Sit Rep: Still Stuck

[Samarath]

Originally Posted by joeblack5

Having a spare and knowledge and experience is what you have gained.
Was that fuse inside the ecm?

Good luck,
Johan

No, it was in the fuse box. I had chased all of the fuses from the battery to the firewall, but I only quickly scanned the main fuse panel below the driver side window. We just put in the new ECM, and get this....the turbocharger is functioning properly! A fool's blundering method of bus repair. Thanks to everyone and if the bill doesn't give me a heart attack, I'll be able to let you guys know if my oil/coolant temps are still an issue with a properly functioning VGT.

[Samarath]

The oil temp has gotten as much as 23f hotter than the coolant and as high as 218f during a long climb. I am not happy with the difference, but I think we can limp home. We're monitoring things closely as we crawl along.

[Flying I 365]

Quite a detailed endeavor. At least I know what to watch out for if my VT365 does the same thing.

I’d watch the oil temperature out of caution as I have been warned that there are plastic parts in the oil filter housing that can melt under high heat (around the 250-260F mark) and I’d also double check the mileage on the odometer. I changed out my old ECU in my 2006 CE200 thinking that it was fried (turned out to be the ignition relay went bad) and the new one I got from the salvage yard showed a different mileage (Original ECU turned out to be fine so I put it back in to keep mileage consistent and the replacement is a spare)

Judging by the VIN in an earlier post, I’d guess you got an old FS unit and the transmission info seems pretty standard for a 5sp Allison 2500PTS so it’s a stumper why the ServiceMaxx computer showed it as an Allison MD transmission.

Safe travels with your bus.

[Samarath]

Originally Posted by Flying I 365

Quite a detailed endeavor. At least I know what to watch out for if my VT365 does the same thing.

I’d watch the oil temperature out of caution as I have been warned that there are plastic parts in the oil filter housing that can melt under high heat (around the 250-260F mark) and I’d also double check the mileage on the odometer. I changed out my old ECU in my 2006 CE200 thinking that it was fried (turned out to be the ignition relay went bad) and the new one I got from the salvage yard showed a different mileage (Original ECU turned out to be fine so I put it back in to keep mileage consistent and the replacement is a spare)

Judging by the VIN in an earlier post, I’d guess you got an old FS unit and the transmission info seems pretty standard for a 5sp Allison 2500PTS so it’s a stumper why the ServiceMaxx computer showed it as an Allison MD transmission.

Safe travels with your bus.

Thanks so much! In hindsight, I think I read something about the IDM bottom causing issues. I replaced the whole assembly, but I would bet that I could put the old ECM in with the new IDM and it would probably still function properly. It is only speculation though.

I have been through a few issues with this bus so far, and I was hoping to get home to get into some of the problematic components (oil cooler etc), but I am having a new issue now. We made it to New York and stopped for a pizza last night. When we cranked her up, the brake pressure light came on and viewing the details through Wabco Toolbox, the rear brake circuit has **** the bed. Only one of my hydraulic pumps are turning on. I seem to be getting power at the pins I am supposed to, but nothing. I am going to fully check the circuits when it stops raining. I replaced the entire HCU back in July, and I sure hope the motor isn't burnt up somehow. This "short trip" to pick up Havelock wool has become an exhausting journey...lol

Anyway, I guess I will update as things happen.

[headdownlow0624]

Yikes, more issues. At least every repair makes the bus more reliable! What hydraulic pumps are there? I'm pretty confident the system on my CE200 relies solely on one Bendix Air Compressor, driven by the engine belt, with various relief valves throughout (basically for every component).

[Samarath]

Originally Posted by headdownlow0624

Yikes, more issues. At least every repair makes the bus more reliable! What hydraulic pumps are there? I'm pretty confident the system on my CE200 relies solely on one Bendix Air Compressor, driven by the engine belt, with various relief valves throughout (basically for every component).

We have Wabco Hydraulic Power Brakes. The master cylinder gives a signal to the brake ECU and the ECU controls valves at each wheel. There is a pump for the front axle and a pump for the rear axle + Spring Applied Hydraulic Release parking brake. Generally, the pumps keep accumulators pressurized above 1500psi up to 2300psi~ and the pumps only turn on to maintain that minimum threshold. Anyway, one brake circuit is good, but not the other. I learned my lesson in Colorado not to toy around with the brake pressure light on. The original owner had cut the PB cable to circumnavigate the interlock associated with brake pressure faults, and when my brakes went out, there was 0 redundancy. Luckily there was a saddle in the road on the way down the mountain and through gear manipulation we were able to finally roll to a stop. I will not be trying to get around the safety measures in that fashion...lol

[Flying I 365]

I got the same system on my CE200, the brake pump itself is attached to the drivers side frame rail (a short distance behind the drivers seat) The system itself is quite good and reliable, however I have heard of this issue a few times in my time driving the CE series buses before they were all retired. It could simply be an electrical fault in the system that’s tripping the computer (that’s what I had once that prevented the bus from moving) or a burned out pump motor.

As for the PB cable being cut, that seems to be the only way to circumnavigate the interlock (in no way is it advised) to get the bus moving again (in terms of safely getting it towed without damaging driveline components). That interlock can be triggered by two things, a brake pressure fault, or an electrical fault (low batteries, bad alternator, etc)

I’ve luckily had no such issues with my brake pump though I did replace the computer after the old one was removed prior to my acquisition of the bus. I’ve since acquired two spare (used) units in case of issues (both complete assemblies) If the pump needs replacing, a heavy truck salvage yard that specializes in buses would be a good idea for a short-term fix. (The system itself new costs a pretty penny to replace)

[Samarath]

Originally Posted by Flying I 365

I got the same system on my CE200, the brake pump itself is attached to the drivers side frame rail (a short distance behind the drivers seat) The system itself is quite good and reliable, however I have heard of this issue a few times in my time driving the CE series buses before they were all retired. It could simply be an electrical fault in the system that’s tripping the computer (that’s what I had once that prevented the bus from moving) or a burned out pump motor.

As for the PB cable being cut, that seems to be the only way to circumnavigate the interlock (in no way is it advised) to get the bus moving again (in terms of safely getting it towed without damaging driveline components). That interlock can be triggered by two things, a brake pressure fault, or an electrical fault (low batteries, bad alternator, etc)

I’ve luckily had no such issues with my brake pump though I did replace the computer after the old one was removed prior to my acquisition of the bus. I’ve since acquired two spare (used) units in case of issues (both complete assemblies) If the pump needs replacing, a heavy truck salvage yard that specializes in buses would be a good idea for a short-term fix. (The system itself new costs a pretty penny to replace)

Do you know if you can purchase a new 31 pin connector anywhere? I haven't found one in the wabco-meritor catalog.

[Flying I 365]

Show me what the old one looks like. Depending on what it is, I might have one available from my spares.

[Flying I 365]

Originally Posted by Samarath

Do you know if you can purchase a new 31 pin connector anywhere? I haven't found one in the wabco-meritor catalog.

As for possibly getting a pin connector new? That I’m not too sure. It may not show up in the Wabco-Meritor catalog because the connector might be International specific.

[Samarath]

Originally Posted by Flying I 365

As for possibly getting a pin connector new? That I’m not too sure. It may not show up in the Wabco-Meritor catalog because the connector might be International specific.

I went to pull the codes this morning to share the details with Wabco and both pumps kicked in. I waited for the pumps to build pressure and cranked her up. Someone on schoolbusfleet.com mentioned that you can potentially damage the hydraulic motors if you crank while they're still building psi due to the power draw. It is probably better for everything including the IDM. Anyway, we didn't turn off the engine until we got to Boston, and now we have a spot to do some work. I'll probably be leaning on you guys as usual, but it won't be such a desperate situation now...lol

[Flying I 365]

Originally Posted by Samarath

I went to pull the codes this morning to share the details with Wabco and both pumps kicked in. I waited for the pumps to build pressure and cranked her up. Someone on schoolbusfleet.com mentioned that you can potentially damage the hydraulic motors if you crank while they're still building psi due to the power draw. It is probably better for everything including the IDM. Anyway, we didn't turn off the engine until we got to Boston, and now we have a spot to do some work. I'll probably be leaning on you guys as usual, but it won't be such a desperate situation now...lol

Yeah, recommended to wait for the pumps to build pressure and then shut off before starting the engine. I have heard the same that it can damage the hydraulic motors. (I have also heard that if the bus sits for a long time, it can cause issues with the pumps as well). I do this already with my bus (letting the pumps build pressure and shutting off), and it puts less strain on the batteries from the power draw.

With both pumps kicking in now, it sounds like an electrical fault of some kind somewhere in the system (could be a corroded connector or bad wire) Depending on where the bus was in school service and the road conditions in that particular area (especially wintertime) there could be some corrosion from the conditions the bus was in before.

Sabrina (my bus) was used in school service within Chicago and surrounding suburbs, salt is quite frequently used when the snow falls. Knowing that fact I’ve kept an eye out for any signs of corrosion in the wires or important components as well as looking out for any major developing rust damage (thankfully there was none so far) (The engine leaking oil as diesels often do probably mitigated some of the corrosive effects of the salt) but regardless I have kept a lookout for any issues that could crop up.