Ok, I downloaded Datamaster and used its demo feature to take some recordings from my car over Christmas break. I got some interesting results. Just before my shifts at approx. 6000 rpm, I'm getting 143/135 BLM's, 16.02/15.40 pulse width ms, 81.8/78.6 injector duty cycle, and 866/813 O2 sensor readings. Also getting 33* spark advance with 3.5* retard with 31* adv/5* ret at about 2300 rpm after the shift.

I have not had a chance to check the fuel pressure as I'm away at school, but I wanted to see what my options were first. Also, I installed an Autometer A/F guage a while back and after installing it, it would sweep through the entire arc like its supposed to. Now it only sweeps through about 2/3 of it, more on the lean side, so that corresponds with the readings I'm getting.

Mods include:
stock bottom end
LT4 heads, intake, Hotcam
Proform 1.6 rockers
stock TB and injectors
programming by Bryan Herter

*edit*
e-mail me for the Datamaster file, I can't upload it on Geocities.

 

anyone?

 

jkiley1@cinci.rr.com

 

check yer mail.

 

Interesting its only using 3 BLM cells even after entering closed loop. 16-18. I belive the ECM adjust between cells by map/rpm/speed. Get that VSS sensor up and working for a start.

Second, you really arent that lean. o2s look fine at WOT and are locking at 128 as they should. You are seeing the LT BLMs which are just showing your last driving condition before entering enrichment mode.

I saw you wrote a note... race gas. Was all that knock recorded with some high octane in the tank? The timing is fine, not too high at both cruising and WOT. Yet you are still getting knock across the board. What kind of rockers are you running? I would guess they are SA and driving you knock sensor crazy. Time to desensitze it or eliminate it totally.

 

16-18 are cells used during open loop.

are you using a MAF sensor or speed density?

 

The car is in closed loop, and is trying to learn (values both short and long term changing). It surely isnt functioning properly however, (think because of VSS)

 

Thanks for the replies. I'll have to get the Dakota Digital Speedo box as soon as I get home then due to the fact I'm running a T-5 tranny and VSS. But I'll go ahead and get it and see what that does.

As far as the note, I was using about 95 octane gas, just a little experiment I was trying I guess you could say. My rockers are Proform SA 1.6's, so that could very well be the knock seeing as I can hear the rockers myself. You can completely eliminate the knock sensor? I didn't know that, I guess I thought the computer need some input from it.

Guess its time to break down and get a tuning program. Thanks alot for the help.

 

Im not sure what would happen if you just unplugged the knock sensor (error codes for sure)??

But it can be desensitized and also eliminated via the programming itself. On yours i am certain that you arent seeing "true knock" and its picking up rockers, exhaust etc. Start by desensitizing it and see where that gets you. Best of luck

 

thanks, I just downloaded Tunercat, so I'll try and get some practice with that before I get home at break. I guess I'll just turn the sensitivity way down and try that to see what happens. Thanks again.