1991 fuel pressure test port
 

I need to test the fuel pressure and following the manual see that the port is located at the end of the fuel rail (drivers side). The manual says to remove the top bolt which is small. I have a kit from AutoZone but nothing seems to fit this hole. They do include a banjo fitting adapter which might work on the fuel input banjo on the passenger side of the manifold. Do I need a special adapter to get on the port recommended by the manual? The manual of course specifies a Honda pressure gauge. Or can I use the banjo fitting end? I need to test the pressure regulator. I'm getting a 43 diagnostic code without the 16 that corresponds to an injector problem.
Thanks for any help.

I had a code 43 that would periodically pop up. I think that code is misleading, because I think the problem is more than just fuel pressure. I'll look for a thread that talks about it.

The top bolt can come out, but you can remove the whole fitting. Maybe one of the adapters will fit that came with the kit. I removed the whole fitting on my 95 accord and made an adapter to test fuel pressure. Let us know if this works for you.

Here is a thread talking about the code.

https://www.hondaaccordforum.com/for...ode-43-a-9809/

I was still trying to figure out my problem at the time. I never figured it out. I was still fairly new doing DIY work. I think I would have figured out the problem knowing what I know now. Most of the time the O2 sensor is the problem, but there are a number of reasons for the car to be running rich.

Folks, I made some progress today. The manual says the 6mm bolt is the port for testing but I removed the larger "bolt" that it screws into. That is a 12mm X 1.25 thread and it took me a few hose shops to get a proper adapter assembled. Basically it required a male threaded adapter with a barb adapter attached to that. Then I could connect a hose. The set I borrowed from AutoZone has a tee fitting with the gauge Schrader attachment on the middle and a hose barb on the two ends of the tee. Pressure with the regulator vacuum line disconnected was 41 psi and with the vacuum hose on 31 psi. These are both a little low so the filter may need changing. BTW where is the filter located on a 1991 EX wagon? Tomorrow I'll tape the gauge to the windshield and try to reproduce the failure because it idles fine and in fact the problem of rough running only arose after about 10 minutes of normal local driving. That left my wife stranded at a friends. I drove the car back home and experienced the same rough, no pep problem about 10 minutes after starting. I managed to keep it drivable by keeping the RPM up around 3000 to 4000 RPM in a low gear.
Stay tuned!
Bob

The filter on the 91 is on the firewall. Just follow the fuel line from the rail towards the gas tank and you will find it. Look up the part on a parts site like autozone or rockauto to see what it looks like.

Today I test drove with the fuel pressure gauge taped to the windshield. The problem arose again after a short run. The pressure stayed up at a steady ~40+ psi so it apparently is not the fuel pump or pressure regulator. Seems more like an ignition failure. Symptoms are no power, sputtering with some backfiring, If can get it >3000RPM in doesn't seem to miss. So at a stop sign I crawl to a stop and give it lot's of gas to get started. It sputters and eventually goes up to 3000 RPM but with lot's of hesitation. Next I'll check the suggestions about the O2 connector. I changed the exhaust pipe about 3 years ago and replaced the O2 sensor at that time so it only has about 10,000 miles on it. Could be an intermittent failure of the coil?


This is an old car with 225k on the odometer. It's been in the family for it's entire road life and owes us nothing, so I don't plan to go crazy trying to track this down. I just would like to figure out which part of the car is dying: ^)
Bob

A code 43 (to me) means the engine computer can't adjust the fuel injection to get complete combustion as indicated by the O2 sensor.

The problem could be spark/ignition, too much air (vacuum leak), fuel injector, exhaust leak, O2 sensor, engine compression/valves, or engine computer.

If I had this car, I'd probably put an oscilloscope on the signal wire from the primary O2 sensor to see what kind of signal it is putting out. I recently purchased a diy oscilloscope kit for ~$30 that I soldered the components on the board that could handle this type of testing.

I don't know what tools you have available to you. The code 43 can easily lead you down the path of throwing parts at the car.

You may want to pull and inspect the spark plugs to see if one of your cylinders is misfiring.

I just pulled the distributor cap which I changed with the rotor, wires, and plugs and adjusted valves about 10 years ago (30k miles). Rotor looks burned and cap contacts are oxidized. That's about $15 for RockAuto parts. I think I'll start there and clean the O2 contacts while I'm waiting for them to come. The coil is the original part so I guess that's suspect also.
Bob

OK ignition parts didn't solve the problem, but I have a few more details. The car starts and idles fine. After a short distance or time of road driving the sputtering kicks in. If I drop the gear to 1 or 2 and keep the gas pedal down after a short time the engine returns to normal but at a high RPM. If I stay over ~3000 RPM it continues to run well. When the CEL comes on all is fine even at lower RPM. I drove around the block 6 times with no problems. When I turn the engine off, the CEL goes away and the whole cycle starts again. Last thing to check is the condition of the O2 connector that was mentioned earlier. It does have a lot of oil on it. BUT I can't figure out how to release the connector so that I can clean the contacts:^( I see there is a tab on the O2 side of wires but pushing that in doesn't seem to release the connector. It's hard for me to work on my back under there so I need some guidance. Should I post a picture?Thanks,Bob

Follow-up. I figured out the clip and got the connector apart. Cleaned up the insides and applied a contact enhancer I use on the MB electrical connections whenever I separate them. I'm saving the test drive until low traffic hours later and I'll report the results.
Bob

Well, cleaning the connector didn't help things. If I want to pursue this I guess I could change the O2 sensor but it's only about 3 years old and <10,000 miles. Not sure I want to do anymore: ^(
Bob

Didn't solve the problem. I'll pull the O2 sensor next and see what that looks like although it is relatively new so doubt that's the problem.


Bob

Looking at an O2 is hard to tell if it is good or bad.

I've heard of some O2's going bad after a year or so - Bosch mainly.....so the fact it was replaced 3 years ago does not rule it out.

From reading on here (in other threads) you really want to go with a Denso O2 sensor. It appears that they last the longest.

A side note: a lot of Bosch's products are being manufactured in 3rd world countries, so the quality might not be as good as it used to be. Just a heads up.

A friend I know has a 96 Canadian Accord that was having a "no code" drive ability issue. Upon first description, I suggested a lazy O2 but he ruled that out as it was replaced a year before.

About six months later it finally threw a code for the O2 - he had put a Bosch unit in it the year before. Replaced it with a Denso the next time and has been driving it for about three years now without any engine issues - is having a DRL issue right now but that is another story.

Well Poorman212 you were correct:^) Today I got to change the O2 sensor Denso) and that solved the problem. I looked up my records and the old O2 sensor went in March 2013 about 7000 miles ago when I replaced the exhaust pipe. What mislead me was the manual description of the 43 error. Although it starts by suggesting the O2 sensor, it also says if accompanied by poor drivability it's the fuel system. So I hit the O2 sensor last when I should have hit it first. Anyway now I know the fuel system is OK, the ignition is refurbished and the O2 replaced. About $120 in parts because there isn't a standard adapter for the fuel port, had to kluge one together.
Thanks all,
Bob

Congrats on fixing it.:)
The fuel adapter is available thru " thepartstree.com ", as it's also used on Honda Marine engines. They're getting 15 to 20 bucks for it, but, you still have to modify it so you can use a conventional pressure gauge on it. That's what I had to do for my 97 Accord to test pressure.

In talking with an old Mercedees mechanic, he tells you to go thru the check list of problem solving first. But more importantly, don't think, just do it. Tht's because if YOU start thinking, you'll only create new problems to solve. The engineers were pretty damn smart for you to "out smart".;) I look at it that way when going thru the Honda FSM too.