"DE-Tuning" 2005 Hemi - This should be a first !

[HaasExp]

I dont think the IAT dropping from what is your avg? 85? to -4 does anything to the fueling.

The fueling strategy is still based on the SD algorithm and intake air temperature is one of the key parameters to calculate the actual air density.
Calculating the air density for 85F (30C) and -4F (-20C) for dry air at 100kPa (approx MAP at WOT at sea level) you get ~1.15kg/m3 and ~1.37kg/m3 respectively.
Therefor the air density will be over estimated by approx 19% and thus the fueling will go rich by a similar amount to match the over estimated air density.

[ECM] 44280 - VE IAT Factor would be the table to tweak this if it becomes an issue using this strategy.

The

[acln99]

Thanks again everyone - so question becomes - with the low - -20c IAT - cause a change quick enough , or will PCM ignore this change and/or use an averaging approach.

[LilSick]

Will changing the temp from 68 to 85 for the PT reference spark change the open loop fueling by changing what the VE is based on?

[rays04gtx]

Will changing the temp from 68 to 85 for the PT reference spark change the open loop fueling by changing what the VE is based on?

no, open loop is
Engine>Fuel> Oxygen sensors, Table(S) 2460,34450,44539,34454 Max values out.

[rays04gtx]

Wow so those tables control timing voltage and amps? So if for instance if the pt ref is IAT 20c (68 deg f) and your IAT's are actually 30c 85f what does that do to voltage and amps?

Table 44664/44665/44663 are the Temperatures the spark plug amperes are referenced to, the Higher the temp the weaker the spark, it's not a trigger point, it's not a way to change heat range.

Ric(Purple Ram) and I spent a few hours yesterday trying to see if we could use Cold Launch(table 12675) to some how trigger and pull spark(see attached ) we tried a few different temp settings , RPM Windows, cut up a nice 05 Ram Wiring harness, several different resistors, even tried a dimmer switch.......... ..........Nope No Go .

Once the ECU is on to WOT tables there NO WAY to get them off those tables unless you lift your foot to drop TPS voltage, only the Knock Sensors cam pull timing while on the W.O.T tables......(Hint Hint)

I spent the better part of the morning talking with the 68dart owner referenced earlier in Ric's post, he said the IAT trick never worked out for him, he wound up using a trigger switch on the BARO voltage to trick it in to hitting 70KPA as the RPMs drop to their recover point from the shift.

I've made a few comments(in different threads) about my Middle son Benny , he worked for DCX/FCA from 01-19 , he was on the team that wrote the ECU programs for the Hemi , we bent his ear last night , and Benny says ........NO , on the NGCx ECU's the IAT's only function is to help determine the quality of air, (like Hasesxp states) all NGCx ECU's use MAT for spark calculations PERIOD,

ECT Spark tables are triggered by Table 44661/44662/44663.....but again, once the WOT tables are triggered the ECU will not step down till the TPS Voltage drops below it's trigger point.


Now Benny says the one option none of us have thought about is Knock Voltage,( sooooooooo) We played with that concept for a bit and YEAH!!!!!!!!!!!!!!! we got it to pull timing based on jumping Knock Voltage to 5v at shift point to trigger table 44701 which we also rescaled ******** Important point, make sure ALL Retard tables have the same Value , we used 6* degrees as a value , we managed to get the system to pull from 24*s at WOT to 18* when 5V was triggered. again the Important point is to make all values = , it was the only way we could get constant results.

[LilSick]

These Hemi need to be pulled back to 0 deg or darn close or they are still gonna drive thru the clutch pack

Does not seem that going from 24 to 18 (or from 20 to 14) is gonna help

[rays04gtx]

These Hemi need to be pulled back to 0 deg or darn close or they are still gonna drive thru the clutch pack

Does not seem that going from 24 to 18 (or from 20 to 14) is gonna help

RFE545 maybe , but a well built 904 will do 600HP in 3500lbs or Less with ease, the 05 ram that Purple Ram talked about in post #2 had a John Cope built 904 in it , truck weighed 3800 was solid 580HP 10.90s @122-125MPH 362CI G3 , never pulled any timing on that combo, ran 24* from 1600-7700 RPMs on the 05 ECU , truck had a total of 105 passes on it before the 441& lenco ST1200 went in it.

My Brother and I campaigned a 68SS/AH Hemi Dart for 4 years , the trick to those is running 904 sun gear and a few other 904 parts in a 727 case, those cars are 3k lbs between 1050-1100HP , yes the trans has to be rebuilt after each track session, we would get 12-20 passes on one of those hybrid trans, replace all soft parts and go at it the following weekend.

[HaasExp]

Once the ECU is on to WOT tables there NO WAY to get them off those tables unless you lift your foot to drop TPS voltage, only the Knock Sensors cam pull timing while on the W.O.T tables......(Hint Hint)

Them NCGx ECUs must be quite different to the GPECs as I regularly use the IAT and ECT hot/cold spark tables to remove/add timing, especially to remove timing on boost applications at WOT once the IATs starts to climb.

Nice trick on the knock sensor voltages!

[LilSick]

yeah except the op basically has a 904 w o.d. so with the right valve body he will be fine shifting it at wot lol does not need to pull power

plz explain how knock voltage would work if he did? How can you make knock sensor sensitive enough to pull 20 deg when 5v present and not have it pulling 10 when ya dont want it pulling anything?

[PurpleRam]

yeah except the op basically has a 904 w o.d. so with the right valve body he will be fine shifting it at wot lol does not need to pull power

plz explain how knock voltage would work if he did? How can you make knock sensor sensitive enough to pull 20 deg when 5v present and not have it pulling 10 when ya dont want it pulling anything?

You would want to set it up like the gm guys do with IAT,

The ram we used had the knock sensors removed a while back, I wired the leads to a on/off switch to trigger the ECU , we used 6* as a start/test value. Doesn’t matter what value you use….

Hassexp, ngcx is Stone Age compared to GPEC

[PurpleRam]

Them NCGx ECUs must be quite different to the GPECs as I regularly use the IAT and ECT hot/cold spark tables to remove/add timing, especially to remove timing on boost applications at WOT once the IATs starts to climb.

Nice trick on the knock sensor voltages!

there's one 05 I tuned a few years back, with a 416CI(5.7 based, 4.03X4.08) , all timing tables are set to Max 26* if it's a table that has timing, it's set to same values as the WOT table... but yet , I have 25 out of 130+ logs that shows it will hit 27* on deacceleration when the TPS is @2.27-2.28 , MAT is 100,IAT is 90F and ECT is 183F, it will not hit 27* if any of those values are different, all 4 factors have to right....

Benny has said a few time that the IAT is just about useless on the NGC's , because DCX officials felt that the End users would place the sensor in other places( like the Magnum guys would do) so MAT is the main temp source for emissions reasons

[acln99]

yeah except the op basically has a 904 w o.d. so with the right valve body he will be fine shifting it at wot lol does not need to pull power

plz explain how knock voltage would work if he did? How can you make knock sensor sensitive enough to pull 20 deg when 5v present and not have it pulling 10 when ya dont want it pulling anything?

LilSick - even worse A606 transmission.

[acln99]

Thank you again for your comments and research !! Currently trying another route as well. Fool accel pedal voltages during shift , so PCM thinks driver has taken foot of the gas. To save transmission , I have been doing this while driving the car. Not good for anyone else though !!!

[PurpleRam]

Ahhh 42LE makes sense Now........................I didn't think you could bolt a Hemi up to the "606"

https://spprecision.com/products/42l...yABEgKpVPD_BwE

[LilSick]

What did you do??? Did you put a gen 3 hemi in a front wheel drive mini van???

[PurpleRam]

What did you do??? Did you put a gen 3 hemi in a front wheel drive mini van???

I was thinking maybe a prowler, when we did my cousin’s SRT6 we used a 904 , there’s a prowler with a t56 behind a SRT8 crate engine, I see that once in a while at some local cruise nights

[acln99]

Bingo - Hemi Prowler. www.hemiprowler.com

[PurpleRam]

Just awesome.

[acln99]

rays04gtx -- sent you a PM !!

[acln99]

Well the weather is finally good enough to do a real test drive. Car was just up on blocks before.

Regarding the Torque Management issue, I am testing fooling the APPS with a couple of resistors to simulate reducing throttle pedal position. Seems to work but am getting a DTC P2138 - APPS Voltage Correlation. I need to refine my resistors !!

Todays question is - Engine idles at approx 2000 rpm when I am coasting to a stop sign , foot off Accelerator Pedal. When I actually stop (or just before) RPM drops to 624 rpm just like is set in the idle tables. On a 2800 lb car, 2000 rpm is enough to keep it moving and you really need to use the brakes to stop. On startup, engine starts and immediately drops to 624 rpm as expected.

Any help is appreciated ! Thanks .

2004hemi-rolling-high-idle.hpt