I Hate an Intermittant Problem

[Jerry Winchester]

Well I thought I was over this one, but alas it is back.

The engine (8V92TA) runs fine down the road. Pulls good, no problem. Until I stop or the engine comes to an idle. After a few seconds, the yellow and red light for the engine both come on and if you don't idle the engine up, the engine will shut down momentarily.

You can instantly restart it and again, if you idle the engine up the lights will go out. You can also try to pull off and eventually the engine will "resume" running okay (turbo will spool up and the fuel will follow), but not being a DDEC guy, this is perplexing.

Anyone have this problem or willing to venture a guess? I may go a month without it happening again and it never occured during the 2000+mile trip to Florida. I thought one of the sensors might be bad or it got wet (see associated radar photo), but we ran thru some serious rain coming back from POG ONE and no problems.

Also a new first today. The Garmin 396 GPS speaks the words, "Tornado
Warning" as we were going down the road. Guess what? It was right where it said it was.

Eerie.

http://jdub.smugmug.com/photos/71741475-M.jpg
http://jdub.smugmug.com/photos/71741730-M.jpg

[Jon Wehrenberg]

Jerry,

Try this real quick. You will have to call Prevost or maybe someone else can post the answer, but jumper between two pins on the DDEC reader. A and H come to mind, but do not trust my guess. All my books went with the old coach.

The code will blink and beep. A call to DD will tell you the code and that should lead you to the problem. Have you checked the coolant level sensor?

Jon

[Jerry Winchester]

Jon,

I really think it is something like the coolant sensor. I know the reservoir is full, but if I unplug the sensor and jump across the terminals, will that make the computer think it is full?

The reason I suspect the coolant level sensor is that this problem used to show up with the engine was first started and somewhat cold. After it warmed up, it would go away.

As it is Saturday of a holiday weekend, I will struggle thru until Tuesday and see what DD says. Thanks for you help.

JW

[Jon Wehrenberg]

Jerry, I know how frustrating it is to try to deal with this kind of stuff, especially on a holiday weekend when away from home.

I do not trust my memory otherwise I would tell you if the circuit should be open or closed. I ran into that with Classy Chassis and a sensor replacement cured the problem. I think this is a case where Prevost has to give you the correct answer. In the meantime I will review my service manual because it might shed some light on it.

Jon

[Jon Wehrenberg]

Jerry,

Your bus may vary because I think I have a later model DDEC, but see if this helps.

The code for a low coolant level is 13 and code 14 may also indicate a coolant level sensor problem as well (in addition to some other problems).

On my coach to access current codes the procedure is to have the ignition key "on", bus off or idling, and to press the override switch. That should bring up the active codes on the stop engine light. There is nothing in the manual to confirm that a jumper between sensor poles will "fool" the computer to thinking the sensor is OK. I wish I could have confirmed this.

Jon

[MangoMike]

It seems to me a seminar at Sante Fe about the ins and outs of code reading would be interesting. Do you need a reader or are the codes displayed on the dash somewhere?

Or in Fast Rogers case instead of code reading it would be palm reading.

MM

[Prevosttech]

Yesterday I read your problem and being that I was on my way out the door did key into your whole problem. My concern is your brief dicription about your turbo spooling up.On and 8V the turbo is fed off the exhuast.The next time you have the power problem take notice of your pyro guages if the temps are not the same or close to it you need to take a flash light and look at the exhaust manifolds for soot also for loose pipes from turbo to exhaust man's.and also closly look at man's for cracks and or holes with the exhaust system to turbo all jiouts need to be sealed because this is what makes boost pressure also give me a day or two to track it down but I have a flash code reader card ,also the software is sold to hook up to ddec to dia. prtoblems with engine but it is costly.

John

[Jerry Winchester]

Well I unwired the low coolant sensor and joined the wires together, but that didn't fix it.

I made it from Loveland, CO to Jackson, WY today and the engine runs fine out on the road. But when you go to stop and it idles down below 1000 rpm, the yellow and red lights come on. If you don't move or shift to neutral and idle up the engine, it will die. And it does it at the worst times.

I hope someone knows which jumpers to use and what the codes are, because I hate to think about driving this thing like this the rest of the trip. I don't know if there is anyone in Jackson that knows squat about 8V92's but if I could get the computer to tell me what the problem was, I'll bet I can fix it. How many sensors can there be?

And John, thanks for the reply. If the engine were not running well (other than the described problem) I would suspect something else. I suppose it could be a faulty sensor somewhere else on the engine, but I don't know what other items are monitored by the DDEC system.

Other than that, the drive across southern Wyoming is lots and lots of nothing followed by some intense scenery you can't imagine. It is snowing here and the temp is 37. But it is a dry kind of cool........

[lewpopp]

Jer... For Cripes sake. You said it was snowing. Your first mistake is that you went too far north.

Prevosttech is on your case. He will come thru for you and us. This form will not let you down. You have too much vacation time.:)

[Jon Wehrenberg]

Jerry, can you get the codes? Once you can read a code you know exactly where to look. DD and Prevost have 24 hour phones.

You can either read the code as I described above or by running a jumper as I did in my old coach.

As your last description indicated it is a situation found only at idle. The 8V92 is a low oil pressure engine at idle, but there is still a minimum pressure required and now I am leaning toward that just because of how you last described it. I think the oil pressure sensor is located on the forward upper bulkhead right under or near the rear oil pressure gauge.

[Just Plain Jeff]

JDUB:

Remember that PASS/ACTION card I sent you that you were supposed to keep in the bus?

This might be a good time you make a coupla calls to DD/Prevost?

[Jerry Winchester]

I am going to jumper the reader today and see if I can get the codes. I thought about low oil pressure, but I didn't know how it got the info (from the pressure sender or from another source).

The engine holds 45-50 psi of oil pressure running down the road and about 60 psi when you first start it up and it is cold.

Is there a sensor for any of the transmission functions? The trans fluid level looks ok, so I can't think of a reason it would be an issue, but a faulty sensor at any location could be an issue.

Its a snowy Monday in Jackson and with it being a holiday I doubt any help is available here, but I will see if I can roust anyone at Prevost for some info. I know a guy with DD in OKC, but they won't be in until in the morning.

Lots of "Friends of the Earth" types up here. Lou would be right at home.

[Jon Wehrenberg]

Your transmission has a separate warning light. I also think if you have a transmission problem you may have the "do not shift" light up on the gear selector pad.

I think it is a round gear looking symbol. I suspect your problem is not a problem, but a defective sensor.

Codes, my man, codes.

[Jerry Winchester]

Well it's a good news bad news kind of deal. Finally located the guy with the DDEC code reader. He had to drive over from Idaho Falls to Jackson. Not a nice drive.

Anyway, he shows up with the unit, we open the door where the DDEC plug is and he says, "*(*#$@". He goes back to the box where the $7000 snazzy reader of any codes on any engine and guess what? The plug for the DDECII is not amongst the myriad of plugs with the unit. Book shows the plug, but it isn't in the kit.

Not being one to punt so easy, we go flip the switch and count the flashes to get the codes. However, the snazzy unit doesn't have a book with the codes since the unit is supposed to just tell you what the problem is. However, one of the "example" readouts lists Code 36 - Low Engine Oil Pressure and low and behold, we have code 36 on our list.

I had already surmised this after chatting with Jon. I started the engine this afternoon after a day of sub 40 degree weather and of course the idle oil pressure was in the mid 40 psi and there were no fault lights on, so the deduction was the oil pressure sensor.

And the mechanic said the same thing, so he is going to order one tomorrow and we are going to stop by on our way from Yellowstone to Salt Lake and have him install the new sensor and read the codes with the snazzy reader with the correct plug. What a pain.

Anyway, the codes were 43, 45, 16, 31, 32 and 36. We will know tomorrow what the other codes mean and then we will erase them Friday and start over.

22 inches of snow in Yellowstone last night, so we may not get there tomorrow if they don't get the roads plowed tonight. However the weather is forecast to improve. It even snowed today in Jackson. And it was 96 when we left Houston. Thank god we fixed that AquaHot at the POG rally.

[Jon Wehrenberg]

From my book for DDEC III:

43 Coolant level low
45 OIL PRESSURE LOW....I'll bet that is the sensor problem
16 Coolant level circuit failed high
31 Multiple aux. output issues
32 SEL open circuit or short to battery
36 Oil pressure failed high

The following is speculation: The coolant codes may have been from the previous problem and the 16 code is possibly from tying the terminals together. 36 may be because you were playing with the sensor or it might indicate the sensor is bad.

[truk4u]

Jerry,
Hang in there, we're all learning something. Amazing the temps and snow where your at, we're cooking here in GA. Just came back from 5 days at Charlotte for the race and 90 every day. With all that snow, must be your having a blast with the Hummer.;)

[Jerry Winchester]

Jon,

The mechanic confirmed the codes you have are correct. I actually think all the codes are the same for all engines as there is some kind of standard for this deal. Except the plugs, so he will have the correct plug when we get there Friday. Go figure. :confused:

I think the sensor replacement will be the ticket, but we are going to read and erase the codes, drive the coach with the bad sensor to get it in the clean memory then download the codes again and replace the sensor.

That way we can see if or how the codes are related.

I also have to think there is a simpler, less expensive code reader for this engine. I will check with United Engines and see what they know. We buy enough crap from them at work to warrant a little customer service for the CEO.

Sun is up this morning and it is already 41 deg. so I hope we can stick to the original schedule and motor on to Yellowstone. And yes Tom, this is exactly why we bought the Hummer, so we have had a large time in it as it looks battle weary from all the slush / mud. There is no bling out today. The coach is covered in crud and I can't do a MangoMike and wash it in place (park rules) and I won't be able to do it in Yellowstone, so it looks like the return to bling will be in Salt Lake or Las Vegas.

And Lew, someone is flying a radial engine biplane over town this morning. VP Cheney showed up here yesterday, but I didn't see him at the gunfight on Main Street..........

[Jon Wehrenberg]

Jerry,

As a confirmed tool collector, I am still a ways from getting a reader. You are in the midst of a run of codes, and once you have developed the answers and experience you will find that as long as you know the trick to flashing your codes you will be able to sort out the problem.

A reader is a pure luxury in that it will go beyond the code and give a value, such as how low the oil pressure was or how hot the transmission got.

If you monitor your gauges and are alert to your warning lights and can do what you need to read the codes in your bus you are probably 99% capable of addressing the problem.

If you insist on buying a reader check ebay. I often see them there. At one time a new one from DD was $700 but I'm sure that has changed.

[Jerry Winchester]

Got to Idaho Falls today and hooked up the reader and yes this was the culprit.

Failed Oil Pressure Sensor
http://jdub.smugmug.com/photos/73062899-M.jpg

We found it with this

http://jdub.smugmug.com/photos/73062432-M.jpg

You plug it in here....

http://jdub.smugmug.com/photos/73061694-M.jpg

And in the end, it tells you to replace the old one with this one

http://jdub.smugmug.com/photos/73064713-M.jpg

Now we are humming down the road headed to Salt Lake City. The sensor was $79. The service call from Idaho Falls to Jackson, WY on Memorial Day was $500. And those aren't LewBucks.

[truk4u]

Excellent Jerry, the 8V guys ought to just change theirs out as PM. Hey Jon, did you notice clean non-grease hands. Must be Rae does the dirty work like Nancy.:o

[Jon Wehrenberg]

I not only noticed the clean hands, undamaged by manual labor, but I also noticed the paint run on the engine block and the overspray on the wire looms. Some folks worry more about LEDs than they do about details.

[Ray Davis]

the 8V guys ought to just change theirs out as PM.
$79 sounds like cheap insurance. Where exactly is that sensor located on an 8V engine?

[Jerry Winchester]

Ray,

It is just to the right of the crankshaft pulley. You can see it on one of the photos up in the post.

[MangoMike]

JW,

Did you ever get a final price on that DD code box? Is it something that we need as joint ownership?

MM

[Jon Wehrenberg]

Mike,

With the key on (engine running or off) depress the overide switch and your codes will flash, starting with active codes. The reader will give you more detail.

I have found that just knowing the code leads you to the problem, but if you need the detail any local DD or Allison shop can plug their reader in and give you the detail.

If a reader counted as bling, however I would be buying one today.

[MangoMike]

Jon,

Where do we get a list of the codes for Series 60, and where exactly does it flash?

And I think it should count towards the Bling show.

Mike

[Jon Wehrenberg]

It will flash on your check engine or shut down engine light. You will know because it will flash right before your bling seeking eyes. You may wish to replace those bulbs with LEDs.

I have a list of the codes in the shop manual and I can print copies and bring to POGII, or if your bus is in dire need of repairs I can fax them.

Good job on the swim. I couldn't stay afloat for that long much less actually travel any distance.

[Jerry Winchester]

Hold your blinging horses.

If I have worked the magic right, I will have a gratis code reader winging our way shortly for group use.

As I discovered in my odessy, having the BIG code is only a part of the issue. There are two other codes that make the whole thing gel. You have to have the MID and SID codes. With these three codes and the troubleshooting book (I also have one of these in route), you can get down to the gnats ass with respect to the problem.

Case in point; I had a code 042 or something like this as an "Active" code. When we read the SID and MID, you go to 042 in the book, then down to which ever one is first (SID or MID, I can't remember) and you follow the flow chart doing whatever it says until you solve the problem and the reader reads the all clear code (I can't remember that one either). In my case, the 042 was some kind of aux sensor fault and when you followed it thru, it said the cruise control indicator light was malfunctioning or the bulb was burned out.

Now, I know just enough about this to be dangerous, but we will have one of these readers at Santa Fe and we will learn how to use it to do good rather than evil. And we will get a PDF file of the codes and post them on this site.

And the bling gods will smile upon the unwashed. :)

[MangoMike]

Jerry,

This is one serious reason to make the pilgrimage to Sante Fe, lets get Jim to add this to the seminar list. Where else could you get this kind of education, unless you spent a week in Jon's Pit.

Can't wait to get plugged in.

One of the many unwashed.

MM

[Jerry Winchester]

MM, are you camping somewhere? And you are logged on with the Verison card sitting in bed whilst your wife tunes on your for not turning the light off?

[MangoMike]

We're you in bed with us?

That's exacty what was happening. We came down to Frontier Town www.frontiertown.com (South Ocean City, MD - a very nice campground w/ 50amp, no drive thru) after the swim. Getting ready to head back to Va and work. Life is good.


MM

[Jerry Winchester]

No, It's just that the same thing happens to me and I have no private place in the coach at night where I can be and not bother someone. Unless I go to the bathroom, sit on the crapper and put my laptop on the vanity.

Not that there is anything wrong with that or that I would do it............:eek:

But that is a cool looking campground.