I'm f*cking fed up with driving normally and out of nowhere - SES light and MAJOR timing retard!! It's got to be the knock sensor right? There's got to be some way to block or bypass that sumbitch! Or safely take it out. If so can someone please tell me how so I won't get that damn code thrown. Please, anybody... Thanks

nForm91

('91 Formula 305 TPI 700R4 - 43k miles)

 

It could be the KS, or it could be other parts of the ESC. In your case (for a '91) I believe the ESC is integrated into the ECM - there is no separate ESC "box" on the firewall. There are also connections between the KS, ECM, and distributor, as well as the HEI module itself, and the EST bypass connector. Any problems with any of those can set the '42' and cause base timing to take over.

I know that the older systems with a separate ESC will allow bypass of the KS with a 3.9K ohm resistor in place of the sensor. I'm not certain what the required resistance value would be with the newer systems, but I seem to recall someone mentioning 1.9K ohms. You might want to search the archives for that information.

You can disconnect the KS and insert the resistor in it's place in the harness. That will remove teh KS from the circuit and satisfy the control, but you'll have no timing adjustment if you generate detonation. In other words, it isn't really a safe way to operate, but can work for testing for an intermittent or faulty KS.

 

Thanks Vader,
Does anyone know the procedure for removing or bypassing the knock sensor on '90 to '92 TPI cars.

nForm91