1993 Jeep Wrangler (YJ)

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(Yea, I know square headlights)




Post the Paint and Reassembly

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  The weather warmed up, and I put 33 miles (for a total of 37) on the Jeep on the road today after installing the side markers.  The Jeep exhaust volume has moderated downward, and the A/F ration is a little better.  At road speed it's bouncing between 14.3 and 15.5, it does bounce more than I expected.  It did developed a miss at speed after it warmed up, but it wasn't predictable or re-creatable or always there.  Also on hard full throttle acceleration, it also misses some above 4,000 RPM before it shifts.  I'm thinking I might have a fuel delivery/pressure issue.  2013-02-04

  Took the Jeep to the Exhaust Shop to get a 2.5" tail pipe made and installed.  I'll need to trim the rear off so it doesn't extend beyond the fuel tank and spring, but they were able to tuck it up high enough.  The bends do add some restriction, and the addition of the tail pipe, along with some run time on the engine/muffler has toned it down so it's not as loud.  I also need to install the tail pipe band clamp once I trim the tail pipe.  I did experience the miss again, after the engine get up to good running temperature.  I watched the A/F ratio, but it bounced both high and low on the miss.  Also the miss was there occasionally at idle, so I'm think perhaps more plugs than fuel.  2013-02-06

  First, it's amazing how much quieter the Jeep is with the tail pipe and the plug gap closed down a little.  It still sounds good, just not as bad a$$ as before.
I pulled the tail pipe out after marking where to trim the exit end.  I then cut and cleaned up the ends and pipe before painting it.  Once dry, the Pipe was re-installed and checked for exit clearances.  As long as nothing gets between the spring and fuel tank it should be relatively safe.
Based on how the Jeep ran yesterday, and that the miss seems to come on after the engine was well warmed up, and the miss was present at any engine load/speed and not consistent, I believe the issue is plugs and not fuel.  So I pulled the plugs.  They were a strong 0.055" gap that I initially set them at, and looked decent.  Plug 3 looks whiter, while plug 5 is darker, but "I" don't see anything that tells me anything.  Based on others knowledge and comments, I decided to close the gap up some, so I re-gaped them to a strong 0.040".  So I start the Jeep up, and the A/F ratio gauge doesn't bounce around nearly like it did before at idle.  So I take it out for a test drive.  Everything seems good, the Jeep sounds quieter, and the A/F ratio gauge doesn't bounce near as bad as it did before, even at engine speed.  Well, once the Engine was well warmed, the miss was back, and again at all engine loads and speeds.  Not consistent like it's a single cylinder, and it's very very bad at had acceleration once it tries to exceed 4,000 RPM.  I watched the A/F ratio gauge and when it misses now it seems to bounce more to the rich side, suggesting (to me) that it's still a plug problem.  The plugs are NGK BKR6E-11 (yes "E", not "3" as written on the cardboard).  The stock plugs would be Champion RC12LC4.  Based on what I've found the NGK's I'm using are one temperature range cooler, which is what was a recommended starting point for my stoker.  So now do I go one more step cooler?  2013-02-07

  Installed the "Jeep" decals and a new set of one level cooler NGK Spark Plugs (BKR7E-11). Still have a miss in the Jeep after going another range colder on the plugs (now 2 cooler than stock in NGK brand). After installing the NGK BKR7E-11 (Gaped at 0.044) I took the Jeep out for a spin. A/F Ratio seems even more stable. However is started missing even before it warmed up. Might have just been new plugs, but nope. A few miles down the road I got on it. Missed at high RPM, at 4,000+ RPM, A/F ratio in 10-11.5 range (rich). Attached is a random plug (#5) I pulled after getting home. Engine was well warmed, and missing, and running at 2,250 RPM when I shut it off and pulled the plug. Now I wonder where I go next? A/F Ratio at High RPM is Rich (10-11.5 range), and in the normal range (14-15) while driving, so Im still not convinced the miss is fuel related.  2013-02-08

  In going back over my notes and research, and I think the plug recommendation I got from the Strocker community is off. They recommended the NGK BKR6E-11, but it's tip did not protrude as much as the stock plugs. In doing some part number cross referencing and deciphering I thought I needed the NGK BPR6ES-11 as it's a Projected Insulator Type plug like the stock Champions. However it wasn't. So I went back with a set of stock Champion RC12LYC Plugs. The miss started again cold, but it cleared up. was it because of just being new plugs? Well no, the miss did eventually come back just as before. I tried the old coil and the miss was still there. I pulled the plugs, again with a hot engine and running 2,250 RPM. the looked OK to me, except for a small imperfection on plug #3's insulator, a defect/crack? It's getting replaced. the fuel pressure gauge test kit was out on load at the Auto Parts store, so I decided to go ahead and install the fuel pump anyway. The pump looked to be the original 1993 Bosch pump, and I found some debris in side the strainer, so it might be having problems. Well, the new "I call generic" pumps the auto parts store had in stock fit like crap, the pump was loose and would surly rattle. So I'm waiting on a new Bosch which I should have tomorrow. I spoke with the machine shop that did my block/head work, and the guys at the parts stores, and they suspect I might have an intermittent air leak. guess as soon as I get the pump back in and re-install the stock plugs, I'll see what I can track down next. 2013-02-09

  Before I go on my rant about Aftermarket Parts Engineers and Bean Counters (My degree is in Engineering so I can rant), I think I might have to concede and say I'm running Lean. Fist I want to know who the (Expletive removed) Engineer was/is and the (Expletive removed) Bean counter who probably forced the Engineers had to make a (Expletive removed) generic fuel pump and sell it as an exact fit that in no way fits the vehicle! Even the Bosch replacement unit (The 3rd one I tried to make fit) fit's kind of crappy! It's in and at least it's snug and fits good enough that it isn't loose in the sending/pump bracket. Not the easiest to install, but it's in and working, quietly. I also changed the fuel filter, but first a warning. If you own a Bone Creeper, and are in a low humidity area, or like me keep the shop humidity low, be very carful of electrostatic electricity. Every time I get on the creeper, and go under a vehicle, as soon as I touch the vehicle, ZAP! I got hit so hard the other day, my finger still hurts. I had to be sure to not let a spark fly while changing the filter, as fuel always runs out of the line and starts evaporating. I re-installed the Champion Plugs, and a new one to replace the defect in #3. Well, after this, it was still raining and wet out, so I backed the Jeep up to the door and opened it enough to vent the exhaust and shop. I started the Jeep and let it idle for a long time, and a few off misses, but all was well. A/F Ration was 14.6-15. After everything was good, I revved it up and held it at 2K, 3.5K and back to 2K RPM a couple of time. On the third time, I got the miss I'd had before. So I held the throttle between 3 & 3,500 and started checking for air leaks or any other issues. None found. Then I saw something, and got worried, the exhaust header was glowing red, and bright. I let off the rpm, let her cool down and shut her off. Oil is still right on the mark, and as clean as brand new oil, no issues seen anywhere. I know with no air flow over the engine, they can sometime glow, but I suspect I must indeed be running lean. The A/F Ration gauge was showing 14.7-15 at these RPM's.  2013-02-10

  I've done some research and learned that the distributor pick up coil (or what ever you want to call it) doesn't affect spark timing, it's used for injector timing.  Indexing the Jeep 4.0 HO Distributor Wrangler Forum- How/Where to adjust the timing?  So I Indexed the Distributor. As you will see in the pictures, the distributor would have been sending the injection pulse just a little late. I opened up the slot on the "ears" and re-installed the distributor properly indexed.  Took the Jeep out for a leisurely drive, no high RPM's or hard accelerations. It did miss some after I started it and drove it out of the shop, but shrugged that off to the computer learning the slightly new curve. And again, after everything got well warmed and up to operating temperature it started missing again. When it did this I pulled off the road to a safe place, and opened the hood. At idle all was fine, revved it up and the miss started.  Held it there for a little bit, and could see the header starting to glow red. So I headed back home.  After this mornings test with the re-indexed distributor, it looks and seems to me that the fuel was still getting into the exhaust manifold and burning there. This to me it was still a spark/timing issue. So since I'd been through everything else except the computer and CPS that is as you see above where I went.  SilverXJ over at Jeep Strokers yesterday suggested:  "after having ruled everything else out that I should check the CPS as a weak signal as the engine revs higher and the sensor gets hotter could be the problem."  Thinking through it, if it's spark timing related, perhaps the new CPS sensor was bad. Could it be getting hot and causing the problem?  So I grabbed the old one and pulled the new one out.  You can see that it looks like the flywheel has rubbed across the face of the new CPS, and a small sliver torn loose. The new one has no slot for adjustment, just a hole, unlike the old one that has a slot.  I just completed a 26 mile trip in the Jeep, and for the first 3/4's of it I just cruised, no hard accelerations or high RPM's. No misses like I had this morning, so I did the 3,500 RPM at 55 MPH for a while and then shifted to 3rd, and unlike before, still no misses. Next I did a couple of hard accelerations, and even at 5,000 RPM and an 80 MPH (it still didn't shift to 3rd until I let up a little), still mo misses. I'll have to adjust the cable a little more to see if it correct the shift issue, if not I'll let the transmission guy address it.  So after the 26 miles and no miss, it looks like, and Lord please let it be, the CPS was indeed was the problem.  The A/F Ratio seems to average out about 14.4/14.5 at cruse and idle. On hard accelerations, it doesn't go as rich as before, and seems to hit 11.0 at 5,000 RPM.  Guess I'll stay on my old factory CPS until it fails. Guess that's what I get for replacing parts that were still good. The 1" body lift sure made it easy to change it though.  I want to thank everyone here who has helped, not just Silver XJ. This is a great community and I've sure learned a lot and I'm sure there is more to learn.  2013-02-11

  Took the Jeep for a couple more test drives today.  So for all is well, the miss has not returned, YEA!  It still amazes me how much pep the Jeep has with the 3.07 gears and 31" tires.  Now to not break an axle too soon.  The shifting seems to be better after a couple of kick down cable adjustments.  It's now shifting just above 4,500 RPM when the pedal is to the metal.  2013-02-12

  Made the trip (hauled the Jeep, didn't drive it) to MO.  The Jeep passed the safety inspection with flying colors, now I'm fully street legal.  The right front wheel that was leaking air, slowly, was also apparently bent.  I now have the good wheel from the spare mounted at that location.  Took the opportunity under a very bright February sun to take a few pictures of my YJ with my brothers CJ7.  The CJ's 35" tires and it's suspension set up sure make my YJ look short.  2013-02-15

  Fabricated a bracket to mount the CB where the radio was mounted in the dash.  I've also mounted the fire extinguisher.  Now other than not having the spare tire mount fabricated and a properly sized spare I should have everything I need for the MIJC Annual Jeep Inspection Event.  2012-02-23

  Started building the Rock Sliders today.  Decided to use a piece of the 2" x 4" x 0.120" steel tubing I had left over from the Power Wagon Stake Bed project, and split it rather than having a piece of steel bent.  Since these are not my permanent Rock Sliders.  Once I swap in some 1 ton axles and build by own Tube Fenders and Rear Fender Flair, I'll need to build new matching Rock Sliders.  Now to get some tubing and finish them off.  2013-03-05

  Finished the fabrication of the tubes for the Rock Rails.  I've got a total of probably 12 hours of design and fab into them.  Now to finish some cleaning and the paint them.  The extend out from the body by 3.25"  2013-03-06

  Got around to finishing cleaning up and painting the Rock Sliders and got them installed as well.  I also checked my fuel pressure, Engine running it's at 32.5psi, under under acceleration it goes up to 40 psi.  2013-03-23

  Decals arrived and now installed.  Still need to finish the on-board-air, but the Jeep is sure fun to drive now that warmer weather is hear.  2013-04-29

  Took the opportunity to do a few candid, OK poser shoots.  The color doesn't photograph well, not enough contrast on body panel changes.  2013-05-01