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.
Maybe that one was put together by Toyota! ;D ;D ;D
::)
Do you have a tach if so tell us what the idle speed is it maybe set too low
good luck
Quote from: Ednj on February 16, 2010, 05:43:40 PM
Maybe that one was put together by Toyota! ;D ;D ;D
::)
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.
If you have a automatic it should be 650 rpm a manual transmission 500- 550 rpm
good luck
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?
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
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?
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
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.
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
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?
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
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.
Removed
What a brilliant idea - See if it is blowing bubbles. Sounds like fun !!
How do they get past the separator? or are they coming into the lines after that?
Removed
I have a strange idea. (not my first!)
What if there is a crack in the pickup tube inside the tank, and when the fuel level goes down to a certain level, then the problem begins? There does not appear to be even a chance of a crack elsewhere, as I have inspected the visible lines and they look good, but I am going to work out the full/empty tank option to see if the problem only occurs when the tank is below a certain level.
That would be a real tough one to have found, if it is found to be true, without all your collective intellects coming together to think up such a crazy idea, but that is starting to make some sense to me. So I will try to document tank levels with happenings of the kick.
Higher engine speeds would cause the bubbles to go unnoticed, right?
Please tell me how on an ECM DDEC equipped engine how you can change the engine rpm with a reprogram. As I understand it is preset and non adjustable. Cheers Gerry
If nobody answers the question about adjusting the idle on a DDEC ECM before then, I will be talking to a DD dealer about adjusting the idle this morning.
I hate the kick, and it concerns me, because it feels like it will let me down one day, and, if the usual takes place, it will be in the middle of Hollywood and Vine, on 42nd Street, or during rush hour in the middle lane on the Interstate.
Quote from: hargreaves
Please tell me how on an ECM DDEC equipped engine how you can change the engine rpm with a reprogram. As I understand it is preset and non adjustable. Cheers Gerry
Gerry, Certain people (mostly DD dealers) have computers that are capable of re-programing or changing certain perimeters of the DDEC ECM! Most of US, and your little hometown diesel shops are not able to do this. It is done with a very expensive and complex DD program that is expensive to buy, and hard to get DD to sell you it unless you meet the licensing criteria such as authorized DD repair shop, or certified technician having go through their extensive training program (supposedly to protect them from liabilities and warranties from Joe Blow altering his RPMs, or top speed, yada yada yada, but mostly to keep the $ in the DD loop. IE if the only ones who can change those things, where will all the DIY guys like us have to go? Right to a DD dealer!)
;D BK ;D (the politically incorrect busnut! ;) )
Ya and if I remember correctly its about $200 bucks. I think most are set at 650rpm for an auto trans. Cheers Gerry
First, i'm not trying to hyjack this thread, but do have a question about adjusting the idle speed. I've got a 1955 Scenicrusier repowered with a 8v92ta and 754 allison. Now the 8v92 is totally mechanical. How would i check the idle speed and adjust it. I've got a lot of other things to get done first, but wanted to tuck this info away and have it ready for when that day arrives. THanks,
Mike
The last non ECM controlled diesel I worked on had an idle set screw that could be adjusted to raise or lower the idle, similar to a gas powered engine.
Look where all the fuel lines come together and near there you should see lever/s that move with the throttle, either air controlled, or fully mechanical. There should be a screw there that will move the lever to set the idle speed.
I hope that matches what you have, and this information helps.
I just love being able to find a peculiar problem so that a thread can have an end.
When I asked about the kick in my 8V92, I got a lot of suggestions, but this solution might be one for the books.
The previous owner had installed a small inverter and had connected it to the 12V feed (after the shut off). The inverter was failing, and intermittently dropping the voltage sufficient that the ECM would shut down, just for a split second, creating what felt like a problem with the engine.
I found this only when I turned the inverter on one day as she was in slow idle, and the engine kicked. When I turned the inverter off, the kicking never happened, but as soon as I turned it on, it kicked again.
Where you connect does make a difference, and so does the accessory equipment.
Thanks for y'alls help and advice. I so appreciate being able to ask about things.
Keith
PCC
OOOHH KAAAYYYY! And just where is your idle set? Getting back to the post. ;D ;D ;D
John
Nothing has changed with regards to the idle speed, and I have not even worried about it since the kick has stopped.
It sits at a traffic light, or other stop, in gear (automatic), and just purrs, so I am a happy camper.
What is a happy camper? Have you ever known a not-happy camper? What defines 'happy'?
So for what it is worth, I am pleased that it was not something serious in the engine or the fuel lines.
I will have the idle speed checked next time she goes in for service.
Thanks for asking.