-
Stop engine and check engine lights coming on
Drove my bus from Orlando back to Cape Coral today with many a stressful moment!
(The bus had been sitting outside and plugged in for the last 90 days)
All was fine for the first hour, then both stop engine and check engine lights came on for a few seconds then went off. This went on four more times and they always went off in a few seconds. Also, the engine brake worked fine yesterday but would not work today in either position.
I called my Detroit diesel mechanic friend who had repaired the overheating problem I had earlier, he said as long as they both go off in a few seconds, no worries, he also mentioned the possibility of moisture in the electrical system (we had torrential rains yesterday and the bus was outside.
Then both warning lights would come on and stay on, I pushed the engine shutdown override switch, regained power and all was fine for a while.
We stopped for lunch. After a couple of hours were underway again, this time the engine brake worked, but everytime I came to a stop, both stop engine and check engine lights would come on again!
This happened about four more times, each time I would push the shut down override switch, power would be regained and we made it home. The last 10 miles or so, I did not use the engine brake but dowshifted to slow for traffic lights and this seemed to work, the 2 engine lights never came on again.
Oil and coolant levels are normal and all engine instruments had normal readings……..can anyone solve this mystery?
-
31 Replies
-
Your gauges will tell the story. If your temperatures and oil pressure show good it is unlikely you have a problem with either of those..
There are only three reasons for a stop engine light. The two you can check on your dash will be high engine temperature, or low oil pressure. If they are good then the problem could be the coolant level sensor. I am not clear on conditions when the stop engine light comes on, but if it is at idle, does increasing the revs correct the problem? If so suspect an oil pressure sensor. That sensor is not reflected in your oil pressure dash gauge and can have an error even though your pressures are fine. If that does not cure it you can jumper between the two pins on the coolant level sensor plug and that takes the sensor out of the equation. If the problem goes away after that you have isolated the cause.
Before you go beyond that, flash the codes and see what they say. They will tell you why you are getting the stop engine light. Even if I thought I found the problem I would flash the codes to verify my findings or start by flashing the codes so I could zero in on the cause.
-
The stop engine light came on both while driving and when stopping.
How do I locate the pins for the coolant level sensor and how do I flash the codes?
-
The coolant level sensor is on your coolant header tank and just put a paper clip or wire between the two terminals on the connector. Some coaches have had the wires to the cable pulled too tight and that has caused some problems.
I cannot tell you how to flash the codes on your model coach. The Prevost shop manual should tell you how to access them and it is available on line here:
http://prevostparts.volvo.com/technicalpublications/en/manuel.asp
On our 1987 we put a jumper between pins H and M on the plug for the reader in the steer compartment and the codes flashed, and I know other vintage coaches had different ways to check the codes.
-
I thank you.
-
Georges,
I assume your is like mine since they are close in age. The DDEC connector is in the bay door under the drivers window. There is a switch on either side of the connecter with one marked DDEC and one marked ATEC. Flip the switch on for the DDEC and turn the ignition to the on position. One of the lights on the dash will flash the codes, but I forget if it is the Stop Engine or Check Enginge light that flashes.
-
Thanks for the info.
I did get the fault codes and they are as follows:
35 oil press sensor hi voltage
36 oil press sensor low voltage
43 low coolant level
45 low oil pressure
All the fluid levels are fine, the oil pressure and water temp gauges read normal.
Also, I could not locate the coolant level sensor terminals.
Although I don’t really want to, I will probably have to get it to the Ft Myers Detroit Diesel service center and have the pro$$$ fix it.
Having just read the post on bus towing, I am not looking forward to that option, so I will have to drive it there (20 miles).
-
Took it to Detroit Diesel on Tuesday, didn’t hear anything yet so I called the service Mgr today, he informed me they cleared the codes and only the low oil pressure code comes up and check engine light comes on, however they cannot get any throttle response!
This no throttle business has happened to me before and I had called my mechanic about it, he informed me the 8v92 is a very cold blooded animal and needs to be warmed up before it will move. So I always made sure it was warmed up before getting under way and it always worked.
I think these characters at DD are not properly trained in the antique technology that is the 8v92 and just did not let it warm up enough.
Am I right or wrong? or somewhere in between?
-
I am not advocating you ignore the advice or information you receive from DD mechanics but it bothers me when “professionals” spread fertilizer around.
Whatever your problems are causing the lack of throttle response or a low oil pressure code they are not related to a cold engine. What is correct is that you do need to get a little heat into the engine and transmission before you move down the road, but that applies to folks living in MN in January. Where you are located excessive idling to get the engine warmed up is not required. Start it, let it idle for a minute or so to insure oil circulation, another minute or so at high idle to get a little heat into it and you are good to go. Getting the engine up to temperature is nice, but the best way is to start driving moderately.
If it is not responding to the throttle the throttle sensor may be part of your problem, but a turbo boost sensor may also be a part of it. On your engine the turbo boost sensor is on the passenger side, a small playing card sized black plastic device that needs a good hose connection between it and the manifold. If the turbo boost sensor has failed or is failing your throttle will not respond. On an older coach I would check all connections. Once you are confident connections are clean and tight then verify the sensors are functioning, including the oil pressure sensor.
-
I assume they are describing a no throttle as nothing happening when the pedal is pushed! It so, could also be the throttle position sensor at the pedal. I don’t remember the official part name, but the throttle is electronic.
-
My use of the word “characters” was not in a demeaning manner, rather a cartoonish visualization of a garage.
Excellent advice you have suggested (as always).
The other thing I noticed is, occasionally, when slowing down, the jake would not work and those warning lights mentioned above would come on shortly there after, then, later, the jake would start working again. Sounds like a failing throttle sensor since the jake kicks in when the gas pedal is released, so I think we are looking for a bad connection or failing sensors or both.
Just spoke with the S.M. he said turbo boost sensor was not showing any codes.
-
Georges,
On early DDEC 2 the engine fuel is used to cool the ECM. It runs hot.. When you lose your cruise and have multiple sensor failures this is usually a sign of the ECM failing. I would be looking for a used ECM. There are a few companies that rebuild them. I think that DD wants around $2K installed. Good luck.
Kevin
-
Where exactly is the ECM located?
-
I guessing here, but if you are standing at the rear doors looking at the engine the ECM will be in the “v” on top of the engine. There will appear to be fuel lines going into and from the unit, but they are merely feeding a heat exchanger.
The ECM will have a pair of multi wire terminals bolted to the RH (side). It is a rectangular box about 6″ X 9″ and about 1 or 2″ thick.
-
Thank you.
-
Epilogue………
Finally picked up my coach today… two and a half weeks…..He told me they are short staffed.
This time some funny things were going on that never happened before.
Power driver and co pilot seats inop, TV camera inop, bus air inop (fan worked), air horn inop, step well inop and maybe a few more pneumatic devices that I didn’t check.
Then, I fired up the generator and in a couple of minutes all of the above (with the exception of the warm bus air) came to life!
???????
Log in to reply.