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Discussion Starter · #1 ·
Hi guys, I'm new to the forum, but have been using it since i bought my car for tips and ideas.

Not too long ago, I came across an issue on the motorway, where i went into "PGM-FI" mode (limp) in 6th gear cruising at 120km.
I analysed the issue and found the code (P1065) popping up.
After clearing it, I drove it and everything was fine except once i pass 120km somewhat harshly accelerating. The same issue arises.
So after research, the first thing i done was replace the fuel filter, I installed an OEM honda denso fuel filter and the issue was fixed for perhaps 6-7 hours.
Then it came back.

I was confused, and began to research more, I saw various answers to my issue such as , "a worn fuel pump, fuel pressure sensor and perhaps a new fuel rail.
As two of the three options are quite expensive,
I didn't see it being plausible as the car drives perfect, starts like a charm and no weird noises cranks what so ever. But suspiciously, once i pass 120-140km. I go into limp mode.

So today, i found out that, this limp mode and error code only pops up when i some what harshly accelerate past 120km. (Half pedal down), but if i accelerate slowly past this point. I don't get this issue.

So in conclusion, i only go into limp mode and receive the error code (P1065) "low fuel rail pressure" when i accelerate harshly at 120km.
I'm worrying that this could be signs of a worn fuel pump but I was wondering If anyone would have any opinions on this confusing situation before i get it diagnosed or buy a new fuel sensor for it not being the cause

Thank you very much in advance
 

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No point in replacing the fuel rail as it's basically just a hollow tube manifold with a sensor at one end and a relief valve at the other.

Well done for replacing the fuel filter with the OEM Denso, probably would fix this problem most times! Other reasons would be the rail over pressure relief valve leaking (easy to reroute the output as a check that nothing is being passed), one or more injectors might have developed excessive leak back (reroute all 4 leak back outputs into 4 separate containers and see if any pass significantly more than the best one). All that's left then would be the pump (try substituting a known good one)
 

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Discussion Starter · #5 ·
No point in replacing the fuel rail as it's basically just a hollow tube manifold with a sensor at one end and a relief valve at the other.

Well done for replacing the fuel filter with the OEM Denso, probably would fix this problem most times! Other reasons would be the rail over pressure relief valve leaking (easy to reroute the output as a check that nothing is being passed), one or more injectors might have developed excessive leak back (reroute all 4 leak back outputs into 4 separate containers and see if any pass significantly more than the best one). All that's left then would be the pump (try substituting a known good one)
thank you very much for your reply,
I'll perform the tests you mentioned this week, and i'll let you know if that was the cause or not
appreciate the help!
 

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Bye bye Honda...
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thank you very much for your reply,
I'll perform the tests you mentioned this week, and i'll let you know if that was the cause or not
appreciate the help!
The rail over-pressure valve leaking away rail pressure is a common problem with this engine. The forum has a great thread on diagnosing and repairing this fault... How to diagnose and replace a faulty over pressure...

That linked thread also has guidance and advice on testing injector leak-back flows. There are also quite a few useful vidclips on YouTube.

Please let us know how you get on!
 

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Discussion Starter · #7 ·
The rail over-pressure valve leaking away rail pressure is a common problem with this engine. The forum has a great thread on diagnosing and repairing this fault... How to diagnose and replace a faulty over pressure...

That linked thread also has guidance and advice on testing injector leak-back flows. There are also quite a few useful vidclips on YouTube.

Please let us know how you get on!
Hi ,
I've been busy the last couple of days, but i'm hoping to perform these tests in the next few days,
I'll keep you updated!
 
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