98 knock sensors vs. new type
05-11-2012, 09:44 AM
#1
98 knock sensors vs. new type Has anyone heard that replacing the knock sensors in a 98 F-body with the new kind requires some changes to the tune? My tuner desensitized them but it's still pulling timing occasionally around 2800 rpm. Someone told me the new style sensors require some parameter changes....
05-13-2012, 11:39 PM
#2
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That idk about and would love to know. Im sick of my car pulling timing at random events and during hard shifts.got me thinking I need to look at some stock files on the repository to do some compairing
05-14-2012, 10:31 AM
#3
Tell me about it, I only had slight problems with knock retard until I replaced the damn knock sensors. Now I can actually feel the reduced timing. If I unhook the battery and let it sit half an hour, hook it back up and take it out, I get one good WOT pull with the car making full power with no timing reduction. After that, it feels like maybe 4 degrees in anything past 2nd gear. And, this is with the sensors desensitized. Before that, it was pulling up to 15 degrees, which feels like 100 ****** horsepower!
05-14-2012, 09:56 PM
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I downloaded a stock updated file from the repository, funny thing is the comments mentioned a update in knock tip in for the 01 silvarado my sensors are from and some other stuff. I changed my knock sensor data to correspond with the sensors. Ill know this weekend if it changes anything. But idk if its a software issue in the pcm. Im seeing most of my timing pull during wot shifts, either from shifting hard or my wastegate is enough to do it. Otherwise I get it at random times say at 95kpa at 2500 rpm or 140kpa at 3500 rpm but never at 175kpa at any rpm. And my timing is low enough and afr is good. Damn 98s lol. Only thing I wish I had was rtt
05-15-2012, 10:15 AM
#6
Finally, someone else asks about this. I tried digging into this and got no responses. If you look up a stock 1998 tune and a 2002 tune, the knock sensor thresholds are WAY higher and it would seen way less aggressive on the 2002 stock tune. I've been contemplating just copying all the tables from the 2002 table into my 1998.
05-16-2012, 09:30 AM
#11
its been awhile since i looked but i was under the impression that the 98 used more aggressive timing than the 99+ therefore had more aggressive knock retard tables.
if you started getting the issue after replacing the sensor/s then you probably over torqued them.
if you started getting the issue after replacing the sensor/s then you probably over torqued them.
05-16-2012, 12:02 PM
#13
They definitely aren't over torqued..I made sure of that after it took me 5 hours to get the old one out because it was stripped. Had to use a torch for that...pretty hairy. If anything, they might be under torqued. I should pull my intake and check it out.
05-16-2012, 12:31 PM
#14
Heres a stock 98 high octane table and a stock 2000 table. The tables look very similar, albeit the 2000 table goes above 1 g/cyl. However, the knock sensor thresholds are almost twice as high on the 2000 as opposed to the 1998.
On a 2002, the spark tables are much less than on a 1998-2000, but the thresholds are high and the knock sensor sensitivities are also zero'd out.
Certainly seems like there is room for improvement. Although it looks like it would make more sense to copy the 2000 tables, otherwise we'd have to modify the spark tables to match the 2002 as well.
On a 2002, the spark tables are much less than on a 1998-2000, but the thresholds are high and the knock sensor sensitivities are also zero'd out.
Certainly seems like there is room for improvement. Although it looks like it would make more sense to copy the 2000 tables, otherwise we'd have to modify the spark tables to match the 2002 as well.
05-17-2012, 01:02 PM
#16
Your tuner would have to pay attention to any differences in table size/limits, but otherwise, yes, it should be a simple copy/paste. The other options are to set the timing tables to a 2002 and use all of the 2002 knock sensor tables.....OR, copy all of the knock sensor tables from a 2002 and leave the stock 98 timing tables, but watch for real knock since you're still using the stock 98 timing tables which appear much more aggressive than a 2002 stock table. Do you have a way to log your car or pull your tune?