""Sneezing" 2v

Discussion in 'SN95 4.6L Mustang Tech' started by madmike1157, Feb 13, 2012.

  1. I've solved the problem, so I'm offering this as a tech tip.

    I don't know if the same symptom appears w/ an injected engine, but on my carbureted engine, I had a problem where the engine would backfire through the intake on a hot restart. It would start fine cold, and it ran great, but it would "sneeze" everytime I tried to restart it after it ran. Didn't matter if it was 150, or 180 degrees, it would always cough back through the carb everytime.

    Although the carb really had little to do w/ it, I still looked there. The fact that I can alter the timing on my engine w/ my laptop had me attempting to clone the factory ECU's timing curve. After several adjusted curves, the thing kept backfiring on the restart. I was about to throw away the carb, and convert it back to EFI. Then I called an expert at MSD.

    I told him what was happening, and said the car starts cold and has been running fine except last night, and today it died at a light while at idle.Immediately, the tech says it's your cam position sensor. Wouldn't it cause the engine to run bad? He said no, it could run fine, but it was having a problem w/ the initial restart after it started to get hot sending the correct values to the ecu.

    He was exactly right. Replacing the sensor immediately cured the backfire, the car hasn't died at a stoplight yet