Odd Renix No Start: Have Fuel/Spark

[gilman711]

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?

[Jeep Driver]

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. 

[Jeep Driver]

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.

[omega_rugal]

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...

[gilman711]

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

[gilman711]

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)

 

[Jeep Driver]

http://www.bteventures.com//mj1988electricalmanual.pdf

 

 

 See page 16

[gilman711]

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. 

[Ωhm]

CPS (Crank Position Sensor) = Engine Speed Sensor.

[gilman711]

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.

[Jeep Driver]

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. 

[gilman711]

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!

[Ωhm]

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.

[cruiser54]

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. 

[Eagle]

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?

[omega_rugal]

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?

[gilman711]

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

[gilman711]

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. 

[gilman711]

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. 

[omega_rugal]

if you have spark, the ECU is reading the CPS properly, is not the CPS...

[gilman711]

I have air, fuel, spark and compression...indexed distributor...I just don't know what else to check...

[omega_rugal]

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!!!!

[gilman711]

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

[Ωhm]

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.

[Pete M]

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.