sa863c

I have a 96accord, 190K miles, new motor about 2k miles ago. Sorry if this post is long, but i think lots of details are needed.

About a month prior to swapping my motor i had a misfire problem; i was leaving work one day, foot to the floor, just shifted second gear and the car fell on it's face, MIL indicator came on. I drove it around the block and back into the parking lot, fiddled with it for a few minutes(pulled each plug and watched the motor run more rough, got to cylinder 1 and no change-->problem with cylinder 1). So I shut the car off and check all the plug wires connections to the distributor. I started the car back up and it ran fine all the way home (70 miles). the next day, the car was going to honda for an alignment, so i asked that they check out the trouble code and see what the problem was. they told me that it was a misfire in cylinder 1 and they would replace the cap / rotor / wires / air filter / plug under some warranty extention. I got the car back and it ran fine, for about 2 weeks.

I was 1/2 way home from work one day and the same exact thing happened; car fell on it's face and began running really rough. i pulled over and checked all the sparkplug wires, again pulling one at a time to look for a change. Surely enough I got to the number 1 cylinder and there was no change. At this time I am thinking that it is a faulty injector, so I popped off the injector wire for the #1 cylinder and verified that it was getting current via a test light. That furthered my idea that I had a faulty injector. So I drove the car the rest of the way home with intermittent sessions of misfire( it would 'clean itself out' for short periods of time). of course within 5 minutes of my house, the problem went away and didn't come back. At this time I had my newer motor sitting in the garage ready for a swap and yanked the injectors from it putting them in the car. I had also purchased a OBDII scan tool by this time and once again the ECU read misfire on cly 1. I cleared the code, threw in a bottle of 'NOS fuel injector cleaner' and everything was great.

I swapped the newer motor in about a month ago and it has been running great, except a small very minute idle problem(seems to jump around a bit +/- 50 rpm). Today, I got stuck in traffic on my way to work for about 1.5 hours. When the traffic finally broke and I started to accelerate the misfire problem returned. i turned back for home and the problem didn't corret itself until about 5 mintes from my house. So i decided to drive right by and get a bottle of fuel injector cleaner from the auto parts store. I ran fine all the way there and most of the way home. Once home, i put the injector cleaner in and let it idle for about 20 minutes and once again the mysterious problem went away. I pulled the plugs and all of them look fine. i checked the injetor resistance and it was fine. I swapped the #1 and #2 injector just to make sure and drove it around this afternoon, about 50 miles...no problems.

Just for a bit more details: the wiring harness and the fuel rail is from my original motor,the injectors are from the newer motor, and the only sensor the was moved over was the IAT; and since the ECU isn't reporting weird temps, I guess it isn't that.

Does anyone have any ideas?

My current thinking is that I am going to replace the fuel filter and have it Mitovaced? I haven't checked the fuel pressure yet, but in 15 years of playing w/ cars I have never seen a fuel pump die intermittently. The thought that the wiring harness has a broken wire has crossed my mind, but if true the problem should present itself differently.


Any help would be greatly appreciated


Thanks

-Keith

sa863c

I think I have narrowed the problem down to electrical. The problem reproduced itself over the weekend and I whipped out the multimeter and began testing. I verified that when actively misfiring, the injector wasn't working. I checked the voltage on injector wire 1, 2,3,4. #1 wire voltage was about 90% less than all the others. Since I don't have a PGM tester, it is kind of hard to diagnose the ECM versus the engine harness, however my money is on a broken wire in the harness.

I called honda, and I am going to let them diagnose the problem from here...

Has anyone ever had an engine harness go bad? How about a ECM? My thought would be that the ecm would just go bad and die, not go bad intermittently

ItsaHonda

Im surprised they did the emissions extention warranty tune-up with 190k miles on the car, since the recall only called for free tune-ups up to 150k miles.

sa863c

speedo has been broken for 40k miles... and the people at the dealership i go to are really nice...