All posts by cruiser54

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.




They are high quality, refurbished and TESTED. You’ll get flow matched injectors with the spec sheet included.

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!!!

Throttle Body to MAP sensor hose fix

The Renix throttle bodies have a strange and failure prone connector on the side where the MAP supply originates and then runs up to the MAP sensor located on the firewall. This hose/pipe assembly is no longer available for purchase.

The real kicker here is how critical this line is in supplying the correct vacuum signal to the MAP, the most relied upon sensor for the ECU to read regarding air/fuel ratio. Any cracks, melted spots, or loose rubber connectors can cause major starting and driveability issues.

There’s a simple fix though. All that’s required is a 1/8” NPT tap, a new throttle body gasket ( Napa FPG 60742 ), a vacuum fitting (Napa 05703-B102), two vacuum elbows (Napa CRB2670), and a length of new plastic piping (Napa CRB2672).


Remove the throttle body and take it to the workbench.

Using an oiled tap along with a driver, carefully thread the lower of the 2 holes of the throttle body where the old fitting was plugged in. Don’t go too deep. These are pipe threads.

Flush the hole with carb cleaner and inspect for any left over cuttings.
This is an excellent time to do a complete throttle body and IAC cleaning.  See Tip 11.
Take the vacuum fitting (05703-B102 ) and apply a LITTLE bit of thread sealer on the threads only. I prefer Permatex #2 but almost anything is fine.

.1-TB to MAP hose-001

Carefully screw the fitting in until snug.

Install one of the vacuum elbows on the MAP sensor so it points toward the throttle body, and the other vacuum elbow on your new throttle body fitting so it points up to the MAP sensor.
Cut a length of the new plastic tubing (approximately 13 inches) to fit between the vacuum elbows and install it making sure there is enough slack for some engine movement. Route it according to the photo. We don’t want any rubbing or chafing with engine movement.  Not a bad idea to use some contact cement or Gasga-Cinch sparingly on the tubing to elbow connectors.

1-TB to MAP hose

Revised 2-06-2016

Adding the Sentinel headlamp feature

I love the Sentinel Headlamp feature. It allows my Jeep to provide me with safe lighting after exiting it at night. We live in a rural area with no street lights. Here how it works.headlamp delay module instructions

I researched an old wiring diagram and found that all that was needed to have this feature was plugging in a relay!! And, the plug is already in our Jeeps. Headlamp delay module wiring diagram

The relay is part number 56000636 or 56009324 and sells for about $50.Headlamp delay moduleHeadlamp delay module connector

Since I part out XJs and MJs, I went through my stash and found I had saved a few without knowing what they were. Think “junkyard” here.Headlamp delay module location

I simply plugged the relay/timer in and instantly had sentinel Headlamps.

Revised 1-31-2016

Renix oil filter to SAE filter

Tired of having a poor selection of oil filters for your Renix Jeep? Limited availabilty a pain for you? 20mm threads? We don’t need mumblemeter threads on our oil filters.

Here’s a simple mod that allows you to use the very popular SAE threaded oil filters which are more readily available. The old standard 3/4″ SAE thread.

You can purchase a new oil filter nipple from the dealer for under $10 and never be bothered again. Part number 53007563AB. It’s the one on the left. 53007563AB 7-8 15-16

Or, grab one off a 91 and later XJ at the junkyard. Be forewarned though. You need a 7/8 wrench to remove a Renix nipple, but a 15/16 wrench for the later style.

And just in case you need to replace your oil filter adapter o-rings, here’s a handy guide.

Oil Filter Adapter O-Ring Sizes
87-90 Renix Model O-rings

0.799 x 0.103 AS568 size -117
1.296 x 0.139 AS568 size -219
2.484 x 0.139 AS568 size –230

Dealer Part Numbers for Renix. Sold individually:

33002970, 33002971, 33002972

Renix kit from Crown Automotive-33002970K

91-01 HO Model Orings

0.676 x 0.070 AS568 size -017
0.859 x 0.139 AS568 size -212
2.484 x 0.139 AS568 size -230



Revised 03-07-2017

Improving the fuel pump ground

The fuel pump and fuel tank sending unit ground at a sheet metal screw up behind the spare tire on an XJ, and behind the driver’s taillamp on an MJ.

Not only is a sheet metal screw a lousy way to ground things, this ground path is long and travels through some connectors that are prone to corrosion and moisture.

Locate the black wire on  the HARNESS side of the fuel pump/sender 3 wire connector. Remove a 6″ length of the split loom covering. Strip back about 1/2″ of insulation from the BLACK wire.1-fuel pump ground MJ

Take your new ground wire, preferably at least 14 gauge and 12 to 18 inches long as needed, strip it about 3/4″, and wrap it around the exposed part of the harness plug wire.1-fuel pump ground mj-002Solder the connection. Tape it up and reinstall the split loom covering.1-fuel pump ground mj-003

At the other end of your new ground wire, add a crimp on eyelet. Attach the eyelet under a bolt that goes directly into the chassis. Be sure to clean the attaching point til shiny and apply OxGard to the contact surfaces.1-fuel pump ground mj-004

Revised 10-16-2018



Improving blower motor performance

On 1984 to 1990 MJs and XJs, the blower motor’s factory grounding point is on the driver side inner fender under the sheet metal screw. This ground is shared with windshield wipers, front windshield washers, rear windshield washers, AC clutch relay, fan control relay, fog lamps, fan motor, headlamps, front turn signals, front side markers, and park lamps.

So your blower motor has its ground point 10 feet away from where it is located!!

What we’re going to do is leave that ground intact and also ground the blower motor on the passenger side inner fender much closer to the blower motor itself. This will also benefit the other components on the factory ground circuit. Take this opportunity to refresh the factory ground as a matter of course. Remove the screw, scrape the surface to bare metal and reinstall the screw securely.

Here’s what I do to get the ground much closer to the blower motor and add another ground point to this overloaded ground circuit.

Find the blower motor connector on the passenger side. Red and Black two wire connector.

Find a location where the black wire can be made to reach the passenger side inner fender, and cut the wire. You may have to do some rerouting of the harness to achieve this.

Take both cut pieces of wire and put them together into a yellow eyelet and crimp. Fasten the eyelet to a place on the passenger side inner fender with a sheet metal screw after applying OxGard to the contact surfaces. Be sure to scrape the attaching point on the fender to bare metal first.

Your blower motor will now turn faster and last longer, and the other electrical components on the circuit will benefit from a better ground path.Blower motor factory ground Blower motor new ground

Revised 01-31-2016