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Topic: Turbos are good to have (Read 753 times) previous topic - next topic

Turbos are good to have

We're on our way back north, currently in Kansas. This morning I got a CHECK ENGINE LIGHT. A quick look at the computer said "102 35 Boost Pressure High Voltage." The TURBO number on the computer showed 0.0. Okay, we're in Kansas, not too many hills, let's see what happens. Headed out and all was fine. Got a few miles down the road and had to stop, then make a left turn up hill. Turbo is still reading 0.0 and now I know why I have one! We got to the top of the hill and all of a sudden the check engine light is out and the turbo is reading something other than 0.0. Woohoo, the power is back!

A little while later the same error code showed up, but this time the turbo is showing 13.5. That never changed the rest of the trip today. Of course, by that time we were on I-70 so didn't need it.

I suspect that this may be an electrical connection that isn't as tight as it should be, so tomorrow while Jo Ann is at the laundromat I'll poke around some.

Re: Turbos are good to have

Reply #1 –
Update?
Frank & Connie Williams
1999 U320 '36
Build: 5466
MC: 18335

Re: Turbos are good to have

Reply #2 –
I poked at various connections today. Some seemed to be not as tight as the rest, so maybe that helped. We'll see Monday when we head up to North Platte.

Re: Turbos are good to have

Reply #3 –
look for loose, cracked post turbo boots...a leaky boot will do that..
Len Barron
1988 GV36 U280 3208T(250hp)/MT643
1972 Jeep Commando LS2/4L65e
2000 Chevy Express Hightop Campervan
LBZ Duramax /6sp Allison

Re: Turbos are good to have

Reply #4 –
Quote from: len.barron –
look for loose, cracked post turbo boots...a leaky boot will do that..
No boots on the Detroit 2 cycle. No intercooler so the turbo goes straight into the blower with an liquid cooled aftercooler after the blower and then to the cylinders. It's all bolted solid.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Turbos are good to have

Reply #5 –
This morning I got the same error code about high voltage. The turbo showed 0.0 for the first hour or so, then showed 4.4 for a while, and finally 13.5 again. There were times when I was sure the turbo was working and times when I was sure it wasn't. We'll be back in Riverton Friday and I'll start asking around to see if anyone there has any suggestions.

NO poking around until the engine compartment is completely cooled off!

Re: Turbos are good to have

Reply #6 –
Take the little plug off the plenum just below the turbo and then run a small hose to a gauge in the bedroom and have someone watch it when you accelerate. Think it's 1/4" pipe but not positive. $10 should buy a 0-30 psi gauge and ultra easy to install. Normal boost indicates an electrical issue where the ECU is not seeing the boost and won't give full fuel. Repeating it again below but here is how it works.

Turbo will make noise if it's not working right so almost 100% sure it's electrical. How about the turbo sensor? Have you checked it yet? If the DDEC ECU is not getting a good reading from the sensor, it won't add fuel and you will think it's the turbo when it's lack of fuel. To put it simply, no boost seen by the ECU, not enough fuel is injected to give full power. That's why some put a resistor in the wiring to fool the ECU into adding fuel coming off the stop sign or light. It is delivered from the factory with the DDEC in a no-smoke mode to keep emissions down when first accelerating.

But with the codes, there is a good chance there is a bad ground or other connection problem.  Detroit DDEC wiring is pretty bullet proof so doubt anything is wrong with the wiring but sensors do go bad. When the engine is removed and replaced like yours was, there is a chance for error with the electrics.

You badly need the Pro-Link 9000 so you can pinpoint the problem in a minute or two. A super cheap tool considering just the cost of one trip to a shop to have them use the same tool.

Do you have the schematic for your coach? It's online here on the forum. How about all the pages with the DDEC codes that are online?

Pierce


Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Turbos are good to have

Reply #7 –
When Dave gets home I will put my prolink on his bus and see what the problem is.
Andy & Eileen
MONTROSE COLORADO
1992 U300  40' 6V92 TA
2016 4 Runner
1998 Jeep Grand cherokee

1998 Jeep Grand Cherokee) Build # 4135 Skp# 122921

Re: Turbos are good to have

Reply #8 –
Dave,

At the bottom is an attachment with the fault code I think your retrieved from the under dash top switch and blinking light. Here is the link to possibilities. Go up the the blue at the top and in the middle are selections for the previous and next pages. You may be able to do a bit of troubleshooting before you have access to the Pro-Link.  Here is the link and check under "Notes" before reading the rest. Table 2-16. DDEC II System Fault Index

Let me know if you want photos of mine.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Turbos are good to have

Reply #9 –
The ECM reads off the boost sensor. It is located just past the turbo A black rectangular box with a plug and 3 wires. It may be going bad.
91 GV U300 Unihome 40' Build 3811
6V92TA Detroit

Re: Turbos are good to have

Reply #10 –
Quote from: Pierce & Gaylie Stewart –
Take the little plug off the plenum just below the turbo and then run a small hose to a gauge in the bedroom and have someone watch it when you accelerate. Think it's 1/4" pipe but not positive. $10 should buy a 0-30 psi gauge and ultra easy to install. Normal boost indicates an electrical issue where the ECU is not seeing the boost and won't give full fuel. Repeating it again below but here is how it works.

Turbo will make noise if it's not working right so almost 100% sure it's electrical. How about the turbo sensor? Have you checked it yet? If the DDEC ECU is not getting a good reading from the sensor, it won't add fuel and you will think it's the turbo when it's lack of fuel. To put it simply, no boost seen by the ECU, not enough fuel is injected to give full power. That's why some put a resistor in the wiring to fool the ECU into adding fuel coming off the stop sign or light. It is delivered from the factory with the DDEC in a no-smoke mode to keep emissions down when first accelerating.

But with the codes, there is a good chance there is a bad ground or other connection problem.  Detroit DDEC wiring is pretty bullet proof so doubt anything is wrong with the wiring but sensors do go bad. When the engine is removed and replaced like yours was, there is a chance for error with the electrics.

You badly need the Pro-Link 9000 so you can pinpoint the problem in a minute or two. A super cheap tool considering just the cost of one trip to a shop to have them use the same tool.

Do you have the schematic for your coach? It's online here on the forum. How about all the pages with the DDEC codes that are online?

Pierce

Pierce—When you order the Pro-Link 9000, do you specify the application, I.e., Detroit DDEC, for which you will use it, and do you need anything else to use it?
Thanks,
Randall
1989 Foretravel U300 Grand Villa
Build #3410

Re: Turbos are good to have

Reply #11 –
Quote from: RandallBrink –
Pierce—When you order the Pro-Link 9000, do you specify the application, I.e., Detroit DDEC, for which you will use it, and do you need anything else to use it?
Thanks,
Randall
Randall,

Yes, the Pro-Link 9000 is just a reader with a variety of cartridges that fit on the back and lock. All Foretravel 6V92TA that are found in U300s, take either the DDEC I & II or the DDEC II & III cartridge. The later is probably slightly better especially if it has been updated. It may be able to turn off the smoke control and do several other tasks. Some have back lighting in green.

So, the reader is fairly cheap and should cost less than $100. The cartridges are expensive for the Detroit be even more expensive for the Cummins, CATs, Allison transmission and ABS brakes. The Ford, Chevy, Mopar cartridge are only about $5-$10.

It's sold under several names including Snap-On (the present owner), MPSI, Kent Moore and a couple of other names.

It can be found on Ebay, FB Marketplace and other online sources. Andy really got a super deal on his.

PM and I will send everything it can do. It's more of a tool than an overall reader like the excellent display Roger sells for PCs. The Pro-Link can test the injectors a couple of ways, give a Detroit a fast idle (cruise control will NOT do it) and lots of other stuff. It won't update the firmware to fire department (500 hp) or marine horsepower (up to 620 hp).

These are only available on the used market. Snap On sells a new version but it's over $2000. The Chinese have a clone of the late tool for a very reasonable price but I don't know the exact model and if I will work on DDEC II on a 92 series. They advertise it for all late trucks and buses and all in one tool. The Detroit 92 series was the first HD electronic diesel engine made but the 60 series was only electronic with no mechanical version made.

Pierce

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Turbos are good to have

Reply #12 –
I think I found the sensor Stump mentioned. Does it have a small hose also?
 

Re: Turbos are good to have

Reply #14 –
Thanks, Pierce, that's the thing I was looking at.