| How to Stop False Knock Counts in '85-'89 L98 |
| Background The '85-'89 L98 uses an Electronic Control Module (ECS) to listen to the Knock Sensor and relay information to the ECM. |
| Problem Statement I had been troubled by knock counts pulling timing during WOT runs at the drag strip. Backing off base timing to +6deg, running a 160 deg thermostat and a stock CalPac did not cure this problem.. |
| Problem Solution While at Corvettes at Carlisle 2001, I mentioned this problem to Grodon Killebrew and he recommended that I upgrade my ECS module to GM P/N 16038331. |
| Test Results After installing the upgrade ECS module four tests were performed: 1) I connected the AutoXray and made several WOT runs on the street. No knock counts were recorded. 2) I made a few passes down the 1/4mi at Raceway Park. The trap speed was up by nearly 1 MPH from prior runs in similar weather. 3) I installed a HyperTech Stage II chip with base timing still at 8deg advanced, installed the AutoXray and made some WOT runs on the street. One knock count was recorded during the run. 4) I increased base timing to 12deg advanced, installed the AutoXray and made another run on the street. Up to seven knock counts were recorded during the run. |
| Conclusion The ECS upgrade solved my false knock count problem yet still records true knocks to protect the engine from detonation. |