As many of you DIYs know, the accord doesn't have a standard schrader valve to easily test the fuel pressure at the rail. The Honda fuel rail has a special adapter that can be removed where a M12x1.25 threaded hole goes into the fuel rail. Hooking a hose up to this can be difficult, because most adapters to hose I found were in standartd pipe thread.

The Haynes manual has a procedure where you can buy a M12x1.25 bolt, drill out the middle, and grind the one end so you can attach a hose. The only bolts I could find were 8.8 grade and a pain to drill out.

I found at O'Reillys an oil drain plug that is drilled out with a 1/8 pipe thread on the inside and M12x1.25 on the outside. So I basically bought some fuel hose, two 1/8 pipe thread to hose barb, and two hose clamps. I put the adapter information below. I had a gauge from my lab that has an 1/8 pipe thread, so I basically put together a fuel pressure gauge for about $15.

Other Auto parts stores might have this part too.

MOTORMITE - DRAIN PLUG (M12-1.25 PIGGYBACK) Item No: 65228

I will test the gauge I made and my fuel pressure. I will post pics later and let you know how it works.

 

Outstanding tip for an aggravating problem. Good work!

Regards

 

Well, the story isn't finished yet. The adapter that I posted above is a piggy back adapter, so the metric side of it is larger than a M12x1.25 although the threads line up with a 12x1.25 bolt.

I just grounded off the original threads with my dremel and set new threads with my 12x1.25 die. Nothing is ever easy on this car!

I let you know how it works.

 

I picked up one yesterday, but didn't try it out. After reading the fine print, it's intended to replace a stripped 12mm x 1.25mm drain plug, so the threads are slightly oversized to engage a stripped hole. It only measures about 12.5 mm, so I think a die should resize it. I'll be interested to hear how you make out. I think I have that die also for chasing wheel lug threads.

good luck

 

The die wouldn't work by itself.

I ground down the threads till they were gone and ran a die up it. I probably ground a bit too much off, because the threads were off axis a bit. I got the gauge to hook up to the fuel rail, it just didn't seal perfectly at the rail(since the threads were off axis). There was a very thin coating of gas on that plug at the rail, so it wouldn't hold pressure for too long after I turned off the engine. I didn't have any problems reading the fuel pressure.

The fuel pressure checked out at 31psi w/ regulator, 42 without. That was within spec. Now I can assume that the O2 sensor is giving me the code 43 (or the wiring).

I might pick up another one and be a bit more cautious with my dremel. Overall, it worked pretty well.

 

You tried chasing w/ the die w/o grinding the threads?

I would have thought the die could deal w/ 0.5mm oversize. That's only about 0.020" per side to remove. Steel is tough stuff though!

regards