: Detonation knock



jesseprestwood
05-26-11, 04:32 AM
Please Help! I have a 91 Fleetwood Brougham with a TBI 305 with 180,000 miles, it has a moderate to severe knocking that appears to be coming from the driver side cylinder bank. I have recently cleaned out the intake with Seafoam, installed a new heavy duty water pump and a thermostat and flushed the radiator, timed the engine to 0 degrees (factory setting), checked the PCV system, changed the oil with slick 50 high mileage treatment, and cleaned and re-gapped the spark plugs, although one on the drivers bank showed signs of detonation and the others on the bank had a considerable amount of white ash deposits, the passenger bank all looked normal (wires and cap and rotor in good shape). The engine only knocks when it is under load, it won't do it when the engine is idling or if in park and revving it up. I have recently discovered that it doesn't knock at all if I disconnect the EST wire (electronic spark timing). I took it for a drive down the road with the wire disconnected for quite a few miles and it did not knock at all. Could this be a problem with the computer or the ignition control module? Or maybe the Knock sensor? I plan on checking the EGR system tomorrow to see if it is functioning properly. Other than that i'm pretty much at a loss. Any feedback would be greatly appreciated, Thanks for your input.

jayoldschool
05-26-11, 10:46 AM
When you set the timing, did you follow the proper procedure? There are things to disconnect. Also, replace the plugs. And, drain the Slick 50. Bad, bad stuff.

jesseprestwood
05-26-11, 01:30 PM
hey, thanks for the reply. Yes I did follow correct procedure at least the same way Iv'e done it on my other 305's. I Loosened the distributor clamp bolt, unplugged the EST wire so it would not advance, started the motor up and checked the timing. It was 4 degrees advanced at idle so i retarded it back to 0 degrees, i revved up the motor to make sure it would still idle at 0 degrees and I shut off the motor, tightened the distributor bolt and reconnected the EST wire and started back up. It idled much better, in fact it now pers like a kitten, but it still was knocking when I took it for a drive down the road.