dave1123

In all my Chevys, the fan shroud was molded in 2 pieces, stapled together on side flanges. I just cut the staples and added sheet metal screws instead. Come to think of it, I cut my 97's in half and added aluminum plates with screws to it. As I was putting it back in, I noticed there was no room for a screwdriver to take them out, so I changed them to hex-head screws so I could use a 1/4" ratchet. Without cutting it in half, you have to slide it over the fan blades and then remove the fan, pulling them out together in order to get to the water pump.

97grand4.0

Yeah I never even contemplated taking the fan out..suppose I could have...might have been the right way to do it..but I just was thinking really, all that just to get at the thermostat? So, the tin snips worked just as well.
Just noticed your photo album. Nice paint job. It is...distinctive.

dave1123

One older gentleman asked me if I was an animal handler at the zoo! Can you believe that? I jokingly called it "snow camo" once, but you know, it sort'a disappears in the snow! People don't see a car coming! I've got a pair of 70-watt amber fog lights on it now and I usually drive with them on if there's snow on the ground.

The zebra stripes were just a brain fart I had once while drunk. The more I thought about it, I figured "why not?" It's vinyl sheeting for die-cut decals for like business logos and lettering. They've been thru 2 winters and are still pretty good. All the cops and my customers know the jeep now. The cops are great! They flag me down on the route sometimes just to BS! They have a "stealth" Dodge Durango and he came up behind me one night when I was sitting bagging some papers, then blasted me with the high beams! I almost soiled my pants! 5 minutes earlier and he would have caught me taking a leak.

This should be a PM. Sorry to clutter up the post.

I trimmed the fan shroud on my ZJ with a dremel and saw blade. That was before I did the water pump. I put a piece of bright yellow electrical tape on it so any mechanic would watch out for the fan. My brother painted the tips of the blades on his truck to look like aircraft propellers. The 4.0 is so long, there's isn't much room for anything on the front.

97grand4.0

So far still have the 4 not ready's. However now that the temp is correct, the overhead monitor now says I get 17.2 stop and go to the store and back for the last 18 miles. Big change from 13.7. I'll take that.

dave1123

You should be getting better mileage now that the PCM is getting good info for the fuel trim.

97grand4.0

I'm hoping that's what it is, and that means the pcm is now in fuel trim mode where it wasn't. If so I might start clearing these monitors. Does the PCM send that info to the overhead display?

dave1123

Ah...No.

97grand4.0

Ah....well....hmm.

dave1123

Your scan tool should though.

97grand4.0

Yeah, Im just wondering out loud how the overhead deal knows the mpg. Scan tool shows short and long term trim, but I'm not schooled enough to know what to look for if its working right. I still havent addressed the front 02 sensor.

dave1123

I just looked at my FSM about the overhead console and it says the console measures fuel usage compared to miles driven. The average mpg is based on mileage since the last trip counter reset. The is no flow measurement, so it must use fuel gauge info and odometer mileage. The funny thing I've found with mine is if I'm sitting idling for a long time and have the "distance to empty" reading on, I can watch the miles disappear one by one pretty quickly! The instant fuel mileage reading takes injector on-time into account, but that will remain at zero without speed or mileage input.

97grand4.0

AS always thanks for that explanation. This morning I unplugged my front sensor and ran it, to check heater voltage and ground, it was ok, but,, I thought it was odd that it didn't set any code, pending or otherwise. Of course I was not yet at operating temp...
I add that the resistance of the front sensor heater was about 6.5ohms

dave1123

The 02 sensor has to reach 600*F before it starts sending data to the PCM. When it's cold, I sit and wait for my newspapers for a long time and turn the engine on once in a while to warm me up. When the air is cold and the engine is still warm, it idles a little rough until the pipes get hot enough for the 02 to come back online.

97grand4.0

IT is fixed today and inspected, got 2 monitors to run. Turns out Jeep and Chrysler trucks use the ...are you ready for this? Battery Temperature Sensor, (aka batt/ambient temp) to find the ambient temp for the EVAP and O2 Heater monitor tests. If that sensor is not between 30F and 90F, it won't be ready. Well, I had disconnected mine to put a resistor in there so I could go around the charging problem inherent with the jeeps pcm, and the 50K resistor had it thinking it was -20 all the time. Oh, it charged fine, 14.2vdc all the time..arguable not fine, but better than the weak charge I had. Anyhow, ..autozone says this:
Enabling Conditions To Run EVAP Leak Detection Test
Cold start: with ambient temperature (obtained from modeling the inlet air temperature sensor on passenger vehicles and the battery temperature sensor on Jeep & Dodge Truck vehicles) between 4 C (40 F) and 32 C (90 F) for 0.040 leaks. Between 4 C (40 F) and 29 C (85 F) for 0.020 leak.

Also, there is an order, the evap monitors has to run before the o2 sensor heater then the 02, then the cat efficiency. If the first one don't go, you go nowhere.

So, patched the bat temp sensor back in this morning and the 2 monitors were ready 4 minutes down the road, was so pleased went right to the tire shop and they stickered it.

Who knows how many shops would have charged hundreds and likely not even solved it. This was one you had to figure out, myself.

97grand4.0

Final Resolution: All 7 monitors ready, 0 not ready. Batt/ambient temp sensor was to blame for all of the 4 that were not ready.

Didn't have to do anything else, the first 2 cleared right away, then drove it. When I checked it today, all had cleared. They go in order; if the first one doesn't run it holds up the rest.