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8950 Strange Problem


TB5288
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Well this one will be a little hard to explain. When my 8950 gets good and warm the engine has a "stutter" or "flutters" when running at any speed and "no load". It does not do this when pulling and does not do it until good and warm. When it's parked it'll actually shake the tractor a little bit. Plus today I had a god awful gear noise coming from I think the transmission. I think it's gear chatter from the engine fluttering, at least I'm hoping that's what it is. It all runs fine on the field. Anyone ever heard of such a thing? It's like the governor has a problem, but I've not heard one like this. First I thought it was missing out, but I don't think so. I cracked each injector line, they all act the same. Check exhaust manifold when first started and everything consistent there also. But, it sounds fine when cold. While revving up it's smooth and when it reaches set speed it starts fluttering again. Exhaust is steady, very little blow by and it's consistent. Anyone got any ideas? I have not checked valve adjustment. Timing good, fuel pressure good. Don't know boost pressure but don't think that's anything with this problem. Appreciate any thoughts.

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I had this same issue with a 2366 combine with a P pump. Went on for years sometimes more noticeable than others. I had the injectors serviced and that made no difference so this year I sent the pump away to our local shop and they say the fuel delivery on one cylinder is below spec. I thought the governor must have some issue but they think it is fine. I am about to reinstall the pump for fall harvest so hope the problem is solved. I harvested wheat with a pump off of a 2388 that a friend let me use and is works great with that one.

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broken spring in the return fitting causing low fuel pressure at low rpms causes one cylinder in the pump to drop out. 

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16 minutes ago, Injpumped said:

broken spring in the return fitting causing low fuel pressure at low rpms causes one cylinder in the pump to drop out. 

I had just replaced the fuel return valve with the latest greatest style. I realize that doesn't mean it's good but the reason I replaced it was because of low fuel pressure. It fixed the low pressure fuel problem at that time, that was only about five engine hours ago.

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Just now, TB5288 said:

I had just replaced the fuel return valve with the latest greatest style. I realize that doesn't mean it's good but the reason I replaced it was because of low fuel pressure. It fixed the low pressure fuel problem at that time, that was only about five engine hours ago.

Fuel transfer pump is new also.

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Well, pump to the shop and tore down. Not good, not good at all. Pump must have sat with water in it for a while. Lots of rust on plungers and barrels. $3500.00. I don't know why it ran as good as it did. I doubt injectors are much better the way the pump looked. Fuel tanks coming off to make sure they are clean. Not looking forward to removing the bottom tank, it's got the one that wraps around axle housing. On another note, anyone know what the accumulator charge should be?

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27 minutes ago, TB5288 said:

Well, pump to the shop and tore down. Not good, not good at all. Pump must have sat with water in it for a while. Lots of rust on plungers and barrels. $3500.00. I don't know why it ran as good as it did. I doubt injectors are much better the way the pump looked. Fuel tanks coming off to make sure they are clean. Not looking forward to removing the bottom tank, it's got the one that wraps around axle housing. On another note, anyone know what the accumulator charge should be?

I wouldn't take the tanks off. There is a drain on the bottom that is probably going to drain as well as any other way. I would drain it off the bottom and add a good additive to deal with moisture removal

Hopefully this chart is readable. Temperature dictates the PSI

IMG_20210914_223405424.jpg

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1 hour ago, bitty said:

I wouldn't take the tanks off. There is a drain on the bottom that is probably going to drain as well as any other way. I would drain it off the bottom and add a good additive to deal with moisture removal

Hopefully this chart is readable. Temperature dictates the PSI

IMG_20210914_223405424.jpg

Thank you bitty got the chart. Yeah I'm trying to talk myself out of removing the tank. I opened the drain on the bottom tank and the didn't seem to be anything but clean fuel coming out.

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On 9/15/2021 at 9:57 PM, TB5288 said:

Anyone know what max turbo pressure should be on an 8950? It's got the waste gate, when should it open? Also, can I install a non waste gate turbo if I need to replace it? Well I know I can, but will it generate too much boost?

LOL!!  Too much boost?! Better question, How much boost will the head gasket handle?  Sorry, I’m really no help, other than to tell you that my Cat truck engine now boosts to 42 psi instead of 30. 

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1 hour ago, ihrondiesel said:

LOL!!  Too much boost?! Better question, How much boost will the head gasket handle?  Sorry, I’m really no help, other than to tell you that my Cat truck engine now boosts to 42 psi instead of 30. 

Yeah the Detroit in my truck now will boost up to 48 psi but I set the liner profusion at .004 to handle it. But a truck engine doesn't run at max HP for long periods of time. A farm tractor doing tillage work could be a little different, it probably runs at higher HP/boost levels for longer periods of time. I really don't want to raise liner heights to hold more boost on this tractor. That's why I'm asking.

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6 hours ago, TB5288 said:

Yeah the Detroit in my truck now will boost up to 48 psi but I set the liner profusion at .004 to handle it. But a truck engine doesn't run at max HP for long periods of time. A farm tractor doing tillage work could be a little different, it probably runs at higher HP/boost levels for longer periods of time. I really don't want to raise liner heights to hold more boost on this tractor. That's why I'm asking.

Yeah, I get that. Like I said, I’m not much help on the subject, other than to note that the earlier Magnums didn’t have wastegate turbos, I believe the switch to wastegates had to do with emissions. 

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22 minutes ago, ihrondiesel said:

Yeah, I get that. Like I said, I’m not much help on the subject, other than to note that the earlier Magnums didn’t have wastegate turbos, I believe the switch to wastegates had to do with emissions. 

So you're saying like a 7150 did not have a waste gate? 

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Waste gates were brought about so they could use a tighter ar exhaust housing, thus increasing lower end turbo response without the risk of over boosting an engine and causing damage. You can buy little elbows that let you control the opening psi of the waste gate if you so wish, but I used to use one on my pickup, but mostly seen little to no performance gain out of it.

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