weird idle issue

[sj-performance]

I am having a terrable idle problem...It will pop,buck go lean the rich ect... so far I have cut alt c,disable eld,tuned battery offsets the best i could,ect,iat ect..... even when I rev and hold it while sitting say 4000 rpm it will does this. my mid and top is perfect runs like a champ..... I am starting to think it is something with the car My set up is precision 880s (new) walbrogh pump 255 obx fuel rail mangafuel fpr (the boost one no vaccum only boost on charge pipe) msd ignition I am a licensed tech and this one has me stumped.. I have addresed every isue I could think of... any ideas would be apreciated

[danny]

what wideband are you using...????

[sj-performance]

Aem uego, its not the wideband it is accurate we used my friends plx aswell just in case it was off but it was the same reading........I am posting my cal needs a bit more tweaking but it is the best I can get it to idle. Please check if you can, im pretty sure its the car but I might have missed something

[David974]

Hi post a datalog file of you idle it should help did you check for vaccum leak, how is your vacum value at idle? bouncing?

[sj-performance]

Vaccum seems good..... I will do a smoke test to be sure, I checked it pretty good I will record a datalog when i get home tonight and post it. Thanx

[sj-performance]

I did a smoke test no leaks on the mani, only a small leak out the b.o.v......... Im pretty sure this is normal but I could be wrong.

[sj-performance]

heres my datalog at idle have a look for me.... its rich as hell but thats the only way I could get it idle decent .....Thanks guys

[RoadXY]

What kind of WB do you have and at what offset?

[sj-performance]

I allready addressed that, I have a aem and we used a friends plx and it is in sinc with ectune

[xenocron]

mangafuel fpr (the boost one no vaccum only boost on charge pipe)

Huh?

[sj-performance]

Yes I know I thought it was weird to.... I called magnafuel and they said that regulator is only supposed to see boost and not vaccum off the charge pipe....anyways I put my stock rail,regulator and lines on tonight it was beter but when it gets warm it goes to shit when its cool I can idle it in the 14s???atleast now I can idle 13.0 afr when its warm.

[JaredKaragen]

I would think they don't want it to see vacuum because it may have a reverse effect on how the FPR diaphragm works; either that or the diaphragm doesn't take kindly to vacuum pressure on it; being the reverse of how it's intended to operate.

[sj-performance]

Still having a problem I have tried just about everything.... I think It might be the injectors..... I am going to grab a different set possibly a high imp.. Any recomendations on a good injector?.. im shooting for about 450-500hp.

[butch11a]

something like that happened to me, i have 750 cc injectors, walbro and oem fuel reg. turns out it was the iat compensations, when iat reached 70 deg, fuel was reduced and timing retarded, just added a bit to correct a/f...

[sj-performance]

still nothing... I am so pissed with this thing...... I have tried just about everything... I did notice that if I take out excessive amounts of timing like 8.75 in the idle area i am able to idle in around 14-15 afr with no pops but it will surge every so often????