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Jeep Wrangler YJ
YJ General Discussion
TPS setting
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<blockquote data-quote="deadpool1" data-source="post: 439696" data-attributes="member: 21229"><p>my JK jeep map does this. 2008, so may yours.</p><p>key on and WOT are near the same. (at 0 HG for sure)</p><p>the PCM uses the MAP and IAT and RPM to calculate injection rates. (it does math in the PCM to computer air flow ) and is trimmed by 02 readings.</p><p>keyon is let side. if PCM is 4.5Vdc out then the MAP is 4.0v max.see how that works. ? The map depends on the 5vdc pins actual voltage for DC power.</p><p>a GM map works the same way, linear out put. not log like ECT/IAT. or cars with MAF.</p><p>[ATTACH=full]121930[/ATTACH]</p><p>the power pin is in fact 4.5 to 5.5vdc spec, it is not 5.0vdc unless it is. eacH PCM you try is different for this one pin, power.</p><p>you can not get more out than what comes in, on power pin. so we measure that power pin first. (for sure it being dead)</p><p>no sure why but , jeep fails to post MAP data. in their FSM. (new cars, sure tell you it is dead)but not so much 1990.</p><p>the map sensor can also be tested. (even engine missing!)</p><p>just key on (dmm back probing pin B)</p><p>and vacuum hose removed</p><p>and stuffed on the end of my hand vacuum tool. </p><p>and see 4vdc out, the I hand pump it to 20" and see 1.5v and I see the voltage falls from 4 to 1.5vdc in slow linear way, no drop outs, or odd actions</p><p>the sensor is fully predictable and easy to test,</p><p>only 02 sensors are hard to test for many reasons, (long story, full stop)</p><p>TPS is easy to test too, on car, and back probed with needle probes.</p><p></p><p>learn to test them, replacing them all invites , adding new problems, , like wrong or bad new sensors added, CHAOS ensues.</p></blockquote><p></p>
[QUOTE="deadpool1, post: 439696, member: 21229"] my JK jeep map does this. 2008, so may yours. key on and WOT are near the same. (at 0 HG for sure) the PCM uses the MAP and IAT and RPM to calculate injection rates. (it does math in the PCM to computer air flow ) and is trimmed by 02 readings. keyon is let side. if PCM is 4.5Vdc out then the MAP is 4.0v max.see how that works. ? The map depends on the 5vdc pins actual voltage for DC power. a GM map works the same way, linear out put. not log like ECT/IAT. or cars with MAF. [ATTACH type="full"]121930[/ATTACH] the power pin is in fact 4.5 to 5.5vdc spec, it is not 5.0vdc unless it is. eacH PCM you try is different for this one pin, power. you can not get more out than what comes in, on power pin. so we measure that power pin first. (for sure it being dead) no sure why but , jeep fails to post MAP data. in their FSM. (new cars, sure tell you it is dead)but not so much 1990. the map sensor can also be tested. (even engine missing!) just key on (dmm back probing pin B) and vacuum hose removed and stuffed on the end of my hand vacuum tool. and see 4vdc out, the I hand pump it to 20" and see 1.5v and I see the voltage falls from 4 to 1.5vdc in slow linear way, no drop outs, or odd actions the sensor is fully predictable and easy to test, only 02 sensors are hard to test for many reasons, (long story, full stop) TPS is easy to test too, on car, and back probed with needle probes. learn to test them, replacing them all invites , adding new problems, , like wrong or bad new sensors added, CHAOS ensues. [/QUOTE]
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Jeep Wrangler YJ
YJ General Discussion
TPS setting
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