Travis89

I recently finished my build with decapped truck injectors. 93 mustang coupe around 3k lbs/ th400 with ck valvebody and brake. Bone stock 5.3. Using megasquirt 2. First outing on 5lbs and leaving off idle (brake and launch control are not wired yet) car went 7.60s at 96 on first two passes with steady a/f of 11.2. The problem I seem to have with the injectors that I can't get them to lean out around light throttle cruise and idle. The a/f at idle is around high 10. I try to scale the fuel down at idle and it won't get leaner than a high 10 without shutting down injectors completely. Just wondering if this was a common issue. Sorry if it's been dicussed before but I'm new and couldn't find it searching under decapped injectors. Thanks.

JoeNova

What is your fuel pressure at idle, and what is your pump/regulator combo?
What are you using for injector offset?
What is your pulse width at idle?

I've used decapped flex fuel injectors in a 4.8 before and was able to get it to idle nicely around 13.5:1. Any leaner than that with a batch fire like microsquirt and it doesn't want to idle very well.

Travis89

I'll have to recheck everything. I'm using stock truck rail and regulator. Aem 380 pump. Idled fine before I decapped them around 13.5 like you said but I tried to scale down the fuel map by adjusting for 60lb injectors. I rigged up a flow test station at the house using some pipe and my air compressor set at 50lbs. They all flowed 1-3lbs from 60lbs with 60 being the lowest. I know my test is not 100% accurate but I figured that much off wouldn't matter that much. I'm not much of a reader and more of a figure it out kinda guy. This is my first time joining a forum. But I didn't know if I needed to look further through my tune or if it was the nature of the injectors after being decapped bc I noticed they have no spray pattern anymore and just **** fuel in the intake when the injector is fired. I'm guessing the injector offset probably comes more into play the bigger the injectors are??

JoeNova

You should not have changed your table, just adjusted the required fuel until they were close to where they needed to be.

Travis89

Sorry that's what I meant. I used 60lbs in the required fuel settings and didn't touch the maps until it warmed up and was idling that rich. I tried to lower pulse width at idle and it never changed until it died.

JoeNova

You'll likely have to change the injector offsets. What are they at now?
I can't remember if it was .8 or 1.8 where I got them to idle. You should technically be reducing the offset from stock once they are decapped.

Your values will be different since I was using different injectors.

Travis89

Ok I'll check the offsets when I get home this evening. I didn't think they would change. Thanks.