Logging fuel pressure

[blowngt]

I'm new to this forum and the world of megaquirt. So far everything that I've done has worked out better than expected. What a great product!!!

I've been chasing a lean condition over the past few weeks. Yesterday we decided to watch fuel pressure while under boost to see if there were any issues. Sure enough, we found the problem (secondary fuel pump was not turning on quick enough......hobbs switch not adjusted properly we're hoping).

It came to mind that if I was smart enough, I would have found a way to log fuel pressure as well and maybe I would've seen this problem quicker.

I did a quick peek thru the megalog viewer but I didn't see anything referencing fuel pressure.

Anyone have any ideas??

[msiddalingaiah]

Some of this information might be of help, just focus on the fuel pressure sensor details:

http://www.madhu.com/content/Main/FuelPumpController

You can use either the AEM sensor or the Bosch sensor to measure fuel pressure. You can connect sensor output to one of the spare ADC channels and view it with MegalogViewer. This is known to work.

[blowngt]

Thanks for the link!!

I'll give it a shot this weekend......

[devastator]

Did you ever get this to work?

[blowngt]

Did you ever get this to work?

Just got it to work a few weeks ago.

It's awesome.......

[devastator]

devastator wrote:Did you ever get this to work?

Just got it to work a few weeks ago.

It's awesome.......

Are you running MS2? Was there anything special you had to do to MT, or MLV, to get it to work? What port did you tie it into?
Hope all the questions don't bother you, but I'm anxious to do the same thing you did for the exact same reason.

[blowngt]

devastator wrote:Did you ever get this to work?

Just got it to work a few weeks ago.

It's awesome.......

Are you running MS2? Was there anything special you had to do to MT, or MLV, to get it to work? What port did you tie it into?
Hope all the questions don't bother you, but I'm anxious to do the same thing you did for the exact same reason.

Running MSII.

We installed into input adc7 (I left the hardware install to a friend that knows what he's doing).

You do have to make some software modifications to both Megasquirt and Megalog viewer, but it's pretty simple and straightforward.

It tools us a few hours to do the first time, but I bet if we had to do it again it would take less than an hour.

Let me know if I can help at all.

[convertables_10]

Im interested in the code side of things and what the hardware mods was. Ive seen bits scattered and would like to make sure what im looking at is gonna work.

[msiddalingaiah]

Im interested in the code side of things and what the hardware mods was. Ive seen bits scattered and would like to make sure what im looking at is gonna work.

Not sure what you mean. The standard code samples the spare ADC channel and logs it just like everything else. All you need to do is connect the fuel pressure signal from your sensor to the spare ADC input. It's not that complicated, you might be over thinking it.

[devastator]

The standard code samples the spare ADC channel and logs it just like everything else. All you need to do is connect the fuel pressure signal from your sensor to the spare ADC input. It's not that complicated, you might be over thinking it.

It does? COOL! I've definitely been guilty of over thinking things before.
Thanks man!

[grippo]

Before you datalog it you have to add it to the end of your inif file. Make a backup copy of it, go into the file with a text editor like NotePad, and go to the very end, and after afrtgt1, add the following line:

entry = knock, "knock-V", float, "%.2f"

This will record what is in the spare ADC7. However I noticed that there are some other things that need fixing: there were 2 input variables that were mislabeled and should read knock Value at 0V and .....at 5V. This allows you to scale your gauge. For example, if you know 5V is 60 psi of pressure, then you can set it to 60 instead of the default 5V and you will record directly in psi. The output knock value was also incorrectly scaled in the ini file. So I fixed these and put it all in the 2.905 ini file attached. I will get Lance to put this in the official 2.892 ini, but if you want to upgrade to 2.905 there is no reason not too. There were no radical changes in it. You will still have to add the above line to the end of the 2.905 ini because this is rarely used.

[Bernard Fife]

I have put the 2.892 code and INI here:

http://www.megamanual.com/ms2/code.htm

It has Al's fixes and adds the line for the knock in the datalog.

The 2.905 INI has also been fixed ( http://www.msgpio.com/manuals/mshift/betacodeCPT.htm ).

Lance.

[devastator]

Thanks guys. I'm looking forward to trying this on my MS2.
Did I read correctly that this code only works with TS and not MT?

[Bernard Fife]

devastator,

The 2.892 code works with either.

The 2.905 code works best with TS, because it has table burning and CAN functions in the INI/code that MT isn't compatible with (the most recent version of MT was written long before these functions were conceived). However, the 2.905 code/INI might well work with MT as long as you aren't using the missing functions. MT may give you some error warnings if it doesn't understand added parts of the INI, but it might then work fine. I haven't tried this, though.

Lance.

[devastator]

Thanks Lance.