1989 Accord – Weak Fuel Pump?

[Swap_File]

My 1989 Honda Accord SE-i’s first cylinder is misfiring.

First, I figured it was a spark problem. I pulled off each sparkplug wire one at a time, and when I pulled the wire for the 1st cylinder off the engine barely changed its idle. When I pulled each wire off, I had a strong spark from the wire to the distributor cap. I replaced all the plugs, and the cap and rotor anyway. I still had the same problem. I also unscrewed #1 cylinder sparkplug, and held it against the engine to make sure it was sparking.

Now, I figured it could be an injector problem. I had some leaky injectors a few months earlier, and had replaced 2 of them with junkyard parts. I listened to the injectors with my stethoscope, all sounded fine. I unplugged each injector, and used my electrical meter to make sure they were all getting pulses to fire from the ECU. I checked their resistance, and the resistance of the resistor pack. I also unplugged each injector one at a time. There was almost no change when I pulled the #1 injector. I pulled all the injectors out, and put them in my extra intake. I then hooked up the fuel pump to this intake, and turned the fuel pump on. I saw that no injectors were stuck open. I fired the injectors one at a time with a 9v battery, and each seemed to work fine. At this time, I did notice that very little fuel was coming out the fuel pressure regulator. I reassembled everything, but made sure to swap the #1 and #2 injector. Cylinder #1 still wasn’t firing.

(Note, I do not have access to a meter to measure the fuel pressure while the car is running. I ordered one but it will take several weeks for it to get here.)

Finally, I figured it must be a fuel delivery problem. The 1st cylinder is the last cylinder on the fuel rail… Maybe if there was a lack of fuel pressure it would show up there first. The Honda shop manual said that I should get 8oz of fuel out of the fuel pressure regulator return line in 10 seconds (with the car not running, and the fuel pump on). I got about 1 oz out. I replaced the fuel pressure regulator with a similar regulator I had sitting around from an Integra, and had the 1 oz of gas come out again. The regulators are probably fine... I doubt I have two that are broken. Next I removed the regulator and did the test again. This time I had about 14 oz of fuel come out in 10 seconds. Then I went to the fuel pump, and hooked a pressure gauge up directly to it. In a few seconds the fuel pump was able to make around 60 PSI before it blew my home made fuel pressure gauge off the hose it was clamped to. I also put a new fuel filter on. No change. I finally hooked it all back up like normal, and measured that the fuel pump draws about 5 amps, at 12 volts. I do not know what normal is for this pump. I also took the pump out and physically inspected it. It looked OK to me.

I have tested everything I can; the only thing I can think of is that my fuel pump is weak, or dying. The regulator seems OK, filter is new, hoses don’t seem to be plugged with dirt... Is it time to buy a new pump?

Someone also suggested that my #1 cylinder stumble could be due to EGR blockage. I guess the problem is that the EGR malfunctions and it turns on while the car is idling, and then if the majority of EGR tubes are blocked the remaining open tube gets a pile of exhaust in it, and it causes that cylinder to misfire. This is very common on the 4th generation Accord, but I own a 3rd gen. Even if this is a problem, it does not explain why I am not getting at least 8 oz of fuel in 10 seconds out.

Also, My compression is 195, 195, 185, 185 according to our old compression tester. Also, the first cylinder spark plug did not come out easily, and it chewed up the threads in the head a little bit. I was able to fix it, but could this have been caused by the first cylinder running lean for an extended ammount of time?

[Strugglebucket]

from reading your post, the only thing i can think of would be some kind of problem with the fuel pump. but even with inadequate fuel pressure it seems strange for only the #1 cylinder to be having problems.
i don't see how the egr would affect only the #1 cylinder. the exhaust comes in through a single port on the distributor side of the intake manifold.

i would just wait for the real guage and see what your fuel pressure is at when the car is running.

[Oldblueaccord]

Ill have to check the amp draw on mine as well.

Remember even if the pressure is correct the volume might not be.

I have a spicet here at my new house wont do shit. Put a pressure guage on it and I get the house pressure 60 psi. Pull the guage off and let it run out it prolly take an hour to fill a gallon bucket.

Not to scare you but being in the rust belt have you checked the condition of your gas tank inside.I think ours still have the pep cock might be worth it to drain the trash outta it.


wp

[w261w261]

I've noticed that the #1 plug is always harder to get out. That condition then might be universal and unrelated to your problem.

[w261w261]

From your remarks, it seems that there is adequate flow from the pump (when you removed the regulator). With the regulator in place, the flow is restricted. Why wouldn't it be the regulator, or what else could it be? Are you inferring that the fuel pump might be able to deliver a certain volume as long as it doesn't have to do it against the resistance of the regulator? I can't remember the exact circumstances, but a couple of times in my life I've been faked out by having two bad parts, and, having assumed that the second part couldn't be bad as well, went down some long, wrong paths.

How much does a regulator cost? My philosophy, which is admittedly not the cheapest way to go about things, is to replace something (replace with a new part, usually Honda brand) as a shot, as long as it's the original part, figuring that even if it's proven not to be the problem, in the long run it is one more thing that won't go wrong. To that end, I put in new rear wheel bearings at about 140k. I knew that the rear tires, wearing, could be making a sound which is very similar to a bearing going, but I thought that it wouldn't be a bad thing to have two new bearings in there anyway. Turns out it was the tires, so I was wrong. But I now have new bearings. I can't remember the exact circumstance, but I also had my mechanic put in a new fuel pump, which I probably didn't need right then. But I am now approaching 180k on the SE-i, and really don't want to be in a situation of waiting for something to fail and strand me. I'd rather replace stuff preemptively. Maybe it's because I used to be a pilot and that's the way they do it in aviation.

Sorry for the rant. Good luck.

ps...I grew up outside of Mpls (Excelsior)

[Swap_File]

Well, I did the test again with the car running, and I got plenty of fuel flow with the regulator on. Almost 16oz in 10 seconds. I am not sure why the shop manual says to preform the test while the car is off.

A friend of mine listened to the car and suggested that my problem may be a burnt exhaust valve (or wore exhaust cam lobe). I know my compression tested good, but I do get a bit of backfiring. The backfiring goes away when I unplug the 1st cylinder sparkplug.

I am currently building a leakdown tester ( http://www.xs11.com/tips/misc/misc3.shtml ), and will see what I find out. I already ordered a head gasket set just in case I need it, and will probably practice ripping apart my old junk head from my old engine.

[HOOPTIE]

Well, I did the test again with the car running, and I got plenty of fuel flow with the regulator on. Almost 16oz in 10 seconds. I am not sure why the shop manual says to preform the test while the car is off.

A friend of mine listened to the car and suggested that my problem may be a burnt exhaust valve (or wore exhaust cam lobe). I know my compression tested good, but I do get a bit of backfiring. The backfiring goes away when I unplug the 1st cylinder sparkplug.

I am currently building a leakdown tester ( http://www.xs11.com/tips/misc/misc3.shtml ), and will see what I find out. I already ordered a head gasket set just in case I need it, and will probably practice ripping apart my old junk head from my old engine.
Mine did the same thing but it was #3 cyl. I adjusted the valves and all is good. I was leaning towards a burnt or bent valve and something told me to check the valves and they were way off on that cylinder. Way different now!!!!!!

[bobafett]

just thought i would throw in my input as well..

i was experiencing similar issues. after resetting the valve lash the car fired up and ran perfectly. :) though you have done a compression test, which is something i hadnt done.

so i would give that a shot, its free. :)

[Swap_File]

I had forgotten about this thread... I should have updated it with my final solution.

I did manage to get it fixed about a week after my first post about the problem.

Turned out it was something simple. One of the new sparkplugs I had used was shorted internally. It looked fine from the outside... I finally noticed it when I went to do another compression or leakdown test or something, and reinstalled the plugs in a different order. I could have sworn I had already tried that, but oh well.

My main relay was also weak, which caused some weird fuel pump issues.

It is all fixed now.