Barometric pressure sensor Strategy input
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From: Quesnel, BC, Canada
Barometric pressure sensor Strategy input
taken from baz's site:
since I live way up in world, haha, Im sure mine doesnt read 4.6v. Like all the other little tricky mods, would there be a way to amplify the voltage to maintain a 4.6v signal?
Ive been reading baz's site again...and these kind of things pop into mind while Im reading through the 'glossary'.
BARO: Barometric pressure sensor Strategy input; PCM uses this to adjust fuel quantity and injection timing for optimum running and minimum smoke, also glow plug on time to aid starting at higher altitudes; 5 volts in, @4.6 volts/14.7 psi at sea level, decreasing as altitude increases. PID: BARO (pressure)
Ive been reading baz's site again...and these kind of things pop into mind while Im reading through the 'glossary'.
Post Fiend
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From: MICHIGAN
I don't see the advantage you may get from tricking the PCM with a high/low BARO reading. The BARO actually increases your GP on-time with an increase in altitude.
However there is some advantage in the Timing Control. The BARO signal is used to determine altitude to adjust timing and fuel quantity to optimize engine operation and control smoke throughout all altitude conditions.
So if you sent a Higher/lower signal to the PCM you may get more fuel and timing but you would throw codes (P0107, 0108) and the PCM would use the MAP sensor instead. The MAP sensor is somewhat of a BARO it self. It register pressure and sends a signal to the PCM. If the difference you trick the PCM is too much from what the MAP senses the PCM ignores the BARO and uses the MAP.
0107 = BARO sensor circuit low input
0108 = BARO sensor circuit high input
Good thinking though, that's the kind of stuff that creates MODS
Maybe someone can come up with a way to stop the CEL's and make the PCM ignore the cross-check between the 2 sensors.
However there is some advantage in the Timing Control. The BARO signal is used to determine altitude to adjust timing and fuel quantity to optimize engine operation and control smoke throughout all altitude conditions.
So if you sent a Higher/lower signal to the PCM you may get more fuel and timing but you would throw codes (P0107, 0108) and the PCM would use the MAP sensor instead. The MAP sensor is somewhat of a BARO it self. It register pressure and sends a signal to the PCM. If the difference you trick the PCM is too much from what the MAP senses the PCM ignores the BARO and uses the MAP.
0107 = BARO sensor circuit low input
0108 = BARO sensor circuit high input
Good thinking though, that's the kind of stuff that creates MODS
Maybe someone can come up with a way to stop the CEL's and make the PCM ignore the cross-check between the 2 sensors.
Last edited by Cuda_jim; Oct 25, 2006 at 07:32 PM.
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MAP: Manifold Absolute Pressure sensor Strategy and feedback input; The PCM monitors manifold pressure to control fuel delivery in order to minimize smoke. It also optimizes injection timing for detected boost. It also monitor boost to limit fuel delivery to control maximum turbo boost. Frequency output; 111Hz=14.7psi, 130Hz=20psi, 167Hz=30psi. PID: MAP (pressure basline 14.7psi), MAP HZ (frequency), MGP Manifold Gauge Pressure (pressure base line 0psi) turbo boost
The only reason I think of that is when I had the bronco map in my truck it worked real nice off idle to about 1250rpm, but once the rpm and load increased it just wasnt supplying enough fuel so I took it out.
The timing could be solved by the EOT mod tho, whatever advance you loose with the MAP you could get back by advancing base timing by telling the PCM the engine oil is cooler than it is.
just how do you amplify the MAP signal and stop it from sending too high of one that tricks the computer into thinking youve exceeded 25psi ya know? Maybe if there were a way to get it to read 24psi when it was at 15-20, and then get one of those things you stick in the line that doesnt let more than Xpsi to the MAP sensor...having it set for where you reach max allowable boost. This keeps getting harder to explain...maybe one of you will pick up what Im getting at lol.
/theory
Last edited by pud; Oct 25, 2006 at 08:44 PM.
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http://www.kemparts.com/TechTalk/tt11.asp
http://www.asashop.org/autoinc/feb97/techtotech.htm
the secon link has a couple good points in it, like this one
thought someone else might want to read those. Theres a wiring diagram in the top link at the bottom of the page, and explains how to test it.
http://www.asashop.org/autoinc/feb97/techtotech.htm
the secon link has a couple good points in it, like this one
So, why does the MAP sensor drift and where does it drift to? It drifts because the diaphragm relaxes with time. This results in a lower voltage reading, which translates into a lower BARO reading, which translates into less fuel delivered, causing a chronic lean condition if the fuel delivery drops out of the O2 sensor's command window. It is also possible for the sensor to drift up or down if the circuit has more resistance in the ground or power and signal lines.
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I wonder if that applies to our trucks? The one in the link is for gassers. It's a comination of MAP & Baro in one housing. Our diesels use 2 seperate sensors. The Baro is under the dash, MAP is on the firewall.
Our MAP sensors read pressure. The gassers read vacuum.
Our MAP sensors read pressure. The gassers read vacuum.
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There are 3 different types. 1,2 and 3 bar. 1 is to 0psi, 2 is to 14.5psi, and 3 is to 29psi....or so I read. The ones in our trucks would be 3 bar then. I think the barometer sensor part of the MAP is to establish a baseline.
I was more intrigued by the quote I posted up.
I was more intrigued by the quote I posted up.
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