Hey guys, need some help.

I have been searching this site for days but can't seem to find the answer to my issue.

I have a 96 accord 5 speed 2.2 with the vtec. Approx 200k miles.

The car has been driving great up to about 3 weeks ago. It developed a pronounced miss under light acceleration at first. It has gotten progressively worse to the point of misfire at idle and WOT.

A week ago, I was starting my drive home from work. The car idled for about 5 minutes before heading out. Idle misfire present. Made it about one block, car died. Immediately restarted for 30 seconds, died again, no restart. Came home on the hook.

Started diagnostics. Found a bad spark plug wire. Decide to do a tune up as it was well overdue. Used Honda parts and replaced the plug wires, cap, rotor and swapped the ngk spark plugs. Car started and idled fine on high idle. When warm, the miss reappeared. Holding the throttle to 1000-1100 rpm showed no signs of the miss.

After test driving, the idle miss has remained. Cruise seems to be fine. I cannot see, feel, hear anything although it may be happening at cruise. And WOT usually results in backfiring.

Never have had a CEL set. No codes when pulled with a scanner.

Alternator appears to be okay as battery is charging.

Cleaned battery terminals and lugs.

Checked all grounds. Everything looks tight and clean.

No jumping of the tach gauge. Simply follows the speed of the engine including the lower idle from the miss.

Used a inductive timing light at night and observed the flash. The miss shows up immediately by the light not flashing. Does this on all four wires.

Okay, so how to I diagnose this without replacing everything under the hood? Since I have no CEL and no codes, and based on my initial findings, I am thinking weak spark due to a failing coil. How can I test the coil is getting a constant signal from the igniter with the car running? How can I verify the ecu is sending that signal to the igniter?

Just need some help so I am buying the right parts. Everything points to ignition components.

Thanks!

Dave

 

Any suggestions?

I have to get this thing running right.

Thanks

Dave

 

I could give you a crapshot guess, but instead I'll post a helpful link for you to do diagnostics...

http://techauto.awardspace.com/ignition.html

 

Thank you. I actually came across that on a search. Since my car runs, none of the diagnostics directly apply. There are some good bits of info as to what connects to what.

Maybe I'll try cutting a Window into my old cap and see if I can rig up a led to see the trigger events. Sure would be easier with a scope, wish I had one! Tough nut to crack.

Thanks again

Dave

 

I only know my civic, but does your accord distributor have an ignition control module? It tells the coil when to fire. If it does you might want to take it in and have it tested.

 

Yes it does. I had no idea I could have it tested. Is this a Honda only service? Or can I get it done elsewhere?

Thanks!

Dave

 

That is what the 'igniter' is. It can be hard to test if it only fails when the engine is warm. Would need to have a meter hooked up to it and watch for intermittent voltage issues.

 

Okay. This what I thought. I get the miss as soon as it comes off high idle. The car is not even to operating temp yet.

Dave

 

have u ever replaced the oxygen sensor ? if u do only buy Denso

 

I have replaced the O2 sensor once. Had a check engine light and horrible economy. Could a bad sensor cause the engine to not have spark when running?

The frustrating part of this whole thing is that I don't have a no start condition. If I did, it would be easy to diagnose.


Dave

 

A car engine needs 3 things to run:
1) Air
2) fuel
3) Ignition source

I know you have done an ignition tune up. How is your air filter? Clean, replaced? Clean your throttle body with throttle body cleaner fluid.

Any ideas about the fuel filter? Do you know if you are getting proper fuel? Bad gas has also caused my car to run LIKE CRAP in the past. Try getting a full tank of good brand gas from a gas station which is very busy, close to the busiest intersection in your town. My boat mechanic told me that gas stations that are not busy tend to have lots of water in their gas, and he has had a lot of boat repairs from people using gas with water in it. You could also use some fuel injector cleaner in your gas. I use "Lucas tune up in a bottle".

Have you ever cleaned your EGR and IAC valve? I am not sure if these would cause misfire, but now would be a good time to give them a full clean up. You can also check out the condition of your fuel injectors and give them a good clean.

For your ignition, you can probably do a spark test to make sure that spark is going to each plug. Pull out your new plugs and inspect them to 'read' their condition. You could also do a compression test on your engine while you are on it.

 

I appreciate the response. I did not include my basic info in the first post.

After the initial issue I had I did the following.

Complete tune up with honda parts. Cap, rotor, wires and ngk plugs. Gap was verified. New oem fuel filter verified fuel pressure. New air filter. Car started, had idle miss.

Cleaned IAC, EGR with all the passages and throttle body pulled off the engine and cleaned. Even lubed up the cables. Idle miss still present.

I have used a quart of oil every oil change forever. Did a wet and dry compression test. All cylinders within 5%. Did a leak down to verify oil consumption is in the guides.

I did not do anything with the injectors. I planned on ultrasonic cleaning them. Waiting on o-rings.

The only constant I can locate is all cylinders show loss of spark when running. It's random. I would love to be able to accurately test output to reach plug. Don't have the equipment for that. I really need a way to "see" the trigger events from the ecu and the ignitor to accurately tell if the coil is getting the proper signal to even fire.

I'm definitely not a pro mechanic. I have an extensive background fixing things with wheels, tracks and turbos. My home built sequential efi on my 68 Pontiac is like a carburetor and points compared to this thing.

Dave

 

The ecu advances and retards timing accordingly. As long as you have confirmed strong spark, that's normally sufficient. You may be reading a little too much into seeing random spark. If spark totally stops that a different story.

 

Yes. Spark stops randomly on each cylinder. This coincides directly with an audible miss.

Dave

 

Did you test the coil for resistance ? Should be .09 ohms or so on the primary and atleast 13k on the secondary or visa versa, can't remember at the moment. Normally this is all you need to do to find a bad coil.

 

fishin2deep4u I initially suspected your Igniter may be going out, but the tech auto link would be a better solution to go through the process and verify. With that said, when ignition components like the igniter begins to fail it will have an intermittent issue. If you can witness spark loss/drop while the engine is running more than likely it is the igniter. Most of the other components in the system are fairly simple and 'dumb'.

The igniter is the halls effect device that controls when the coil fires, coils rarely fail. Hall effect devices can be a PITA to diagnose, as they may have an issue only once in a blue moon, a random intermittent issue, or flat out die without any previous issues.

As holmesnmanny said, the spark timing is controlled by the ECU. With the car warmed up, turn off the engine, jump the blue two wire connector. This will disable ECU adjusting the timing. Restart engine. If you still see the spark drop/loss event while using your timing light, then you will know it is a real event, and not the ECU doing anything.

 

Ya, there you go, do what mike said and jumper the service connector.

 

I did check the coil. Should have brought it inside to allow it to temperature stabilize. Been below freezing for several days.

Got .7 ohms on the primary and 20.3k on the secondary. Picked up a replace meet coil and it was at .5 ohms and 19.29k ohms respectively.

Dave

 

Perfect. I'll give that a shot tomorrow. Still too much snow on the car to do it tonight. I did not realize the ignitor was a halls effect device. I assumed, probably incorrectly, it was a solid state switch. And the pickup near the distributor shaft was a magnetic pickup.

Thanks so much and I'll report back!

Dave

 

Was there any dust inside the cap ? Sometimes as the distributors age the bearing starts to go and it starts giving off this red dust that can get inside and prevent the sensors from reading properly.

 

No. Was very clean and oil free.

Dave

 

I may have mispoke.
On the 96/'97 the cyl sensor is down on the crank and it the pickup for actual crank position, however it is a ~$300 part.

Again if you can diagnose the part via the TECHAUTO website then I think you will be golden. Test both Igniter and Crank sensor.

 

No problem!

What's the web address for techauto? I cam up with a few sites doing a search.

Thanks again.

Dave

 

The link in post #3 is for ignition testing.

 

Okay,

Jumped the service connector. No codes were stored first off. I verified the base ignition timing as well.

Same issue as before. As the water temp climbs, the miss gets worse. It is definitely dropping spark. I did not drive the car to warm it up. Just idled in the driveway. Within minutes of settling down to normal idle, the miss reappeared. The temp gauge was of the cold post, but nowhere near normal operating temp when the miss began.

Does this result tell us anything?

I am gathering some parts to build an led tester to hook up to the negative side of the coil and the triggered side of the ignitor in hopes of finding the problem before the ecu.

Just a thought, could an internal problem with my alternator be causing any of this? I have no reason to suspect it, but I have seen funny things with electricity before. I know the battery acts as a filter, just curious.

Dave