Hey guys, so Ive been learning this tunning thing for a while and in the progress of trying to tune my motor. Last week I decided I wasn't making progress so I started over with a different bin. So now I'm starting from the beginning.

Heres the question...

Am I tuning my Main VE table right? heres what I'm doing...

Finding a steady load/rpm rate in my datalog then take the BLM value and devide it by 128 then multiply it by the current value in the VE table.

It seem I'm showing lean so I richen it up then I show rich and not just by a little. my BLMs are anywhere between 107 and 140 when this happens...So I readjust and the opposite occurs.

Now BLM is short term and INT is long term right?

I noticed in my last 2 logs taken today, both a good 45 mins. My first my BLMs were running between 110 and 138 not good...Then my second drive/log only 5 mins later after filling up for the whole drive my BLMs were way better ranging only slightly off of 128...

Can someone enlighten me a little more on BLMs and INTs?

Am I going about this all wrong?

Im running a 7477 and using tunerproRT.

Thanks in advance!

I can post my latest 2 data logs if that would make what I'm describing any clearer to anyone!

 

Just one thing to get you on the right track.
BLM's are long term, INT's short.

 

I've seen that behavior for a number of reasons:

Fill-up time allowed the intake/heads to heat soak. '7747 = no IAT, it's assuming a stock setup with thermac air cleaner.

Sock on pickup in tank gets coated with crud during the drive, at shutoff the crud falls off and things return to normal at startup (for a while).

You're sometimes sucking air with less than full tank of fuel.

Your case sounds like 1 or 3, or combination of them

 

This can occur when there is a problem w/hose connection between the fuel pump & sender tube inside the tank, pull the pump & check that & pickup sock.

 

Thanks guys, That would make sense. The heatsoaked heads I think I can rule out but physical blockages in the feul system is a possability.

The reason I dont think its the heatsoaked heads is when I stop and filled up afterwords it is consistent for the next 45 or 50 mins which a heatsoaked head should return to normal conditions after starting and driving again.

I have an inline pump but I may have to pull the tank and give it a good clean.

To check if im sucking air would a feul pressure gauge tell me that? I know I'm running at 13PSI. Think the gauge would drop a little if I sucked air?

Im about to leave to on a good 1.5 hour trip. I'll hook up the laptop and monitor it again and see what I come up with.

Thanks!

 

It's more the intake than heads heatsoaking, but often once they're hot they won't cool off to the same point as a cold start and drive cycle. An hour of highway on a TBI app could be enough to cool it down, evaporating fuel can absorb a lot of heat.

Are the exhaust crossovers open (or not totally closed)?

Most stock carb apps pull one tank of fuel past the strainer once per tank of gas. EFI can recirculate it numerous times.

If you can monitor the gauge while driving, yes.

 

An exhaust leak will do what you described. I had same situation due to loose header collector to ext pipe bolts.

Do not use any data on a less than fully heat soaked engine. Also expect seasonal changes to affect BLM. EFI-BLM is designed to handle the seasons. yo can if you wish run a VE table for spring fall vs summer.

Switching to 8746 ECU allows IAT control. Helpfull in perfecting tune when air temps change morning to late afternoon.

 

All good ideas. But I've got it fixed!

I threw in an old burn that worked good besides the fact it had a very high idle that wouldn't go away. With it my BMLs were in check. Made me think it was more of an issue with my new bin rather than component failure. I ran a compare in TunerProRT and the obvious ones came up like my VE vales and PE. My SA came up to so I checked how much off it was. It was a good 10 to 12 degrees more advance then the my old bin. So I upped my Main Spark Bias by about 10.5 degrees. I also at the same time changed my BPW EGR Off from 135.00 to 145.00. Increased my Main VE values by 10% across the board, and realized I forgot to unset the code 32 for the EGR code so I did that.

Went for a drive and my exhaust immediately sounded louder and I wet for a pretty good drive. My BLMs never went lean and only went rich under a few conditions. Also knock counts that I was getting before but forgot to mention completely went away even under heavy load.

Can excessive timing give a lean or all over the place BLM's? I know to little timing can give false rich readings...does it go the other way? My SA is the only think I changed that I can see would have done anything....

Thanks for the suggestions guys!