Jump to content
Smity42

RTD EGT Problems

Recommended Posts

I am currently wiring and setting up my VL Link plugin ECU.

I have an AEM RTD EGT (http://aemelectronics.com/files/instructions/30-2050 RTD Temperature Sensor Kit.pdf) wired to AN T4, and entered the calibration table to match the one in the document (Cal Table.png).

However, if I set AN T4 to be "RTD EGT", it seems to take the calculated temperature and then multiply it by 10. The picture EGT1.png shows the value with the engine off (cold) and a resitance of about 222R across the sensor, and it is showing 300 degrees. I expected to see about 30deg.

After a lot of mucking around I figured out that if I set AN T4 to be "Fuel Temp", or any setting other than "RTD EGT", then it displays the temperature correctly (EGT2.png).

However, setting it to "RTD EGT" just seems to multiply the calculated value by 10 for some reason.

I have worked around this by dividing the cal table values by 10 (Cal Table 2.png), but I would prefer not to have to do this if I don't have to.

Is this x10 functionality by design? Why? I couldn't find anything in the doco about it. Or is it a bug?

Secondly, I have a MicroTech LTC display dash connected, and the RTD EGT temperature value does not seem to be sent to it. I expected to see it as "EGT-1". Can this be added in the next firmware version? Or can it be configured using a "Custom CAN Stream" as mentioned in the doco? Any help would be appreciated.

Thanks,

Martin

Cal Table.png

EGT1.png

EGT2.png

Cal Table 2.png

Share this post


Link to post
Share on other sites

Hi Martin,

It sounds like you might have stumbled upon a bug.  I will have a play on the Simulator to confirm when I get a chance but it will probably next week.

As for the LTC dash we send out MicroTech's "Automotive CAN protocol V2.0".  According to their data sheet, these are the only channels within that stream:

131ux3U.png

So although the G4+ is capable of sending out a custom stream with EGT included that is pointless if the dash is not capable of receiving a custom stream.  You will have to direct your stream improvement request to MicroTech.  Another option is I see they do also sell a CAN-EGT module that is meant to work with the dash but there is no published info about the CAN protocol it uses - so if you can find out that info then we can probably send EGT data to your dash by duplicating their CAN EGT device message.

 

Share this post


Link to post
Share on other sites

Thanks Adam,

I noticed in the CAN setup "Test Calculator" the RTD EGT only has a resolution of 10deg, presumably to allow the much larger range necessary for exhaust temps. I suspect there is just a "divide by 10" missing from the calculation somewhere.

Can I get a copy of the MicroTech "Automotive CAN protocol V2.0" datasheet? The dash seems to be capable of receiving a lot more inputs than those listed, so maybe it is a newer version of the protocol. If I can get the datasheet, I will try to reverse engineer the additional values I want to send (EGT, Oil Temp, etc.). But I can't seem to find this datasheet online.

Cheers,

Martin

 

 

 

Resolution.png

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×