Diagnosing multiple misfires in a computer controlled car

[charge70]

No,valve adjustment tightens up with milage,not loosen.Properly adjusted valves do make a little noise.Tight valves are quiet,less gap.

 

[RiverRaider]

No,valve adjustment tightens up with milage,not loosen.Properly adjusted valves do make a little noise.Tight valves are quiet,less gap.

Tight valves cause the missfires. I think the Honda scheduled service is every 30,000 miles to check the valve clearance.

 

[toolmanmike]

Please forgive me if this topic is deemed inappropriate for the forum...
The wife and I have a 2003 Honda CRV that we have had since it was new. We keep it to haul our dogs to the vet and out to play. It has been great and required very few repairs in the 20 years, 130,000 miles.
The problem....Yesterday it was running rough and it lit up the engine light. My code reader showed a DTC of cylinder 3 misfire.
It has sat since New Years eve with the same gas in it since before Christmas.
Today I pulled the coil pack from #3 and swapped it with #1.
Then the code read cyl # 1 misfire. Score...that must mean the coil pack is bad so I bought ONE....$80 retail for ONE.
Back home, I swapped the new coil plug into #1 and started it up. Now I got a code for cyl #3 misfire again. The spark plug for cyl 3 looked okay but I don't recall when I changed the spark plugs. Maybe I should just put in a new set. A closer look at the code reader showed THREE codes....cyl 1 misfire, cyl 3 misfire and random misfire. It does feel like it is missing a bit but not 2 cylinders. Maybe they are intermittent?
I swapped coil packs all around but keep getting the same 3 codes.
I wanted to pull some gas from the tank to get a look at it....cloudy means water in the fuel. The system is sealed but we have had a lot of rain lately and the Honda sits outside most of the time. I went out to drive it to use up some gas but the damned thing barely used any fuel. You'd expect a misfire or two would really cut down on the fuel economy but that wasn't the case. It is down on power though and I can feel the engine lagging.
The fuel filler neck must have some baffle in it because I couldn't get the fuel hose to go in very far. I guess I'll have to just run the gas out and then pour in fresh gas to see if the problem is fuel related. The air filter is fairly new and still clean.
We have mice and rats crawling around this rural area so I looked at the wiring underhood. Nothing looked bad from what I could see but it has happened before. I had to solder in wires for the transmission solenoids a few years ago.
Before I take it to a shop....do you have any ideas on what else I should look for to fix this thing? It seems like I'm forgetting something.
Thanks

Running good one day and then rough the next?

 

[DeltaV]

Running good one day and then rough the next?

The car sat since New Years

The problem....Yesterday it was running rough and it lit up the engine light. My code reader showed a DTC of cylinder 3 misfire.
It has sat since New Years eve with the same gas in it since before Christmas.

 

[toolmanmike]

The car sat since New Years

I didn't read far enough. I tend to turn off when reading more than a short paragraph.
Knowing the timetable, there's 3 pages of armchair diagnostics above that don't apply. Things don't just ''go bad'' while setting in the California sunshine for a month.
This is what we have here.

 

[Rebelrouser]

Please forgive me if this topic is deemed inappropriate for the forum...
The wife and I have a 2003 Honda CRV that we have had since it was new. We keep it to haul our dogs to the vet and out to play. It has been great and required very few repairs in the 20 years, 130,000 miles.
The problem....Yesterday it was running rough and it lit up the engine light. My code reader showed a DTC of cylinder 3 misfire.
It has sat since New Years eve with the same gas in it since before Christmas.
Today I pulled the coil pack from #3 and swapped it with #1.
Then the code read cyl # 1 misfire. Score...that must mean the coil pack is bad so I bought ONE....$80 retail for ONE.
Back home, I swapped the new coil plug into #1 and started it up. Now I got a code for cyl #3 misfire again. The spark plug for cyl 3 looked okay but I don't recall when I changed the spark plugs. Maybe I should just put in a new set. A closer look at the code reader showed THREE codes....cyl 1 misfire, cyl 3 misfire and random misfire. It does feel like it is missing a bit but not 2 cylinders. Maybe they are intermittent?
I swapped coil packs all around but keep getting the same 3 codes.
I wanted to pull some gas from the tank to get a look at it....cloudy means water in the fuel. The system is sealed but we have had a lot of rain lately and the Honda sits outside most of the time. I went out to drive it to use up some gas but the damned thing barely used any fuel. You'd expect a misfire or two would really cut down on the fuel economy but that wasn't the case. It is down on power though and I can feel the engine lagging.
The fuel filler neck must have some baffle in it because I couldn't get the fuel hose to go in very far. I guess I'll have to just run the gas out and then pour in fresh gas to see if the problem is fuel related. The air filter is fairly new and still clean.
We have mice and rats crawling around this rural area so I looked at the wiring underhood. Nothing looked bad from what I could see but it has happened before. I had to solder in wires for the transmission solenoids a few years ago.
Before I take it to a shop....do you have any ideas on what else I should look for to fix this thing? It seems like I'm forgetting something.
Thanks

The missfire counter in your computer operates off of crankshaft speed, if the computer sees the crankshaft slow down at the same time it sets a code for that cylinder. Or if it can't pick out a cylinder it sets a random missfire code. Often when an engine missfires it will affect other cylinders close to it in the firing order depending on what the problem is. If you can get to the coil pack connectors just unplug one at a time to do a cylinder balance test to see which cylinder is missing the worst. Just listen and feel the vibration, if you unplug one and the engine does not change it is the weak cylinder.
Then what I would do is pull the plugs and do a compression test. If compression is good start with the rest of the ignition system.
You said you have over 100,000 miles so why do you think it would not need plugs? One of the killers of coil packs are huge gaps on worn plugs, bigger the gap more energy required to fire the plug.

 

[toolmanmike]

I don't think anyone mentioned a critter chew on a wiring harness. Looking for something that could happen while the car sat for a month. (like fuel gone bad)

 

[DeltaV]

I don't think anyone mentioned a critter chew on a wiring harness. Looking for something that could happen while the car sat for a month. (like fuel gone bad)

Keep reading

 

[toolmanmike]

Keep reading

Now that's funny. 4 pages. I don't have the time. I haven't even been to C bodies yet this morning.

 

[eldubb440]

these guys need to appear in the "DOGS" thread every now and then

 

[DeltaV]

Old Honda with 130,000 miles, but let's recap:

Valves haven't been adjusted
Spark plugs haven't been replaced
Coil packs haven't been replaced

Someone said Mopar guys are cheap, but dang @Kern Dog !

 

[QuickBpBp]

After thinking about this it literally could be the loss of a good ground... Happened on my sons Mustang his had "misfiring" and a discharge situation. He spent $$$ on parts NOT needed but 3 different shops recommended "this" was the 'issue". We replaced 2 alternators, 2 batteries, a computer and had to reprogram keys. Still did the same thing. We were replacing what the shops said was testing "bad" as it turned out I found it was just a bad ground at the radiator support. Cleaned it up, put dielectric grease been fine for few years now.

 

[MarPar]

After thinking about this it literally could be the loss of a good ground... Happened on my sons Mustang his had "misfiring" and a discharge situation. He spent $$$ on parts NOT needed but 3 different shops recommended "this" was the 'issue". We replaced 2 alternators, 2 batteries, a computer and had to reprogram keys. Still did the same thing. We were replacing what the shops said was testing "bad" as it turned out I found it was just a bad ground at the radiator support. Cleaned it up, put dielectric grease been fine for few years now.

Ah yes. The low-hanging fruit. 9 times out of 10 it's that damn fruit.

 

[toolmanmike]

Old Honda with 130,000 miles, but let's recap:

Valves haven't been adjusted
Spark plugs haven't been replaced
Coil packs haven't been replaced

Someone said Mopar guys are cheap, but dang @Kern Dog !
View attachment 1614026

All of it is probably needed but what on that list shot craps while the car sat in the garage for a month? I'm sure it didn't loose valve adjustment on all cylinders in a month of setting. Just sayin. Something is causing a "random misfire" that skips around to different cylinders.

 

[toolmanmike]

Here's something no one has brought up. Someone got ticked of at KD and jammed a potato up the tailpipe.

 

[Geetex]

Here's something no one has brought up. Someone got ticked of at KD and jammed a potato up the tailpipe.

If that's the case, I would suspect car forum moderators first.

 

[Kern Dog]

Old Honda with 130,000 miles, but let's recap:

Valves haven't been adjusted
Spark plugs haven't been replaced
Coil packs haven't been replaced

Someone said Mopar guys are cheap, but dang @Kern Dog !

I have changed the plugs, I just don't remember exactly when. I keep excellent records of maintenance for the Truck and Challenger and almost fanatical notebook on the classics. This Honda? Barely any records of what I've done to it.
I do change the oil twice a year despite only driving it about 500-700 miles each of the last few years.
The engine is quiet but has never been impressive in regards to power. The wife absolutely LOVES the Challenger simply because it scrams compared to the Honda.
I'll admit, adjusting the valves has never crossed my mind because it is quiet. Valve lash closing after time? That seems so counter-intuitive to me.

 

[RemCharger]

I have changed the plugs, I just don't remember exactly when. I keep excellent records of maintenance for the Truck and Challenger and almost fanatical notebook on the classics. This Honda? Barely any records of what I've done to it.
I do change the oil twice a year despite only driving it about 500-700 miles each of the last few years.
The engine is quiet but has never been impressive in regards to power. The wife absolutely LOVES the Challenger simply because it scrams compared to the Honda.
I'll admit, adjusting the valves has never crossed my mind because it is quiet. Valve lash closing after time? That seems so counter-intuitive to me.

Yeah, the exh valves close up and the intakes get looser. It was bad with the 1st gen B series motor.
It's a good idea to see what's up. Especially if you're retired

 

[Kern Dog]

Yeah, I'm surprised how many things seem to be pulling me in multiple directions...
Tree fall and disposal:

Dwayne's Plymouth A/C installation:

The dogs needing their attention....

PLUS....as the "retired guy", I took on 90% of the housework to lessen the load on the wife.
Working 40+ hours a week sometimes seemed like an easier life.

 

[moparwacko]

Yeah, I'm surprised how many things seem to be pulling me in multiple directions...
Tree fall and disposal:

View attachment 1614148View attachment 1614149

Dwayne's Plymouth A/C installation:

View attachment 1614150

The dogs needing their attention....

View attachment 1614151

View attachment 1614153

PLUS....as the "retired guy", I took on 90% of the housework to lessen the load on the wife.
Working 40+ hours a week sometimes seemed like an easier life.

Wait until your inner chef comes out. As the "retired guy" here, I do 90% of the cooking. I'm always trying new stuff, and sometimes not successfully. As for the rest of the house stuff, nope. Tip of the day- turn everything pink one time in the washer and you get a lifetime ban.