Dungeoner

I have a 97 Accord SE 2.2 (Non V Tech). It's my son's car

Car misfired badly & the engine light was on so I checked things out.


2nd cylinder was leaking oil onto the plug from the tube seals. Cleaned it all up. Changed the seals & valve cover gasket, all shiny and like new & everything. Still same prob. Took it to my old man's shop. Has all state of the art Snap-on scanners & all that nice stuff. Only error code produced was a misfire on cylinder 4. Okay. not the same plug that was saturated with oil, but who cares.

Changed plugs & wires. . . . Same problem. Same code/message

Checked compression in all cylinders. All perfectly fine.

Checked fuel injectors with the light kit. Showed poor power getting to the 4th cylinder compared to rest. Figured okay. Maybe a bad PCM. gotta a place near me that has them cheap enough, so I picked one up. Installed it. . . Same problem. Same exact code/message

Checked wires on the PCM/ECM plug while plugged in & running, to all fuel injectors, via AllData wiring schematic. The power coming out of the PCM to the plug was equal to all injectors. Odd... Checked all the injector plugs at the motor, to see if the juice getting to them was equal also, and sure enough, it was. Not sure why the test kit showed poor power the first time. Perhaps it was a fluke or perhaps my old man plugged the wrong light from the kit, in. Who knows. But since then, I used a trusted & true test light. Anyway... Kept getting the same message each & every time about cylinder #4 misfiring, so I said screw it & bought a new injector & switched it out. Same problem. Same code/message.

I even tried wiring the ground coming out of the PCM plug for the 4th cylinder directly to the ground on the injector plug at the 4th cylinder injector figuring maybe the ground got corroded or broke somewhere along the line, again with the same results. I even tried grounding the injector plug directly to the main ground coming out of the PCM plug. Same deal.

The car runs just as rough with or without the 4th injectors plug plugged in so it seems like that cylinder is starving for fuel. This was with both the old & new injector. If I unplug another injector, naturally the vehicle stalls out. So...

I'm running out of things to try here & figured I'd give this a go. I'm not a Honda pro by no means. I might know a thing or two here & there, but I know when I'm beat & I'm beat. So, HELP! Please... lol

skracer13

First of all, your ECU sends a negative pulse to your injectors, power is supplied as an constant when ignition is on, grounding the injector wire would only keep your injector at 100% duty cycle which is bad (always allowing fuel flow). You didn't mention that you changed the rotor button and cap. A crack in the cap will cause irregular arcs and misfire. Check that first.

Dungeoner

Thanks for the reply.

Yeah I didn't mention the cap & rotor. I had changed that 2 or 3 weeks prior to this happening. For some reason this car has a history for cracking caps & making starting it a nightmare in wet weather days.



As to the ground wire by-pass... that was done to see if I can get fuel pumping into the injector, which did not happen... or if it was, was happening way too little.

I might as well check the cap again. As I said, this car does have a history of cracking them. Though I tend to lean towards the manufacturers making inferior products nowadays. Can't hurt to check & it would be a lot cheaper.

fastlane2

Mesure the resistance on the coil, the wires should be between 10k-15k ohms. All checks out whats your vacum with engine running. Whats your TPS voltage via your snap on tester, whats you Map values are they with in spec?, Any by the way I've had nothing but problems from anything but OEM igntion wires and cap/rotor.

fastlane2

http://www.obd-codes.com/trouble_codes/honda/

Also there is no such thing as a cylinder miss fire code on that model. Look on the page above

Dungeoner

Splitting hairs here. I said code/message. And since I did research it, the code is:

P1204 Cylinder 4 Misfire - Compare possible causes/symptoms for this Honda check engine light code to the Generic OBD II code P0304


Which was taken from the link that you provided no less.

However... thanks again for the input.

skracer13

Is P1204 the actual code that you got? I know you said that you got a new injector for #4 (from honda I assume) but try swapping the injectors around. Really, you can listen to your injectors while your car is running and listen for them to be ticking. Also, forgot to mention, seem like you have a good source for info at your dad's shop. Check the TDC and CYP sensor to make sure they are ok. Use an air gun to blow out any possible metal shavings inside the distributor assembly. And lastly make absolute sure your compression (do a leak down as well)is good and all four cylinder is within a certain amount of psi of each other.

fastlane2

Unplug cylinder 4 spark plug wire, what does it do?

slomofo

iTrader: (1)

Get an ohm meter and check the ohms from the yellow wire coming out of the #4 injector to the yellow wire on the ECU harness. The ECU wire location is A1. Ohms should read 0 and if it doesn't, you've found your problem.

Do you have an injector node tester by chance? If so, plug it into the #4 cylinder's injector plug and see if it's functioning properly.

Check these first and come back if it ends up being okay.

01S2king

iTrader: (1)

adjust the valves

Dungeoner

Hey all. Thanks for the replies. Still working on it. Been slacking the past few days.

Haven't gotten it back to my father's shop yet since the last check. Though I did just rip off the cap & yet again it looks cracked. Gonna go replace that & see what happens. As to taking the 4th cylinder plug off, it pretty much runs just as rough as if I left it on. If you pay really close attention, it fluctuates ever so slightly when the plug is put back on. Again, both ways are still within the poor performance margins by a long ways. lol

I'll update again once the cap & rotor are replaced.

Dungeoner

Back again.

Changed the cap & rotor. Still have the same problem.

Compression is fine & no leaks in the 4th, or any cylinder for that matter.

The injector node (the light with a little injector plug to check for correct power/pulse) tester kit was used first, which is mentioned in my thread starting post. Was faint when first checked. The other cylinders seemed strong & normal. When I checked with a test light after that, it appeared to be the same as the other cylinders.

As for the ohms, wouldn't bypassing all the wiring harness wire from the yellow wire from the injector, directly to the yellow wire on the ECU with a separate wire fix the problem if it was a faulty wire within the harness? As long as I don't have two ECUs with the exact same issue.

Thanks for the ideas all.

kageshin

just a couple of suggestions:
1.) recheck the gap and be sure to use NGKs
2.) check fuel pressure/PCV valve(also make sure canister is not clog/IAV
3.) ign control modules or 4th wire arc to chassis?

phootbag

I've read the thread you have here and it appears the problem is directly related to cylinder 4. That is good because it narrows things down quite a bit. This rules out things like fuel pressure, ignition coil, igniter, CKP sensors and stuff like that because those items will affetc all cylinders equality ( usually ) when they fail.

Check your spark plugs for cracked insulators, worn electrodes or anything else that could make the spark plug short circuit preventing proper ignition.

You can carefully remove the spark plug and insert it into the number 4 ignition wire, touch the tip of it to the valve cover bolt and watch the spark to observe it's health. * besure to unplug the #4 injector to prevent a fun and exciting fire in your face *.

Measure the current pattern on the #4 injector and compare to the rest. That will tell you if there is a problem with the injector or the driver/wiring to/from the injector. The problem will be simpler than you think. Focus on cylinder 4.

Dungeoner

*Update*

After hours of checking things out, the culprit was found. It was the positive lead going to the 4th injector. It was getting ground, but was losing power somewhere between the plug & ECU. A little wire jumping here & rerouting there & all is fine again in the Accord world.

Thanks for the help & ideas all.