Initial fire (6.1 turned 426ci)

I am working on my first hemi and could use some help.

It started as a 6.1 from an SRT8 which was bored and stroked to 426ci. It has been swapped in to an off road 2002 Jeep Grand Cherokee with long travel suspension and uses a 2005 Ram ECU and base tune (attached) from Hotwire who also did the wiring harness integration.

Only modification to the tune from HW I have made is injector tables as it has Trackhawk injectors installed. I found a couple stock Trackhawk tunes in the repository (one attached) to compare the injector flow info against each other to ensure they did not differ from one another and reconfigured the tune from Hotwire with that info (again attached). I will say that the TH injector table does have one additional cell which I omitted (0.0074/0.8000 on INJPW vs. Fuel Mass table and 0.8000/.0074 on the Fuel Mass vs. INJPW table).

Once cranking vehicle will fire, but wide band goes rich (10.0afr) and it stalls. If I crank more, I feel it loads up and doesn't want to fire.

My question here is what is the best approach to reduce cranking fuel?

From there I assume making changes to the VE table(s) like you would for a mafless LS1 0411 ECU to get running idle AFR in line?

Any other thoughts, suggestions would be great.

Thanks in advance!

Hi,
worked also on an enlarged SRT8. and had to change the injectors.
I started using the SRT8 Tune, modified the injector data, then going into detail. BTW. Your injector data possibly may need some attention. [ECM] 34200 - FA Ratio of the SRT8 Maximum is set to 0.1030, yours is set to 0.118?
Then I would have a look at the O2 delay, ... .
I'm not sure whether this will help instantly but maybe give an approach.

NA or boosted ?

Quote:

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Originally Posted by PurpleRam

NA or boosted ?

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It is a N/A. I used the 392 injectors using the data provided by a 392 stock tune. It worked fine. Therfore I also suggested to a look at the injector data. Super73's given Fuel vs PW looks odd
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The only data you swapped over from the Trackhawk file is the flow rate. There's more to it than that.

Attachment 145874

Open your Trackhawk file in your compare feature and transfer over just the blue in these 2 tables.

Attachment 145875

These are your offset tables. You obviously can't copy one to the other and it's a little unclear what the 03 Jeep calibration is using for what would be a second axis for that table. But if you compare the 03 Jeep calibration at 14 volts to the TH, the offset is double the highest value in the 14.1 column in the trackhawk cal, and it's triple the lowest value. I would reduce the entire green part of the Jeep cal by 20%. See how that acts. Might even go a little farther with it if the results are as expected.

The offset tables are a big deal when it comes to low pulse width control. Getting the injector data much closer is going to help your start up not to mention the rest of the operating range.