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weird idle issue

Posted: Wed Oct 01, 2008 4:45 pm
by 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

Posted: Thu Oct 02, 2008 7:51 pm
by danny
what wideband are you using...????

Posted: Thu Oct 02, 2008 9:35 pm
by 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

Posted: Fri Oct 03, 2008 12:50 am
by 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?

Posted: Fri Oct 03, 2008 12:00 pm
by 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

Posted: Fri Oct 03, 2008 4:36 pm
by 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.

Posted: Thu Oct 09, 2008 9:25 pm
by 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

Posted: Fri Oct 10, 2008 8:51 am
by RoadXY
What kind of WB do you have and at what offset?

Posted: Fri Oct 10, 2008 9:32 am
by sj-performance
I allready addressed that, I have a aem and we used a friends plx and it is in sinc with ectune

Re: weird idle issue

Posted: Fri Oct 10, 2008 4:54 pm
by xenocron
sj-performance wrote: mangafuel fpr (the boost one no vaccum only boost on charge pipe)
Huh?

Posted: Fri Oct 10, 2008 11:48 pm
by 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.

Posted: Sat Oct 11, 2008 1:44 am
by 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.

Posted: Thu Oct 16, 2008 11:16 pm
by 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.

Posted: Fri Oct 17, 2008 1:40 am
by 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...

Posted: Fri Oct 24, 2008 10:17 pm
by 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????