Ive been thinking about this for a bit... Im thinking that the car type TPS AE is almost entirly just for the initial tip in when the intake itself fills. The TPS AE is the last big issue that Ive had with this peticular car. With the stock values the motor would hesitate for a split second, well, more like just sit there as soon as the throttle was opened and not do anything untill the AFRs came up. With the small injectors Ive had to add in almost 4x the ammount of TPS AE to keep it from going lean (the O2s would dip into the double digits for a split sec and Id get lots of detonation).

To make a long story short, with the temperature correction I have developed a vicious off idle stumble when the motor is cold since the injectors are momentarily going close to static from all the PW. Is it safe to assume that the TPS AE is mostly dependent on the intake and tbi and not really on the engine or engine temp? Ive been thinking of jsut performing the temperature correction on the MAP AE alone since the TPS doesnt really seem need it as much, or maybe do it seperatly for each one.

 

Now where'd I put that reply.
Oh ya, cleverly hiden in quoted material

 

The thing is is that there is a huge disconnect between the TPS AE and the MAP AE when it comes to temperatures with my engine. This is actually the third time ive been through this. Get it good when the motor is warm but when its cold, forget it. The temp correction for the MAP AE is fine. The car works reasonably well throughout the temperature range. Just that damn TPS AE...

I guess ill have to mess around with the MAP AE and temp correction and see if I can get the two AEs to meet in the middle as far as the temp correction goes. Really need ALOT of that momentary TPS AE to keep the AFRs from cratering when the manifold first fills. I guess I should also add that my TBI is too large for my motor. Anything over around 35% tps usually gets MAP readings of 95+ kPa.

 

I can't disagree with anything Bruce has said. The RPM compensation would have been really nice. I'd be happy with a switch that turned off AE vs TPS above a certain temp and RPM. Then just use the map AE. AE is SO hard to get right without a wideband and without good datalogging. If there were a major draw back to keeping TBI, tuning AE would be it. The code is lacking (especially in 61) and when increasing plenum volume it's just crazy hard to keep it from effecting the VE tables. AE can hide a lot of an offset tune where for example the VE table might need a lump at low engine speeds just off idle or right where you get back on the throttle. This past weekend I was working with a corvette that had this problem (big injectors low fuel pressure) along with pegged VE tables (above 100).
I haven't done this yet but I think I'm going to try and disable TPS AE with zero's and see how close I can get the tune with just MAP AE. I might even try the other way around and take data with notes. I had to take the wideband off again to tune our unrestricted formula car for Alumni weekend but the narrow band should be enough info for watching the difference.
Dim, did you ever figure out the code on TPS AE? Is it like the 8746 or is like the 7747? If it's like the 8746 then your TPS AE might only be looking at the first 2 cells. Anything "faster" like at 12.5% is going to require Superman speed on the TPS . "DA MAN" showed me this a while ago after I had been playing with the TPS AE higher cells and getting no difference. All along I was figuring since the 7747 went up to 25% that I would be at LEAST in the 12.5% when I stab the throttle.... but I was wrong.
One little trick I use to tune the MAP AE is to watch the narrow band sensor after a transmission shift (automatic). This isn't as good as a wideband or nearly as fast but it'll show lean/rich wish is all I really needed to get close.
Keep up the good work .
edit; almost forgot... check the choke AFR table and the open loop AFR tables. This too effects the level of AE required because if it's always rich then there is no need for AE and vice versa.

 

As far as the TPS goes, I primarily use the first two and get half way to the third if I really step on it. I got within spitting distance of 12.5% (averaged over .05 secs) by winding up and slamming my foot down to the floor. Nothing that it would normally encounter but evedently it is possible. I did try zeroing it out... Definatly not a good idea with my setup. It was like network lag in a video game. Stuck the pedal down, and about a tenth of a second later it took off as though I had just pressed the gas that instant. Adding in PW to the MAP AE covered it but then left the motor gagging for the duration that the AE was in effect. Definatly need the TPS AE. Again, my theory is the rapid but momentary filling of the manifold as soon as the throttle opened. I guess it sort of acts like a capacitor by being able to fill as rapidly as the tbi will let it. If I snap the throttle open, I get a loud 'WHOMP' sound so its definatly taking in alot of air for a very short period of time.

Although its invisible on the regular ALDL, it shows up on the higher speed serial communications as a single frame having very low O2's and knock counts. As a matter of fact, I only get knock counts when I stab the gas. Taking out timing at the higher map areas helped a bit but still didnt solve the problem of being lean. I can go through the datalog and at each point where there is detonation, the throttle is opening very rapidly at the same time and the SA drops like a brick. Of coarse, it takes off like a honda civic since there is hardly any timing. This is also agrivated by the MAP AE since, without the extra timing to prop up the VEs, it goes rich as soon as the detonation appears. With the right ammount of TPS AE, it takes of like it should. Stab it, and the tires instantly spin and it gets going.

As far as the AE goes, the 8063 code for the AE carried right over to the 8746, so theyre the same. I guess ill increase the resolution of the TPS AE so I have more then 3 cells to work with and Ill try adding some MAP AE and see if I can get the two on the same plane as far as the temp compensation goes.

Or, I guess I could get rid of this block of lead I have for a right foot. Might also do wonders for my fuel economy as well.

 

If the AE is the same as the '8746 the AE multiplier vs. coolant table affects all three adders: MAP AE, TPS AE, and IAC opening pulse. In the '8746 this table is at $D332.

I'd also be reeeeeal tempted to paste in the '747 delta TPS% code and tables. It uses a table of filter coeficients to lag the TPS. Much more control and works better then the '8746 TPS AE method.

RBob.

 

I did what I origionally planned by adding a touch more MAP AE and making a slight reduction in the TPS AE and then toning down the temp correction and it seems to be a step in the right direction. Still needs some tweaking but its definatly better. At least it doesnt pick up an s-load of knock when I hit the gas. Also reduced teh threshold for TPS AE some because I was getting momentary hesitation when accelerating normally from a stop. Seemed to help that as well. Still have to work on the temperature correction, though. Stumbles a bit when its cold.

 

Might try adding more VE in the lower RPM high load areas. While the transistions thru that area are quick it can really make a difference for low RPM Accleration.

The other thing is the TPS PE enable, If your trying to use a 70% enable, and cover getting there with just AE, your going to have alot of problems. If you go with lower TPS PE enables, then lean down the low rpm PE AFRs.

Just glancing at the EE cal, it starts at a 40% TPS enable at the lower RPM and then drops to 10% at higher RPMs.

FWIW, here's what I run on the GN, for PE enable.

F62 FCB 66 ; 400 RPM
*::EQU N=E*2.56 ::
FCB 66 ; 1200
FCB 66 ; 2000
FCB 54 ; 3200
FCB 45 ; 4800

;-----------------------------------------------
;
; F38_TABLE RPM Multiplier For Accel Enrichment
; Result is (AEPW * AERPM) / 256
;-----------------------------------------------
AERPM:
;-------------------------------
; Fact ; rpm
;-------------------------------
FCB 150 ; 400
FCB 145 ; 800
FCB 145 ; 1200
FCB 135 ; 1600
FCB 130 ; 2000
FCB 120 ; 2400
FCB 110 ; 2800
FCB 110 ; 3200


LMainVe:
FCB 0 ; min rpm val, 400 rpm
FCB 0 ; min map val, 20 Kpa
FCB 17 ; map bp's per row

;--------------------------------------
;Map: 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 ; RPM:
;
FCB 68, 75, 88, 90, 90, 90, 90, 94, 96, 98, 100, 100, 100, 100, 100, 100, 100 ; 400
FCB 68, 75, 88, 90, 90, 90, 90, 94, 96, 98, 100, 100, 100, 100, 100, 100, 100 ; 600
FCB 68, 75, 84, 90, 90, 90, 92, 98, 98, 100, 100, 100, 100, 100, 100, 100, 100 ; 800
FCB 40, 60, 70, 82, 95, 100, 105, 125, 135, 160, 160, 160, 160, 160, 160, 160, 160 ; 1000
FCB 40, 50, 60, 82, 105, 120, 125, 130, 140, 160, 160, 160, 160, 160, 160, 160, 160 ; 1200
FCB 40, 50, 60, 80, 120, 133, 133, 133, 135, 145, 155, 160, 160, 160, 160, 160, 160 ; 1400

You can see how fast the VE ramps up at the lower rpm on this main VE. It might be a little misleading in so far as with a boosted engine I can start making pretty good power way down low.
And yes this is with the 60 PPH injectors.

HTH....

 

Ive been thinking about adding more AE in at the low rpm, high map areas as well to help bolster it. Below around 1200 rpm the VE table drops off and even with that it still gets low BLMs and has a bit of a stinky idle. Probably more a mechanical problem/mismatched parts then anything else. I also have PE come in at around 30-35% tps, probably one of the first things I did. The MAP is usually around 70 kpa by that time anyway so its a good place to enable it. It used to come in higher with the stock tune but by that time it was already pretty much at WOT and it didnt work too well trying to do closed loop instead. The rpm multiplier looks pretty cool...

 

Its finally nice to be able to burn some rubber from a standing start. I dont know what they where trying to do with the stock AE temp correction table. Some of the values there specified more pulsewidth then could be supplied at anything but off idle even with the stock tables. Must be because of the small injectors they used. I was doing something that I never usually do by momentarily flooring the motor in neutral when it was cold and actual gas was coming out of the exaust.

RBob, its funny you should mention the IAC opening pulse. I removed some timing from where it idled and noticed that it stumbled and gave a puff of smoke when I first stuck it in gear. Thought it was probably the shot of fuel given when the IAC opened but didnt give it much thought other then that Id take a look at it when I got around to it. Guess I should have payed more attention... Its still kind of funny that the temp compensation didnt seem to affect teh MAP AE all that much. Maybe the thing that did it when it was cold was having the TPS AE thrown in on top of it.