Mine seem high but the truck is dyno tuned and very driveable, I have no problem sending my wife out alone in it, it has excellent manners for what it is. Before I got it fixed it would lean out and die with increased TPS or MAP. Mine just seem so high to me, what are your AE's at? Somebody please, this is the 2nd time I had to make a thread like this, my last one got no replies either. It just takes 15 seconds to open your tuner and copy/paste the table here.

Are you wanting AE vs. Differential MAP or AE vs. Differential TPS?

All I can say is TONS of AE for that head, intake, TBI combination. I no longer have my .bin from my setup due to a hard drive crash, but I remember running on TBI it needed a TON of AE. My van needed even more than your S10 likely wants. Mine would lean pop unless it was blowing soot out of the exhaust on the transition from idle to WOT. Even running the Vortecs on a 305 with TPI and starting with a 350 calibration running 28# fuel injectors from a LT4, mine would lean pop on the stock TPI AE settings. I had to play with AE settings and filter settings to get the fuel in and get it in quick.

Heres mine. I had an edel RPM airgap with my TBI, which required corrections based on the actual temperature of the manifold (I had a homemade sensor on the side of the plenum). When cold, it needs tons of AE as the fuel just plops down on the floor of the intake and the incoming mixture stratifies. Like fast said, this required lots of AE to avoid lean misses and poping even though it caused sooting. When the manifold got hot in traffic, no MAP AE was required. This is mainly due to the fact that once the manifold is above the temperature of teh boiling point of most of the components of gas, it cant settle out, so no long term AE is required. you may ultimately find that as the weather changes, you will have to revisit the MAP AE due to the changes in manifold temperature. This was a huge problem for me in the winter before I added the ability to compensate based on manifold temps. The AE would swing from dead lean to pig rich and vice-versa as I drove in traffic.

The settings in the graphs below worked very well for the MAP AE year around. The AE is actually given in injector duty cycle. For reference, each of my fuel injectors flowed around 120 PPH.

Im having that same issue with my setup with the 1000 CFM progressive throttle body. With the stock SFI calibration, the engine actually just shuts off when I open the throttle quickly. With some tinkering I can get decent response on teh primary throttle blades, but If I quickly open the primaries and secondaries, I get a nice resounding bang out the intake. Of course, the newer OBD-II PCMs are inflexible with respect to AE and difficult to patch, so I'll probably have to live with it.

Transient engine operation is always a PITA to tune for.

Dimented: I am seeing that now here in WI. Past week temps 89F. I pulled out 25% of my AE in TPS before the temps rose and I still see 9.9/1 on WB past week on a hard accelleration. When cooler (65F) with 25% more AE before charnge I believe I was like 10.5-11.0/1 on WB. Under hood temps were 90F when cool and now are 140F on IAT. Amazing to see that multiplier for -40C ! I park it when that cold !

Is the only compensation for enviormental temp affecting AE in the IAT vs Coolant tables?

I added a lot of AE to my tune thanks to this thread and it helped immensely. It runs quite well during normal driving now. Since the temps have dropped (especially today at 0F), I have noticed I get a nasty lean spike when I let out the clutch from a stop, and it can be pretty bad even when shifting gears and getting back on the throttle.

I noticed last week even with the engine to temp the intake felt fairly warm, but the TBI was ice cold and had condensation on it. It needs more AE apparently with lower ambient temps, so I'd like to add a MAT sensor.

Most of my winter driving with this truck is the 1-mile commute to work, so cold driveability is a priority to me. I stalled it twice this morning because it was being miserable.

Their may still be available a spacer that utilizes coolant(heat) within it. Between the TBI and the intake flange. Not sure who made? Maybe GM maybe Holley.

I have similar issues but store car when temps under 40dF for season. R bob posted a fit by tapping the intake manifold crossover under mani plenum. Search a thread I started and he responded to 1-2 years back.

GM made a heated mounting base for the BBC TBI on a spreadbore flange.

Interesting...my carb manifold is a spread bore with an adapter and a spacer. SBC and BBC TBI units are the same pattern I assume.

I found one of those heated GM spreadbore/TBI adapters. Looks like a decent way to go about it.

I ended up taking it for a drive last night and it ran great after it was up to temp...even in the cold...and the TBI felt cold, but worked well. So maybe the heated adapter isn't my highest priority. My 1-mile trips to work dont get the engine up to temp, so I dont think the heated adapter would help much in that situation.

I see a table for AE correction vs temp that I will play with to add AE when very cold and see how that helps. If that makes accel too rich at higher ambient temps (with same coolant temp), then a MAT is probably the best way to straighten it out, am I right?

I believe that to be coolant temp...May not help as sensor is not seeing what TB is seeing.

Here is RBobs tip:

[quote]You can add coolant to the crossover in the intake manifold. This is the way I have it set up on the 331 engine. Heads don't have exhaust, just blank areas that block off the intake crossover.

Drilled and tapped the manifold and plumbed coolant through it.


With IAT functional this past Oct-Nov I find the A/f is good and engine runs good on cold start OL. Once it goes CL if I drive steads cruise and stay off the throttle stabs for a few min all is well as heat is now at TB. I did not do the crossover mod that RBob mentioned.

Is there a diff between IAT and MAT? I think so as my IAT is 10 inches from TB in cold air duct..

From what I understand, when installed the MAT gets blended with the CTS as a temp reading for fuel. There is a table that figures the CTS/MAT bias for different temperatures. (IE: 50/50 for cold and 90CTS/10MAT for warm, etc)

MAT is different than IAT. On a TBI the MAT will pick up the temp drop from the fuel flow in the intake runners where an IAT is basically ambient underhood temp.