Hondata

Hi all

I have a weird issue with my MAP sensor on my Kpro v4.

Engine setup is a built k24 with Jenvey ITB (running Alpha N) in a DC2 with a modified DC5 type R loom and Rywire 'race' fuse box setup.

Now with the sensor plugged in im getting 10kpa with 0% throttle and 100kpa with 100% throttle. The interesting thing is when I unplug the sensor i get the exact same readings.

This is with the sensor in open air, so really it should just be sitting at atmospheric pressure and not changing with throttle.

I have reinstalled my vac block and will test those readings tonight.

Any help would be appreciated.

I have spoken to 2 different people that have said that when using Alpha-N, the map readings will match the scale of the tps.

Is this correct?

I have attached a log from today. Car was just idling with some revving, tried to give the throttle a good stab to get the TPS to go as high as i could.

This is with the MAP sensor inside a vacuum manifold with a line to each runner, but these values are the same no matter if the sensor is plugged in or not.

Did you edit the open and closed values based on actual readings you see with the ignition on, but engine not running?

Spunkster wrote: Tue Jun 29, 2021 9:29 am Did you edit the open and closed values based on actual readings you see with the ignition on, but engine not running?

Everything was set by the tuner.

I know that the values set are 10kpa with no throttle and 100kpa with 100% throttle while the engine is running.

Should those figures in the Alpha-N menu be set while the ignition is on but engine is off?

Thanks in advance.

Those are the default values, so it sounds like it has not been setup correctly.

OK thanks.

Those are the KPA figures the MAP is showing while the engine is running.

But are they supposed to be set while the engine is running or not?

should be set without it running

Spunkster wrote: Tue Jun 29, 2021 11:22 am should be set without it running

Thanks a lot, i'll have a look tonight.

Are the map sensor values with throttle open and closed not ACTUAL values?

If we are to enter the values with ignition on engine not running?

If this is the case I’d suggest updating be help file on this section. What are those values used for exactly?

I assume the Ecu is sent a derived map value based on TPS open and closed?

It does explain this in the help file: http://www.hondata.com/help/kmanager/ma ... tsub=alpha

Its stated in the help file yes. Explained how to set them (especially the closed value) or WHAT they are used for is what we want to know please.

I assume this affects fuel cut settings as this car has an issue not getting out of fuel cut decel even when throttle input is used.

"Map value with the throttle closed - is the assumed minimum MAP pressure equivalent."

So we enter what the min map pressure actually is with ITBs when we decelerate and datalog the map value ? Or what it SHOULD be if running a plenum intake? (equivalent if it was running a plenum)

I mean what it should be is around 100-250mbar under deceleration with a plenum intake (or 10-25kpa). BUT with ITBs and a vacuum box it might not be...


"Map value with the throttle closed - is the assumed minimum MAP pressure equivalent."

This will usually be atmosphere as ITBs/plenum doesn't change this (altitude and intake restriction does)
So I am fine with the full throttle one, I just want to know how important to closed one is, how to set it and what its used for.

Thanks

Spunkster, any thoughts on the above comment from coupe_r?

The values must be measured with the ignition on, but the engine not running. You must then input those values. These values are very important and if they are not set correctly it will not work properly. It is recommended to use a vacuum accumulator that is connected to every ITB.

Thanks.

I tested it with the ignition on and engine off and there is no change in the map reading from 0 or 100% throttle.

There is only a change in the reading with throttle while the engine is running.

I tested the sensor and there is 5v going to the reference wire and ground is also good.
Signal wire was 2.9v with the engine off but ignition on.