Driving me nuts

[bcjjones]

Got a SAFC 2 for now, untill i find a great price on link.

Now i think im getting phantom knock. No knock at most of the rpm range and then all of the sudden at higher rpms its jumps to 30-45 counts of knock, then as soon as i let off the gas it goes back to zero. I might have one or 2 counts here and there but im using the SAFC 2 still to fine tune. Thats another problem all together though.

Basically my question is simple, and common sense tells me my answer to it is correct but. When going plus on the settings (ex. +10) that is "adding fuel." As in telling the computer there is more air thus compensating with more fuel.
Just keep reading different answer but like i said, it only seems to make sense that + is adding and - is removing air thus fuel.

Also seems like everyone is in the - on there settings. Im running a completely stock car with the exeception of a 2.5 inch downpipe, MBC and walbro 255(soon getting 650s an AFPR, wideband and a few other parts). So my common sense again tells me that I will probably be in the + to get my fuel trims in check and to be on the safe side and run a little rich until I get my wideband?

Running around 15 psi of boost

 

[XiKeiyaZI]

Well for one you shouldn't be running that 255 without an AFPR. If you aren't already, your stock fpr is going to give and then you can just say hello to running pig rich constantly.

Secondly, you are likely seeing phantom knock. This can be caused by a faulty or loose knock sensor. Try reaching back there with a wrench and giving it a good quarter turn. That is after you feel around for any sort of goopy liquid slathered on the back of it which would indicate that it's shot.

Another thing, that SAFC will play hell with your ignition timing. You likely need to research the pros and cons of running it before setting out to tune and add/remove fuel.

 

[tom_and_case]

Another thing, that SAFC will play hell with your ignition timing. You likely need to research the pros and cons of running it before setting out to tune and add/remove fuel.

Agreed.... safc2 came in my car when I bought it. I had to re-do the timing and it still ran like crap after that. I had to completely reset the safc for my set up I followed this link for my set up RRE's Super AFC Setting and Adjustment Tips Haven't touched it since. but seems to be ok now... still can't wait to get dsm link for my car.

 

[bryanwheat]

The safc with 650's can cause a lot of detonation problems with pump gas. When you hide 20+ percent of airflow from the ecu it will add timing. The extra timing will sometimes cause uncontrollable detonation problems. Phantom knock usually occurs at a low load cruising or under light throttle. Being that you are getting it at wot in the upper rpm's i would assume that it is detonation. A good way to test this theory is to go buy a few gallons of race gas and throw in the tank with a few gallons of pump gas. If the problem stays than it is likely phantom knock. If it goes away than you are experiencing problems with excessive ignition timing.