!New engine! Having trouble getting going!
07-23-2012 | 07:59 PM
#46
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Joined: Aug 2011
Posts: 209
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From: Quincy
Year: 1996
Model: Cherokee
Engine: 4.0L HO
AH yes you were one of the lucky ones with to have to deal with that lovely single port injection system and AMCs waining funds forcing them ask Puegot to lend a hand. Im glad i am not old enough to have seen those days or maybe i should have. It would make the idiosyncrasies of my 96 XJ seam like nothing. The funny thing was when i started looking for cherokees one of my criteria was a 95 and older.......unfortunately i couldn't find one for the rite price so i ended up with this lovely 96 nightmare. I was within grasp of a beautiful 92 XJ laredo but it was sold out from under me a day before i was scheduled to go see it.....
07-24-2012 | 02:03 PM
#47
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Joined: Aug 2011
Posts: 209
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From: Quincy
Year: 1996
Model: Cherokee
Engine: 4.0L HO
ok so i think i solved the issue but not entirely. first issue the "downstream" sensor i bought months ago was not a "downstream" sensor it was intact an upstream sensor and do to one of the plastic barbs being missing on the body connector it connected some what well. so lets call this partly my stupidity 
. so i moved that sensor up front and bought a replacement downstream and put that in. cleared the codes, started it up and no CEL yet but still it is running rough. Based on how its running and its hesitation i am guessing that i may have shorted the "downstream" sensor that was really and upstream sensor by putting it where it doesn't belong. I have also read in a bunch of places that Bosch do not work? Can someone please confirm or deny this. that was what they had in stock so i assumed that all sensors worked fine.....
. so i moved that sensor up front and bought a replacement downstream and put that in. cleared the codes, started it up and no CEL yet but still it is running rough. Based on how its running and its hesitation i am guessing that i may have shorted the "downstream" sensor that was really and upstream sensor by putting it where it doesn't belong. I have also read in a bunch of places that Bosch do not work? Can someone please confirm or deny this. that was what they had in stock so i assumed that all sensors worked fine.....
07-24-2012 | 09:25 PM
#48
Senior Member
Joined: Feb 2012
Posts: 864
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From: Arlington, Texas
Year: 1998
Model: Cherokee
Engine: 4.0
I'm not going to say what others may or may not have said about Bosch sensors, but I can relay my experience with them. From one of my posts on another thread:
I'll be curious what you find here.
I have a newly remanufactured ATK longblock in my '98 Sport, along with a 2" lift, Surco rack, and 235/75-15s. New plugs, wires, cap rotor, cooling system, neon 4-hole injectors, cat and muffler, O2 sensors, and a reset computer, stock intake, intake, air cleaner, TB, exhaust manifold and downpipe. After about 8000 miles of break-in and the motor not being so tight, I was getting about 13.7 with an even mix of city/highway in my daily work commutes, and about 17.8 on highway only.
Someone mentioned in a thread about cheap O2 sensors and problems they can cause. While I had no obvious troubles or CEL, I did have the cheap O2 sensors. I switch them out to Bosch units. My mixed use went up to 14.8 and my all-highway went up as well. This past weekend I loaded up me, the fiance, and our 140 pound Mastiff in the XJ. I also hooked up my 5'X10' foot single-axle trailer and about 250 pounds worth of stuff on it and took it to our family land; about a 110 mile round trip. Set the cruise at 65 and had the air going full blast in 97 degree heat. I got 18.2 MPG on that trip. Towing a trailer! Glad I got the Bosch units!
I am curious if there are any options for reprogramming the computer on anything pre-99 to get even better mileage.
I have a newly remanufactured ATK longblock in my '98 Sport, along with a 2" lift, Surco rack, and 235/75-15s. New plugs, wires, cap rotor, cooling system, neon 4-hole injectors, cat and muffler, O2 sensors, and a reset computer, stock intake, intake, air cleaner, TB, exhaust manifold and downpipe. After about 8000 miles of break-in and the motor not being so tight, I was getting about 13.7 with an even mix of city/highway in my daily work commutes, and about 17.8 on highway only.
Someone mentioned in a thread about cheap O2 sensors and problems they can cause. While I had no obvious troubles or CEL, I did have the cheap O2 sensors. I switch them out to Bosch units. My mixed use went up to 14.8 and my all-highway went up as well. This past weekend I loaded up me, the fiance, and our 140 pound Mastiff in the XJ. I also hooked up my 5'X10' foot single-axle trailer and about 250 pounds worth of stuff on it and took it to our family land; about a 110 mile round trip. Set the cruise at 65 and had the air going full blast in 97 degree heat. I got 18.2 MPG on that trip. Towing a trailer! Glad I got the Bosch units!
I am curious if there are any options for reprogramming the computer on anything pre-99 to get even better mileage.
07-24-2012 | 10:46 PM
#49
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Joined: Aug 2011
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From: Quincy
Year: 1996
Model: Cherokee
Engine: 4.0L HO
Interesting. Well I'll take your word for it. You have been rite through out this thread so I have no reason to doubt you now. Your situation sounds surprisingly similar. The only things I have not replaced with in the last year are: from the down tube to the tail pipe and the radiator (that had been replaced months before I bought it).
All that being said it still does not explain the chunky idle and hesitation. Now that the engine and it's sensors are all working together it's running rougher than when I first got it started up. I will take a multimeter to the upstream sensor tomorrow to see if I killed it by putting it in the wrong spot. Another issue I am in dire need of fixing is the exhaust hanger that comes off the trans x-member. All the original exhaust hangers rusted away and broke ad some time in the past and the po took it upon himself to reweld those broken hangers but they did so in a way that raised the exhaust a 1/2 inch and cuz the x-member hanger hadn't broken and wasn't working with their plan they just lopped it in half leaving the exhaust to rest on the x-member...... Smart right so I need to fix it and I'm not sure the best way.
All that being said it still does not explain the chunky idle and hesitation. Now that the engine and it's sensors are all working together it's running rougher than when I first got it started up. I will take a multimeter to the upstream sensor tomorrow to see if I killed it by putting it in the wrong spot. Another issue I am in dire need of fixing is the exhaust hanger that comes off the trans x-member. All the original exhaust hangers rusted away and broke ad some time in the past and the po took it upon himself to reweld those broken hangers but they did so in a way that raised the exhaust a 1/2 inch and cuz the x-member hanger hadn't broken and wasn't working with their plan they just lopped it in half leaving the exhaust to rest on the x-member...... Smart right so I need to fix it and I'm not sure the best way.
07-25-2012 | 12:52 PM
#50
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Joined: Aug 2011
Posts: 209
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From: Quincy
Year: 1996
Model: Cherokee
Engine: 4.0L HO
Got my plates and after a year its finally legal to drive on the road! took it out for a drive to try and figure some things out. First note i do need a new rear seal for the t-case because to spite the slinger being back in place it still slinging oil out of the case, not as fast but still. Next major issue, o2s are working fine the rough idle is beyond their control. My cat is Toast. I stuck my head under the jeep while it was idling after i drove it a bit and all the rattling is coming from the cat. I can't seem to get ahead with this jeep....
. I stuck my head under the jeep while it was idling after i drove it a bit and all the rattling is coming from the cat. I can't seem to get ahead with this jeep....
Last edited by Shamrock96; 07-25-2012 at 12:55 PM.
07-27-2012 | 02:59 AM
#52
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 19
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Just "breezing" past again..read a good bit. Curious of the idle rpm. Plugs are .035,..that secondary spark can get wiley, even swapping in an old cap for a minute might yield info. Watch it in the dark for sparks..... I didn't catch....in the last 50 posts if you cleaned the IAC..course you must have.
07-27-2012 | 04:59 PM
#53
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Joined: Aug 2011
Posts: 209
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From: Quincy
Year: 1996
Model: Cherokee
Engine: 4.0L HO
Idle rpm is with in normal range. I want to say a tick under 1k on warm up and after a few seconds it settles around 600-700. Cap is new in the last year and I don't have a spare or the old one. I can check my rotor and see if it's in rough shape. I cleaned it up really nice while the engine was out but I should check it again. If u check my very first thread it is about my IAC. I thoroughly cleaned the TB and the iac. Plugs are gapped right but I should check them. I haven't checked them since Sunday when I installed them. Gapped them all to .035 and checked them over once more after I did them all. The only thing of note is the back end of the engine is kinda dancing around as it idles. Air filter is new. I installed a 94 intake box that pokes through the header panel. No vac leaks, no fuel issues, injectors are all new, new fuel filter.
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