Page 2 of 3

Re: 5l knock sensor

Posted: Mon Oct 26, 2020 3:00 pm
by vn_ss_cm
Hey guys ended up putting in a 4500ohm resistor and that has stopped the engine light coming on but I have an interesting issue that maybe related...
car hasn't been driven since putting in the resistor....took it out for its maiden voyage with new fuel and pump and once its warm out of know where you cannot accelerate past 3000rpm underload its like its in limp mode but there is no engine light...remove ecu fuse and its fine again any approx 10mins later back to no acceleration. wondering if this could be related to having the resistor in place? I'm currently waiting for a new chip to arrive so I can reburn the tune with knock turned off fully as the current tune has the knock sensor limit all the way up but the flag is still set to yes.

Re: 5l knock sensor

Posted: Mon Oct 26, 2020 3:37 pm
by vlad01
It maybe detecting "knock" and retarding the engine by 12º all the time once the engine reaches a certain enable temp.

Re: 5l knock sensor

Posted: Mon Oct 26, 2020 3:52 pm
by Dylan
Stock is 44c from memory and as stated it will pull 12 degree's so that may be the issue.

Re: 5l knock sensor

Posted: Mon Oct 26, 2020 3:55 pm
by vn_ss_cm
ah thats strange that it would detect knock as I have placed the resistor in place of the knock sensor.....? . I wish I could burn a tune but both my chips I have here will not erase :(

Re: 5l knock sensor

Posted: Mon Oct 26, 2020 4:05 pm
by antus
the filter board send pulses back to the ecm, not a static value. now i see this thread with fresh eyes i'd say you would be better off having nothing and let it set the error code and see if the problem goes away, then disable the knock sensor in the tune so that it doesnt set the check engine light, or set the enable temp to max so it never turns on.

Re: 5l knock sensor

Posted: Mon Oct 26, 2020 4:51 pm
by vlad01
Yeah you have to max out the enable temp to 151ºc.

I tried to use the knock ignore table and fully maxed out the table but it would still pull the timing regardless, so only maxing out the temp enable would work.

There really should be a flag for knock retard on/off.

Re: 5l knock sensor

Posted: Mon Oct 26, 2020 5:09 pm
by vn_ss_cm
thanks guys. its strange as I had set the enable coolent temp to 151.. and with the knock sensor unplugged the engine light would come on when you start it and go into limp mode..with the resistor it has stopped that. the memcal it self has no knock filter board. The tune was based off a VP clubby bin file.

Re: 5l knock sensor

Posted: Mon Oct 26, 2020 5:18 pm
by antus
If you want to post the bin and a log we can take a look.

Re: 5l knock sensor

Posted: Mon Oct 26, 2020 6:55 pm
by vlad01
yeah sounds like its still on.

Re: 5l knock sensor

Posted: Wed Nov 04, 2020 9:36 pm
by vn_ss_cm
fixed the issue guys the Knock Code was still on and my Chinese made chip failed :lol: