Digital Tuning New Powerjection 3, looking for tuning advice...

95RedCobra

New Member
Aug 7, 2008
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Just got a Powerjection 3 fuel injection system and was looking for a little tuning advice. I have read some of the posts from other owners on this board and everyone seems fairly happy with them. That's part of the reason I ended up getting one.

Initially the only adjustments I made in the config utility was to set my intake manifold and cam type.

Started it up for the first time yesterday and it initially ran very poorly. Hard to start, would die if I didn't constantly give it gas and was very rich - around 11.0 - 11.3. I tried to keep it running for a while hoping it would adapt and get better, but it didn't.

Searched for vacuum leaks, and took the unit back off to see if I could spot any problems. I did notice that both idle adjustment screws were about 1/16" away from contacting the adjustment surface. I tightened those down to about 1/4 after they made contact. Then in the config utility I set the minimum and maximum TPS settings.

Started it up again and it immediately ran much better. Sounded much better, would idle on its own and had an AFR of around 13.0 - 13.5. Let it idle for a while blipping the throttle a few times hoping it would adapt and improve. It was looking better. After shutting it down I pulled the plugs and they were all black with soot.

Today I replaced the plugs, let it idle for a while and went for a drive. It's doing OK. Going very easy on it, but it has good throttle response and runs nicely. Still fiddling with idle adjustments and wondering if I should be adjusting anything else.

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Wondering what adjustments other people have made that improved things, or what I should be looking for in the software interface. There is a lot of info there, and I'm not sure what I should be looking for to verify that everything is working as it should.

The first specific question I have is how is the idle speed supposed to be set. It does have an Idle Air Control valve, so should I expect to adjust the throttle blades all the way closed and let the IAC handle everything, or should I open up the throttle a little with the idle adjustment screws? I'm not seeing in the software any sort of target idle speed setting. Does it have something like that?

Right now the idle air port is whistling fairly loudly. Kind of annoying when you are poking around under the hood, and can even hear it when sitting in the car with the hood closed. Is that normal? Do I have it adjusted somehow that too much air is going through that port?

Would also be interested it hearing anything that you have done or have learned that helped it run better.
 
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You will get more and better information form the Powerjection Forum. A LOT of guys there with more experience.

You need to set your cam type and estimated HP. Do not be genrous on your torque. Go under what you think you have.This will change the premapped fuel curve. From there you can go in and tweek the rpm range if its too rich or lean.You cannot drive it easy. The purpose of the self learning is for the PCM to fill in all the cells on the map.If there is a open cell where it did not see any data, it will make its own parameter and it could be rich or lean. Put it in the self learn mode and go through the gears. The more you drive, the better it learns.

For the idle, theres 2 ways. The first way is to cover the hole on top of the TB with tape and set the idle screws and then set the TPS settings. That way has not worked for me. I just let it idle and adjust the screws. You want the front and rear butterflies to move in unison.If one moves first it will throw it off. ANYTIME you mess with the screw, you must reset the TPS calibration. I have mine set about 90% so i really dont mess with it.Havent used the sofware in 2 years.

http://professional-products.com/forum/forumdisplay.php?6-Powerjection
 
FYI there is a table that show what your iii is changing bout your tune. it can only change your tune by 25% in either direction so if you see high number in the Learned fuel cells change your own fuel cells and rest the learned fule number so that it can make a new adjustment and you can gotr from there. Make sure you are leaning with a fresh O2 sensor a very old one would deffinatly mess things up.