No Start, mechanics have no clue

[cadillackid]

I unplugged the baro sensor on my T444E and it started right up.. it also turned on the WARN light..



are you sure your glow plugs are getting power and that you are showing RPM? if the injectors are firing (how did you test?).. then if theres fuel the engine should start. the computer wont fire the injectors if it doesnt know where the cam is..



a new ECM is something to try (I never have paid 400 for one though... ebay and alot cheaper)...



I didnt read back through the whole thread but im assuming you tested fuel pressure at the schraeder? you need 40-75 PSI to be in spec (yours likely in the low-mid 40s as its earlier model)...

[Booyah45828]

Originally Posted by bachataBus

I pulled the ECM out today, cracked it open, and it is frustratingly *spotless*. No bad connections, no bad components (singed connections, bubbling plastic, oxidized solder), everything is visually 100%.

Sign #1 that your ecm is likely fine.

Originally Posted by bachataBus

The error codes are specifically for corrupted RAM, so I'm guessing I have to replace the ECM.

The error code, DTC 224, is for KAM power or lack of it, not corrupted ram. DTC 615 is for corrupted ram. I've never had a faulty ecm because of solely DTC 224, it's nearly always accompanied by an active DTC 615. Yes, the troubleshooting chart for 224 gives faulty ecm as an option, because if the pcb between the ecm pin and the ram is burnt or open, it will cause the issues you're having and require the pcm to be replaced. But with a clean ecm, the odds of that goes to near zero

Straight from the troubleshooting chart : If the KAM PWR to the ECM is good and ground circuits are good, and Flash code 224 or 615 remains active, the ECM is defective

If you have the troubleshooting chart, follow it.

Here is one that you can download if you don't. https://s9c749554ed0cf09e.jimcontent...c%20Manual.pdf

Originally Posted by bachataBus

I also followed the diagnostic service manual procedure and determined that the circuit around the barometric pressure sensor is all good, and since I'm reading a bad pressure, the sensor is likely bad.

IF you followed the procedure, and the circuit is fine, which component did it say had the fault? The sensor? Then the sensor isn't likely bad, but it is bad, and should be replaced before you throw an ecm at it. Those procedures are pretty accurate at honing in on faulty components.

What's your map sensor reading during all of this? With code 152 present the ecm should use the map value as a baro baseline vs the baro value. So if your map is reading wonky too, then you might have a failed map sensor as well. DTC 152 won't set a check engine light, so it is often failed for awhile before someone realizes it's failed.

As a quick test, you should unplug the baro and map sensor, and then try and start the bus. Unplugging both will default the atmosphere value in the ecm to the 29.6 value.

[bachataBus]

Originally Posted by CHEESE_WAGON

Something to consider. The sensor may ground through the ECM and once the circuit is broken the reading ghosts out. Something that is common but overlooked in regard to barometric pressure sensors is conventional gas engines have these connected to the engine through a hose to help it draw vacuum, as they help the ECM determine the Manifold Absolute Pressure (a mean value of pressure inside intake manifold and outside ambient air pressure). Not doable on a diesel as they don't generate vacuum, so I am guessing this sensor simply reports ambient. Either way, it certainly sounds like the ECM and the sensor need each other in order to complete the circuit and get any reading at all.

Not sure about all diesels, but the t444e definitely has a manifold absolute pressure sensor. In fact, if the barometric pressure sensor is removed, it *should* default to using the MAP sensor to determine the pressure. And since I have no codes related to the MAP sensor, I have been assuming that guy is okay!

[bachataBus]

Originally Posted by Booyah45828

If you have the troubleshooting chart, follow it.

I have been following the trouble shooting chart, that's how I determined the baro sensor is bad. And the trouble shooting for the KAM was trivial, without even opening the document I can tell you the whole thing "Battery voltage between pins 1 and 60". Yah, there's battery voltage there. I was hoping it was an internal short, or something, but it isn't. If it's getting power, and there's no internally broken components... somethin's wrong. I'll do some more poking around the power circuitry today, but everything has been looking good so far.

Originally Posted by Booyah45828

What's your map sensor reading during all of this? With code 152 present the ecm should use the map value as a baro baseline vs the baro value. So if your map is reading wonky too, then you might have a failed map sensor as well. DTC 152 won't set a check engine light, so it is often failed for awhile before someone realizes it's failed.

I was under the impression the MAP doesn't produce a comparable baseline atmospheric pressure measurement,but that the engine would try to estimate the pressure at idle from the MAP. I tried to unplug just the BARO, that didn't get it to start, I suppose I can try to unplug both today. Seems like at some point, unplugging sensors is going to become problematic... but I'll try anything.

[Booyah45828]

Originally Posted by bachataBus

I was under the impression the MAP doesn't produce a comparable baseline atmospheric pressure measurement,but that the engine would try to estimate the pressure at idle from the MAP. I tried to unplug just the BARO, that didn't get it to start, I suppose I can try to unplug both today. Seems like at some point, unplugging sensors is going to become problematic... but I'll try anything.

Try that. Disconnecting both should get you a default value of 29.6.

I've seen battery disconnects create the 224 and an inactive 615. If you can find an ecm cheap, throw it at it, but I don't want to see you throwing parts at it and not solving anything. Which is what sounds like has already happened by your mechanic charging you 2000.

[bachataBus]

Originally Posted by Booyah45828

... but I don't want to see you throwing parts at it and not solving anything. Which is what sounds like has already happened by your mechanic charging you 2000.

Unfortunately Although I did get new glowplus, glowplug harness, a compression test on all cylinders, and I think a new power steering hose... but yah, at a ridiculous markup! A lot of diagnostic work that didn't really go anywhere. It's a good shop, I think I just got a technician who was not super efficient with his time spent...

[family wagon]

Originally Posted by bachataBus

The bus is not on my land, I am not lucky enough to own that space, and I have to move it.

Of course moving the bus under its own power is ideal, but considering the substantial effort you've already invested in getting the engine running, you might consider just towing it to its next home.


I've DIY flat towed a disabled bus on three occasions. Two were short trips of about 16 miles; the third was 83 miles. I used a generator and air compressor to charge the air brake system on the bus and towed it with a 2500 or 3500 pickup truck. I mention this only to suggest that you might alleviate some of the stress and expense of troubleshooting if you resort to move it first, fix it later.

[bachataBus]

Originally Posted by family wagon

Of course moving the bus under its own power is ideal, but considering the substantial effort you've already invested in getting the engine running, you might consider just towing it to its next home.

That would imply I had a place to move it to! I'm parked on the street, which is legal, but I have to move it at least once a week. I'm also at a workshop, for the construction, but I can't park overnight at the workshop. So there's a lot of moving... Which shouldn't be a problem, it's a vehicle! But it is a problem, go figure.

[Jolly Roger bus 223]

Originally Posted by bachataBus

Also, can I say,

I understand ether is bad.

I cannot explain how frustrating is to read in every thread where someone is clearly trying to fix their engine, and has resorted to ether, the legion of commentors who chime in "ether just covers the symptoms, you better find the root cause and fix it". I honestly cannot imagine anyone who has used ether has thought it was good. It puts a pit in my stomach every time I spray a ***** explosive into my engine, but I literally do not have a choice. The bus is not on my land, I am not lucky enough to own that space, and I have to move it. I have spent thousands of dollars at mechanics trying to fix it. Please try to be more empathetic to the people who are in dire engine troubles!

i have worked on alot of older heavy equipment and can say that gasoline in a cheap spray bottle works as good as ether, is alot softer drug for a diesel and unlike either i have never seen one get addicted to gas but i have had some that were used to ether start on a few sprays of gas.
good luck.

[bachataBus]

So, I have cleaned the ever loving crud out of all battery terminal connections, and I even moved the ECM power cables to their own dedicated cables (previously the ECM power was spliced into a battery cable, I cut it and added battery lugs so it can have its own power). I scrubbed each of the connectors with mineral spirits and a wire brush, it's all as squeaky clean as can be. Connection must be solid, still have corrupt memory codes... I didn't get to test unplugging both the baro and the map sensor, because for some reason she started today, although all I've done is cleaned the connectors. It's been a flaky effect from the start, so I wouldn't read too much into that. I got a new ECM in the mail today, although of course it broke in shipping, so I can't really swap 'em out. New BARO is arriving next week.

[ol trunt]

Codes may have to be cleared with a scanner. I'd hold off on replacing the damaged computer 'till you have cleared the codes and run the bus a while (preferable on the hwy). Maybe you'll be able to just send the broken one back for a refund.
Jack

[bachataBus]

After unplugging the comp and cleaning everything I did clear the codes. I only drove it for 5-10 minutes though, maybe not enough driving? Who knows. The company is letting me return the item, and depending on how it goes tomorrow I'll either request another one or try to get my money back. Honestly, I'm thinking it's time to replace the computer. I get that $400 bucks is annoying, but it's a hell of a lot cheaper than continuing to mess around with ether.

[bachataBus]

Unplugging both sensors doesn't help the engine start, a new IDM doesn't help the engine start, a new ECM doesn't help it start! I have a new idea, and it's the old idea.

I mentioned at the beginning that I had a fuel leak at the banjo fitting, and my engine was losing prime, and it wouldn't start. I had ordered new gaskets, put them on, and now I can't spot a leak (using a UV light and some dye). This was all way back.

Could I have simply messed up the repair, and now I have a suuuuuuuuuuuper slow leak? I know for a fact I over-torqued the banjo gaskets, significantly, could they be crushed and letting in just a touch of air over 18 hours or something? The mechanic doesn't seem to think any fuel is leaking, but I don't know how to check if it's leaking real slow. I've exhausted a ton of other avenues, it seems like maybe I just never fixed the original problem...

[cadillackid]

at some point in time the actual problem needs to be diagnose..

plugging in a fuel PSI gauge to the test port will tell you if you have lift pressure going to the bowl..



plugging a computer in and watching for HPOP pressure while cranking will tell you if your HPOP is draining basck and you'll see no HPOP pressure while cranking.. or very low..



looking at the computer will also see if you see RPM signal registered indicating the CPS is working correctly...



checking for current draw across the glowplug feeds in the harness will tell you if your glowplugs are working (I believe you said you have 444E and not 466E? )



diagnose it methodically

[orangebus]

Can a DT 466 E for evil be converted back to just a DT 466 ? That's what I have and I love it.

[joeblack5]

Wow , what a nightmare and frustration..do you have 10.5 volt at the ecm during start. Can you confirm the hpop pressure changing from contact to start...and if running does it vary... Maybe hpop sensor is giving wrong info and pressure is not really there.

It would be nice to be able to verify if the injectors are getting actuated... Not sure how to without a scope.

The fluctuating tacho needle indicates that your ecm gets signal but there are people stating that that might not mean that your cam sensor is actually good

I have a mechanical pressure gauge hooked up to the schrader valve( as Chris suggest) because pressure there indicates that your lift pump and your pressure pump are working.

Hope you find this..becoming an expert this way is no fun.

[bachataBus]

Originally Posted by cadillackid

at some point in time the actual problem needs to be diagnose..

plugging in a fuel PSI gauge to the test port will tell you if you have lift pressure going to the bowl..



plugging a computer in and watching for HPOP pressure while cranking will tell you if your HPOP is draining basck and you'll see no HPOP pressure while cranking.. or very low..



looking at the computer will also see if you see RPM signal registered indicating the CPS is working correctly...



checking for current draw across the glowplug feeds in the harness will tell you if your glowplugs are working (I believe you said you have 444E and not 466E? )



diagnose it methodically

The thing is, all of this has been done, and by an actual mechanic (not a dope like myself). As I commented previously in the thread, the mechanic basically tested everything (and replaced the glow plugs), and couldn't find the issue.

HPOP is between 3000-3200 (3000 is spec)
Fuel pressure while cranking is 42 psi, in spec

[joeblack5]

I understand your frustrations and hesitation but the reality is that the mechanic is the dope...not you..so now you will have to continue on your own power with the help of this forum or others..
So you will have to retake all the steps from the beginning and find out for your self what the mechanic overlooked.

Good luck
Johan

[orangebus]

OK, cracks knuckles, how about your fuel pump solenoid? I had a huge problem once , the fuel cutoff actuated by the key had 2 solenoids, first opened the valve for fuel and second holds it open while driving, well my first solenoid burned up and I could not figure it out , Genesis Flatfront 39'Dt466 1995, and eventually I rigged it so I pull a cable to start it and the other solenoid keeps it running , all this was tied into the door and window safety switch to prevent statrting while doors were open, to circumvent the switch , one has to ground out another solenoid in the door below the driver window. Good luck

[cadillackid]

Originally Posted by bachataBus

The thing is, all of this has been done, and by an actual mechanic (not a dope like myself). As I commented previously in the thread, the mechanic basically tested everything (and replaced the glow plugs), and couldn't find the issue.

HPOP is between 3000-3200 (3000 is spec)
Fuel pressure while cranking is 42 psi, in spec

HPOP while cranking is 3000??? Ive never ever seen it that high.. it will run that why when the engine is running under full load.. the reason i ask about HPOP during cranking is if for some reason your HPOP is draining down.. its happened to some of the ford guys.. what results is 0 or very Low HPOP pressure whole cranking till its cranked enough to refill the reservoire and generate pressure.. the HPOP will read perfectly once the engine is started because the pump is good, IPR is likely good and ICP reading correctly..