Having a transfer pump failure on my 3126. Proved the pump was not working so I changed it. Same condition. No fuel output. I’m now suspecting the drive on the back of the HEUI pump has failed. This seems like an odd failure point. Wondering if anyone has heard of this?
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It would appear from diagrams ( illustration #7 )and text in the pdf ; the transfer pump plunger is driven by a roller bearing mounted on an eccentric at the end of the main HEUI pump shaft .
From the diagram it appears the shaft is one piece from the drive gear to the eccentric .
Can you remove the transfer pump and check to see the shaft is turning ?
Have you checked to see if the HEUI is boosting engine oil pressure and suppling it to the gallery in the cylinder head ?
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.
That’s it… My concern is that offset gear. I can pull the transfer pump but it’s hard to get to. I just replaced it yesterday and didn’t think to check that gear. I’ve never heard of it failing before.
At this point point I have a no start so I can’t check HEUI pressure.
There’s no other way to check it besides pulling the pump. I was hoping to get some validation that those gears do indeed fail at the back of the HEUI pump before digging in.
I've not heard of the offset drive failing on this style pump. How did you check the pump? Did you run new suction line from bucket to pump-- place finger over the suction port while cranking to feel suction. Just curious. Once these pumps get air into them it is extremely difficult to get the air out and the fuel to the pump.