Please interpret these diagnostic numbers.

[Scott & Heather]

My wife is driving our coach today all day so I've been using my Nexiq for the first time while under way. I wanted to post some numbers and see what you guys notice. If anything seems out of the ordinary I'd love to know. Thanks so much!

Current outdoor temp: 67°F
Current elevation: 680ft
Driving speed: 60mph
Some rolling hills through northern Texas.

Here are my numbers:

Max boost up a hill was 16.5 psi
Max engine oil pressure: 53.5 psi
Average engine oil pressure: 30 psi
Coolant temp steady around 195°F
Max coolant temp so far today: 200°F
Max engine speed: 2199 RPM
Fuel Temp: 100°F
Fuel delivery rate max: 28.7

Some screenshots:





Sent from my iPhone using Tapatalk Pro

[azdieselman]

Baro is off.
It should be closer to 14.4 or 14.5 for your posted elevation.

[Scott & Heather]

It's at 14.4 now. That initial baro was probably 90 miles ago


Sent from my iPhone using Tapatalk Pro

[Scott & Heather]

AZ, I know you're a guru so can I ask you, what is torque limiting factor exactly? And why is it always 100%?

Also, how do you interpret injector response times? Explain that to me in baby terms?


Sent from my iPhone using Tapatalk Pro

[azdieselman]

Scott,

Sorry for the delay, Travelling today.

You want the torque limiting to read 100%.
Anything less means it's in de-rate.

Injector response time is a measurement of the time between the ECM request/command and injector solenoid closing. It watches the current.

It is measured in MSec.
I don't recall what the spec should be, I generally look for 1 or more that are significantly different than the rest. The value will change with engine operating conditions, (warm/cold) and load.
If the response time is either too short or long it will set a cylinder specific code. Always verify the wiring integrity before replacing an injector.

[Scott & Heather]

Great info. Ken Arnold had explained the torque limiting to me earlier today so I have a good idea of how that works now between the two of you answering my questions. Good to know about the injector response time. They are all very close to each other so I have nothing to worry about at this point I guess. Thanks again!


Sent from my iPhone using Tapatalk Pro

[blue_goose]

You should be able to get at least 25PSI of boost on a good pull.  About 10PSI on level road.
Jack

[lostagain]

Going up a hill does not always create maximum boost.

Boost, or manifold pressure, is done by hot exhaust gases spinning the turbine wheel of the turbo. So the rpm have to be high near max. And the gases have to be hot and expanding (flowing faster), from the engine under maximum load. So you could be climbing a hill at say 1500 rpm, and showing 16 psi. Or climbing the same hill in the next lower gear at higher rpm, less load on the engine, and showing 12 psi. Then the next hill is steeper, and the bus is giving it all it's got at 2100 rpm and holding there, showing 25 psi. If it gets steeper and it slows down in that same gear, it still giving it all it's got, but the rpm are slower, blowing out less volume, and the psi diminishes.

I am sure you all knew that, but it is kind of fun thinking it out loud...

JC

[blue_goose]

Scott said (Max boost up a hill was 16.5 psi) That isn't much boost.
Jack

[Scott & Heather]

I've never had more than that...but I'll keep monitoring now that we are out west and about to do some serious climbs


Sent from my iPhone using Tapatalk Pro