gilman711 Posted May 5, 2018 Author Share Posted May 5, 2018 This is what my CPS was plugged into initially. The wire comes from the firewall. I'm thinking the picture of above is the actual CPS Connector and this is possibly for something else? Link to comment Share on other sites More sharing options...
Jeep Driver Posted May 5, 2018 Share Posted May 5, 2018 1 hour ago, gilman711 said: Found another random unused connector which is right next to the CPS Connector...or is this the CPS Connector? 2 Wire BLACK WITH WHITE STRIPE WHITE WITH BLACK STRIPE Should be this one, violet with w/tracer and white with tracer. Link to comment Share on other sites More sharing options...
Jeep Driver Posted May 5, 2018 Share Posted May 5, 2018 BTW, you have not mentioned MAP. Might start if not connected but will not idle..........may not even start. You need to check all your wiring against schematic. Link to comment Share on other sites More sharing options...
omega_rugal Posted May 5, 2018 Share Posted May 5, 2018 you get spark so the CPS is good, leave it alone for now puttin gasoline / starter fluid directly in the air intake and "tries" to run... check for compression and see if the valves are actually opening all the way... Link to comment Share on other sites More sharing options...
gilman711 Posted May 5, 2018 Author Share Posted May 5, 2018 6 hours ago, Jeep Driver said: Should be this one, violet with w/tracer and white with tracer. The original one it was plugged into seems to be for CPS as plugged in the other connector and then instantly no spark. Swap it to other and have spark. Connector with RED WITH GREEN STRIPE WHITE WITH BLACK STRIPE Link to comment Share on other sites More sharing options...
gilman711 Posted May 5, 2018 Author Share Posted May 5, 2018 6 hours ago, Jeep Driver said: BTW, you have not mentioned MAP. Might start if not connected but will not idle..........may not even start. You need to check all your wiring against schematic. MAP sensor plugged in and tested according to www.lunghd.com and tested good (I can't test the running voltage obviously though) Link to comment Share on other sites More sharing options...
Jeep Driver Posted May 5, 2018 Share Posted May 5, 2018 http://www.bteventures.com//mj1988electricalmanual.pdf See page 16 Link to comment Share on other sites More sharing options...
gilman711 Posted May 5, 2018 Author Share Posted May 5, 2018 15 minutes ago, Jeep Driver said: http://www.bteventures.com//mj1988electricalmanual.pdf See page 16 Thank you so much for that! I don't see CPS on there though? Are they calling it something else? Side note: I am trying out a new CPS Sensor next week. Link to comment Share on other sites More sharing options...
Ωhm Posted May 5, 2018 Share Posted May 5, 2018 CPS (Crank Position Sensor) = Engine Speed Sensor. Link to comment Share on other sites More sharing options...
gilman711 Posted May 5, 2018 Author Share Posted May 5, 2018 During Re-test of CPS...I'm getting an ohms resistance of 178ohms which is within normal range. When cranking on AC Volts though I'm only getting .35 which is below the .5-.8 range. Link to comment Share on other sites More sharing options...
Jeep Driver Posted May 5, 2018 Share Posted May 5, 2018 2 minutes ago, gilman711 said: During Re-test of CPS...I'm getting an ohms resistance of 178ohms which is within normal range. When cranking on AC Volts though I'm only getting .35 which is below the .5-.8 range. New CPS. Link to comment Share on other sites More sharing options...
gilman711 Posted May 5, 2018 Author Share Posted May 5, 2018 7 minutes ago, Jeep Driver said: New CPS. 3 different tests over course of about a week and each time get different results so yes time for a new CPS. I'll keep everyone updated! Link to comment Share on other sites More sharing options...
Ωhm Posted May 5, 2018 Share Posted May 5, 2018 If you got two wires that go from the CPS to and through the firewall, vehicle has TSB fix for CPS. This fix took CPS wiring directly to the ECU. Drop ECU and visually check CPS wiring at the ECU. Make sure both wires are connected and terminated properly. Easy check before new CPS arrives. Link to comment Share on other sites More sharing options...
cruiser54 Posted May 7, 2018 Share Posted May 7, 2018 On 5/5/2018 at 4:35 PM, Ωhm said: If you got two wires that go from the CPS to and through the firewall, vehicle has TSB fix for CPS. This fix took CPS wiring directly to the ECU. Drop ECU and visually check CPS wiring at the ECU. Make sure both wires are connected and terminated properly. Easy check before new CPS arrives. Yes. And part of the instructions in that TSB was a note to cut the old CPS connector off. Wasn't always done. Link to comment Share on other sites More sharing options...
Eagle Posted May 7, 2018 Share Posted May 7, 2018 On 5/5/2018 at 7:17 PM, gilman711 said: During Re-test of CPS...I'm getting an ohms resistance of 178ohms which is within normal range. When cranking on AC Volts though I'm only getting .35 which is below the .5-.8 range. I'm fairly certain the specified resistance for the CPS is to be measured at normal operating temperature. That always bothered me, because how do you get it to normal operating temperature if the engine won't start and run? Link to comment Share on other sites More sharing options...
omega_rugal Posted May 7, 2018 Share Posted May 7, 2018 2 hours ago, Eagle said: I'm fairly certain the specified resistance for the CPS is to be measured at normal operating temperature. That always bothered me, because how do you get it to normal operating temperature if the engine won't start and run? heat gun? Link to comment Share on other sites More sharing options...
gilman711 Posted May 9, 2018 Author Share Posted May 9, 2018 Well new CPS installed and AC Voltage when cranking still low...fluctuates between .44-.56 which I believe is still too low? I'm still getting spark but will not fire up. I did pull ECU and checked wiring going in from CPS and it's good there. Cleaned and Dielectric Grease done for good measure Link to comment Share on other sites More sharing options...
gilman711 Posted May 9, 2018 Author Share Posted May 9, 2018 I cleaned and drilled out the original CPS Sensor (couldn't return a modified part to store) and can now get anywhere from .5 all the way to 1.5 AC Volts but STILL will not fire. Link to comment Share on other sites More sharing options...
gilman711 Posted May 10, 2018 Author Share Posted May 10, 2018 Any negatives to have the CPS Voltage be 1+ AC Volts? I've adjusted 3 different voltages and tried but no make any difference in attempt to fire. All positions are allowing for spark and no noticeable difference in spark regardless of position/Voltage of CPS. Link to comment Share on other sites More sharing options...
omega_rugal Posted May 10, 2018 Share Posted May 10, 2018 if you have spark, the ECU is reading the CPS properly, is not the CPS... Link to comment Share on other sites More sharing options...
gilman711 Posted May 10, 2018 Author Share Posted May 10, 2018 I have air, fuel, spark and compression...indexed distributor...I just don't know what else to check... Link to comment Share on other sites More sharing options...
omega_rugal Posted May 10, 2018 Share Posted May 10, 2018 1 hour ago, gilman711 said: I have air, fuel, spark and compression...indexed distributor...I just don't know what else to check... are the valves opening? same thing happens when a timing belt breaks, cranks but no start... also remove the dizzy cap and see if it`s turning... if still doesn`t work pour gasoline and set it on fire because it`s cursed, CURSED I TELL YOU!!!! Link to comment Share on other sites More sharing options...
gilman711 Posted May 10, 2018 Author Share Posted May 10, 2018 I know cap is turning by how I'm watching spark. I have not watched it crank with valve cover off but if I have good compression the valves have to be working as I have good pressure out of tailpipe too Link to comment Share on other sites More sharing options...
Ωhm Posted May 10, 2018 Share Posted May 10, 2018 On 5/3/2018 at 7:12 PM, gilman711 said: I have 38psi Fuel Pressure when cranking. Check manifold vacuum using a vacuum gauge. While cranking fuel pressure should drop as manifold vacuum increases. EDIT: With throttle plate closed. Link to comment Share on other sites More sharing options...
Pete M Posted May 10, 2018 Share Posted May 10, 2018 how strong is the spark? my 86 wouldn't fire and it turned out to be a weak spark cause by corrosion on the + feed wire to the coil. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now