Ok guys I have a problem. I have a 1990 cherokee sport with the renix 4.0. Previous owner swapped engines with another 4.0(unkown year). any idea where the stamp is? The flexplate was cracked and so we swapped the flexplate(identical) and now the jeep runs like is out of time. I changed the cps and it changes nothing. Is there a re learning procedure for the new flexplate? Also my scan tool will not communicate with the computer to see if it is throwing codes. HELP!!!!!!!!!!!!!!!!1

 

First off, Renix throws no codes.

Did this engine run with the cracked flexplate?

No learning procedure either.

 

Date code is on right side of block between the 2 and 3 plugs. Should look like this example:

The digits of the code identify:

• 1st Digit—The year (9 = 1999).
• 2nd & 3rd Digits—The month (01 - 12).
• 4th & 5th Digits—The engine type/fuel system/ compression ratio (MX = A 4.0 Liter (242 CID) 8.7:1 compression ratio engine with a multi-point fuel injection system).
• 6th & 7th Digits—The day of engine build (01 - 31).

FOR EXAMPLE: Code * 903MX16 * identifies a 4.0 Liter (242 CID) engine with a multi-point fuel injection system, 8.7:1 compression ratio and built on March 16, 1999.



Scan ports are located in the right side of engine bay on a Renix, covered by yellow caps. Live data only, as mentioned no codes. Snapon mt2500 is the only scanner known to me that works besides Chrysler scanner.

If all you did was change flex plate I would suspect you got a defective flex with the timing rings not properly done. The HO and Renix flex plate timing rings are totally different, you would of noticed that and probably would not run at all.

 

It's the 91 and later flexplate that will not work in your Renix. They could look identical, but it's the gap spacing around the edge that matters there. You need the renix plate, it's ECU and the two wire CPS.

Not knowing the year of the current flexplate sucks. Guessing Cruiser is asking if it ran before because there is a greater chance you got the wrong plate if it did.

If you can see any number on the flexplate with the inspection cover off, that might help.

Checking the gaps and their spacing could be another way to see if you got one from an 87-90.

Did you swap in the flexplate from your original 90 engine?

 

The flexplates were exactly the same gaps and spacing and all

 

MMMM... See what Cruiser thinks. One through 5 in his link, excluding anything about a C-101 connector, I'd bet.

Somebody might have gotten the renix dizy in a tooth off. That's in Cruisers link...... Also>

There is a brittle little tube. It comes out of a rubber plug, low on the engine side of the throttle body. It runs back to the firewall, then up to your MAP sensor sort of high up there near center on the firewall. CRUCIAL!! The MAP will tell the ECU to dump fuel with less/no vacuum. Any crack or blockage and it will be pig-rich. (black smoke, fouled black plugs). You can pull the line off the MAP and feel for vacuum with your finger.

 

Yep. Could be something else that got messed up in the process. Pinch the CPS harness?

 

I think he actually paid for it.

 

Alrighty then.....