INTRODUCTION
This is some sort of exaggeration though. No matter what he does every now and then, the engine just keeps firing. Oops! I meant to say, engine misfiring.

So, what does engine misfiring really mean?
It just simply means a distortion in a car's fuel/air mix ratios, which would result in either a lean or rich condition.

MISFIRES CAN RESULT FROM ANY OF;
¶ Ignition system. They are systems responsible for spark ignition in petrol based engines(S.I).

¶ Related parts include ignition coils, spark plugs, crankshaft position sensors and ignition wires.

¶ Mechanical system. Engine compression problems, resulting from excessively worn engine compression rings; carbon fouled or faulty throttle position assembly, and a stuck closed EGR system.

¶ Fuel related systems. Clogged, or failed fuel pumps, injection nozzles, fuel filters (internal and/or external out a fuel tank), are some of the major causes of engine misfires.

SOME SIGNS OF ENGINE MISFIRES
¶ Excess fuel consumption. In some occasions, this would be noticed by black smoke from the exhaust.

¶ Engine misfires. Engine vibrates, and attempts to stall when idling or in traffic.

Related trouble codes for a misfiring engine are P0300…..P030nth.
Where n=1, 2 ….n.

EFFECTS OF MISFIRES
Ignoring a misfiring engine, could lead to catastrophic engine damage, and a financial strain on your pocket.

¶ Destroys catalytic converters
¶ Increased petrol cost/consumptions


CONCLUSION
Engine misfires, do not suddenly occur without prior warning(s). They occur gradually, until it gets to a state where it becomes significant; with its attendant symptoms.
Some symptoms might be intermittent, which takes time to detect the problem.

The key to solving problems like these is to employ patience in your troubleshooting strategy.




Regards,
Joseph
DW Nig Ltd,
Lagos
08066643532(WhatsApp/call)










CASE STUDY

VEHICLE DETAILS

Vehicle model: 2005

Vehicle type: Sienna; FWD

Transmission type: Automatic

Engine capacity/displacement: 3.3L

Engine configuration: V6


CUSTOMER’S COMPLAINT:

Here’s an excerpt.
Hey, Joe. How you doing?
I have being having some problems with my car recently.

Here are the symptoms I have observed:

¶ Immediately the engine is started, it immediately stalls when the AC system is ON, or OFF. In some other occasions, it doesn’t stall, but instead, vibrates, and the tachometer (RPM meter) suddenly fluctuates.

¶ Appearance of CHECK ENGINE and MAINTENANCE REQUIRED lights on the dashboard.

¶ Loss of power. You drive the car; it feels like its being held down by some sort of force, despite flooring the accelerator pedal.

¶ Poor fuel economy (excessive fuel consumption). Before now, the fuel economy has being good, driving from Ajah to Osodi. But right now, it's terribly poor.


THE FIX!

1. Troubleshooting. First and foremost, the car was brought to the workshop, and a troubleshooting chart prepared.

WE BEGAN SIMULATING THE CLIENT’S COMPLAINTS, lest we exceed the customer’s terms of reference (TOR).

2. Scanned the car for trouble codes, and the following codes were obtained:
P0354: Ignition coil D Pri/Sec circuit
P0037: HO2S heater control/circuit low Bank 1sensor2.

***Parameters at which these faults were always being triggered at, ETC 149 degree Celsius, and RPM 791rpm (Freeze frame data obtained).****

3. The check engine light was erased immediately with a scan tool. 2(a) and 2(b) above, has given an indication of the source of the misfiring, which has limited the fault to the ignition system. This has narrowed down our troubleshooting to only the ignition system.

****Finding the culprit ignition system(s): Ignition tests***

∆ Carried out visual inspections of the ignition systems, specifically the ignition coils, and its connectors.

∆ Started the engine, and allowed to run for some minutes (at 149 degree Celsius).

∆ Bank 2 ignition coil pack connectors unplugged, to determine which of them was failing, or had already failed.

Notice as you remove any of the coil connectors, the engine tends to stall. When fixed back, engine rpm stabilizes immediately.

NB
*Bank 2: cylinder head close to the radiator system.

*bank 1: cylinder facing the firewall, or cylinder opposite the radiator system.

∆ Because of the tedious tasks involved in accessing and removing the rear bank(bank 1) ignition coils and spark plugs, all the ignition coils and spark plugs were interchanged with those of bank 2. Doing this, saved much time.

∆ Repeated test carried out in (a), with, ignition coil packs interchanged from bank 1 to bank 2.

∆ Started the engine, immediately a check engine light appeared on the dashboard.

∆ Scanned for trouble code(s), and obtained P0354, on bank 2.

∆Cleared the code; removed all coil packs on bank 2, cylinder 4; interchanged them on the same bank, by taking ignition coil pack 4, to ignition coil pack 6.

∆ Started engine, immediately the check engine light came up, and realized engine was still misfiring.

∆ Scanned for trouble codes and got P0356, which meant the misfiring had being transferred to cylinder, number 6(F).

∆To get a definite conclusion on what the problem was, the coil was replaced with a known good one, and immediately the check engine light left, and the misfires stopped.

∆Completed a drive cycle at the parameters which fault was recorded to see if the FIX was perfect.

Returned from the test drive, without any problems.

Misfires gone; the only code retrieved from the ECU was related to the oxygen sensor.



PS:

¶ Jobs like this, offers a better opportunity to replace spark plugs, or service the car’s fuel injection system, because of the tedious nature getting access to them.

¶ Always use recommended spark plugs, or an iridium or platinum tipped one.

¶ Ignition coil pack connectors and/or wiring harness are sometimes the problems faced by such engines.

¶ Ensure power, and signal tests are performed on ignition coil harness using a digital meter before blaming a misfire on an ignition coil pack.

¶ Remember, the cost of coil on pack ignition coils are expensive.

For this car, #1 of such coils costs, N7000.

K

Nice One and Great i Love that from --- www.40ng.com

@40ng! Hey, how you doing?! Thanks a lot, though.

What sort of fuckery is this.?
Na because of solving ordinary misfire wey guys dey solve on an almost daily basis dey make TRYGO write complete encyclopedia for sienna?
If he see E90 M3 V8 or S600 engine misfires wetin he go write??
Just passing by and minding my own business tho

∆ Started the engine, and allowed to run for some minutes (at 149 degree Celsius).

www.nairaland.com/attachments/5049122_img20170311132440420_jpeg330b220e27cb74bbbbf4232c037fa2ec

@kingreign. Hmmm. You see this as "daily norm" for you as daily? Well, I don't see anything that simple o!

This is how I work:
*I don't assumed to have known a job, no matter how simple it is. I assume I don't even know it. That way, I acquire more knowledge and experience from such jobs.**

*At the end of the day, I sit down, prepare some kind of writeup, tailored to:

∆∆∆∆EVERYONE WHOSE IN THE AUTOMOTIVE CHAIN∆∆∆∆

Lots of folks here would even prefer if its possible, for them to do most of the simple jobs you guys have to do on their cars. But we all know it isn't possible. There are jobs, or simple stuffs a car owner, whose good with simple tools can do. I think I prefer going into details like these, to help people out.

¶¶¶¶I don't work on the engine brands/capacity E90 M3 V8 or S600, you've mentioned(Benz)¶¶¶¶.

I work on other brands, asides the one you've mentioned.

But it would behoove you to note that almost all misfires from any engine brands, are caused by all of what I have mentioned, or some other ones I haven't mentioned here.

¶¶¶For me, this writeup is part of how I work(my trademark™)¶¶¶

¶¶I'm not here competing with anyone.¶¶¶

GAZZUZZ:



www.nairaland.com/attachments/5049122_img20170311132440420_jpeg330b220e27cb74bbbbf4232c037fa2ec

The guy write ups dey always carry multiple cylinder misfires.

@Kingreign. Observation(s) noted.

did u deflate the tyres during the job?

cos the first picture of the dash show cel on

and d second picture still has d same cel,but with tpms now added

Find something more challenging to write about.
Even with say Na simple fix ,still lot of holes in your procedures and recommendations.
Personally I feel u do more exploit as a sales guy rather than technical.

@diportivo. No tyre wasn't depleted.
1st pic showing CEL ON was showing the car at idle speed, with the problem.
You can see that from the Rpm reading.
Codes related to the PRI/sec ignition coil, and oxygen sensor was already recorded in the ECU.

2nd pic. Showed the car driven after the job was completed. The CEL ON you complained about, was related to the oxygen sensor, and not the misfire that was experienced.
TPMS was as a result of the rear RHS tire being under pressurised.

Pictures 1+2, was for comparison purposes. Pre-and-post.


@honmusa. I think this is also MORE challenging. If you're a technically inclined person, I bet, this might be less challenging to you. But to some folks here, its cool.

If you have some suggested topics,.or problems you're currently facing, I'd be glad to face such a challenge here on this platform, or physically, at the shop.
I don't just write stuffs here, I practically do the job.
I'd be glad if you point out some procedural flaws here. I'd react to them immediately.
Well, for the salesmanship job, I've being found that for years, and that's the same thing that applies here on this platform now: DOING A SALESMAN'S JOB via stuffs like this.

honmusa:
Find something more challenging to write about.
Even with say Na simple fix ,still lot of holes in your procedures and recommendations.
Personally I feel u do more exploit as a sales guy rather than technical.

[quote author=TRYGO


***Parameters at which these faults were always being triggered at, ETC 149 degree Celsius, and RPM 791rpm (Freeze frame data obtained).****


∆ Started the engine, and allowed to run for some minutes (at 149 degree Celsius).



[/quote]
My own concern is.... should an engine be allowed to operate at 149 degree Celsius

@149 degree Celsius as suggested by trygo ,the engine is already fried !!!

First and foremost, I think you guys did a nice job pointing out those technical typos.

@honmusa. Fahrenheit, and not degree Celsius.

So, converting the 149F>65° approx.

@Iyke turns. If an engine operates at that range, the engine e would "fry" like someone just commented.

@Gazzuzz. The normal operating temperature of an engine, is(should) be: 100°C

@

TRYGO:


@Gazzuzz. The normal operating temperature of an engine, is(should) be: 100°C

@

Your response to this answer truly truly show that u are not really touching the cars .
Just leave the repairs for the boys ,do the talking ,who knows what you will make out of it!!

@honmusa. What sort of response do you want? Can you give me a preview, or sample of f the kind of response you want?
Haba mallam. We don't work that way na. We do the working, and do the writing do. If you have concerns on the pattern of response(s) you'd want, just stick it out!

TRYGO:
@honmusa. What sort of response do you want? Can you give me a preview, or sample of f the kind of response you want?
Haba mallam. We don't work that way na. We do the working, and do the writing do. If you have concerns on the pattern of response(s) you'd want, just stick it out!

a typical Toyota coolant temperature that indicated 100 degree Celsius is already on it way to overheating condition .
most asian cars operating temperature is between 85-95.if you actually do cars repairs in a professional way ,you would have observe this with your scan tool on the live data.

I personally prefer write up that is based on reality on the field not what the OP feel it should be and what you read somewhere else!!
U need more experience before u can do the writing on public domain !!!

@honmusa. I do understand what you're saying. That temperature was the freeze frame data when the fault usually comes up. Are you saying its not possible for problems like that or any other to occur at that temperature?
Fix the fault, checked for any codes related to the misfire problem. If there was any, we check the FFD again for what parameters came up.

***about Toyota coolant on its way to overheating, I disagree.

Check out the Gazzuzz asked: What is the normal operating temp of a running engine (pressurized system)?

Or, maybe TRYGO is getting your question wrong? Can you decipher what he meant, @honmusa, just in case?

TRYGO:
@honmusa. I do understand what you're saying. That temperature was the freeze frame data when the fault usually comes up. Are you saying its not possible for problems like that or any other to occur at that temperature?
Fix the fault, checked for any codes related to the misfire problem. If there was any, we check the FFD again for what parameters came up.

***about Toyota coolant on its way to overheating, I disagree.

Check out the Gazzuzz asked: What is the normal operating temp of a running engine (pressurized system)?

Or, maybe TRYGO is getting your question wrong? Can you decipher what he meant, @honmusa, just in case?

This is question you will find in most Yahoo site ,it still the way it is "normal operating temperature of a car" check Google it is a common question!!
you can actually get it from any car by running the car till the fan triggers and check the range of the ects temperature with your scan tool ,very simple !!!

@honmusa. No wahala. Would do.

Just saw this link now, thought to post it here. Maybe it would help.

Check it out. What do you infer from it?

https://www.quora.com/What-is-the-normal-operating-temperature-for-the-coolant-in-cars

Na wa o!
This kind TRYGO magana na wa o. He don full seun webpage with crap and fallacies.

@kingreign. E fit b "true" o! So far one can defend all what's written na. Anyhow you see am, just take am. How work today na?

@Lejuen3. smh! Hehehe.

Whoever your wife is, she is a lucky woman. TRYGO

@kjnwancaro. Hehehe! You don bring diversionary tactics here o! Emmmm, abeg. Y you say so na, no vex? I hope no b dis coolant temperature thing, and salesmanship o!

@Gazzuzz. You de funny o! I'm both o! Engineer, not a mechanic*

GAZZUZZ:


Very true. He is a true gentleman.







But not a mechanic

Half bread is better than none