Ed in North Ga.

I don't think that I over tightened the belt, and the pump is a new one from napa not a reman. over my lifetime, owning an 89xj, and now my Mj, I have replaced maybe 8 waterpumps- 3 were bad right out of the box, all were new- not remanufactured. I drove/drive alot- one area I found over the years of visiting different websites, was the failure to flush the system before replacing a pump- allowing crap to eat the seal/bearing in the pump itself. A new happy pump will readily pull every chunk of corrosion out of your radiator and engine....and sometimes I swear that new pump bearing and seal is a magnet for it. too tight of a serpentine belt can kill a pump fairly quickly....followed by the torsion bearing- which squeals like a cat being cut up slowly in a meat grinder, tail first. off center belts will kill a pump, but its fairly visible upon viewing- it should be centered, but I have run one rib off , for exactly the amount of time it took to throw the belt into little chunks. whats really fun, it putting on a new one, and realizing its the wrong rotation...and its getting dark....an cold....and raining.

see, the odd part of all this, is the TPS has very little effect on base idle- it sets it up, but the IAC controls it (renix)- anytime the idle is/was off on either of mine- throttle body clean, IAC clean, bore for IAC clean- THEN reset the TPS, and a quick search for a vac leak- it solved my idle problems every time, without fail. It never was anything else. In my opinion, its ALWAYs related to one of the above, and instead of searching for the single problem, I shotgun`d it. Ive yet to run into one of the high / low idle problems, the 2500/3000 high idle start up- but when I do, I`ll learn that fix.

the "percentage" is from Chiltons manuals- and some haynes. It is a descriptor- merely a way of explaining it and not its actual basis. I`d have to pull the original chilton manual to explain it better- its like the "final result" of the equation, when the answer isnt explained as what it is (example .10) as what it could be (example 10%)- half inch vacuum, 50% of an inch, .50- beer need more beer.

most times it IS the IAC, sometimes its the IAC`s bore- you have to clean both to get the full effect. Then theres the ever present vacuum leak- a TPS thats got a slight dead spot off idle (or several dead spots in most cases) a map sensor thats having a day moment...a fuel leakage through injectors before startup...an 02 sensor throwing an ultralean condition.... start easy, clean the IAC bore and retest-

Ive had real good luck with OSPHO over the years, but like everything else the non-pro can by, its no magic pill- Osphos kinda different- you let it sit, the rust changes over to a gray metal...but you cannot rush it. I just did the deck on my mower, it took 3 days to convert over- Ive found that once converted, and washed with laquer thinner, the rust stays away for about 2 years if painted over with anything- but it never really go`s away. They taught us in tradeschool- its almost always better to cut rust out and replace with metal, then to grind and fill...then pray. Lavaliner, POR15- they all work- between the two, lavaliner for me.

the CPS go`s across that area, and terminates right there- also the renix era oil pressure sensor- or are you further down?

do a fuel pressure test- see what the hold pressure is- leak down test. run the pressure up, let it sit, then test for pressure. seems like the hotter it gets, the longer a renix takes to start- add a little bit of air into the mix, and it gets downright fun. not.

ANY new injector is going to beat a 1990 injector- I went with 5.0 Motorsports injectors- prototypes. I think they are the mustang version/high flow with a fan pintle tip. Made a decent enough difference to notice, more so at high speed than idle. If I had to do it again, I`d just do stock denso`s.

you are hearby nominated "master dashboad electric fixit guru", with all the pride and know how that comes with it. hey, no one ever said it`d be easy- just fun. Because if it isnt fun, its work....an no one likes work. ;) theres a "bypass" hidden somewhere on the back of that board, that once cut- shows the true voltage of the system instead of "downstream" voltage- or "whats left over" volts. I still can't find that write up- Stu over at NAXJA did it...and it vanished.

This is why I like to call it "bench guessing". Behind a computer screen, without the actual vehicle in your hands, your basicly down to getting as much information as possible, and breaking it down to a solution. I may have got it wrong, but what I used led me to my guess. "reinstalled then alternator was charging and reading 14.2 volts with all of the lights on or off. All was good. I finished up some other details and was ready to call it fixed. Later in the day when finished I checked voltage one last time and nothing" to me, what you wrote screams a voltage drain. If the alternator was charging the battery- you shut it off, and came back later, and the battery had no voltage.

Remember, its a balance act. The more air you give it, the more gas it needs- most of us are already running lean. First thing I would grab with one of those is an adjustable MAP sensor and go up on the fuel pressure regulator....and it STILL isnt going to be worth it to me.

swapped BATT and ignition on wire harness to multiswitch/ignition switch on lower column? having the ignition "on" would cause the acc to be "dead" but cause a common drain- maybe eat a battery in a couple of hours/maybe not. It`d still start and run... I guess you could have done the same thing on the ignition box under the hood- it sounds like a common drain off a wire that should be dead with ignition off.... make me feel dumb. :doh:

NAPA carries the entire vac kit on the top- sometimes they sell both together...sometimes front half/rear half. Mopar will sell it as well, and depending on the day, it can be 3 times as much as NAPAS, or half as much... spend wisely, shop for price.

you`ll hear that 800 to 1000 rpm is normal idle- and it is. most all idle problems are traced to the IAC- clean that, if it works, its golden! then...theres a possible vacuum leak that throws everything out the window. 600 to 1000 or so, good- higher/lower bad.

after replacing mine, deformed from heat- I wrapped it. I got a roll of aluminumized tape and wrapped the entine bottom of the clamshell, and removed the cold air/ hot air diverter- keeps the box mighty cool, and hasent deformed yet.

nope- thats common. But I have run into a few that were very quiet and still worked fine. Could be any number of reasons. The one on my 89xj was getting noisey at 250,000 mile so I replaced it (my first tank drop...that laned on me) I still have that pump, it was OEM 89, and still use it every now and then to transfer fluids around the yard. My 89MJ was noisey when I got it- it aint comeing out till it dies. the 86 w/2.5 has a pump inside the tank, or exterior? I forget...

Did you just plug off the vacuum lines? yes and no- I bypassed the xj`s lines with a T fitting- the MJs I used the same fitting, but used RTV inside to block it- no difference either way, but looks completely stock.

all the above, and- used for the wires to go into a camper, also for reference point for pulling on a framerack. Dodge/chrysler ended up popping it and putting in plugs.

From experience and many different websites visited, it depends- about half say its bad and does bad things, half say no problem...and no one can say why- I bypassed my MJs, and the XJ when I had it- both 89s. The XJ actually had a rotted out diaphram, so it was a no brainer to bypass it. It drove much better at full throttle. The MJ was just having problems one day, and it was on the "bypass and recheck" list- it also drives better- neither showed any ill effects- no overheating, no weird idle, ....and no flat spot at full throttle hits! :brows: now- many people have said exactly the opposite- some overheat, have idle problems, ec,ect- I think it really depends on the condition of the internals and age of vehicle- can't hurt to try though.

"when you let off the ignition it will shut off." to me, that says shes running while your holdng the key in the start position. verify the ignition stays "on" after the key is released from the start position- sounds stupid, but if the power is cut once the key is released, its basicly dead. On my 89, that screams lower column ignition switch is out of place, or melted, OR a fuselink has departed and commited suicide.....post 91s are funky, and may have more evil tricks up their exhaust pipe...but this is the gist of it..... verify power to necessary stuff with key in "run" position first- rule it out, THEN get busy. She won't run brain dead. if its got power to everything it should with the key "on", its not electrical- IF its running while starting...and your starter aint gonna be happy long. :brows:

3 things come to mind- leather- replaceable, it can be waterproofed, cut to any shape- leater/vynal "pleather" how about a "universal CV boot"? get a soft one off a weenie car with small axleshaft and use a hoseclamp- or, digging deep here- a house vent cap- their stairstepped, cutable for size- come hard and soft. I replaced one years back with what came in a old honda accord- any sheet of rubber will work as long as its super flexable-

turbo? supercharger!

Ive seen 1 that was two tone- owner swore he ordered it from the factory (probably a lie), and 1 all black...it looked stock...really stock. It looked so stock, it couldnt be stock!

that "tar" could be a good thing...or very bad. If it looked like it was slathered on, was sticky, AND the plastic was not gooey OR brittle, then the previous owner had a neat idea and sealed it up- probably with urethane sealent- but...if the plastic was iffy...gooey...or the least bit brittle...you know the problem. The fluid has been in there awhile, and it loves to weaken plastic- it "can" cause a fire, or the problems you listed simply because of weak contacts. Some of the bone stock XJ/MJs Ive played with and worked on came from the factory with "goo"- but it was visible on the clamshell itself- stock sealent. usually hard as a rock- but with a little brake fluid/clutch juice, it turns to goo...

acually- thats where I`d start, because he already said it leaked..and the connections are loose- why chase obscurity when the problems are easy to find? running throttle up to 60, then coasting with eratic engine response- but evens out with minimal throttle input? TPS w/vac problem- recheck it at idle, + a hair- see if the throttle response wanders- if it wanders AT ALL, do a quicky check of the EGR valve- because if its leaking a hair of vacuum- or stuck- it will do exactly what your seeing- all day long. Too much air into the intake/lean condition. If the EGR chacks out as good- ohms check the TPS- look for the dead spot low on the scale- adjust as needed- reset. verfiy your holding vacuum- check the lines behind the battery box and down at the tank...you know this if your a renix head-its just another fun renix day. if you STILL have problems- time to check the electricals and start bypassing. :D hope the bulkhead connector is not trashed...if the juice is down there, it needs to come apart, and get cleaned....or it will self destruct later.