Hi there guys,
I have been reading here and on other prom tuning boards on and off for about a year. I have just started doing some data logging the last few days. The short logs I have done while driving around town have some numbers that seem WAY out of whack. I think I have a grasp of what this stuff means, but a comment or two would be appreciated. I am ordering a pocket programmer and getting tunercat in a week or two. I am using Moates datalogging.

1)My BLMS tend to be real high, only one or two single samples have them as low as 129. Many times BLMs are 140+, this mean I am running very rich?

2)I get lots of knock counts, even on easy acceleration from a light, WOT records knock so fast it is amazing.

3)There are times where total spark advance reads as high as 47*. Isn't this high? I am correct in reading this as advance over base timing right?


Thanks for taking the time here and even more thanks if you have something to add.

 

Sounds like your running lean and have too much spark advance. Maybe you could give a little more information on the car?

 

To lean will be **** to detonation, try to get your blm's where they belong, in the meantime maybe set your distrib to 0* untill you can get more fuel/less timing in there.

 

The car is a 1988 Corvette A4 with 2.73 gears. Pretty stock with a cut air cleaner lid, no maf screens, slightly ported plenum, Borla catback, no pre-cats, and an AFPR. Thanks for the looks and advice.

Bob

 

Crank up the AFPR

Those gears are fairly low meaning more load on the engine thus knock in the right circumstances

 

First thing is getting a good MAF.
GM didn't put the creens in there for grins, they are vital to get an accurate AF sensing.

Vettes are really bad about trapping hot air under the hood.

With 2.73s it's not going to tolerate much timing, especially below the stall speed of the converter.

I posted a timing table within th elast few weeks, you might want to see what works with a tall geared car.

 

Yeah, I saw that table a few days ago and saved it, thanks. I raised the fuel pressure (a bunch, but dunno how much, no FP gauge at the time) and that seemed to help.

thanks guys.

 

1)My BLMS tend to be real high, only one or two single samples have them as low as 129. Many times BLMs are 140+, this mean I am running very rich?

Actually if you have BLM's at 140 you are running lean.Anything over 128, it's adding fuel anything under 128 taking fuel out.I made the same mistake awhile back too