So for the last couple days I been reading and reading and reading....

Today I pulled the trigger and installed my PTE 780cc injectors.

I took Fostytou's setting from the "how to scale injectors" thread

PTE 780cc

Scaling: 680

Latency:
4.6875 3.624
7.03125 1.992
9.375 1.344
11.7188 0.984
14.0625 0.744
16.4062 0.576
18.6768 0.456

First when the car iled for about 30 minutes my Low LTFT got to about -7.5%. I increased the injector scaling to 696 and I did not pass -3.9%.

I figured that was good enough and went for a 30 minute cruise on the highway. My mid LTFT was way off, I got to +9.8%.

This is where I get confused on what to do next. Can someone steer me in the right direction?

Also my STFT is all over, at cruise, it ranges from -17% to +15%, and at idle -3% to +7%.

Any help would be great

Current settings:
PTE 780cc

Scaling: 696

Latency:
4.6875 3.624
7.03125 1.992
9.375 1.344
11.7188 0.984
14.0625 0.744
16.4062 0.576
18.6768 0.456

 

What does your target AFR look like at WOT? If its in the 10s to mid 11s out the top then everything is pretty close and I wouldnt worry about it. If its off one way or the other you need to look at it all over again.

FOR INSTANCE-

I see a map that is 10.1 from 140-300 at 3k and 11.5 at 8k straight across.

You have a map that is 10.8 from 140-300 at 3k and at 8k its 12.3 straight across, you are a little too rich and the scaling needs to go up and you need to play with the latency. Cruise and idle are ALWAYS latency when you get it close at WOT.

The next thing is if the trims are close enough cool, if they arent it throws a light. Striving for perfection with a system that was designed to be flexible because of altitude, humidity, and temp is typically fruitless. Get it close and dont worry about it after that.

 

Can't do any WOT pulls. We are getting couple inches of snow at I type

Once I can do some WOT pulls I will let you know.

 

Did you change anything else with the injectors? Do you have your breather hose connected to your intake pipe? Are you venting your BOV? Are you sure you have no vacuum/boost leaks?

If no for all of those, the easiest thing to do is check the scaling of the injectors via your AFR at WOT. Match your stock injector AFR.

Then see what the LTFT Lo + STFT is at idle and LTFT Mid + STFT is at cruise. Use latencies to adjust as good as possible (latencies will affect idle more than cruise). If both trims are still very far off from each other, use the latencies to get the LTFT Mid in line and then use the maf scaling table to get the LTFT Lo in line.

 

I think I'm an idiot...

I had EvoScan injector scaling still set to 513 when I did the logging. That needs to be set to 696 to get correct readings correct?

 

thats only for logging 1-byte load, im pretty sure

 

No, it will effect the logs.

 

The only thing that injector scaling value seems to be used for is the loadcalc formula - so if your not using loadcalc then it doesn't matter.

That scaling value in evoscan has zero impact on the fuel trim data....

 

^ Gotchya.

 

I think that the injector scaling value also matter for logging Injector Duty Cycle correctly.


OP, PM if you need any help scaling your injectors.

 

No it doesn't, look at the Evoscan functions for IDC and IPW to see.

- Bryan

 

Good to know.

 

Well I changed the scaling in EvoScan for 696 and my STFT and Low LTFT are all within 4%.

I did not have time to go for a 30 minute ride yet, but I have a feeling my mid LTFT will also be good.

I will keep you guys updated.