My friend has a 98 accord lx that is misfiring. He had the codes scanned and he said 3 of the 4 cylinders were misfiring and it had a lean condition. I checked the plugs and 3 out of the 4 were really white. I replaced the fpr on suspicion but that was not it Im pretty sure it is fuel related though. I Still need to check fuel pressure also. It runs like it has a miss and at idle sometimes for a few seconds it will run perfect then miss again.

Any ideas? I been meaning to get me a nice scanner for my laptop but dont want to spend the cash right now. How do you check the fuel pressure on this car also I did not see a service port like gm cars have.

 

There should be a service port somewhere. You'll need to find/rent a gauge to check the pressure.

 

Thanks Ill look better maybe its farther up on the line. I know ill need a gauge but do you have to check it with it running on this car I thought I read that somewhere.

 

Fuel pressure test is not very reliable unless its really low, but you will need to set up the gauge so you can see it while you are driving the car, watch pressure while it is misfiring, if it goes lower, then misfires, you may have found your issue, even good pressure will cause problems if you have low volume.

If it misfires most of the time, you can do a Dead Head Pressure Test, clamp off the return hose to the tank, if the miss goes away, you have a fuel related issue, is it pressure or volume. You have to understand what causes fuel system pressure first. Its not the pump, its the restictions after the fuel injectors, ie, fuel pressure regulator, slightly restricted fuel rail after your test gauge, slightly restricted fuel return line, a weak pump will not show as weak if you have these issues.

A good tech with an oscilloscope will see a lean cylinder on a Snap Throttle Test right away as higher KV's on the lean cylinders. How old are the spark plugs, what is the gap, are they OEM NGK's, what is the timing, what is the voltage on the MAP sensor at a fully warmed up proper idle, MAP voltage is my first test, 1.0 volts DC, slightly higher ok, a little bit lower is better.

Is there a 10mm or 12mm bolt on top of the fuel filter?

 

Plugs are newer oe ngk's. I havnt checked the map voltage yet cause I wanted to get a scanner/logger hooked up to it.
I didnt think this car had an external fuel filter.

 

the service port on my 94 accord is on the fuel rail. if you can't find one, call your local dealer and ask. MAYBE they will tell you. yes, check the pressure with it running. the fuel pump must be running constantly to read the pressure.

 

Thanks I read somewhere that it should be 40-47 psi with the fuel pressure regulator vacuum hose disconnected and pinched. Is that correct?