[xafalcon]

I have an annoying RPM flare-up when the NDS switches from a Neutral setting to a Drive setting. It makes the engine bang into gear which i would like to eliminate. When the engine is cold it flares up about 400RPM, but only about 100-150RPM when warm. The revs stay elevated for about 10 seconds if I trick the NDS into thinking I've put the auto into gear.

Now Since the RPM flare-up happens to a greater extent when cold, I've checked all the ECT related parameters without finding anything that looks likely. I've also checked idle and NDS related parameter but came up empty again.

The application is an Auzzie 5.0 with 1991 EEC4 ecu very similar to A9L/A9P.

Can anyone point me in the right direction so I can reduce this RPM flare-up.

[decipha]

go change the trans switch to forced neutral state

[xafalcon]

The definition seems different from A9L here. There only seem to be 2 choices - 00 = manual, 01 = automatic. So should I switch to manual?

[decipha]

thats what i would do

[xafalcon]

OK, I tried changing "Transmission Type" from Auto to Manual but it made no difference, I still get the rpm flare. Also tried increasing the "Time Delay Before N/D or D/N Switch Registers" from 0.25 seconds to 2.5 seconds. But this also had no effect.

Any other ideas much appreciated.

[decipha]

well its not obviously not working in the tune so you might as well just ground out the nps that way you don't have to worry about it

[EDS50]

The definition seems different from A9L here. There only seem to be 2 choices - 00 = manual, 01 = automatic. So should I switch to manual?

TRLOAD only has two choices in your definition? Interesting..

[xafalcon]

The definition seems different from A9L here. There only seem to be 2 choices - 00 = manual, 01 = automatic. So should I switch to manual?

TRLOAD only has two choices in your definition? Interesting..

As best as I can tell. I've dumped or otherwise obtained binaries from various Auzzie EEC4 V8 ecu's. Some auto, some manual. They all follow the trend 00 = manual, 01 = automatic.

The auto ecu's do have some VERY basic transmission related parameters (but no actual direct transmission control functions) as the transmission was a locally produced electronically controlled (by a seperate tcm) unit rather than the US AOD non-electronic transmission. There are two one-way data links between ecu and tcm, one in each direction. Ecu tells tcm about engine temp and A/C status (which effects shift points and converter lock-up under certain conditions). Tcm tells ecu about reverse gear selection and transmission LOS (both invoke torque reduction).

I have not tried inputting numbers other than 00 or 01. But it clearly doesn't follow the A9L style of coding for this parameter where 00 - 03 were manual trans and 04 - 06 were auto trans.

[xafalcon]

well its not obviously not working in the tune so you might as well just ground out the nps that way you don't have to worry about it

Thanks but I'd prefer not to do this. The starter inhibit is a safety feature that needs to work for our local 6 monthly vehicle safety inspections. And if my wife ever drives the car, it needs all the safety features posible. Otherwise it's likely to get all banged up when she starts it in gear and it moves off the mark.

Maybe an RPM switch with a switching point of 400RPM would be a safe way of doing it, but I'd much prefer to find the code that controls it and modify it the right way.

[decipha]

you can still have a functioning nps just remove it from getting to the ecu, then just ground that pin from the ecu and all is taken care of ecu wise and everything functions as it should mechanically,

t'would' be nice to find that scalar in your tune but if you don't have that option then

can you post a log of when it does this, that's assuming you have some type of datalogging capabilities??

[xafalcon]

Thanks decipha, but I currently have no data logging capability.

But I decided to have a try through modifying the ISC transfer function. As an initial rough test I scaled the mass flow (except first and last entries) by a factor of 2. On a warm engine it works great. Tomorrow I'll know what a cold start and drive-off goes like. If this is OK, I'll try and re-curve the ISC transfer only in the area where it causes this RPM flare.

[decipha]

can you send me what you got and i'll take a look??