seems the AE TPS is OK for hard accel. i am going on belief the AETPS is the first PS followed buy a second being AEMAP. The TPS is greater due to my doing in eprom. i used the set values in the "stock" bin and just factored them higher by 250%. i am noticing at 55 mph if i goose it a little say from 15%TPS position to 25% TPS a stumble appears. now this is a guess and i will need to confirm but i believe the issue may be the air flow capability of TB/xram exceeds the ability for AETPS to respond. a lean stumble. i will look at the winaldl TPS position where where stumble occurs and increase that AE TPS about 10%. is this reasonable? also as a side note i think i can monitor the 02 off winaldl. i think stoich is about .45 mv. if i goose it a little the volts will change. lean i think is a greater number and rich is a lower number or vice versa? Please correct me on this if error. also on hard WOT accell in 4th gear of 5 (manual) from 50 to 85 mph(under load) i get a gurgeling sound from engine. it his possibly too much PS from the AEMAP? PE set to 12.5/1. Comments please. OBTW no vac leaks. VE tables pretty close. PE is 12.5 on dyno WB.

 

Couple of things. The TPS% AE is based on a delta, not a set value. So the 'from 15%TPS position to 25% TPS a stumble appears' is not directly convertable to the TPS% AE table. The TPS% AE table location/value will be the amount of TPS% change that occurred when the TPS position went from 15 % to 25%.

Use the Innovative WB unit and see what happens to the AFR when the engine is stumbling/gurgling. It will show whether the engine is going lean or going rich. Adjust accordingly.

RBob.

 

Bob: A Q. let me say the throttle is 1/10 open as far as range of operation. lets further assume that is 50 MPH. now i move throttle position to 2/10 open quickly and accell to 60 mph and leave it there. this is a change on my tunercat AE/TPS of 10% to 20% so it provides an injector spray of 1400 usec of petrol (i assume) per my table which is value at 10% TPS. i would assume this is a one time PS occurance over possibly .25 second. i am of opinion this scenario above is related to AE/ TPS values and my stumble is from too much air but lack of PS. should i be looking elsewhere? i will have WB hooked up in about 2 weeks. currently just trying to work without it and learning. only been tuning since 7/03 with winter came and past. please explain further.

 

You have a decent understanding of how the TPS% AE operates in the '7747. Before I go into it in more depth I would like to add to the 1,400 usec of AE pulse you mentioned. That value will be further modified by the ACCEL ENRICH vs COOLANT table at $40C.

If the value from that table is 32 (at the currect CTS), then the injector will spray a 1,400 usec pulse of fuel. If the value in that table is 16 then the injector will spray half that for 700 usec of fuel. If the value is 48 then the injector wil spray half again as much for 2,100 usec of fuel (1,400 * 1.5).

The base factor for this table is 32, 1-to-1. So a value of 64 will double the AE fuel pulse.

As for the delta TPS% term, it is created by lag filtering the current TPS% with the last filtered TPS% term. This in effect not only creates a magnitude of TPS motion, it also creates a duration of TPS motion.

So a sudden opening of 10% TPS will taper off over a period of time. The smaller the lag filter coeficient the longer the duration (lag filter terms in table: ACCEL ENRICH COOL TPS FILT COEF vs COOL TEMP @ $31D).

I was looking for some data logs where I did TPS/MAP step AE tuning but can't find the right ones. Otherwise I could show this affect. I try not to do this often as it attracts the attention of the guys with the funny red & blue lights. . .

The MAP AE operates in the same manner. It has tables of the same functionality as the TPS AE.

The basic flow is: create a delta TPS% term by lag filter. Uses table at $31D for filter coeficient.

Use this delta TPS% term to lookup AE fuel pulse from table at $313.

(do same with MAP and add the MAP & TPS AE terms together, along with IAC throttle follower fuel pulse).

Factor MAP/TPS/IAC fuel term by value in AE vs CTS table @ $40C.

Program hardware to fire injectors asynchronously and simultaneously.

12.5 milli-seconds later do it again.

RBob.

 

thanks. i will study this for a while. accel enrich vs coolant (i assume) fuction is to enrich the PS when engine is cold(open loop)? it then works along with and in addition to the commanded values for choke enrichment. so that when the car is cold and you accellerate(TPS %%) it provides more PS than it would when up on temp to say 185 deg? i have been living with aa doggy startup in morn(open loop) when i get to Xway (one mile) a non issue. not sure ig tunercat offers the ability to change the AE coolant values but i have not looked. now all this changes in 10 days when the notorious xram and it unique plenum design come off and the GM454 /adapter goes on. all this AE function stuff will change as my spray will no longer be on plenum floor and taking a convoluted route to valve. plus the cold temps here in wis dont help ae matters any. condensation/falling out of atomization(ie plenum)....