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My Detroit diesel on GE frame 6 refuse to accelerate after 2 minute warm up. It is controlled by ddec iii

 

Have you tried spanking <b>your</b> Detroit diesel to make it behave when it doesn't do what you want it to do?

Seriously, when did this problem start? After a maintenance outage?

If I recall correctly, there is a 4-20mA output from the Speedtronic to provide a speed reference to the DDEC. if this is true, have you verified the output is getting to the DDEC?

If it is, then it's likely a problem with the DDEC or the fuel rack actuator.

 

DDEC has electronic injectors, so no actuator on the rack...just FYI.

 

Diesels that don't accelerate need X'tramile. (Shameless plug of a product marketed by my company). Tried twisting the fuel rack when the engine is not engaged to any load? As CSA said, how is the fuel rack position determined? Electric, pneumatic, hydraulic through actuators? A lot of details are desired.

Regards,
Tomy Zacharia

 

Friggin' electronics are taking over....

 

> Have you tried spanking <b>your</b>

Engine starts and runs on idle and warm up. After 20secs the reference increases to 2200rpm but engine speed PN does not follow.

 

This was first posted to the world on 10 March 2011. It's now 16 March 2011 and apparently the problem still exists, and you haven't been able to tell us if you have verified if there is an analog signal being sent to the DDEC and if so, is it making it all the way to the DDEC input terminals.

Even if the reference value in the Speedtronic is increasing, if there's a wiring problem it can't get to the DDEC. Or if there's something wrong with the output of the Speedtronic, then something may be wrong with the Speedtronic. (If that were the case, there would likely be a Diagnostic Alarm to indicate a problem, but you haven't told us if there are any Diagnostic Alarms, or even any Process Alarms, when this failure to accelerate is occurring.)

Or, if the analog signal is getting to the DDEC input terminals, then it certainly seems like the DDEC isn't working correctly.

But, you have to determine if the signal is getting to the DDEC. If it's not, then that's likely the problem (to be clear--the problem would be that the signal isn't getting to the DDEC). If the signal is getting to the DDEC, then the DDEC is likely the problem.

And, if you have determined the analog signal is getting to the DDEC, then you haven't told us that--just that the reference is increasing. Is that the reference in the Speedtronic, or the reference at the DDEC input terminals?

Even if it's just a discrete signal being communicated to the DDEC to tell it to accelerate to 2200 RPM, you still have to verify that the signal is or isn't getting to the DDEC terminals. And then you will have more information than you had on 10 March 2011, or on 16 March 2011.

Best of luck with <b>your</b> problem.

 

This one raised my curiosity. From what I have read on the internet, the DDEC module (ECM) used on this particular engine can be troubleshot (pardon the usage) only with its programming terminal. Even the injector parameters have to be entered in to the EEPROM for the engine to work satisfactorily. This also means that a fairly experienced engine mechanic would be required with sufficient knowledge of the electronics part to be of some use.

Get help, quickly.

Regards,
Tomy Zacharia

 

>Even if the reference value in the
>Speedtronic is increasing, if there's a
>wiring problem it can't get to the DDEC.
>Or if there's something wrong with the
>output of the Speedtronic, then

Please my 4-20ma signal is not increasing

 

Please have a knowledgeable person come to site to assist with the problem.

 

> As CSA said, how is the fuel rack position determined?
> Electric, pneumatic, hydraulic through actuators? A lot of details are
> desired.

The fuel control is electronic ddec iii

 

This thread is like a slow death by starvation, with periodic feedings of a couple of dried and moldy bread crumbs.

As CSA has also said, have someone knowledgeable come to site to assist with the problem.

We don't even know if the Speedtronic is a Mark V or a Mark VI; we have virtually no information and any information provided has been virtually useless.

You say the reference increases, but the 4-20 mA signal does not change. Is it not changing from the Speedtronic, or is the signal not getting to the DDEC III?

It's pretty clear that site does not have much, if any, experience with troubleshooting, or even in using an ammeter to measure output current from the Speedtronic to the DDEC III.

We have REPEATEDLY asked what Diagnostic Alarms are being annunciated, and have received NOTHING in response. If the 4-20 mA output is not working properly, then there is most likely a Diagnostic Alarm to alert a conscious operator or technician (conscious as in 'awake and aware') there is some kind of problem.

I would ask which output of the Speedtronic is being used to send the signal to the DDEC III, but it's doubtful if we would get a response to be able to suggest a troubleshooting path.

Have someone come to site to help resolve the problem.

And, when it's resolved let us know what it turned out to be.

 

Can anybody tell me about DDEC. We have frame-VI machine controlled by Mark-IV & the Diesel Engine is accelerated using 20DAR and 20DCS

 

I can tell you that you have a Frame 6 machine with a Mark IV controller.

DDEC is Digital Diesel Engine Controller. It's an electronic fuel rack control that is being provided with new units with diesel starting means.

You would have to contact your local diesel supplier to see if they have a retrofit kit which could be used to replace the hydraulic fuel rack and solenoids with a DDEC and electronic fuel injectors.

It's not likely that a Mark IV could be modified to output a 4-20 mA signal to drive a DDEC.

 

Thanks for your explanation. The GT is commissioned in the year of 1990.

We are going to upgrade Mark-IV to Mark-VIe. So we will consider for the same.

 

The fact is that the mark V does not produce more than 4mA even when the command for it to go to 2200rpm. The ddec disconnected to be sure nothing is dragging the signal to ground but mark V still produce 4mA. What I need to determine is which of the card in the C core generate 4-20mA?

 

The facts are that the <C> mA outputs are driven by <Q> via F:\UNIT1\MAOUT_Q.SRC.

The fact is that the I/O Report, file F:\UNIT1\TC2KREPT.TXT, lists the output terminals on the CTBA card for the output which was assigned the signal in MAOUT_Q.SRC.

The fact is that the Mark V Application Manual, GEH-6195, Appendix D, Signal Flow Diagrams, somewhere around Pg. D-16, shows that the <C> mA outputs on the CTBA card get their current from the TCCA card in Loc. 2 of <C>.

And the TCCA card in Loc. 2 of <C> gets the assignment and scaling from F:\UNIT1\MAOUT_Q.SRC.

It's now 1 May 2011. This thread was started on 8 March 2011.