While coming back from a bus get-together last weekend my engine suddenly died. All gauges were reading normal, the CEL and SEL did not illuminate, the injectors' and ECM's fuses are OK, there's only one old inactive code 35 (Oil Pressure Sensor High Voltage) flashing out on the CEL, the engine cranks over but will not start, and the CEL and SEL correctly illuminate for a few seconds then go out when trying to start the engine. The bus had been driving perfectly until it wasn't. It took Good Sam 25 hours to get my bus towed the 1 mile or so to the RV storage yard where I park it!
This morning I scanned the engine again with my Pro-Link, and it confirms just the one inactive code 35 that I cannot clear (I think that code has been there for years). However it also shows that the Synchronous Reference Sensor may perhaps have a problem - against SRS Received it shows No. Shouldn't it say Yes? Strangely, code 42 for the SRS is not showing on the Pro-Link or when I flash out codes on the CEL. I disconnected the Engine Harness connector and checked the resistance between pins 110 and 111 (from the SRS), and it reads 128.7 ohms. My DDEC Troubleshooting Manual wants me to check for a short at the SRS connector, but I don't want to start down this rabbit hole unless I know for sure that there may be a problem with the SRS. Wouldn't I have got a code 42 if there's a problem with it? To access the SRS and TRS behind the camshaft pulley I need to remove the ECM, and that's a royal PIA to reattach later. I have a spare ECM, but I don't have any spare engine sensors.
Any ideas on how I proceed next? Should I focus on the SRS, or is it OK even though the Pro-Link says that there's no output from it? Bear in mind that I was scanning the engine while it wasn't running (obviously!), so does the SRS Received change to Yes when the engine's running?
Thanks, John
on ddecII there are only a few things that shut it down.. Ck water level in reservoir. Common problem--- oil pressure sensor wire off or bad sensor. low battery voltage to ecm=under 11.6 volts shuts everything down. One bad battery in bunch could be one 12V supply is hooked up to. There is a starting place. been there on all three of these... also heard of fuse holder for ddec getting corroded -had the old style glass tube fuse.. Best of luck.. Bob
Damn, John. And here I thought that beauty was in totally pristine tip top shape. Just goes
to show you, there's Always Something.
I was so happy to see you there Saturday and getting it out on the road. Maybe one of
the secret agent Gillig guys sabotaged it because it was such a cool Crown..... All this tends to
reinforce my latent distrust of the DDEC engines. All mechanical for me thank you very much.
As shown from previous failures by other owners it's not always a DDEC problem, but a
sensor (way too many for my comfort), or wiring and grounding issue to be resolved. Best
of luck and at least you got it that close to home. Could have been so much worse. I'll put the
word out to get you some local help too. Hang in there Buddy.
Try using a electronic cleaner on SRS behind the pulley,they can get enough build up to shut it down or the bolts comes loose, and they lose their adjustment, I hope you didn't break a cam the SRS is one the same cam as the friggn 50D alternator, here's hoping it is a easy fix for you
Quote from: luvrbus on October 19, 2022, 01:27:37 PM
Try using a electronic cleaner on SRS behind the pulley,they can get enough build up to shut it down or the bolts comes loose, and they lose their adjustment, I hope you didn't break a cam the SRS is one the same cam as the friggn 50D alternator, here's hoping it is a easy fix for you
OK, I'll try that tomorrow. Should I be worried about the "SRS Received - No" message on the Pro-Link, or does it always say that if the engine's not actually turning?
Thankfully I don't have a 50DN alternator, just a good ol' belt-drive Leece-Neville, so I hope I don't need to worry about broken camshafts!
Thanks, John
Quote from: Coach_and_Crown_Guy on October 19, 2022, 01:14:47 PM
Damn, John. And here I thought that beauty was in totally pristine tip top shape. Just goes
to show you, there's Always Something.
I was so happy to see you there Saturday and getting it out on the road. Maybe one of
the secret agent Gillig guys sabotaged it because it was such a cool Crown..... All this tends to
reinforce my latent distrust of the DDEC engines. All mechanical for me thank you very much.
As shown from previous failures by other owners it's not always a DDEC problem, but a
sensor (way too many for my comfort), or wiring and grounding issue to be resolved. Best
of luck and at least you got it that close to home. Could have been so much worse. I'll put the
word out to get you some local help too. Hang in there Buddy.
Thanks for giving my number to Mike F. I'll call him tomorrow and see what he can do.
John