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Intermittent P0087

LostDeere59

Rookie Expediter
Mechanic
Offline
2012 258ALP - when on a long hard pull, for instance loaded on a long grade on the Turnpike, Check Engine light comes on, engine de-rates into limp mode. Checking codes returns the P0087 low rail pressure. If I clear the faults the truck will usually be ok for a while, however sometimes the issue returns quickly and frequently, and sometimes it goes away for days or weeks, even when put under the same conditions. One consistent thing I have noticed is that this problem is definitely related to underhood temperatures - last summer it was giving me fits, but through the fall, winter, and early spring the problem never showed up. Recently, on a couple of particularly hot days, and again under high load, the problem showed up once or twice, but has been fine since our weather has moderated.

I have read most of the threads related to this issue and have checked the fitting at the fuel tank, and inspected the inside of the tank - everything I have checked is clean and shows no debris at all. Because of the temperature factor I'm thinking I have an issue with the SCV - but when I contacted my two Hino parts departments I was told that there are no serviceable components on the injection pump, which is where I thought the SCV is located . . .

So my question is really a couple of questions - Is the SCV on the injection pump, or have I completely misunderstood the system structure? Does this sound like a possible/probably SCV issue to those with experience? I do have the pressure limiter/relief valve for the fuel rail and plan to install that, as well as check the fittings at the fuel filter, bubble filter, and injection pump for debris, as well as verify that the correct bubble filter is installed. And last, if Hino has stopped servicing the SCV, what do I need to identify the correct replacement so I can source one form someplace online such as EBay or other vendor?

Thanks for any input.

P.S. - As I said I've read a great deal of the postings here, and found them to be a wonderful source of information when dealing with our 4 truck 2012 to 2015 258 fleet. Whatever happened to GreasyTShirt - nothing unfortunate I hope?

Gregg
 

greasytshirt

Moderator
Staff member
Mechanic
Offline
I have had a lot of medical issues. Bleh. It sounds like you're on the right track. I would be looking at historic fuel temps with DX software. If the temp is over 200 degrees, I'd suspect a high rate of internal leakage with the fuel pump. This can cause P0087 in some cases, and it makes sense that the problem is showing up more often with higher ambient temps.
 
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