Weird MAP sensor issue

K-Series Programmable ECU installation questions / support issues
brenthay
Posts: 34
Joined: Sat Jun 20, 2015 10:05 pm

Re: Weird MAP sensor issue

Post by brenthay »

I have attached my vacuum block setup.
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Spunkster
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Posts: 22737
Joined: Fri Sep 20, 2002 5:06 pm
Location: Hondata

Re: Weird MAP sensor issue

Post by Spunkster »

The MAP sensor appears to be unplugged.
brenthay
Posts: 34
Joined: Sat Jun 20, 2015 10:05 pm

Re: Weird MAP sensor issue

Post by brenthay »

Come on now, it's just not plugged in for the photo haha.

It's 100% plugged in and getting the right voltages.

I have also tried another known working sensor, with the same results, no change with the engine off, but it changes with TPS while the engine is on.
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Spunkster
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Posts: 22737
Joined: Fri Sep 20, 2002 5:06 pm
Location: Hondata

Re: Weird MAP sensor issue

Post by Spunkster »

I would recommend that you try this ECU on a known working vehicle without ITBs and use a normal calibration and see if it runs as it should. If it does, then it sounds like a setup/tuning related issue.
coupe-r
Posts: 11
Joined: Wed Mar 04, 2015 8:41 pm

Re: Weird MAP sensor issue

Post by coupe-r »

The values must be measured with the ignition on, but the engine not running.
So I assume you are saying the map pressure changes with throttle position WITHOUT THE ENGINE RUNNING?

There is obviously some TPS/MAP related trikery going on if this is the case.

I'll get Brent to try exactly that (while Datalogging)
It is recommended to use a vacuum accumulator that is connected to every ITB.
Yes it is, however in the previous step we are to input values generated without a running engine. Interesting...
You must then input those values. These values are very important and if they are not set correctly it will not work properly.
Won't won't work properly? Map related trims and parameters such as map based fuel cut? I'm going to assume so unless you can explain further.

This is what I meant by the help file doesn't explain this neither does it explain HOW to set them.

We will try your recommendations of setting with engine off ignition on and datalogging the TPS closed and open values.
sivo535
Posts: 9
Joined: Mon Jul 18, 2022 12:51 am

Re: Weird MAP sensor issue

Post by sivo535 »

If you have the ITB ALPHA-N mode on, the signal from the MAP sensor is ignored. The ECU does not search for it or solve it at all, it relies on the TPS -> MAP conversion table and guesses the values of the MAP data from this table. That's why your MAP values change with the engine off and the ignition on when you press the accelerator. So if you use ITB suction and want to use MAP, you have to cancel ALPHA-N.
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