Renix Computer Demon

[my2monkeys]

Check the connector at the firewall for the cps. I've had to unplug and plug back in this connector a few times on a no start.
If your tach isn't moving whilst cranking, cps is suspect. Good luck

Also there was an upgraded wire harness that bypasses the loom and goes cps directly to ECU

 

[CBJeeper]

Check the connector at the firewall for the cps. I've had to unplug and plug back in this connector a few times on a no start.
If your tach isn't moving whilst cranking, cps is suspect. Good luck

Also there was an upgraded wire harness that bypasses the loom and goes cps directly to ECU

Do you have a link to information on the harness change/modification?

 

[Saudade]

Do you have a link to information on the harness change/modification?

I posted this earlier.

No Start, Hard Restart or Engine Die-Out, '87-'88 XJ/MJ TSB

Those of us with Renix may be aware of a TSB that rewired the CPS directly into the ECM (bypass the C101 connector) to improve the signal from the CPS. I was able to find the TSB # but I could not find the actual TSB on TSB Search (www.tsbsearch.com). One of the options presented was to...

naxja.org

You can read the entire TSB from the link inside that post.

However, this TSB doesn't apply to your XJ as your year does not have the C101 connector.

 

[CBJeeper]

I posted this earlier.

No Start, Hard Restart or Engine Die-Out, '87-'88 XJ/MJ TSB

Those of us with Renix may be aware of a TSB that rewired the CPS directly into the ECM (bypass the C101 connector) to improve the signal from the CPS. I was able to find the TSB # but I could not find the actual TSB on TSB Search (www.tsbsearch.com). One of the options presented was to...

naxja.org

You can read the entire TSB from the link inside that post.

However, this TSB doesn't apply to your XJ as your year does not have the C101 connector.

Got it. Thank you.

 

[Saudade]

The manual says this to test the CPS

"Speed Sensor (Crankshaft Position Sensor-CPS) Test

Disconnect the speed sensor connector from the harness. Place an ohmmeter across terminals A and B (marked on connector). The meter reading should be 200±75 ohms (hot engine). Replace sensor if readings are not to specifications".