2012 Hino 258 No Power

likemlow

Seasoned Expediter
Mechanic
Hi All! Love our 258. So now it has no power. I checked the fuel pressure with our scanner. It shows the fuel pressure drop as we accelerate. We changed all the filters. Found the Over pressure valve leaking, replaced that. Ran it off a bucket. Even swapped the High pressure pump with the SCV from another truck. No Change. Just for the hell of it today we clamped the fuel return line and what do you know the fuel pressure came back and now the truck has power! Anybody know what part has failed? Is there some other valve that we missed? Thanks for any input!
 

greasytshirt

Moderator
Staff member
Mechanic
It sounds like it needs an injection pump, as you've ruled out the usual suspects. Clamping the line has the risk of blowing the shaft seal out of the pump. Watch the oil level.

If clamping the line raised pressure, then that tells me that the pump has an unacceptable rate of internal leakage. One clue would be to look at the fuel temp history. The ecu logs max fuel temp. If it's over 200-210 or higher, that's a sign of either internal leakage or past fuel contamination.
 

likemlow

Seasoned Expediter
Mechanic
We're still fighting this one. We removed the injection pump and sent it out for testing. It failed the tests. Great! We thought. Re-installed it and it still is doing the exact same thing. Here's some pics of the data from our Snap on scanner. 67 3.jpg
Above is at Idle.67 2.jpg
Above is at Full throttle pressing the pedal SLOWLY67 1.jpg
Above it at Full throttle Punching the Pedal to the floor quickly.
- We have even swapped engine computers, fuel rails to no avail. We're Stumped:dash2:
 

likemlow

Seasoned Expediter
Mechanic
So we figured it out. After replacing the Air compressor we accidentally crossed the two Banjo bolts from the top the bubblier and the rear of the pump. Apparently there's an internal filter in one that killed our fuel pressure. Uncrossed them and now we're back in business.
 
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greasytshirt

Moderator
Staff member
Mechanic
So we figured it out. After replacing the Air compressor we accidentally crossed the two Banjo bolts from the top the bubblier and the rear of the pump. Apparently there's an internal filter in one that killed our fuel pressure. Uncrossed them and now we're back in business.
That sounds like a nightmare. Good job figuring it out.
 

BigStickJr

Veteran Expediter
Retired Expediter
I came in to make a snarky comment about no power being standard out of the factory.
Then I read the thread, with it’s interesting conclusion and wonder if this is the first time Greasy learned something from us .
 
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BigStickJr

Veteran Expediter
Retired Expediter
And an important lesson about putting bolts into the proper hole on today’s complex trucks.
 

greasytshirt

Moderator
Staff member
Mechanic
I came in to make a snarky comment about no power being standard out of the factory.
Then I read the thread, with it’s interesting conclusion and wonder if this is the first time Greasy learned something from us .
I had learned about this in class, and promptly forgot about it. So technically yes, I learned something.

And that's not fair of me to claim. I've learned a ton by working with everyone on here. I've learned a lot about streamlining the troubleshooting process, since the truck isn't in front of me to examine. Plus lots of other things. Things that I've put into practice at work. I'm pretty sure I'm the highest paid mechanic at my shop, and I know I was the highest producer last year.
 
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