8V92 Kicker

[PCC]

At idle, my 8V92 will, only once in a while, kick, like it is being shut down, but only for less than a second.

Is it probably a safety, like low oil pressure switch, low water level monitor, or whatever? Or should I be thinking about something/anything else?

Runs all day long other than that.

When it kicks, it is very rare, but it happens, like when I was backing out of a tight spot today, and it kicked twice, then no problem.

[Ednj]

Maybe that one was put together by Toyota!     

[luvrbus]

Do you have a tach if so tell us what the idle speed is it maybe set too low

good luck

[PCC]

Maybe that one was put together by Toyota!     

Not Toyota - The tag says "Yugo", (as I recall)

I checked the idle speed. It is about 437.

Thank you in advance for your wisdom.

[luvrbus]

If you have a automatic it should be 650 rpm a manual transmission 500- 550 rpm

good luck

[PCC]

It is automatic, so the idle is too low, and needs to be adjusted up?? Please let me know if that is correct!

I know at fast idle, it is about 850, and never hesitates.

At speed it is smooth as can be.

So set the idle at 650??? The tach shows definitely under 500.

DO I need to adjust the fast idle as well?

Last questions - Does the ECM keep the idle speed up when the engine is cold, and drop it back based on temperature? Is that why the problem only happens after I have travelled?

[buswarrior]

Hold on...

The tach on the dash is not a calibrated instrument.

You need to use the rpm readings in the DDEC ECM or on a mechanical engine, use a handheld optical tach on the flywheel to determine your real engine speed.

happy coaching!
buswarrior

[PCC]

OK - so prove my ignorance and explain to me how to retrieve the engine speed from the ECM.

The tach on the dash has an electronic feed from the ECM. Is it not accurate enough to prove it is well below 650?

[luvrbus]

You got it PCC.If you have a Jake check the buffer switch and be sure the set nut hasn't come loose from the governor housing and be careful in that area that is not where you set the idle speed.
One way to check the idle speed on a auto is if you don't have hold the brakes at a stop lite to keep from moving it is to low your engine with the hicups I would say it is to low.
Fwiw BW my Dixson tach is caibrated so is my Dixson speedometer


good luck

[PCC]

The coach moves ahead slowly. but solidly, in drive (or reverse), at idle, when brake application is released. I was backing out of a tight location when the kick happened today. I was letting it idle, or minimal throttle application to make it through the gate and into the pathway behind the business I had visited.

[buswarrior]

I'll stand by my advice. Attempting adjustments based solely on dashboard indications is bad diagnosis.

Unless you have confirmed the readings, how do you know the current accuracy of your unit?

As the miles and models go by, I have yet to see a set of matched coaches in fleet service with tachs (or other dash gauges) that all read the same from coach to coach.

MCI or Prevost, analog or digital, it matters not. Some show high, some show low, they are all running the same.

A scan tool will let you access the ECM readings, or a handheld optical tach and a piece of reflective tape on the flywheel edge lets you do it older school.

happy coaching!
buswarrior

[PCC]

Scan tool???  More info please.

I have an oil change planned at a truck service facility - should I ask them to give me an engine idle speed reading?

Is that a task that will take much time, or might they do it in just a minute or so?

[luvrbus]

I have no idea where you live but most Detroit dealers will do that free for you and charge you for the work if needed


good luck

[PCC]

I shall ask them to check it out.

Thank you all.

If anyone has any other idea about this weirdness, feel free to enlighten me - won't take much.

[Just Dallas]

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