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-   -   94 YJ running on two cylinders (

ryanwilson277 02-15-2020 07:19 PM

New to the forum, having an issue with my newly acquired yj. Picked up a pretty much rust free 1994 yj 2.5 with mpfi for a good deal to replace my rusted out 90 yj. Has ax15 swap with Ford 8.8 rear. Problem is that it wouldn't start, hense the good price. Got it to fire up when I wiggled the injector connectors so went ahead and soldered new connectors on all four cylinders. Then changed plugs and fired it up. Started right up but on only running on cyl 1 and 4. When pulling connectors to injectors 2 and 3 there was no change. When pulling either connector 1 or 4 it clearly sounds like it's only running on one cylinder and about to stall. Verified running on running on 1 and 4 by reading the plugs. 1&4 nice tan color, 2&3 black and wet. I then ohm checked each injector and were all the same. Then took test leads from the battery and checked each injector for operation and they all clicked. I then started up the Jeep and took a test light from battery positive terminal to the injector ground wire to verify flashing, indicating the pulses. All good so far. Good fuel pressure by the way. Checked timing, was cold and dark and the fan was crying my eyes out so I couldn't count the marks but was halfway between all the marks so somewhere around 12. I then moved onto spark, had spark at each cylinder but removed distributor cap anyway. Contacts were worn so I wiggled the rotor shaft and had some noticable play in a side to side motion not circular. Bought a new distributor. Turned to tdc with timing mark on 0 and rotor facing cyl 1contact. Verified alignment by sticking 3/16 drill bit in alignment hole. Removed distributor and when installing new distributor it was either half a tooth to far clockwise or half a tooth to far counterclockwise of the bolt down hole. Fought this [email protected]# for over an hour so I said F it and picked the orientation of the distributor being to the counterclockwise side and bolted everything back up. Started it up and it ran exactly the same. Timing read the same as well. Still only running on 1 and 4. Getting my compression tester from work in the am. PO said he checked compression and was willing to let me check as well so I took his word for it. Mistake I know. Will see what compression shows in the morning but if good I am at a loss of what it could be. Any help appreciated. Thanks.

Awesome 02-15-2020 08:15 PM

If the plugs are wet, they are getting fuel. That also seems to indicate they aren't sparking. Since you verified spark, but aren't getting ignition, you have an air issue. I'm going to guess your valves are stuck closed.

fishadventure 02-16-2020 06:38 AM

691 Attachment(s)
Like collapsed lifters? Possible

Also possible the injectors are not spraying a nice pattern on 2 and 3

I’d clean the plugs, unplug 2&3 injectors, start it, plug injectors back in and see if the middle two fires. Sometimes things that were sitting don’t survive well

Yes. Compression test might be good

ryanwilson277 02-16-2020 09:05 AM

Well I performed a compression test, all 120psi 1-4. Seems a little low but could be my ****ty harbor freight quick connect testor. The fact that they are all the same leads me to believe it's not a compression issue. Anyway (facepalm) didn't think to check firing order, PO had 2&3 plug wires switched. Running on all 4 now lol. Anyway running a little hesitant so now gotta figure out that distributor problem I was having.

ryanwilson277 02-16-2020 04:07 PM

Drove it down the road today and seemed to be running fine. Am I going to create an issue with the distributor being a half tooth off alignment at tdc? I'm guessing I have a timing chain issue? How can I check the timing chain without pulling the front cover?

GTS225 02-16-2020 08:10 PM

Remove distributor cap.
Get a socket to fit the crank balancer bolt.
Slowly rotate engine in opposite directions, paying close attention to how much crank rotation you get before distributor rotation.
If there's a lot of crank rotation before the rotor starts to move, that's a strong indicator of an excessively worn chain.

If there's no balancer bolt to use, I suggest you pull all the plugs and roll it over by hand, paying attention to the rotor.

It might be wise to have another pair of eyes handy.


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