Supercharger seventh injector versus upgraded six injectors

Okay great so it is wired correctly. Now I just need to sort out the -18% LTFT at idle and around town driving! I'll repost after I get time to do the boost leak test. I'll likely remove the MAF and re-clean that as well.

 

on second thought. Be sure you tapped into the AFR wire and did not intercept it.

As long as you followed the URD wiring guide for the wiring harness/ECU year it should be correct.

I don’t think you have a “boost leak” if it was bad enough at idle that would present as running lean. Your fuel trim would be rolling + not -.



The only reason it would be running so rich at idle would be the AFR sensor reporting incorrectly or too much fuel.

Unless MW sent you drilled injectors I can’t see why that would be happening.

 

Yeah I followed the installation guide to the letter. The AFR's are right where I want them to be now with the new injectors installed through all types of driving. Except as mentioned above when pulling a trailer on the highway and something gets askew... 8.8 and running rough; W hen I pull over it will idle rough with AFR around 11.5-12.7 for a few minutes and it will settle back out again. THis never happens without the trailer.

When idling my stand-alone Boost/AFR gauge will read anywhere from 14.5-15.1 and fluctuate there. All the while the LTFT sits at -18%. SO, I think the truck is actually pulling fuel and doing what it needs to maintain stoichiometric mixture. Question is, why!

 

@jevey1 how is your fuel regulator hooked up?

 

Mine is installed as per the attached picture. The small line from the Tee goes to the AIC/T and my boost gauge.

 

Idk, I'm out of ideas unless those injectors flow more.
In the meantime that heater valve might need some love.

 

HaHa, Thought someone might comment on the valve. Its not leaking. They use Salt on the roads winter time here, so the truck is coated with rust inhibitor.

We can only but 91 octane fuel locally, and I have been using the lucas oil octane booster to add a little protection on my last tune with the old injectors. Perhaps I will just fill with 91 and leave out the booster next time to see if that helps? Would that have an impact on STFT and LTFT?

I greatly appreciate all the feedback so far. BTW I haven't gotten around to performing the boost leak test as of yet, but plan to at least clean the MAF over the weekend.

 

That makes sense, dang salt.

Anything is worth a try at this point. Just try to change one variable at a time.

No worries, I'm interested to see what it turns out to be. Could be helpful later on.

 

Okay, so had time to remove the MAF and clean, no change in the LTFT's. Got to ask what is the best way to look for exhaust leaks? I stuck a small "shop vac" in the tail pipe (while cold) in the blow direction and sprayed it down with soapy water. Found some leaks and got those fixed, but when the truck is cold and warming up it sounds like there is a still a small leak somewhere... like a ticking noise. Any suggestions to narrow it down better?

 

What are your ST trims at idle? Manifold pressure at idle?

 

My STFT always return to zero after about 2 minutes. After a reset and a cold start the truck will start in open loop, afr will read 12.2. Once the truck goes into closed loop the STFT will go to about -17%, afr will go to 14.7 within a few seconds. Then after the 2 minutes the LTFT change to about -18% and the STFT return to very near zero. Manifold pressure at idle is around -10"hg, according to my stand alone gauge. And 4.39gm/sec air flow according to my trucks MAF.

 

Vacuum sounds a little high. Might have a leak in that line which sounds like it's both to the gauge and the FPR?

 

Are you referring to the line in the pictures above? Do you know what a good range for the vacuum pressure is at idle? What would be considered too high or low?

 

Think mine reads like -25 to -30

And to be more clear.. I'm suggesting the higher pressure in that line could be affecting the FPR and leading to an increase in fuel rail pressure at idle.

 

Ah okay, now I gotcha, that does make sense! I will see if i can search google for example and come up with a average MAP value to go by.