NHVett

My newly completed L98 mill has been impossible to time correctly. The engine absolutely will not run with the ESC disconnected and the timing set at 6 deg BTDC. If the timing is advanced to about 20 deg BTDC. It runs well under light and heavy loading, But idles like 3/4 race cam. Cam is a Crane Blue Racer designed for L98 & TPI (very mild) With this timing, acceleration is awesome up to 4200 - 4400. When decelerating without lockup, it gurgles and pops like a retarded spark. When decelerating under lockup it comes down under engine drag normally. It has a new Delco knock sensor put in during the rebuild, and does not exhibit spark knock that I can detect by ear. I reconnected the ESC and took the car 2000 miles to Nova Scotia and back over 6 days last week with no ill effects except for the lumpy idle, and the deceleration noises. Gas mileage for the trip averaged 24.7 mpg.
Here are my next steps. 1. Take out Craigs chip and put the stock one back in and see if this makes any difference. If not, 2. Have the ignition module tested at Autozone. Next, 3. Replace the ESC module (I don't think that it can be tested). The engine builder swears that they put the cam in straight up and not advanced or retarded.

Any ideas group?

NHVett

Oh yeah, the only code set is when the ESC is disconnected. 43 That's normal

smallblock

Did he degree the cam??

Ron78Z&66Vette

Is it possible that your harmonic balaner slipped to the point that your timing mark is completely wacked? I had a balancer that slipped 82* believe it or not. I discovered it when I replaced my ignition components shortly after I got my 85. I had to set the timing by ear until I could change the balancer.

NHVett

I have checked the TDC at #1 cylinder by making a liquid manometer with my sparkplug air hose adapter and some clear plastic tubing + colored water. The timing mark on the balancer is right at zero when the piston is indicated at TDC.

I replaced the custom chip with the OEM. No change. THe custom chip is back in.

The Knock Sensor reads 300 K Ohms on my digital MM.

Next up at bat will be the ESC module. HighHopes85 on this board has one for sale.

HighHopes85

NHVett-By any chance, have you replaced your pick-up coil recently? I am starting to doubt that it is your ESC, and there are a few ways to keep you from picking a new one up if yours is good.

For timing testing only, disconnect the knock sensor while the car is running at the 20 dbtdc. Check timing again. I have all the notes for voltages coming from the ESC at home, so in a few days I will have them with me. -Matt-