Forums
New posts
Search forums
Image search
Shop
Amazon Store
T-Shirts
Stickers
Members
Current visitors
Supporting Member Upgrade
Sponsors
About
Log in
Register
Search
Search titles only
By:
Search titles only
By:
New posts
Search forums
Image search
Search
Search titles only
By:
Search titles only
By:
Menu
Install the app
Install
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Forums
Jeep Wrangler YJ
YJ General Discussion
Non starting after new thermostat and heater core flush
Reply to thread
Message
<blockquote data-quote="deadpool1" data-source="post: 441170" data-attributes="member: 21229"><p>the truth is , this whole thing fails here, the big gold HV pin is dead, cranking</p><p>and so hard to test, in place like this. for sure the socket 2 B pin is ECU trigger signal.</p><p></p><p>the FSM book (unlike all modern cars) fails to show the wiring equivalences.</p><p>To prove the ICM is bad. below the coil. is not easy. in this form.</p><p>The S2 B pin is the trigger pin if it is failing to pulse the ECU is not happy (CPS dead)</p><p>If S2 B pin pulsed 0 to 5v and 0v over and over the ECU is happy. and the ICM is bad.</p><p>the trouble is not having a scope (lab) to see the dead trigger.</p><p>a LED test lamp works on the trigger. pin. S2 B. it will flash fast cranked.</p><p>even a 10 millisecond flash the human I can see and detect. 0.010 seconds fast, as fast as a human can blink their eye.</p><p>as you can see doing this 1 test, cuts the cause and work in half. if the trigger is good. the ICM is bad.</p><p>see that?</p><p>if bad trigger, S2 B then the ECU is failing, (not saying any ECU is bad) I am saying if the trigger is bad (dead)</p><p>the ECU has bad CPS (CKP modern name)</p><p>or ECU has a power pin dead</p><p>or the ECU as bad ground to it</p><p>The ECU has cranking (start ,named) pin that if broken the ECU may not produce the spark trigger.</p><p>a loose ground can cause this. a loose bolt for ground. or more complex.</p><p>the ECU needs all things I marked with red line. if not the ECU will not work and create the above trigger</p><p>what is this crank case cover? the ? what transmission is there?</p><p></p><p><a href="https://oljeep.com/89FSM/89Jeep_FullServiceManual.pdf" target="_blank">https://oljeep.com/89FSM/89Jeep_FullServiceManual.pdf</a></p><p></p><p>here is the free manual get it and keep it</p><p>there is no way to fix any car this old lacking a real FSM </p><p>8w-94 is wiring YJ</p><p>code 80 and code 81 only means wrangler all other codes are useless for this car, has like 4 engines, so only 2.5page are correct.</p><p>page 8w-1 shows the code rules, on this page.</p><p>with this you can find why the ICM fails or the trigger fails and is ECU bad inputs , mostly</p><p>the ECU is a computer and if inputs are wrong so will be outputs ,related to spark only.</p><p>power, grounds CPS1 ,CPS2 pins,, starter signal.</p><p>per photo 2 below.</p><p></p><p></p><p></p><p></p><p></p><p></p><p></p><p></p><p>[ATTACH=full]122514[/ATTACH]</p><p></p><p>[ATTACH=full]122515[/ATTACH]</p></blockquote><p></p>
[QUOTE="deadpool1, post: 441170, member: 21229"] the truth is , this whole thing fails here, the big gold HV pin is dead, cranking and so hard to test, in place like this. for sure the socket 2 B pin is ECU trigger signal. the FSM book (unlike all modern cars) fails to show the wiring equivalences. To prove the ICM is bad. below the coil. is not easy. in this form. The S2 B pin is the trigger pin if it is failing to pulse the ECU is not happy (CPS dead) If S2 B pin pulsed 0 to 5v and 0v over and over the ECU is happy. and the ICM is bad. the trouble is not having a scope (lab) to see the dead trigger. a LED test lamp works on the trigger. pin. S2 B. it will flash fast cranked. even a 10 millisecond flash the human I can see and detect. 0.010 seconds fast, as fast as a human can blink their eye. as you can see doing this 1 test, cuts the cause and work in half. if the trigger is good. the ICM is bad. see that? if bad trigger, S2 B then the ECU is failing, (not saying any ECU is bad) I am saying if the trigger is bad (dead) the ECU has bad CPS (CKP modern name) or ECU has a power pin dead or the ECU as bad ground to it The ECU has cranking (start ,named) pin that if broken the ECU may not produce the spark trigger. a loose ground can cause this. a loose bolt for ground. or more complex. the ECU needs all things I marked with red line. if not the ECU will not work and create the above trigger what is this crank case cover? the ? what transmission is there? [URL]https://oljeep.com/89FSM/89Jeep_FullServiceManual.pdf[/URL] here is the free manual get it and keep it there is no way to fix any car this old lacking a real FSM 8w-94 is wiring YJ code 80 and code 81 only means wrangler all other codes are useless for this car, has like 4 engines, so only 2.5page are correct. page 8w-1 shows the code rules, on this page. with this you can find why the ICM fails or the trigger fails and is ECU bad inputs , mostly the ECU is a computer and if inputs are wrong so will be outputs ,related to spark only. power, grounds CPS1 ,CPS2 pins,, starter signal. per photo 2 below. [ATTACH type="full" alt="icm-coil.jpg"]122514[/ATTACH] [ATTACH=full]122515[/ATTACH] [/QUOTE]
Verification
Post reply
Forums
Jeep Wrangler YJ
YJ General Discussion
Non starting after new thermostat and heater core flush
Top
Bottom