2011 ctsv Id850 fuel pressure issue.

[supercowboy]

I have a few questions On scaling these Id850 injectors.
when I use the spread sheet in the how to section I copy and paste these values into the inj flow vs pressure delta. When I log fuel pressure I get 60 psi. Car is running between 13.4 and 13.6 afr. when I multiply the stock values by 1.55 and enter the values, The car idles at 14.6 with fuel pressure of 50. The 1.55 value is the diff between old and new injectors. Im not sure the what the value of the injectors have to do with fuel pressure. I would think the cars fuel pressure would be the same no matter what the injector calculation is. I do understand the higher fuel pressure will net you in richer af ratio which make sense.

When changing injectors I would think that I shouldn't have to play with maf values to get it right. by adding a few percentage to the flow rate I would assume the value would be closer to the net af ratio you are trying to reach.

Is this the value I should use and tweak the maf to get Afr correct.

Here is a data of what going on. I dont have afr logged due to no input from dyno to laptop.

[SultanHassanMasTuning]

I forgot, but dont these FPCM default something like 65psi at idle, the ID850 are rated at 43PSI

i would def change your PE settings.

[supercowboy]

yes the default under fuel system is 65.3. I only changed the pe eq ratio only to help smooth the fuel curve out. Car is stock with a smaller pulley. Stock injectors maxed out This is why we went to bigger inj.

[4evervette]

You should use the ID data from their web site no need to use any spread sheet ...

[4evervette]

Here is a link
http://www.injectordynamics.com/ApplicationData.html

[DSteck]

Use the ID data, don't modify it, and change your MAF. The reason your tune changes slightly is because of variance in factory injectors. ID also uses different equipment to characterize their injectors, and they use actual gasoline to do it.

[V locity]

Use the ID data, don't modify it, ID also uses different equipment to characterize their injectors, and they use actual gasoline to do it.

Dave,

Would this apply if we switch to e-85 or flex?

[DSteck]

To be completely truthful, injector flow rate DOES change with ethanol. Why? Because ethanol has a different specific gravity than gasoline, and consequently the flow rate (remember, units are MASS flow and not VOLUME flow) does change. This error just gets absorbed by the stoich ratio since the PCM doesn't support altered flow rates based on ethanol content.

That said, stick to their data and just tweak the stoich value.

[supercowboy]

For some reason the link wasn't working for me. I re scaled and ready for install. Thanks

[DSteck]

Use the attached and dial in your MAF and VE. Don't change the injector data that's in this file.

[V locity]

To be completely truthful, injector flow rate DOES change with ethanol. Why? Because ethanol has a different specific gravity than gasoline, and consequently the flow rate (remember, units are MASS flow and not VOLUME flow) does change. This error just gets absorbed by the stoich ratio since the PCM doesn't support altered flow rates based on ethanol content.

That said, stick to their data and just tweak the stoich value.

Thank you

[supercowboy]

Thanks dsteck. car took the change fine. car is smoother with the right file in it. I just get this fuel fluctuation issue but after driving a little the car stabilizes there. I did notice on cold start car stumbles to start. It did it once out of the 3 or 4 days the cars been away. customers been having diff issues with car. you can hear the rear crunching LOL. I want him to fix that before we get back on dyno. I did some street stuff and afrs are 11.5s on average at wot.

[4evervette]

Thanks dsteck. car took the change fine. car is smoother with the right file in it. I just get this fuel fluctuation issue but after driving a little the car stabilizes there. I did notice on cold start car stumbles to start. It did it once out of the 3 or 4 days the cars been away. customers been having diff issues with car. you can hear the rear crunching LOL. I want him to fix that before we get back on dyno. I did some street stuff and afrs are 11.5s on average at wot.

Can u describe the starting issue more.? Does it crank too long?

[supercowboy]

what it does when it starts is that it stumbles when you start. The car cranks like normal butt when it fires under cranking it stumbles then starts. Kinda like loading up some fuel. I put the open closed loop settings back to stock and I haven't noticed the stumble since then.

[SultanHassanMasTuning]

I think was he is trying to say is that the fuel pressure is not stable, I got a CTSV that was previously tune and at idle ist like 77/78psi of fuel pressure WOT drops to 65 default high flow

and low flow it should be 50 psi

[supercowboy]

same issue I have. when car starts it high 70s fuel pressure. have to drive a few minutes and it comes down. Im gonna have some more time with car soon. These gen 4 ecus are difficult to do. I still dont feel good about scaling the sd side of the ecu.

[UberVee]

same issue I have. when car starts it high 70s fuel pressure. have to drive a few minutes and it comes down. Im gonna have some more time with car soon. These gen 4 ecus are difficult to do. I still dont feel good about scaling the sd side of the ecu.

Does this only happen on cold starts, hot starts, or both?

[supercowboy]

Does this only happen on cold starts, hot starts, or both?

both

[ZO6_Bryan]

It happens the first time you start after a new flash, then fuel pressure settles in. The next time you start the car that won't happen. At least thats's what happens with the E67's in the ZL1.

[wetcoast]

Attachment 44099Attachment 44098I'm just starting to learn this stuff myself and I was wondering how to tune an E67 ECM for ID 850 injectors.

I was reading Dave's PDF posted on ID's webpage about scaling the entire VE tables to account for the scaled IFR because the E67 ECM has a limited maximum IFR.

I only question this because when I compare the above file with the ID 850's in it with my stock file there is no changes to the VE coefficients where according to the paper I would expect there to be different VE tables if they were required to be scaled.

I presume it has something to do with the fact that the E67 ECM doesn't use IFR vs. MAP and uses IFR vs. Delta P but I'm not sure.

Here's my current file stock file with just the rear O2's turned off. Attachment 44098

Here's my first attempt at cutting and pasting the values. 2009 CTS-V Modified No Cats, ID850's.hpt

I'm not sure which other tables need to be modified before I move on to MAF and VE tuning.

Can someone point me in the right direction?

TIA,
Chris