Tried to find previous post on this topic not to bore anyone but being old & crusty couldn't find the specific.....After the winter hibernation (Nov2022) went to start my Cherokee for the summer....Long crank figured pump had to prime....no start, poked valve on rail, spewed gas....Got the spark tester on a spark plug...did not see a spark....Now I'm thinking CPS ??? Anyway to check it from under the hood? - also anything else I should look for? ......Any help greatly appreciated.......

 

For all things Renix, start here:

https://cruiser54.com/

 

Wow....I have read the post & comments regarding CPS on cruisers 54 site & I'm confused more now than ever....I just can't imagine how many failed NEW CPS regardless whether they came from NAPA, Auto Zone or China....I am also confused about comments with regards to fuel pumps....in relation to no spark.....It seems the VAC reading has little impact on the operation of the CPS, as there all over the map, & the mod drill out seems to make sense with regards to getting the CPS closer to the flex plate....In my case I never had a starting issue or performance issue until I parked my Jeep in Nov. 2022 outside with a car cover on it...& tried to start it today 6-7 months later, now I have no spark....I'm leaning more towards connection corrosion, or dampness in the connectors... I'm thinking disconnect, & re freshen connections at the CPS harness & C101 connector & CPU, before launching the "Parts Cannon" .....What would be the proceedure in checking the coil with a multi meter?

 

Good plan. The CPS output can be tested easily.

Rodents didn't get into the Jeep under the car cover, did they?

 

Actually in my case rodents would have been a good thing....at least I would have followed their path of destruction & found the problem to fix it....Is there an actual phograph of the CPS end with the plug? & which terminals to test with the multi meter?

 

Tip #7.

https://cruiser54.com/?p=50

 

Well...Cruiser54 has proven to be correct again...I disconnected & re freshened the CPS plug & it started right up....I will say I found that the pins were perfectly clean as the seal in the connector does a perfect job of keeping the oil & dirt out....Sometimes it just takes a jiggle.....I was able to move the Jeep to a more favorable spot in my driveway to continue the long process of restoration....The next step is a tune up & getting the electric fan to operate...Starting with the relay..There are several along the left inner fender skirt is there a diagram of which one is the fan relay???

 

The fan relay is on the driver side just behind the EGR solenoid.




The others:

 

The electric fan operates under 2 conditions:

1. AC is on (and working).
2. Temp sensor in the radiator turns on the fan to prevent overheating. The sensor (switch) is in the left side (driver's) radiator tank. You can disconnect the sensor and then jump the terminals on the harness side. The fan should turn on. You can also disconnect the fan and apply 12v. The fan should turn on.

There is a diode that prevents back feeding voltage depending on which condition turns the fan on. It a small orange (unless it's faded) block below the fuel pump resistor, next to the airbox. (in yellow below).

 

Saudade....First of all Thank you for your time & efforts...I truly appreciate your attention....Not sure if you recall my original posts of a couple of years back but...In 1988 I ordered this Jeep new, I sold it to a friend in 1991 with about 7000 k miles....He & his wife used it for the next 30 years, It went through 30 NY winters, besides normal wear & tear...It now has 210k miles. The only good thing it got regular maintenance, but the rest is shot....One day it broke down, the fuel pump failed, it got pushed to the side, it was headed to the junkyard & most likely be crushed....I couldn't bear to let this happened so he gave it back to me....I cannot devote much time to it but slowly but surely I'm making some headway...Fortunately I have two 1990 XJ's for parts, both vehicles my son had that were retired, so parts are at hand...I am however buying new OEM what ever I can get & plan to bring it to its formal glory....I also have a restored 88 MJ 4x4, & 91 YJ with a 4.0..... as you know the Renix are a class of their own....So my love for my Jeeps are no a flash in a pan, & will keep them for as long as I'm breathing....By the way the electric fan stopped working for years my 85 yr old friend told me....& it did get hot at times but never blew a head gasket....For now I will replace the sensors, but plan to do the upgrade to the later model cooling system....Again I Thank you for all your help.......

 

No worries. We Renix folks need to stick together!!! I've had mine since 2000, so almost 23 years now.

 

Cooling:,..What does that orange diode do besides prevent back feeding, does it have any impact on preventing the fan to come on? - Today I jumped the fan & its working, I switched out the relay with no results, next is replacing the Temp Sensor in the Radiator.....Great illustrations by the way!!!

 

You can test the fan switch in the radiator when the coolant is hot enough that the fan should come on.