holeshot9g

I've got an 87 Cherokee with a 4.0 and a 5spd (230,000 miles) that I bought back in June of 2012. It has an intermittent miss that is driving me bat-s#@t crazy. I have thought several times that I had fixed it only for it to come back again. It started doing it the worst after I changed the RMS and oil pan gasket. Before doing it, I sprayed oven cleaner all under the engine etc and hosed everything down. It was a huge greasy oily mess under there. I sprayed out the oil under the hood on the driver side as well since there was a ton of it there too from the CCV system being clogged and pumping oil out everywhere. After I did all that it idled up really high when I started it to pull it into the garage. After I was done changing the seal and gasket, it idled normally and ran fine, but driving down the road it had a horrible intermittent miss that eventually seemed to be working itself out (something that got wet slowly drying out?) but the miss has never completely gone away. It disappeared for 2 weeks once and I thought it was finally fixed but it came back. I have done all of "cruiser54's" renix jeep refresh tips. I have replaced the TPS, 02 sensor, ignition module (under the coil), cap, rotor, plugs, wires, crank position sensor, and have triple checked all plug in connectors. I recently verified that the distributor was properly aligned and completely disassembled it to clean out some oil that had puddled in the bottom of the housing (also from the CCV system being plugged). It passed emissions with flying colors and starts and runs really good with no issues other than the intermittent miss. The plugs were changed about 4 months ago with Champions and they all still look new. Almost too new looking after 4 months. Running lean maybe? It does it mostly when driving at a steady speed and may do it only once or twice in 20 miles and sometimes it does it every minute or so. It does NOT miss when accelerating or sitting still idling. I don't think its an interruption in spark because the aftermarket tachometer does not glitch when it misses. When it misses it is a very quick slight jerk and sometimes it is a light miss and sometimes it is a hard miss. I have tried every connector under the hood and I can not get it to miss when idling. The fuel pump is noisy sometimes but it misses whether the pump is being noisy or not. The only thing I can think of now that it could be is a sticking injector or a bad ECM since it seems to go away after I've unplugged the battery but it comes back in a day or two. The "up-shift" indicator light seems to have a mind of it's own and apparently thinks my jeep has more than 5 gears since it comes on all the time while in 5th gear. Since the up-shift light is controlled by the ECM and the light is erratic, that's why I was thinking there could be an issue with the ECM or it's just getting bad signals from whatever it is that I haven't found yet. Here's something else that's weird. I did the 4wd actuator cable. The switch in the housing that turns on the green 4wd light has two wires, one hot wire and one ground. I grounded the ground wire to one of the bolts in the actuator cover as per the instructions. A week or so later, after I greased all my tie rod ends and the slip joint in my front drive shaft my 4wd light quit working. Somehow after greasing everything, my entire front axle was then electrically insulated and no longer grounded. I had to run a second ground wire from the cover to the body to get the light to work again. I'm at my wits end. I've worked on cars for over 20 years but this one has gotten the best of me. Surely somebody else here has had the same problem and found the solution. I am fed up with this stupid Jeep and I am dangerously close to taking it out in the desert and tossing a couple of road flares in it and walking away. Or putting it on craigslist. I've put a ton of money into this bastard trying to get rid of this stupid miss and I'll never get out of it what I've put into it. Somebody please help. My Jeep's future is precariously hanging by a thread.

I want to like my Jeep, but it won't let me...

DFlintstone

It's an ECU. Cruiser get's up early in the AM. Bummer! Glad it passed smog though....usually a miss should put HC off the chart. I didn't see you mention you cleaned the IAC...but I assume you did? The C-101 connector? there is a thing Cruiser did on that in my signature. Pete may well ask, are you still running the stock injectors? They are defiantly crap...Idk about a miss, but if you are not going to torch it in the desert better injectors are a good idea, even when it works right.......

Maybe water in the fuel? I might try fuel additive or just a bottle or two of alcohol.......

DFlintstone

I might take a minute to check that new CPS. Soo easy to rule that out. Also, I'm thinking a spark getting away to ground somehow. I might just watch it in the dark just in case I might see it. Nither is supper likely but both tests can be done in a few minutes....

The pump sound changes? Bypass the ballast resistor by the air cleaner, (assuming 87 has one). Check the fuel pressure? That ceramic resistor there on the inner fender is just to quiet the pump some. Bypassing/eliminating it is OK.

cruiser54

Up under the dash in a junction of speedo cables is a speed sensor.

Clean C101?

Ever do the sensor ground test?

Index the dizzy?

holeshot9g

I haven't cleaned the IAC so I'll give that a try. Certainly won't hurt anything. I have cleaned the c101 twice. The second time around I am certain that I got all the gunk out. Yep it still has the stock injectors as far as I know. They have a light green ring around them if that helps. Funny thin is, I filled it up with gas on Friday while enroute to go hunting. It had missed twice on the freeway at 65mph and then twice within a minute at 40 mph. After I filled it up it hasn't missed again since and thats been roughly 70 miles ago. I filled it up with chevron instead of the usual circle K gas. Do you know if the injectors on a 98 cherokee with a v8 will work as long as I change the plug-ins? I have access to a free set of those that I can try, or are those injectors crap too?

holeshot9g

I've cleaned the C101 twice. The second time I'm certain that I got it clean.

Did the sensor ground test and it checked out but that doesn't rule out a bad connection or break in the wires somewhere. I think I'm gonna change the ground connectors where they bolt to the side of the block and solder them all together on one single connector. I have a ground wire from the battery to the radiator support and an additional 4 ga battery cable from the back of the engine to the firewall along with the stock braided ground strap. I also found a junction of black wires in the engine harness when I was doing the brown with white stripe wire fix. I think I should re do the black wire junction too.

I checked the dist. again and I found oil in the housing (CCV & valve cover was stopped up but that was fixed long ago. The wires for the pick up coil were in the oil and were soft and there was some oil on the pick up coil as well. Pulled the dist. and disassembled and cleaned everything really good and put back in. Dist. is indexed properly. (lined up exactly as you described in your dist. write up) Maybe needs a new pick up coil after being covered in oil?

DFlintstone

Ha! Funny I just caught you..just turned it on..No, I don't think you want those. The renix uses 18.6 lbs/hr and a different pressure as well. I'm using 703's but I think I run a bit rich until it warms up and goes to closed loop, and takes longer to warm up running rich! Maybe more of an issue for me as my first 10 minutes is always steep down-hill. Anyway the newer have 4 holes for better atomization of the fuel. You could check with vendors here, Programbo being one.

I'm thinking the 19# Ford yellows is what I'd like to find. I guess they ran them in allot of Mustangs. I had no luck a couple times looking for them. I gotta run now but somewhere I have some #'s for those.

I need to clean my IAC as well, sometimes I have high idle. I sort of doubt it's your miss but something to rule out, and yea...I have found plenty of water in gas here for my generators and other small engines. I've been using Shell now, my local Chevron has a problem with their tank's I think.

A side note. I asked the owner, what was that stuff in the gas. (it burns and kills dandelions). With his arms folded, laening back on his heels he replied "there is nothing in the gas". Now I have saved about three gallons of "nothing", and noticed they now have rubber mats over the lids of their underground thanks! (I guess the ethanol absorbes water, then separates? No fun pulling that cord on the genny in the middle of the night!)

holeshot9g

I had put a new CPS on it before because the wires on the old one were hard and oil soaked. The new one from Oreilley auto parts made it take longer to start so I got one from NAPA. Now it starts up in 3 seconds or less.

I don't think mine has a balast resister on it. I can't find it if it does. The only thing on that side is the air box, the relay and vacuum switch for the EGR and an OOGAH horn. LOL

cruiser54

I'm thinking water in the gas also. Throw a coupla bottles of Isopropyl alcohol in teh tank. Get it at the supermarket or drug store.

cruiser54

Ballast resistor should look like this. Your 87 might not have one.

holeshot9g

Is it better to use the 703 or the #19, or is OEM replacement from NAPA okay? Would I need to change the fuel pressure regulator with the 703s or the #19s?

I have never had a high idle except for once, after driving a long distance at medium slow speed over really rough rocky dirt roads for over an hour. I turned it off and waited a minute or two and all was fine when I started it back up.

cruiser54

Contact Programbo on this forum. He'll fix you up with the right injectors for a decent proce.

DFlintstone

Idk what Napa has. I want 19#, 4 hole injectors in any case. I don't plan on changing my FPR.

Since I average out around 14, "knocking around" with my 703's, (with at least some highway) it must be really sucking just knocking around. I DO get 18 or better on highway trips when the 02 sensor is trimming the mix. (closed loop). "shoot low, theyre riden Shetlans" is not an injector selection strategy. I'm aiming for the correct match this time myself. Google or Ebay 19# Ford Yellows. Heck, if three of us bought set's of 8, we'd have four sets of six 180/4 = $45 a set...for what seems the correct part.

I do have 8, 703's, six in use. They might be 23lbs/hr. Just within "closed loop" parameters. Idles, runs great!

I've just had the same high idle deal btw. Was on the highway...but yea, it went back after turning it off.

Like I mentioned in post #2, a couple bottles of alcohol might be in order, (or one 32 oz bottle). Oh, and some in the Jeep too.

You CAN just stick the 703's right in there. Same connector and fuel pressure. It will feel and run great. I'd make you a deal on mine if I had some #19 Lb in my hand!

DFlintstone

Just might be the 19Lb/hr, (at 3 bar) Bosch 280 155 700, is what I'm looking for for my Renix. (703's, at 23 lbs/hr might be better suited for 91 and on), but DO preform well in Renix Jeeps.

holeshot9g

Yeah mine doesn't have the resistor. The bolt hole is there but no resister. If somebody else took it off and I can find the wires to it, can they just be left unplugged or do they need to be connected?