-
Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!
Cat 955L won't run
- Thread starter hot_rod_eddie
- Start date
hot_rod_eddie
Active Member
Where is the "dislike" button! That is not what I want to here.
Dave Neubert
Senior Member
It is not the injection pump the problem is you are not building pressure it has been a wile since I was into one of those old systems but I believe there is a regulator valve in the pump maybe Nige can help with some info I will research it too where in NC are you
hot_rod_eddie
Active Member
There is a regulator spring in the transfer pump where if the pressure gets too high (about 32psi I think) it will let fuel bypass back around. I haven't checked the one in the new pump, but the old one looked okay considering I didn't check it to specs.
I have the book on this machine. Seems like a simple system until the high pressure pump. Guess you just have to know what you are doing.
I am right outside Kernersville. The machine is in Stokesdale.
I called CAT and they will be out Monday morning.
So I have a few days to get this resolved or I have to bite the bullet.
I am going back out there tomorrow and on Saturday to scratch my head some more.
I have the book on this machine. Seems like a simple system until the high pressure pump. Guess you just have to know what you are doing.
I am right outside Kernersville. The machine is in Stokesdale.
I called CAT and they will be out Monday morning.
So I have a few days to get this resolved or I have to bite the bullet.
I am going back out there tomorrow and on Saturday to scratch my head some more.
Dave Neubert
Senior Member
when you pump the primer can you hear like a wining or hissing noise from the fuel bypassing
hot_rod_eddie
Active Member
Haven't noticed any noise like that. I did take the primer out to make sure the check balls and springs were fine. Everything looks good.
Spyros33
Well-Known Member
- Joined
- Aug 22, 2020
- Messages
- 130
- Location
- Korinth, Greece
- Occupation
- Mechanical engineer, machine operator
Any chance that the engine doesnt build up oil pressure in order to release the fuel pump rack?
Dave Neubert
Senior Member
If have not heard a noise then the regulator has to have trash or is stuck open the hi pressure part has nothing to do with supply pressure go over the supply and supply pump again it has to be there you did clean out the metal fuel bowl at the bottom of the filter housing Right. some models had a fuel l water separator at the back by the tank it is a square glass filter
Dave Neubert
Senior Member
I thought of that but he said it will run for a minute but would not hurt to see if oil pressure guage goes up wile cranking
Dave Neubert
Senior Member
Checked with my pump guy he said that the spring and check valve in the transfer pump controls pressure so if you are sure you have a constant flow to the pump it has to be in the check valve
hot_rod_eddie
Active Member
Everything I can find has been cleaned multiple times. I will hang a bucket fuel tomorrow. The pressure relief spring/valve could be bad, but it would have to be bad in the old and new pump. They look good and the spring is stiff. Only way to know if the spring is 100% is to put on bench and check height at different weights.
I didn't mention before but I've had a friend look at it. He used to work on over the road CATs years ago. We have separately gone through all of this. We both feel it is a fuel supply issue but can't put our fingers on it. That is why this is so frustrating.
Thanks for the replies
I didn't mention before but I've had a friend look at it. He used to work on over the road CATs years ago. We have separately gone through all of this. We both feel it is a fuel supply issue but can't put our fingers on it. That is why this is so frustrating.
Thanks for the replies
DB2
Senior Member
No way to put some air pressure back through the line or in the tank ? Also are you certain you don’t have the square glass filter somewhere along the line ?
hot_rod_eddie
Active Member
I bypassed the tank and all supply lines last night when I ran out of a 5 gallon jug. I will raise a 5 gallon bucket tomorrow to see if I can get gravity pressure to help. No glass filter.
Dave Neubert
Senior Member
Just thinking can you see the end of the transfer pump to see if it is spinning some had a hour meter attach there and you could see it spin also is the mounting gasket in the right position
hot_rod_eddie
Active Member
I noticed the gasket has a right and wrong direction. I removed the hour meter and it is spinning.
Cat977
Senior Member
Cat977
Senior Member
A little off subject. As for venting or maybe not. I Understand that my hydraulic tank needs to build up pressure to work right. So hiss from fuel tank - Bad. Hiss from hydraulic tank - Good.
hot_rod_eddie
Active Member
Yes I took the cap off before.
Found a fixed a couple pin holes in one of the primer pump lines. Someone had put some type of tape around it. I noticed it was wet around there, but didn't think it was that big of a deal. I took the tape off and fuel streams out of there. I brazed it at work. I don't think this is the magic bullet but needed fixing. I will put the line back on and hang the bucket tomorrow. I have CAT scheduled at 7:30 monday morning if that don't work.
Found a fixed a couple pin holes in one of the primer pump lines. Someone had put some type of tape around it. I noticed it was wet around there, but didn't think it was that big of a deal. I took the tape off and fuel streams out of there. I brazed it at work. I don't think this is the magic bullet but needed fixing. I will put the line back on and hang the bucket tomorrow. I have CAT scheduled at 7:30 monday morning if that don't work.