Pirrofab
15+ Year Contributor
- 715
- 19
- Sep 2, 2006
-
gouldsboro,
Pennsylvania
My check engine light came on other day during drive to work in pouring rain and large puddles but went out about 15 minutes later, no noticeable change in performance and nothing weird with anything else. I work for a shop so I hooked up the snap on scanner and scanned for codes, code 31 knock sensor came up along with 4 other "undocumented codes" (e2,e4,e8,e9). In the snap on scan tool is a troubleshooter and it says that the code is set after no knock is detected over 2500rpm and it will use a low octane timing curve as oppose to a high octane timing curve. I am also experiancing a slight miss at w.o.t. Would code 31 set from having to much knock the and the ecu pull timing or is code 31 set from only the ecu losing signal from the knock sensor?
Since then I have cleared the code and for curiousity I checked and regapped the plugs to .28 ( only one was opened to .34) and the idle even seems smoother but w.o.t still has a very slight miss. I have not been able to check for boost leaks but im not noticing weird a/f ratios I'm tuned for 20psi 11.8afr. could this be to lean for pump gas and is it just simply pulling timing? Since that time I have not been able to recheck for codes but the light has not come back on and a slight miss is still there at w.o.t
I have also noticed on my safc2 that the knock setting is just not reading any knock. I do not have a data logger but what I can tell you is that this problem was there before I upgraded my fpr, injectors, 2gmaf, safc2. It might also help that it seems like it is only at W.O.T once I back off the throttle it seems to smooth out. I have done a tps sweep using the safc2 and the snap on scanner and they do not show any issues at w.o.t dropping voltage or showing concern. Timing is set to 5BTDC and tps at idle reads .6volts if its any help to trying to get some ideas about this.
Since I get discounted parts I was thinking about just putting in a knock sensor and wiring up an led to flash on my dashboard if excessive knock is occuring but then I was thinking that the l.e.d. might mess with the signal from the knock sensor. Is there any issues with that?
Since then I have cleared the code and for curiousity I checked and regapped the plugs to .28 ( only one was opened to .34) and the idle even seems smoother but w.o.t still has a very slight miss. I have not been able to check for boost leaks but im not noticing weird a/f ratios I'm tuned for 20psi 11.8afr. could this be to lean for pump gas and is it just simply pulling timing? Since that time I have not been able to recheck for codes but the light has not come back on and a slight miss is still there at w.o.t
I have also noticed on my safc2 that the knock setting is just not reading any knock. I do not have a data logger but what I can tell you is that this problem was there before I upgraded my fpr, injectors, 2gmaf, safc2. It might also help that it seems like it is only at W.O.T once I back off the throttle it seems to smooth out. I have done a tps sweep using the safc2 and the snap on scanner and they do not show any issues at w.o.t dropping voltage or showing concern. Timing is set to 5BTDC and tps at idle reads .6volts if its any help to trying to get some ideas about this.
Since I get discounted parts I was thinking about just putting in a knock sensor and wiring up an led to flash on my dashboard if excessive knock is occuring but then I was thinking that the l.e.d. might mess with the signal from the knock sensor. Is there any issues with that?
