and tried to warm up the engine.

Now it purrs like a kitten. No surging.

I was absolutely blown away at the change. It sounds quieter, it is not surging, and is behaving like a different engine (smooth idle with less clatter).

I plan to add this every fill up and see how it goes.


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