Can a MAP sensor output be split?
Thread Starter
Instructor
Joined: Mar 2002
Posts: 176
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From: Brentwood Essex
Can a MAP sensor output be split?
I have a 3-bar MAP sensor fitted and connected to my FAST. My boost is currently maxing out at 12 lbs, so I only need a two-bar. I didn't think this matterred until I discovered that a MAP sensor has a fixed voltage range, so using it to measure 3 bar instead of 2 gives less signal resolution. It also means there the top third of my fuel map in the FAST is a waste of time, as the engine will never go there!
OK - I also have a 2-bar sensor which drives the water injection. Can I simply split the signal from this and connect it to the fast as well, or will the altered impedance mess up the signal.
I'm betting one of you guys will know the answer to this one....if not, I'll just have to buy another 2-bar sensor!
Thanks,Steve
OK - I also have a 2-bar sensor which drives the water injection. Can I simply split the signal from this and connect it to the fast as well, or will the altered impedance mess up the signal.
I'm betting one of you guys will know the answer to this one....if not, I'll just have to buy another 2-bar sensor!
Thanks,Steve
Burning Brakes
Joined: Oct 2002
Posts: 835
Likes: 3
From: Water Winter Wonderland
Re: Can a MAP sensor output be split? (steveelsbury)
Don't know about your app, but when I used to run a Haltech E6GM and factory computer at the same time, I could "split" the outpout from the MAP no problem. Neither computer objected or read incorrectly.
Good luck,
-Bill
:cheers:
Good luck,
-Bill
:cheers:
Safety Car
Joined: Dec 1999
Posts: 4,691
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From: Framingham MA
Re: Can a MAP sensor output be split? (steveelsbury)
The signal can be split to your ECM. The only problem you would have splitting a MAP signal is if the split loaded down the circuit too much, but this isn't the case with an ECM input.
Drifting
Joined: Jul 2001
Posts: 1,897
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From: La Fontaine Indiana
Re: Can a MAP sensor output be split? (dgoodhue)
Well I have the same problem. I was thinking about installing two map sensors also but was going to run the output from the map sensor to the ecm through a relay use either the ecm or a rpm switch to trigger the relay.
With the relay in one position the ecm will read from the 2 bar when the relay is in the other position the ecm will read the 3 bar. I think for me a rpm switch would work because if I turn enough rpm to exceed 15 lbs. of boost I"m at wot anyway. If you are not at wot then no need to turn rpms that high so about all the three bar would control would be wot at high rpm.
:banghead:
With the relay in one position the ecm will read from the 2 bar when the relay is in the other position the ecm will read the 3 bar. I think for me a rpm switch would work because if I turn enough rpm to exceed 15 lbs. of boost I"m at wot anyway. If you are not at wot then no need to turn rpms that high so about all the three bar would control would be wot at high rpm.
:banghead:
Le Mans Master
Joined: Jan 2003
Posts: 8,596
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From: Portland Oregon
Re: Can a MAP sensor output be split? (steveelsbury)
Yes, you can split or should I say "share" the MAP sensor output to both devices. The main thing to do is to make sure that the grounds for both systems are at the same potential. Easily done by connecting the ground for both systems at the same point.
