Question for ski_down_it
Thread Starter
Racer
Joined: Jul 2004
Posts: 395
Likes: 0
From: Wescosville Pa
Question for ski_down_it
This is for a L98 car (1990)
My car has always stumbled and misfired at 4000RPMS, so I replaced the cap and rotor. I also got new MSD wires. However, I was wondering if you could program a chip to disregard the knock sensor, or something along those lines.
I was only at 14-16 degrees advance timing at idle, with the base at 8 degrees. At 3000RPMS, I was only at like 26 degrees. I would really like to program the chip to get more timing advance and not rely on the knock sensor (the motor has a slight tap that I think might be setting it off or screwing it up). I was told that 42 degrees or around there is what it should have at that RPM under load.
So, can you add timing just through the chip, and can you have the computer not rely on the knock sensor?
-Dave
P.S.- Does aftermarket runners affect the chip if I got them after I got the chip burned, or should I just have you burn it in the chip for the future? Looking to get mine done sometime soon.
My car has always stumbled and misfired at 4000RPMS, so I replaced the cap and rotor. I also got new MSD wires. However, I was wondering if you could program a chip to disregard the knock sensor, or something along those lines.
I was only at 14-16 degrees advance timing at idle, with the base at 8 degrees. At 3000RPMS, I was only at like 26 degrees. I would really like to program the chip to get more timing advance and not rely on the knock sensor (the motor has a slight tap that I think might be setting it off or screwing it up). I was told that 42 degrees or around there is what it should have at that RPM under load.
So, can you add timing just through the chip, and can you have the computer not rely on the knock sensor?
-Dave
P.S.- Does aftermarket runners affect the chip if I got them after I got the chip burned, or should I just have you burn it in the chip for the future? Looking to get mine done sometime soon.
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Racer
Joined: Aug 2002
Posts: 386
Likes: 0
From: Lancaster Lancashire
LD85,
Have you done this mod? I read about it somewhere a long time ago. Do you have to change the knock sensor as well, if you change the module, because the sensors are I think different on the later models.
Have you done this mod? I read about it somewhere a long time ago. Do you have to change the knock sensor as well, if you change the module, because the sensors are I think different on the later models.
Le Mans Master
Joined: Feb 2002
Posts: 5,970
Likes: 20
From: San Marcos Texas
That mod wont work for a 90' speed density car. The knock module is part of the ECM...The 90-91 are good knock modules. I have no problems even with my solid roller cam. Also how did you check you timing at idle and under load? Do you have a scan tool or software?
The computer retarding the timing will not cause a miss. Sounds like another problem. look into the distributor control module or for a weak ing. coil or failing distributor. Before you start looking for a new chip you need to find the real problem first.
My car has always stumbled and misfired at 4000RPMS
Last edited by chriswtx; Feb 9, 2005 at 11:31 PM.
Le Mans Master
Joined: Feb 2002
Posts: 5,970
Likes: 20
From: San Marcos Texas
I also noticed you have headers. Did you change to a heated O2 sensor? A non heated O2 with headers can cause you to run rich. Running rich can cause fouled plugs and stumbling or missing. But I still suspect a bad distributor module or coil or distributor pickup coil if you replaced the wires, plugs and cap/rotor.
