i just put my j&s in and i have all the settings at minimum. i adjusted my cartech fmu top screw almost all the way down base fuel pressure is set to about 38psi on my 370cc injectors. im running very rich but at partial throttle i still hear a crumpling foil popping sound and im omly at 2 psi when this happens. the j&s knock light is flickering wtf???? a/f are way safe. so why the knock?

 

does that sound come from behind the fire wall? Like a whole bunch of ticking sound, i am getting that between 6200rpm's and redline. Is this detonation??? sorry but I don't know much about the j&s.

 

have the J&S pull some timing

 

OVer what rpm range does the sound occur?

 

I am worried about mine too, At upper rpms in first and sometime in second, at 3/4 or wot, I hear this metallic metal vibration coming from the engine bay on the passenger side. I'm trying to figure out if its just a bracket or something metal on metal thats rattle against each other at that certain frequency or if its my timing chain. It only does it in first majority, sometime second and sometime turning left so I am thinking its just a rattle of some sort and not the timing chain since I would think it would be more consistant thru each gear. Would this affect J&S picking it up as knock? Similar to pawnstar's situation..

 

3500 rpm ish

 

That may be light detonation (although I've never heard of it described as a crumpling, it's more of a marbles in a can noise) since timing is fairly advanced in the mid-rpm range at partial throttle. If it is an ignition timing issue, it won't be very responsive to lowering the afr in an effort to suppress it. I had the same problem on hot days, I finally got rid of it by rerouting the intake piping away from the exhaust manifold so that intake air was cooler.

 

I hear this noise from the passanger side as well. Almost sounds the same as noise I have heard come from older pickups or something I have heard before like noise from the amount of air flowing through the exhaust end???

 

Might be an exhaust leak.

 

Thanks Stephen, that would make sense. Just put in new ks the other night. Could not reset ecu by turning screw (brother stripped it a while back). I went with the tapping the battery cables together. Need to adjust bov to get better response but I think it worked. Still getting that jerking hesitation when could like something is leaking. I would think its the gasket on the headers. I have seen some black around the left (front side).

 

i've spent some time researching my prob(reading threads and manuals) and this is what i came up with. my onset on my fmu was way off and the needle valve needs to be adjusted. i guess the dyno shops that i've been to didnt really mess w/ the fmu, they just concertraited on the safc2. the reason why i think this is because at the rpm range that i have knock i saw that my safc2 was adding crazy correction and @ all the other points it was pulling fuel. from what i learned, if you add a bunch of correction the safc2 would add timing which is very bad in my case. @ 10pm tonight im going to the dyno and retuning it correctly. please tell me if my start off base settings are wrong:

base fp-32psi (370cc)
fmu onset-52psi
fmu ratio-2.5 turns in
safc2 correction- 0
safc2 throttle%-?


slimer said that his is set @ 0% low 40% high. that means he is never using his low map just a mathamatical difference of the two until 40% throttle opening, then it follows the high map exactly. in my eyes he would be just guzzling gas @ partial throttle around town driving. im trying to tune for the best around town mileage possiable(93 octane aint cheap)

So what do you guys have for your hi/lo %?

Foot Notes:
tune is all fooked up
adding to much correction on the safc2 causes detonation
im gonna retune tonight starting @
basefp:32psi
onset:52psi
fmu ratio: 2.5 turns in
afc thr%: ?
afc correction:0

 

i couldnt get on the dyno because a damn fully built turbo caviler was on it over night! what a POS! so if i wanna get some free dyno time i have to wait till a weekday late night they charge $190 an hour and its not that serious. it def helps when your boy runs the dyno

 

Or if you run it yourself

 

well thats even better!