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.