I have already worked with a couple of you with tuning my 99 silverado. I finally found time to get my 50# injectors in with the updated injector data, and wanted to ask before I start the tuning process again if there will be much change to my VE table from the tuning I have done so far? I want to make sure I am prepared for anything that might be off. This is a big jump in injector size compared to when I put in the 30's.
Unless the injector data was wrong before there should be very little that changes. The PCM does this thing called 'math' that uses the injector data to calculate how long to turn on each injector to deliver a known amount of fuel. Change the input parameters (the injector data) and the math should come up with the same number at the end.
Thanks Squirrel. I just wanted to make sure I wouldn't be surprised by the scan with a major jump to the rich or even a lean issue for some oddball reason. My son has been driving the truck for the last several weeks without any problems. With the shift in temps though here in Tennessee it didn't hurt to ask.
The two engines are mechanically identical, and so use the same amount of air at a given condition; the one with smaller injectors just does the math to calculate a longer pulsewidth to deliver the same amount of fuel as the one with larger injectors.
I was hoping this would be an easy trouble free injector swap, but apparently nothing I do is going to be easy on this truck. I changed the injectors and added the adjustment in the editor for the flow rate vs. KPA. I didn't disable the ST/LT fuel trim immediately so I could get a scan with the injectors. Then I disabled the trims and ran a base scan to track my adjustments. I errored out the MAF and disabled the trims and started making adjustments. I used the same scanner setup I used for the 30# injectors and I can't get any of my adjustments to work. The truck is staying super lean off idle to 2400 rpm. attached is my tune and corresponding scans so you can see what I am talking about. I didn't drive too long because it was so lean. Maybe I have overlooked something. I put the scan files in order to see the differences or the lack of.
Based on repeated edits of Injector Flow Rate - and none of the other injector fields - that you don't actually have the data for whatever they are and are just guessing?
12613412 Are the injectors I installed. I'm sure you already know which ones they are, but to be exact they are GM 50# flex fuel EV6 from GAP(GlennsAuto Performance). When I added the flowrate vs KPA I did it the way GRG did by increasing by 5% until I got to the correct rate. I changed the flow rate to 50lbs across the table thinking maybe the way I did it originally was the problem, and I was looking for anything to get a response. The 10:37 - 12:19 AM is strange.... Because I wasn't home when those time stamps took place, and there is no reason for making changes that close together. I wouldn't have had enough time to walk back to the truck to load the tune to see if it corrected anything.
The data is the data, it is not something you adjust until it runs right. And it's four tables, not just the flow rate. All of the data for all of the 'good' Gen4 injectors, converted into Gen3 format, is in this file. Plug and play. Also fully listed for both returnless (which yours is not, if it still has the 1999 style rails & regulator) and return style/referenced.
I am going to wait until Friday to get back to work on the truck. My son put the 30# back in and loaded the corresponding tune back to the truck. As for the information that you have graciously shared Thank You. I have watched video after video and none of them are the same. Working with you all has been the only way I have been successful at getting the tune to work correctly. I will update my progress once I have added your Data.
I have been able to use the day to get some tuning in and wanted to share progress. The last time I was at this point I had the 30# injectors in and the duty cycle was maxed out. I am attaching the latest scan and the tune adjustments for before and after the scan to see what you guys think. I know it went extremely lean past 3200 and I'm working on that. Let me know if you see something that I need to look into or pay more attention too. This is just SD. I still need to finish the MAF, and no timing changes have been done yet. I Hope Everyone has a Merry Christmas!
You can disregard the scans. I have found the fuel pump needs upgraded to finish tuning. That being said does anyone know what size I can go with that won’t necessitate upgrading the return line?
It's not the return line/hose that's the issue with these setups, it's the innards of the filter itself. Since they are made to replace the filter on a stock Corvette with a stock fuel pump I'd assume that they don't have any reason to build them to flow more than what a stock pump puts out. I have seen the 255lph number stated as a limit but it's not hard to imagine that some off-brands could handle less, down to the exact requirements of a stock C5 pump. Because of all that, these are really not a good solution for anything other than a stock engine that can run off a stock-volume fuel pump because there's no way to know what they've put inside the filter.
If you don't want that dumb filter to forever limit how big of a pump you are allowed to use, you can use a real aftermarket regulator in the same location and with your same plumbing - there are adapters if you want to keep the push-connect hose ends. If you don't connect a vacuum reference line to it then nothing about your injector data needs to change (but if you do decide to reference it, changing injector data to suit is easy and takes about 45 seconds).
I am guessing when you say filter you are talking about the inline filter on the frame rail? I only ask because I had replaced the pump a few years ago before I did the upgrades, and the pump also has a filter on it as well. I just want to make sure I cover everything so I can finally finish this thing.
What is the fuel system? What pump, what filter, is the regulator in the tank or inline or on the rail. Your mention of 'what size pump' and the return line gave me the impression this was using the C5 Corvette filter/regulator.
It is the stock fuel system. 25gph pump and inline filter. I haven't needed to upgrade the fuel system until now so I'm not sure what the best direction to go is for my setup. I am assuming by your comment about the C5 pump and filter that I need to invest in those and it should be sufficient.
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