neg.timing?

bowtieguy45 · 09-24-2006, 07:35 AM

Hi,I have a 96 Impala SS with the LT1.When I connected my scan tool I noticed that the advance timing reading was in the -(neg.)When I increase the throttle it goes farther -(neg.)Is that the way the timing works on these cars?I thought it was sopossed to go + on the timing?

**jasonisdn** · 09-24-2006, 03:48 PM

thats not supposed to happen. scan a friends car with a lt1 in it and see if it reads the same. if so i say scan tool settings are off. if thats not the case , i cant tell you where to begin looking for that false signal. is it a actron scan tool? with a OBDII plug in?

**pr0zac** · 09-24-2006, 04:04 PM

my corvette does the same thing.. i have an actron scan tool..

bowtieguy45 · 09-24-2006, 08:50 PM

I checked my wifes 03 grandprix and it was +(pos.)and advanced when given the gas like I thought it should.Guess LT1's are a strange breed?It sure runs fine,I just thought the neg.timing was strange.

**BlackLT1Z28** · 09-25-2006, 07:35 AM

Wouldn't negative timing also mean retard timing? Or is that not the same thing? I would think so in saying that the computer just retarted your timing as opposed to advanced it.

**jasonisdn** · 09-25-2006, 01:18 PM

Originally Posted by BlackLT1Z28

Wouldn't negative timing also mean retard timing? Or is that not the same thing? I would think so in saying that the computer just retarted your timing as opposed to advanced it.

yes you are correct.
well if it reads positive on your wifes gp and it reads - on the other guys scan tool, i guess there might be a issue with the scan protocall in the scan tool for the lt1 , it has to be limited to the lt1 since the gp scans normal. call actron , see what they have to say.

**Red on Red WS6** · 09-28-2006, 08:56 PM

Originally Posted by bowtieguy45

Hi,I have a 96 Impala SS with the LT1.When I connected my scan tool I noticed that the advance timing reading was in the -(neg.)When I increase the throttle it goes farther -(neg.)Is that the way the timing works on these cars?I thought it was sopossed to go + on the timing?

Timing should always be negitive. It is how many degrees before top dead center of the piston. Some scanners may read different but it will always be truly a negitive number. You dont want spark after the power stroke.