cruiser54

I agree.^^

kurama49

ok, sorry for not replying right away again. school stuff and internet was down. So the cap and rotor are new, I took the cap off and looked inside, not one spec of grease, dirt or anything. everything was nice shiney silver. And plus my jeep doesent have a cat, its 2.5" pipe from the manifold back to a flowmaster 40, and then out the back.

So, a friend gave me some mustang 5.0L injectors which I read on here you can use to give a bit more "prep" to the renix. So i swapped them in just to try them, and to rule out the injectors being bad, since these ones looked brand new. and he assured me they were clean, so I got some new O-rings, and installed the new injectors.. annd... it still sputtered. So only thing left i could think of, was the fuel pump. so i did a psi test at school, and it came back to 18psi, so I replaced the pump with a brand new Bosch one. i didnt have a psi tester at home, but after the install i took it for a drive, but the sputter is STILL there.. though not as violent... and like i said, when its cold it doesent really do it, its only when it starts getting warmer.

I also had a embarassing moment at the gas station when I went to top it up, it seems the rubber seal they gave me for the sending unit didnt exactly.. seal.. because I lost about $30 worth of gas onto the ground..

So I'll be addressing that after school tomrrow, yay for having to get the bus again.

But on the bright side i did manage to get my rims changed in school when i had it over there, since one of my steelies was bent really bad.. so thats a good thing i guess?



[I love having a offroad area in my backyard lol]

je4reyk

Have you done a compression test ?

kurama49

Yes the shop did it when i thought the head-gasket went. Each cyl came back 130-135psi they told me it was good for how old it was.

kurama49

Hm, a friend suggested to me that the timing chain could have jumped a tooth? And it would cause this high idle and sputtering? Could that be it? Because i dont think the timing chain has been changed since the jeep was new... Just throwing it out there as a thought. I also got my fuel pump problem fixed. All it was was the seal had popped into the tank from my rushing.

cruiser54

LAST place I would look based on many years of experience with the 4.0.

kurama49

ok, so well I dunno where else to look... I've allready replaced and checked everything i can think of
So far I've replaced the:
Fuel pump,
fuel filter
injectors
Cap
rotor
plugs
wires
coil
cps
tps
iac
I've redone all the grounds, and cleaned every electrical connection i can find
All the battery cables are new
Battery is a nice new optima red-top
throttle body has been cleaned
tps is adjusted right
Compression is ok
Spark is good
there is no cat on it to be plugged
EGR valve is working
I cant find any vacuum leaks what so ever
And every shop I've gone to doesent know what to tell me and give up on trying to fix it.

So everyone now is just saying "change the engine" But i the engine isnt really doing anything to warrant replacing it. It doesent smoke, it doesent tick or knock, and it makes really good oil psi.

And ontop of that, everyone who doesent say change the engine says "Oh convert it to a carburetor their so much better" and baisically I'm just...


So What do I do now?... I miss having my jeep the way it was, and i miss my 22mpg. Stupid ranger only get 14, and it feels so weird driving it, everythings so touchy and close together,plus it rides like a brick.

kurama49

Well, i might just be getting a complete renix parts truck this weekend, a 1987 Jeep Comanche,5spd, Np231, and I'm told it runs very well. But the body is destroyed, so My question is, is the computer and stuff any different than the cherokee? Because i had my jeep to the jeep dealer today. they looked it over and said only thing they can think of is the computer being messed up.. so

cruiser54

All that stuff is interchangeable.

DFlintstone

I did read through.(sort of). You guys might have missed something around post #46. Not really "missed" but an overlap.

The line from the manifold to the rear ccv orifice, (top rear of the valve cover). Cap or pinch, crimp it and see if that stops high idle. IIRC it's is suppose to have a 2.4mm orifice in the fitting on the VC. If that were just free idle would shoot up.

Misfire? You can check your CPS before your coffee water boils:

CPS
AC voltage CPS test; Small clips on the meter leads really helps.


Unplug the connector at the back of the manifold with wires going down to the bell-housing/cps.
Probe the two wires to the cps with the meter set on AC volts. (a 200 scale on mine).
Crank the engine and note the voltage. (jump it if your battery is low)


Mine somehow works with only .3 my wiring/grounds must be pretty spiffy. .5 seems to be a good mark. One article talked of .5 to .8.


To your system, a vacuum leak might mimic you having your foot in it.
Vacuum leaks suck. I go around with short little shots of starting fluid, if you hit one the sound of the engine will change. Small little shots! You don't want that stuff to accumulate. It's a fire hazard, but It evaporates right away. Also with a tube, or a section of hose you can listen for it. Don't forget the lower O rings on the injectors need to seal as well. (uppers would leak fuel).
The manifold bolts have a habit of loosening, especially that rear one. On anything like that you never want to tighten only one. It can warp/bend, even crack things. If I found that any that where easy to reach where loose, I'd pull the air cleaner and tighten them all, starting in the middle and working out towards the ends. I go over about three times. It's a bear of a spot to get a torque wrench on them all. Just don't ape on it. If its firm and not turning, no point in going on to break it, a REAL *****. The rearmost bolt underneath takes a little doing, but it can be done with the right extension. For that very back one by the firewall I use way long extensions (18"), with a swivel at the socket. Anyway, that's a good thing to check on any old Jeep. ALSO, there is a large line coming off the intake, rear of the TB that goes back to the firewall, across, then forward down to the vacuum ball behind your right front bumper. You can pinch that off or unplug it and cap the nipple to test if you have a leak there.

kurama49

Well, I fixed my vacuum line that goes to the rear of the valve cover, its siliconed down so it doesent just float there now [still didnt fix any of the problems]

My cps, intake manifold bolts, and vacuum line from the TB to vacuum ball all check out ok..

I actually took it to the jeep dealer and had their head tech take a peek at it and told him everything I've replaced and he told me to change the computer, which was the only other thing he could think of.

No word on that comanche yet... but i had a guy call me about a cherokee like mine.. and guess who it was.. the previous owner

Almost EVERY WEEK he calls me, wanting to buy the jeep back. and even after i tell him no , no , no NO. HE STILL CALLS.


.... and no I'm not selling it to him even though I'm thoroughly angry with it right now.

tbrunke

Did you ever get your Jeep fixed? I am having similar problems and just replaced my CPS today and hopefully that solves my problem. I would suggest checking the timing and also listening for a noisy timing chain or seeing if it has jumped a tooth. Good luck!

cruiser54

Eliminate the C101 yet? Post 27
Index the dizzy? Post 13
Sensor ground test? Post 5

briankk

I went through most of the stuff mentioned in this thread with my '87 Laredo. In the long run, the fix was to replace the brake booster. Very simple test. (1) Start engine, establish high idle. (2) Open hood. (3) With vicegrips, squeeze shut the vacuum booster hose from the intake manifold to the booster. In my case, the high (and intermittent) instantly dropped to 800-850 rpm. Either spraying also revealed a couple of very small leaks at the base of fuel injectors #2 and #6...

Umm.. but the engine does have to run to do this ;-)

FWIW