Many people ask about what spark plugs I recommend in the Jeep 4.0 engine. I prefer the Champion RC9YC. Many people cross this to the Autolite 3923 which I have also used successfully. However Lee of Hesco has this recommendation:
The plug for the 4.2L head that works is the RC12YC @ .037 gap, if you get ping try RC9YC @ .045 gap. The 4.0L head likes the RC9YC @ .040 GAP.
In my daily driver I am currently running the Champion RC9YC with a .045 gap.
I have experimented with things like the Bosh platinum and other expensive plugs. However the standard Champion plugs seems to work the best. The Autolites work almost as well and will do when I can’t get the Champions. Lee says that the Autolite is a hotter plug and can cause pinging.
I often don’t like to eat lunch because I usually have stomach problems in the afternoon. While I enjoy the social aspect of eating lunch the stomach pains and bloated feeling gets in the way of my productivity in the afternoon.
This week I have been experimenting with Market America Isotonix Digestive Enzymes. I just put half a pack in water and drink it with the meal.
Yesterday we had lunch at Burger King and even while we were still at the table I started to feel icky. I remembered my digestive enzymes in my pocket and I mixed the up in my drink cup and slurped them down. By the time I was back at the office I had totally forgotten my stomach pain.
Today, I remembered to take th enzymes before I went to lunch. Now I am back at the office feeling fine and ready to type.
When mixed with water the enzymes have a taste sorta like Gatorade. A little salty and slightly sweet. Not bad at all.
But I really like the way they make me feel. I am sure I will see an overall boost in productivity since I won’t loose an hour or so after lunch thinking about my stomach.
My favorite lift kit for the Jeep Cherokee is part number ZX071866W from JC Whitney. This is a three inch lift that includes an extra leaf for the rear spring pack and a block. It also comes with new front springs.
Click the link below and search for ZX071866W. The price is currently $120 but it varies from time to time.
I have this kit installed on my 88 XJ with 33″ tires. I had to cut the fenders a bit to fit 33’s. Jenny has the same kit on her Jeep with 31″ tires.
It is amazing that this kit comes with new front springs and an extra leaf for the rear andf blocks for the rear for just $120. Most lift springs alone cost more than this.
This past weekend at 100AW I got to spend a little time with Ken Block. Ken won the 100 Acre Wood rally in his Subaru. Here is a cool video of him doing some fun drifting. I love the way he lives his dreams!
Will’s 1991 Jeep Cherokee 4.0 has been running poorly lately. It started dieing at traffic lights. We cleaned the idle air control valve several times. Each time we cleaned it, his Jeep would run fine for a while and them stall again. Naturally it would stall at an inopportune time.
Eventually his Jeep got to where it would run rough all the time. I began pulling plug wires to isolate the bad cylinder. The number one cylinder was dead. It seemed that the injector simply was not firing.
There was good spark, just not firing in the cylinder. Removing the plug wire did not change the engine speed at all.
The plugs were nice and tan but very worn. We replaced them along with the wires to see if it would help. The engine ran smoother but there was still the dead cylinder.
We posted the questions about the Code 27 that the engine computer was showing on a couple of bulletin boards. Both the XJ list and Hesco forums suggested that we test the injector before looking at the ECU.
Code 27 indicates trouble with the injector firing circuit.
The injector tested fine at bout 14 ohms.
As I was showing Will what was involved in swapping out the ECU, we noticed the connector looked strange so I wiggled it around a bit. When Will restarted the Jeep it ran fine.
Later we pulled the connector and sprayed some cleaner on the contacts. So far his Jeep continues to run great with no more stumble.
Hopefully all his troubles were related to this simple bad connection at the ECU.