Also, I'm not sure if USDM evo IX still have the ICS output on the ECU, just not wired to anything. With the tephra mods this would be another alternative way to do this without too much trouble. Jack posted about using it here: https://www.evolutionm.net/forums/7557073-post10.html
...and I'm pretty sure the settings are still there in the IX rom.

Anyone have any input on either of these two bits of info?

 

I have tried to search for code as a followup of this.
For me it seems Pin 21 is controlled by MUT_9B & 0x1, if anyone of you can confirm my assumption via logging, I may have a look futher in disassy, what conditions are affecting it.

 

I'll try to grab a log with this later today...

<DataListItem DataLog="Y" Color="" Display="Fuel Pump V Relay" LogReference="BrakesOn" RequestID="9B" Eval="x bit 1" Unit="On/Off" MetricEval="" MetricUnit="" ResponseBytes="1" GaugeMin="0" GaugeMax="1" ChartMin="0" ChartMax="1" ScalingFactor="10" Notes="Shows when the ECU switches voltage to fuel pump from 9v to 12+v" Priority="10" Visible="False" />

 

I logged it as 1-Byte and it was either 0 or 1 for all conditions I encountered. I have all the emission control stuff disabled.

Most of the time, it was 0. Below are the conditions I noticed it to be 1.
Decel
Idle
Lightly revving from idle with load at 20, it would switch from 1 to 0 at 2400 RPM.

I don't know if I found the right sub or not, but it looks kind of nasty.

 

Did you happen to notice any kind of correspondence with load at light RPM?

I'm guessing it might be activated very low on the stock pump control, just lowered essentially for decel and idle. It is probably activated by cruise because the end user will not see much of a difference and the flow is there if the pump needs it. I'm guessing we wouldn't see much of a difference by raising this to the upper end of cruise levels.

 

I didn't catch a log at cruise speeds. It was mostly a quick drive around the block and then free revving in the parking lot.

I'll grab another log tonight. It seemed like almost any amount of throttle would make the switch.

 

It is 0 at cruise conditions.

I could get it to go to 1 while driving under 2000 RPM with like<30 load.
Other wise, decel and idle where about the only time it's 1.

I would guess it was done almost entirely for noise and maybe reducing fuel vapor emissions.

 

And to minimize any chance of fpr overrun at idle due to the high flow fuel pump.

 

It goes to full voltage at such a low IPW and RPM anyway that I don't think the fuel demand would be any higher then at idle and it's likely just for noise and possibly reducing fuel vapor.

Just looking at the throttle almost switches the state.

If 0x01 on MUT9B is in fact the pump relay anyway.

I'm thinking they probably just designed the fuel system to handle a larger pump, unlike the 1G and 2G.

 

Right, coming from DSM and the fpr overrun issue, and with the Evo having a higher flowing pump as well, I think Mitsu actually designed the circuit for that reason. I think they just wanted a lower voltage at idle only.

Even though the IPW is low during a light cruise, the fuel demand is still higher at cruise. Also, the step in IPW logging is pretty big it's hard to see the difference between idle and cruise. In general your fuel demand is going to be at least double at cruise than at idle, depending on your idle and cruise RPM and your vacuum at idle and cruise.

 

Right, but isn't it at the lower 9v state at cruise?

Unfortunately I won't be able to log since this happened yesterday...

 

No problem I have found the same in the V6 ROM ECU that I have on the bench, I will try to get the control pin via logging

I hope nobody got injured, now you have a good reason to do some styling

 

Nope

 

Ah....damn man. I'm sorry to see that. Everyone OK?

How bad is the damage?




-Bink

 

? Am I missing something?

I should have let the guy hit me. He swerved to avoid a piece of metal. I swerved to avoid him. A few fishtails and into the median backwards . Front and rear passenger side are pretty screwed up, front pass suspension off the car. We'll see what happens, friends with similar damage are saying probably totaled.

I'm a little sore, but frankly nothing more than some exercise does to me.

Sorry for the OT!