Diagnosing multiple misfires in a computer controlled car

[Don Frelier]

Tip of the day- turn everything pink one time in the washer and you get a lifetime ban

Yes I was banned years ago (it wasn't intentional)
I got in trouble just a week ago by moving stuff from the washer into the dryer and starting what I thought was the last load.
Nope got it totally wrong...

 

[Triplegreen500]

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.

And THIS is the argument why our classic cars should be allowed to stay on the road.

WE PAY ATTENTION TO THEM.

Modern stuff....just like a dishwasher. Functional, NOT sexy, NOT fun, NO emotional attachment. Run 'er till she breaks, then a) fix 'er, or b) toss and replace. But our classics? Don't get a CHANCE to break - we're too busy loving on them!

 

[Kern Dog]

Dishwasher….
The mundane daily drivers really are like large appliances.
The slant six and 318 cars were probably treated this way when our classics were daily drivers.

 

[MarPar]

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

 

[eldubb440]

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.

retirement sounds over rated

 

[Kern Dog]

Oddly, I did look to see to make sure it was unobstructed.
The tail pipe was wiggling a bit.

 

[eldubb440]

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

turns out it was just a banana

 

[moparwacko]

retirement sounds over rated

Rebuild a YJ front end one day, bean and ham soup the next.
Setting valve lash on a Honda?
Why not, I'm certified.

I'm not a Honda tech, but I may have played one on the interweb.

 

[eldubb440]

Rebuild a YJ front end one day, bean and ham soup the next.
Setting valve lash on a Honda?
Why not, I'm certified.View attachment 1614213
I'm not a Honda tech, but I may have played one on the interweb.

I stay at a Holiday Inn whenever possible.......

and I've been retired since I was 24............ trust me, it sucks

 

[Kern Dog]

I’m on my way to get a Chilton repair manual. I like books for this stuff. The internet is great but the tactile feel of holding a repair manual just seems right to me.

 

[eldubb440]

I’m on my way to get a Chilton repair manual. I like books for this stuff. The internet is great but the tactile feel of holding a repair manual just seems right to me.

problem with the internet, is you get conflicting information

 

[Kern Dog]

The people are well meaning. I appreciate those that offered advice.

 

[moparwacko]

problem with the internet, is you get conflicting information

What you don't trust watching Hernando do it in less than 5 minutes?
If it's on the internet it's got to be real.

 

[Kern Dog]

New spark plugs and fresh gas….
The problem persists.

Yeah….
First, the man gave me the wrong spark plugs… 13/16 sized instead of the smaller 5/8”.
Here is how the old ones looked:

Cylinder 1:

Cylinder 2:

Cylinder 3:

Cylinder 4:

New plug:

I set the gaps to factory spec.
The tank was down around 1/8 so I topped it off with 89 octane Chevron gas and drove it 15 miles.
It still posts the same 3 codes. It sometimes stalls at idle. It alternates between a slightly rough idle and an idle that feels like it used to run.
Power is down. Braking seems fine so it makes adequate vacuum.
Next up, valve adjustment with the engine cold. I still can’t find any chewed wires but there is plenty of other chew marks. The washer fluid reservoir has holes in it, the insulation on the outside of the firewall does too. There were numerous nut shells and turds in a few places under the hood.
If it runs the same after the valve adjustment, I guess a compression check might reveal something. I’ll need to look closer at the wiring too.

 

[Triplegreen500]

Cylinder 1 looks rich...lots of carbon. Either weak spark, or buggered injector?

 

[Kern Dog]

Numbers 1 and 3 look worse than 2 and 4.
The MIL shows Cyl 1 misfire, Cyl 3 misfire and random misfire.

 

[Kern Dog]

The repair manual.

The schedule:

 

[70 GTX-R]

First thing, what kind of misfire is it? Dead mis? Cold start misfire, hot misfire, under load misfire, at idle, intermittent? Does it run ok cold and get worse going to operating temp?
You did the correct first steps, move coil and plug.see if change. No change. How capable is scan tool? With the misfire cylinder codes and no circuit codes, would be unlikely a bad wire from rodent. Next step I would do would be compression test. It’s easy and fast on that one. I have fixed a few Acura’s that the valves and seats wore causing the valve lash to go tight. Both those were the v6 ones.This usually causes the misfire to get worse when it gets to operating temp from heat expanding valve and not sealing cylinder. I also look at a bunch of scan tool data. Sounds like the valve lash should be done regardless as a maintenance item. So good to rule out regardless.

 

[MarPar]

 

[Kern Dog]

The misfire does not change from dead cold to operating temperature. It didn't feel that bad under a load but the power was down. The code reader isn't a real expensive one. I bought it about 10 years ago for around $100.