Diagnosing multiple misfires in a computer controlled car

[Don Frelier]

Maybe just a 3rd gen hemi swap???

 

[Kern Dog]

Have you ever had the valve lash checked/adjusted? Might be a tight valve that may cause the misfire.

I thought about this. The engine runs quiet, no clattering at all. I'll have to look and see if valve adjustment is part of the service schedule.

If you change the filter you can take a sample of the fuel.
You may be correct - water in the gas.
If that's the case just try adding some Heet or other fuel additive and keep driving it.
Burn as much as you can then get fresh fuel in it.

I've never changed the fuel filter, I'm not sure where it is. My 2007 Dodge only has one in the tank itself.

And pick up the trash in your yard.
It's probably what is attracting the rats.

There is no trash in the yard. I live in a semi rural area near a big lake. We get rodents, coyotes, rabbits, turkeys and even deer sometimes.

How is the battery ? All the electronics in new vehicles put a drain on battery. Had similar problems with 2015 jgc , new battery took care of it.

The battery is dated 2015! I was shocked to see the date yesterday, I didn't think it was that old. The engine cranks over like it should.

check the air filter while you're at it......it won't be you issue, but mice can live in the box and jam it up

Thanks, I did. It was replaced about a year ago and looks new. I thought just what you did...that maybe it was chewed and blocking air flow.

I took some spray cleaner and sprayed every hose and wire connection to see if the engine stumbled. It didn't change. I suspected a possible vacuum leak but so far, I haven't found one.
I think I'll start with spark plugs and test the voltage at the battery. A FBBO member PM'd me to say that some new coil packs have been known to be bad and he suggested to look for used ones. There are a few self serve junkyards here near me so I have that option to explore as well.
Thanks guys!

 

[DeltaV]

I went out to drive it to use up some gas but the damned thing barely used any fuel

On top of the engine (somewhere) there will be a fuel rail with a pressure regulator along with all lines going to the fuel injectors, as well as lines from the tank (supply) and back (return) to the tank.

Find the fuel return line, disconnect it, and run a line from where you disconnected it to an empty gas can. Start the engine and capture all of the gas that would normally return to the tank. It will take a few minutes. You'll probably need a couple of gas cans.

Note: The fuel pump supplies a lot more fuel flow to the engine than needed to run the engine. You might be surprised at the amount of fuel flow that normally returns to the tank.

 

[Kern Dog]

Thanks, Wayne.
I'll get out there elbows deep as soon as the Satellite TV repair guy comes and goes.
Last Summer my roof repairs required me to pull and reinstall the satellite dish. Our reception has been spotty on windy weather so I suspect it is out of alignment and needs a "reset".
I'm a hostage to the house until the dude decides to show up.

 

[RemCharger]

I have an 08 outside that I figured needed plugs due to a slight intermittent miss ( and I know these folks are low on the maintenance scale). So I figured nows a good time to have a look.. it has 170,000 miles on it. The jury is in...

 

[Kern Dog]

You posed all the parts quite well. Kudos for presentation.
The only plug I pulled was #3 and it looked good. I'll still replace them all.
Did your work stop your misfiring?

 

[Triplegreen500]

Computer cars look at a few parameters, for proper timing and firing:

1. base timing
2. fuel pressure
3. air pressure (MAP or MAF)
4. fuel timing
5. spark timing

You can check injectors with a stethoscope...but that won't tell you if they're plugged, only if the servos are clicking open and shut.

Best bet is to play musical plugs, and drive. Test. Follow the changes. Then, play musical coils, drive, test, follow the changes. Lastly, play musical injectors, drive and test. See if any of those produce a pattern.

Clean (or replace) the MAP/MAF. If that gives a bad reading to the ECM, the ECM will have the wrong mixture baseline and it'll put the wrong requests into the injectors and feed either too much or too little fuel, causing a misfire.

Fuel filter may well be non-serviced, part of the in-tank pump. Agree with the idea above to pull the return line, and bottle the excess until you can put fresh fuel in the tank. Keep the old stuff for a mower or something.

You could be getting a random misfire from a worn timing chain/belt. What's the replacement spec for this engine? If you haven't done it....DO IT. If it breaks, you now have a disposable car - head, valves, pistons, and timing set will need to be replaced. "Interference motor" - valves hit pistons when timing is out of whack, and things bend, crack, and dent.

If you replace plugs, INSTALL STOCK PLUGS. And coils. Seriously. You can try aftermarket stuff later, once you have solved the problem...but aftermarket stuff will likely CAUSE problems. Don't go trying to reinvent the wheel, just use stock stuff. You got how many miles out of them? Don't cheap out over $20 worth of plugs....it isn't worth it.

 

[Kern Dog]

Good points made, gents. I appreciate it, especially since this is a Honda !

 

[DeltaV]

His Honda might have a non-interference engine, but change the timing belt anyway and check the tensioner and associated pulley.

The Gates company has a downloadable PDF file for timing belts and it identifies whether or not an engine is "interference".

Your Honda FSM should say if your engine is non-interference or not.

 

[RemCharger]

I don't always present well, but appreciate the positivity.
Just pulled them out, have to run and get some. I can pretty much guarantee it'll clean this up though.
There was no MIL for misfires ( yet)
You could pull the coilpack and stick a plug in there grounded with a jumper cable to have a visual.
And the fuel system is returnless, but easy to pull the fuel line disconnect and pump some in a can

 

[RemCharger]

These are chain drive. It would be noisey long before something real happened.

 

[DeltaV]

the fuel system is returnless

Ugh, those rascals.

BMW owners shouldn't reply to questions about Hondas!

 

[Triplegreen500]

I didn't think there had been ANY non-interference OHC engines since the death of the Mopar 2.2/2.5's....but I suppose it's possible.

I used to work in a metric service lane. Noisy chain? Replace the entire timing set. Noisy tensioner/idler? Replace the entire set. Belt? Check the mileage and replace the entire set.

Chains are not typically scheduled-replacement (in theory)...but noise and/or slop? Swap it out.

If the car has VVT (variable valve timing), it could be part of THAT system. Mazdas, and VWs, we'd run into VVT issues - one of them (can't remember which) was driven by oil pressure switches, and those pressure-driven switches would plug/clog, causing the variable valve system not to work properly, or to get stuck somewhere in the advance/retard curve...and THAT will cause misfires. Think "plugged vacuum advance", only oil-driven. Usually no companion codes, either, so the tech just had to know it was a genetic issue for X motor with Y miles...or dirty oil... Just have to know what to look for.

 

[alsant]

Mine cranked over good to , But over the weekend I would'nt drive it and monday morning I would have the issues

 

[Budnicks]

His Honda might have a non-interference engine, but change the timing belt anyway and check the tensioner and associated pulley.

The Gates company has a downloadable PDF file for timing belts and it identifies whether or not an engine is "interference".

Your Honda FSM should say if your engine is non-interference or not.

Wayne Timing "belts"
aren't they supposed to be changed, like a 60-70k mile R&R deal ?
check the belt tensioner maybe (get a new one if you do the belt),
if you're in it that far, might as well change the timing belt too

if it skipped timing, or a tooth on the belt
IMHFO it'd be way more than an intermittent miss, it'd run like ****
if it even ran
the belt could be (?) stretched some 'maybe',
bouncing around, tensioner not doing the job,
if it has more than 60k
it's time & it's due (both)

Honestly
I'd bet it's fuel or ignition related, injectors need a cleaning
fuel filter, maybe a bad wire, a bad plug
or even a bad coil, but don't think the coil would be intermittent
it'd be a constant miss

or maybe bad ground somewhere, messing with the computer
they are finicky like that, check all chassis to engine & body to chassis grounds
if any are loose (?)
take the bolt out, clean both surfaces & put some dielectric grease
on the connections & reinstall

clogged catalytic converter (?)
I'd assume it would have loss of power everywhere,
if that was the case,
& they start to rattle too, before that happens "usually"

you could pull plug wires, 1 at a time,
till you hear it not change or change a lot
if it's a dead coil or bad plug not firing, that's the poor mans scope
don't get zapped, it hurts
open the hood when it's dark out,
then check see if any crossfire or arching going on

most are common sense type stuff

edited added;
*check MAP &/or MAS sensors, maybe dirty
*O2 sensor (?) acting up

I'm not a Honda tech,
but I once played one on a MoPar forum

 

[DeltaV]

aren't they supposed to be changed, like a 60-70k mile R&R deal ?

Depending on model year and engine for Audi, Porsche (944 family and the 928), and VW I recall 30k to 50k.

If BMW ever used a timing belt, then it was probably in the 1980's 3-series cars and they will be interference engines . I don't know about the 5-, 6-, or 7-series cars from the 1980's having a timing belt. I'm going to guess no.

Here's the rub though, BMW has used (and was recently using) PLASTIC timing chain guides inside the engine. If the plastic guides fail or wear out, then it's a bad and expensive day. My 2004 X5 with a DOHC 32 valve V8 has the plastic guides if I recall correctly. They don't have a history of being a problem, but obviously my X5 is old and I should check them over when I'm replacing various gaskets and VANOS O-rings.

If someone is interested in getting a new or recent model BMW, then they need to make sure it has the B58 engine.

 

[DeltaV]

*check MAP &/or MAS sensors, maybe dirty
*O2 sensor (?) acting up

I would expect the engine management software to be able to detect out of range signals and throw a code for the MAF and O2 sensors. The EPA probably requires it.

 

[Budnicks]

I would expect the engine management software to be able to detect out of range signals and throw a code for the MAF and O2 sensors. The EPA probably requires it.

yeah at a min., a check engine lite

 

[Budnicks]

My sisters Honda (Accord), way back when 'like 2003-2005-ish'
would throw out a code on the dash,
I can't remember what it was now,
I think it was a check engine lite (?)
if her Gas cap wasn't tight enough (couple clicks past) or bad seal,
she had that a couple times, freaked out
one time she forgot to put the gas cap back on after fueling, doh !!!

 

[Kern Dog]

It is quite telling how the term "Check Engine Light" is so commonly used....that started with General Motors. I still sometimes say it.
My 2007 Dodge truck manual refers to it as an MIL, "Malfunction Indicator Light" which feels clunky and odd to say.
My code reader also has MIL on the display so maybe that is the actual industry term for it?
Dang you, GM....your terminology has infected our language!