Category Archives: The history of the 4.0

A GREAT TOOL for Renix owners!

Thanks Nick, for developing the REM. Renix Engine Monitor

Our trusty old Renix systems will carry on even longer now. For the price of one or two sensors that didn’t need replacing, this tool pays for itself. See it here:

I’ve had the factory DRB tool for years, but Nick’s REM is actually easier to use and has a long lead on it so monitoring can be done from the driver’s seat. Factory one couldn’t do that.

I appreciate Nick’s ongoing contributions to the Renix Jeep community. Keep up the good work.


Best injectors for Renix

The original Renix injectors made by Siemens-Deka were only “one holers”. That means the fuel was discharged through only one hole.

Not the most efficient design by today’s standards. Modern injectors have at least 4 spray holes for better fuel atomization.

Another issue is the original injectors were prone to leaking fuel at a seam and spraying gas all over hot manifolds. Not good!!

A nice upgrade is to use Volvo injectors. The use of these injectors was pioneered by Programbo from Cherokee Forum when he suggested them to DFlintstone there.  Flintstone was the guinea pig and reported excellent results. I have experienced the same results as have many others. The 746s, as they’re called, have the 4 hole design  and the complete Bosch part number is 0 280 155 746. Volvo injectors

These injectors can be purchased refurbished for not much money and are a direct bolt-in.



You will experience smoother idle and better throttle response. Perhaps some MPG improvement also.


Even though the indicator lights up in your Power/Comfort switch, that does not mean the switch is working and putting the Transmission Control Unit into Power mode.

The switches had a high failure rate.

Remove and unplug the switch. In the harness are 3 wires.  One has a stripe, one is tan, and the other wire is black.

Make a 4″ jumper wire with a male spade at each end.Jumper wire

Plug one end of the jumper wire in the cavity for the tan wire and the other in the cavity for the striped wire of the harness and you’ll be in permanent Power mode.

Stuff the harness back in and reinstall the switch for looks if you want.

Make sure the 7.5 amp “Trans” fuse in the fusebox is good.

If you happen to have a 91 or 92 XJ/MJ and it has the Power/Comfort switch, just jumper the Tan and Blue wires in the harness plug.

NEVER include the black wire when jumpering!!!