flint54

Sta-bil, check. Battery disconnect, check. Tires off the ground, probably not. Plugging the tailpipe I hadn't considered, but it makes sense and is simple to do. Thanks!

Pressure vs. flow rate? Possibly a weak pump that can make pressure, for a while, but can no longer sustain a reliable flow over time. IIRC, s/b 1 quart/minute or better.

The MJ is going to be parked for six months. It will be in the shade, fully covered. Planning to add a fuel stabilizer and disconnect the battery (there is no nearby power). Anyone have any other suggestions or opinions?

Had to set this aside for a while, but back on it now. The MAP sensor voltage output is 4.83v, way too high. I suppose it is possible for both the original and the replacement sensor to be failed, but seems unlikely. I'll check the line continuity tomorrow, but doubt that would explain the high output voltage. The vacuum is good, right at the sensor. I'm seeing A/F around 8 until warm, then 12-14 except when thottle is closed then it goes full lean (18).

Yes, the MAP sensor on the firewall. Vacuum supplied via hard plastic tube directly from the manifold, connected with two very short rubber hoses. These are all new. There is nothing else tied into that line. MAP sensor input voltage, referenced to the MAP sensor ground pin, (and measured with plug connected through the wire jacket) is 4.95V, very close to what it should be. Also, the ECU connector was recently (last fall back) pulled, cleaned, and pins checked.

And I don't know why this posted three times???

Just when I thought things were running too good to be true. Started running like crap the other day, with A/F ratio wild swings. Fault codes listed: 12, 13, 14, 13, 55. (Not sure why 13 shows twice). All this started right after I replaced my old tired battery, Checked manifold vacuum, it's solid 20 with thottle-induced swings as should be. Installed new MAP sensor. No joy. Motor sputters and fouls out when A/F is overly rich (as one would expect) and and stalls out, with high RPM cutout, when overly lean (as one would expect). And once in a while it runs fine. My O2 sensor was replaced just a few months ago, the A/F meter runs off a separate sensor. Suggestions?

My build sheet was found beneath the carpet on the passenger side. My truck also has a stamped metal dataplate riveted to the crossmember directly beneath the radiator.

Yes, I have an extra one, if you would like it email me your shipping info to: flint54@cfl.rr.com

I think I have an extra, let me check my box of parts tomorrow. Did you stick with the stock shift linkage?

I am delighted (!!!) to learn there are still high school auto shops! The second gear image looks like it might show some damage to the pinion gear, but hard to be certain. My vote is for the 3.55 swap, and perch re-weld if it comes from a Cherokee. Good learning about driveline angles. New perches are cheap, and I paid someone to weld mine when I swapped in an XJ Chrysler 8.25. About $60 total as I recall. Do you have a budget for this project? As you go along, please make a list of parts you need (in addition to the axle), as many of us have spares stashed away. Lastly, I like your "flintstone" brakes! <G> And welcome!

Sorry, I switched threads and forgot to follow up on this thread. Exgrayxj said it, the HB was the culprit, and thankfully I did not pester the good folks at Hesco before I had all the facts. My suspicion was flat wrong, as I've learned countless times when chasing noises. This one fooled me too easily. But, I do not agree that WP replacement is routine maintenance, even if it's an easy job. I expect them to last a very long time unless run dry. Tires, batteries, bulbs, filters, fluids, and plugs are the things I don't mind changing regularly. The other failures are an irritation, proportional to the cost and effort.

Just one opinion, I suggest that springing for an aftermarket header hoping for a performance boost may not be cost effective. Unless you are doing so with some other things to improve overall flow rate (like larger diameter system, like port matching between head and header, like flow improvements to the head), the gain could be very small and mostly at high rpm. Unless you're going to really open the checkbook to buy some more performance, I would just swap in another OEM unit (but I have zero welding skill).

...and the girl at the tag office "required" me to tell her what "MJ" meant when I ordered the plate, so I told her it meant "maroon jeep"..

With this personalized specialty tag, about $80 annual: