Detonation ?
10-26-2005, 09:46 AM
#1
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Join Date: Oct 2005
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Detonation ?
Any one have some sound clips or something 
i always hear people say its pinging ..... i just got the xcal2 and after uploading the 87 tune i hear like a clicking noise under full throttle.
I was worried if it was detonation or not, the only adjustment left open to me by breenspeed is spark but what should i be trying with that ?
THanks
i always hear people say its pinging ..... i just got the xcal2 and after uploading the 87 tune i hear like a clicking noise under full throttle.
I was worried if it was detonation or not, the only adjustment left open to me by breenspeed is spark but what should i be trying with that ?
THanks
10-26-2005, 11:16 AM
#2
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RE: Detonation ?
It sounds like an engine rattle or rapid tapping. You have most likely heard it before in a car or truck when you go pull a hill or something most folks would call it "spark Knock".
You can reduce the timing (spark) a bit or run higher octane may help. It would be best to check the A/F ratio on a dyno. The fuel pressure maybe a bit low causing it to lean out. Remember A/F is adjusted by computer using O2 sensor when not at WOT. When at WOT all is based on air flow, if the fuel pressure is low, you will be lean at WOT.
You can reduce the timing (spark) a bit or run higher octane may help. It would be best to check the A/F ratio on a dyno. The fuel pressure maybe a bit low causing it to lean out. Remember A/F is adjusted by computer using O2 sensor when not at WOT. When at WOT all is based on air flow, if the fuel pressure is low, you will be lean at WOT.
10-26-2005, 02:11 PM
#3
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RE: Detonation ?
thats the sound i think, almost like valvetrain rattling but not rythmic like you would get from valvetrain.could something as simple as a fuel filter drop fuel psi enough to lean it out ? i have only owned the car for 5 or 6 months now i got it with 72k on it and have not done any tune up work like plugs wires or the fuel filter. I noticed the sound/detonation 1 or 2 times before i got the xcal2 but now anytime i go WOT from 2k rpm and up i hear the sound/detonation.
As for the xcal2 i guess i should set the timing way back and bring it up little by little and see what happens.
Thank You for your help.
10-26-2005, 02:21 PM
#4
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RE: Detonation ?
I would have the A/F ratio checked. I assume your new tune adjusted the WOT tables and timing. You may now be running lean. Do you have an adjustable fuel regulator? If so I would raise the seting by 2# and see if things change. If it changes, most likely you are lean and need to get dyno tuned.
ORIGINAL: 98DropGT
thats the sound i think, almost like valvetrain rattling but not rythmic like you would get from valvetrain.
could something as simple as a fuel filter drop fuel psi enough to lean it out ? i have only owned the car for 5 or 6 months now i got it with 72k on it and have not done any tune up work like plugs wires or the fuel filter. I noticed the sound/detonation 1 or 2 times before i got the xcal2 but now anytime i go WOT from 2k rpm and up i hear the sound/detonation.
As for the xcal2 i guess i should set the timing way back and bring it up little by little and see what happens.
Thank You for your help.
thats the sound i think, almost like valvetrain rattling but not rythmic like you would get from valvetrain.could something as simple as a fuel filter drop fuel psi enough to lean it out ? i have only owned the car for 5 or 6 months now i got it with 72k on it and have not done any tune up work like plugs wires or the fuel filter. I noticed the sound/detonation 1 or 2 times before i got the xcal2 but now anytime i go WOT from 2k rpm and up i hear the sound/detonation.
As for the xcal2 i guess i should set the timing way back and bring it up little by little and see what happens.
Thank You for your help.
10-26-2005, 03:00 PM
#5
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Join Date: Oct 2005
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Posts: 8
RE: Detonation ?
I used my lunch break to go mess with it some more and now it is giving me more options, i set the timing back -2 from 2k-4k and it took alot of the detonation away. but while i was in there i found a setting for A/F at WOT so im going to try setting my timing back up and bumping the WOT A/F and see if that helps. If that does not fix the problem i guess i will have to put it on a dyno, does anyone know of a good shop around the cincinnati, oh area that can dyno tune it and any ideas on what kind of cost im looking at ?
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