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4.0 or 4.2???

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jeep yj
4K views 57 replies 14 participants last post by  YJ4LIFE 
#1 ·
Ok I just recently purchased a 1987 YJ Wrangler Sport, i bought it for 2400$ which to me wasnt that bad and i am going to be using it as my daily. The issue im having is that all the emission controls have been striped of the motor, it dont bother me really but since i can look and clearly see that the motor has had someone in it....idk for sure if its the 4.2 that came with the jeep or the 4.0

Im new to the Jeeps..Sorta, my dad had a couple Willis Jeeps a 12v and a 24v mil specs and ive done Mud Pit Jeep ( in Ms and La )....

also ontop of just getting into this stuff, i just moved last week to MD and have no idea were good places are to get work done here since all my tools and welding machines are back in Mississippi lol
 

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#30 ·
Yup, someone called it, a weber. You missed taking a pic of the side with the linkage which would male it easier to yell what model weber bit I believe whoever said weber 32/36 is right. That fist hose with a plug in it is a vacuum source that was plugged
 
#32 ·
The linkage looks like a normal system BUT it had 2 half moon lookin gear componets in the back, the choke linkage goes on the side facing the motor.....if some one could show some pix of the possiblities then i could say yes or no.
 
#34 ·
the red arrow id pointing to where the PCV should go, not to the air cleaner. that should take care of the oil leaking out of the valve cover by the filter.
 
#36 ·
This would be true but all the original emmisions has been removed, no charcoal can or anything. Thats y the valve on the side of the block is taped up also, the vacuum lines has been caped. Which is great cuz motors ran for years in my dads time without all that extra crap, im just tryin to figure out how to make this one runn correctly without it since it wants to die when i go to slow down or stop, its difficult clutching and feathering the gas n tryin to hold the brake on hills lol
 
#37 ·
the PCV requires vacuum, your not getting it with it hooked to the air cleaner. as to removing the emissions junk mine has been long gone but I still run a PCV line, the days of running a motor with just a line to the outside ended in the 60's, I've had them and when a motor got old they dripped oil or leaked it like yours is doing.
 
#38 ·
Ok, all the pcv ive delt with went to the filter, even the original carb on this motor according to haynes book went to filter. But chevy big blocks are different than jeep, so what your telling me is unhook the line from the white part on the filter and put it at the bottom of the carb were the bolt plugs it and this will stop the oil pushing it way out the breather out the back of the valve cover
 
#39 ·
i hope this would help, also anyone know a easy way to extend the manual choke? since it seems to be stuck open, im thinkin the cable may not be long enough since it was ment for the original carb
 

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#46 ·
several things. first of all I had a similar situation with my jeep. bought a 90 yj that had the 4.2 and an aftermarket carb. I used this page to help sort out all of the messed up vacuum lines etc. on the weber. it helped a lot. http://www.jeepforum.com/forum/f12/weber-32-36-install-write-up-382309/

once you get all the vacuum lines sorted out like it shows make sure you have a fuel filter with a return line like it is supposed to have or else you may need a fuel pressure regulator to get the fuel pressure down to the 3-4 psi the weber likes.

after that make sure the p.o. did the nutter bypass. if he removed all the emission stuff and did not do the bypass the computer can mess up the timing. here is the page I used to do that. http://www.jeepforum.com/forum/f12/picture-guide-nutter-bypass-476720/

after that just make sure you have good plugs and wires, good grounds and set the timing by turning the distributor to about 8 degrees BTDC.

and it should run like a top.

I ended up doing a fuel injection conversion later on just to make it easier for my daughter to start and drive it, but it ran great with just those steps.
 
#48 ·
howell TBI vacuum diagram and follow that. and your egr nipple looks busted
 
#50 ·
ah ok. I did all the nutter stuff but I still wanted to pass tailpipe test and supply vacuum to the 4x4.
 
#51 ·
we got severe Test to under go around here....they check EEEEEVVVVEEEERRRRYYYYTHING.....so im getting historic tags on my jeep so i dont have to worry about taking anymore tests......back home is MS and LA..there is no test lol u pay 5$ got a sticker and left lol:banana:
 
#52 ·
ah. our tests are pretty strict but you can't cheat the tailpipe. if you get a big name shop they'll fail you for k&n n bull**** but most mom and pop want you to pass to keep you happy and coming back.
 
#53 ·
I just moved to MD on black friday so im learning how great the south was with that kinda stuff lol everyone ran around, me included, with straights even some with no cats...and noone cared but up here u gotta give ur first born even to buy guns lol
 
#54 ·
I don't know the rules for vehicle inspections in MD, but if they are anything like most of the other northeastern states, you'll honestly be better off selling that Jeep to someone further south and finding another that hasn't been messed with. Many states will fail that Jeep 5 seconds after they open the hood to find all the OE equipment removed, aftermarket carb, etc.
 
#56 ·
I have an 88 that came to me with the nutter done and all of the emissions components were still in place. I pulled up the vacuum diagram from a 258 cj and replicated everything. For a while i was running the filter night off the valve cover like the OP showed. I also had the pcv hooked up to the correct location. Still had oil coming onto the valve cover. The solution i found was to run a 90 degree copper elbow to a heater hose and run it all the way back on the frame rail to just in front of the back tires and put that filter on the end. Just have to be dilligent abut checking that filter and keep it clean. Another thing to name sure of is that the gromets in he valve cover are correct. I was told by my dad that the old school car guys just used to run that hose un filtered. Also the source of that oil culd be a symptim of blow by.
Im no professional by any means but i just thought i would throw my 2 cents. God luck!
 
#57 ·
thanks, theres a place right down the roads....i think imma get them to tune it and solve the issue...im bought ready to move on past this stage of it.....ive thought about just putting a 383 in there and say skrew it lol
 
#58 ·
have them do a compression test. if the bottom is still good you can do 4.0L head and efi. I only kept the 4.2l head because it was rebuilt not that long ago
 
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