89 YJ 2.5 liter engine rebuild

[robschachel]

I have already discovered the major pitfalls of engine repair during my first complete rebuild. I have reassembeled my 89 AMC 2.5 liter 4 cyl engine and it will start however I am seriously having a problem in a few catagories: Vaccum harnesses, I have some left hanging with no home. Sensor connections: again, I am not sure the connections I have made are completely accurate with a few left as well. Timing: It does not appear coorect which I will again attempt to reset tomorrow morning. Finally Throttle body: It was removed with new gaskets installed(by me) with settings changed and no clear consise direction for proper re-setting. I am taking an ASE master course and I am a newby with valuable lessons yet to learn. I am trying to utilize all-data and a Haynes Manual with no great direction nor information provided. Please Help if you have anything that would provide the correct path. Oh Yeah, engine is running really rich... could be multiple causes, hence seeking solutions to individual problems to isolate cause.

 

[TwistedCU]

Sorry I don't have the answers to your questions, but I'm sure some here will be of assistance. Possibly post some diagrams?

I just wanted to say Hi and welcome to Jeepz.com!

 

[Junkpile]

I can't help you either, but the question that comes to mind is: Did you do the disassembly yourself? This is a good reason to always have a roll of masking tape and a fine-tip permanent marker handy when removing an engine. Label everything.

 

[robschachel]

Eastern 4 Wheelers' Florida Vacation

Although I did disassemble the engine myself, I had 3 other students hands in the engine during disassembly leading to one of my most valuable lessons this term... At the end of the day the only one who needs to be disassembeling is the same one that will reassemble and marking corrosponding lines/connections will be vital during reassembly. Unfortunately that moment has passed and learning from it I have now fixing the existing concern is my focus.

 

[Junkpile]

Get your hands on a factory service manual like they use at the stealership. The wiring and vacuum diagrams are more complete than they are in the aftermarket manuals.

 

[Snitty]

i'm with junkpile... if you can grab a factory service manul somewhere, you may find yourself getting closer to done...

side note... how pleased are you with All-Data?

 

[jeep90]

i just found out last week that you can borrow a factory service manual from your local public library. and i almost spent over $100 on one.

 

[currupt4130]

yea i found out real fast that haynes manuals arent good for much unless your learning to put your interior back together or change an alternator, get the factory manual, and use a bright tie crayon to put markings on things, i kno it doesnt help much after the fact, but the best thing you can do is try and line up holes remember that some of what you might think are sensor wires may be for comp diagnostic, not that those engines had much of that but thats just my $.02

 

[robschachel]

I was able to wade through my vaccum line and connector concerns with a lot of patience and even more time( trial and error that is). It was discovered this afternoon whem the plug wire was removed from the #1 and #3 spark plugs with the engine running, there was no audible or detectable change in engine performance(which is still running rich by the way, I need to adjust TBI, not sure how yet). The #2 and #4 plugs were disabled with an obvious drop in idle. I performed a dry compression test discovering 85psi in #1 cyl with 100-110psi in #2,#3, and #4. The spec is 155-185psi. Had no time for a wet test. My engine rebuild had a master kit with rings, bearings, cam, lifters... My brother believes the lifters(which were soaked overnight in oil prior to installation) may have pumped up too much not allowing the valves to close all the way after all the springs due have 130,000 mi. but were within spec's. Any input, suggestions, or words of wisdom. We learn somthin new every day...

 

[whiterubicon]

One more lift question.....

lifters pumping up too much? how is this possable? Who put the rings on the pistons? Were the ring gaps lined up or staggered? This is a somewhat common mistake. Most of the time the electrical conections will only go one place. keep looking and you will find they have a home. Vacume lines on the outher hand can be tricky. I learned a lesson one time by hooking up a windshield washer line to a vacum port. Veary embarasing to say the least.

 

[Tug-n-pull]

Find a jeep with like engin that has not been monkeyed with and take a look or rather many looks and there is your answers. Just do as the orginal does and that should be the fix. tug

 

[robschachel]

I guess the key word to describe me would be student, at least in this forum and with my ASE course. My brother said with no air in the lifter it would possiblly keep valves open, He said I should remove the valve cover, loosen the rocker arm bolts and then slowly tighten them with the engine running? That would explain compression loss...also is very wishful thinking. Wether it is BS or possible I'm not certain but he's been a heavy line corvette guy for 15 years... not the smartest guy but he usually know's car's. The instructions for my rings were to stagger them 180º which is what I did, this would allow the top compression ring and the top oil control ring to align as with the lower compression ring and the lower oil control ring. Possibly 90º would have been wiser however I'm not sure and the engine is together, at least it is today, tomorrow might be a differnt story. I reaaly appreciate the feedback so far, you guy's are great.

 

[Snitty]

97 ZJ fuel sending unit??

i've always followed the 90 degree as a rule of thumb

 

[robschachel]

Well, progress and digressing has all occured in one fell swoop. I discovered today that my #1 exhaust valve and #2 intake valve are not seating properly. This is due to a crappy valve seat cutting job which I the student did all by myself. I went to a machine shop and had them re-cut valves and seats however after retreiving the head and re-installing in Jeep, I found that there was still air loss through the valves. I sent the head back to the machine shop and am anxiously awaiting the results tomorrow morning. I dont beleive the machine shop checked the heads prior to returning them originally. So anyway, hopefully a soloution will be forthcoming. Thank's again for all your help and info.

 

[Snitty]

i hope they are taking care of labor cost on that for you.. unless it is class work, then you're good

 

[robschachel]

Well, it's done, running, and with about 100-miles on it over the weekend, operating as designed. My vaccum harness and connector concerns were resolved with a lot of patience and diagrams from several differnt sources. i.e. Haynes, All-Data, and Chrysler Stealerships Star Program parts break down. My compression concern however was a slightly tougher matter. I removed the head again and after some thought, remembered I used a school valve seat cutter which did not appear to have operated as smoothly or cleanly as I had hoped at the time. I took the head to a local place called cylinder head depot where I had the valve seats re-cut. I took the head back to school and after re-assembling the head to the block, used a Snap-On Leak Down tester confirmed air escaping into the exhaust at the #1 cylinder and air entering the intake at the #2 cylinder. I called Cylinder Head depot and found out they had'nt checked it before returning it to me. Back to Cylinder Head Depot it was Wednesday Morning. They cut a slight more off the valve seat and then lapped the valves. We had success. I reassembled the head and confirmed compression was now good. The rest was downhill and now here I stand with a very valuable lesson and alot of time spent with my Jeep. Lesson: Dont fix it unlesss it's broke :shock: