Could someone look at my data logs and give some advice.

[joegreen]

Hello, I took a couple logs on my commute the other day. 20 miles one way on one log and 20 miles back on the other log. The truck is a 1978 chevy k20. I noticed the blm's were reading around 140. The truck is very responsive when cold but once it runs for a few minutes and warms up there is a 1 second bog when I hit the accelerator before it picks up. Also the iac makes a large sucking noise about a second after I hit the throttle. Is it trying to let more air in the engine? In general the sucking air from the iac is pretty loud almost all the time and is annoying because its louder than the engine or the exhaust. Thanks

[sturgillbd]

If you stab the throttle and it seems to bog, you probably don't have enough Acceleration Enrichment. If I remember correctly, you have a 4bbl intake with an adapter on it. The extra plenum volume will need more AE than a regular throttle body intake. Your INT seem to rise when you push the accelerator also from watching your log. As for IAC noise, you need to open your throttle blades up to where you only have 10-15 counts with engine fully warmed up and idling. After adjusting throttle blades, adjust the TPS so voltage is close to .5 volts with throttle released. you seem to be lean across a lot of your history table. View your history table with BLM data and running average. Use this average and the spreadsheet to adjust your VE table. Brian

[joegreen]

Thanks. I'll try those recommendations. I was reading about setting the throttle blades with the iac unplugged to just where the motor is as slow as it can go but still running smooth. Should I adjust the throttle blades instead based on getting the iac counts down?

[sturgillbd]

Either way you want to do it but you need to end up with 10 - 20 counts when done. The newer PCM's will not close the IAC when the ALDL pins are bridged at key on. the lower counts allow more air through throttle blades for better atomization in intake

[joegreen]

I noticed that my tps shows 91% when the throttle is all the way open. Is there some way to tell the ecm what voltage = 100%tps so it reads proper when the throttle is fully open?

[sturgillbd]

The throttle % is calculated from the TPS voltage in the $42 adx and if I remember correctly, It is not very accurate.