Crabbi

Hey Folks

Im new here, i probly should have come here a long time ago, i have had several Jeeps and restored one, older stuff, 90 Wrangler 4.0 HO with a 4.2 carb on it, was fun to tune, those carbs are ruff,
Im no pro at cars but i can hold my own, this one has me stumped,

Here goes, sorry for the long winded, but i gotta show you how i got to where i am,
My sister tows her 2000 jeep Cherokee 140k AT, to my house,{i had no idea she was even broken down lol} its an AT, has the 4.0 and it is california emissions, meaning it says california emissions and it has the 4 O2 sensors with the two mini cats,
Ok so she dropped a lifter, i pulled the valve cover found excessive sludge build up, several years back she overheated it pretty good and more than likely popped the head gasket, YES its is a 3331 head, she mentioned coolant loss and had been topping it off, i found cylinder 6 lifter colapsed, pulled head, the bridge on top was cracked and needed to be welded, So i could see where the head gasket had been blowing coolant through the gasket, and it has 140k on it so i figured do the whole thing over, brought it to a local machine shop who is known for 100 miles, hes is really good, he went through it cost me about 450, he magnafluxed it checked for cracks welded the bridge, seals and guides all the good stuff, I put it back on with felpro perma torque gaskets, and new head bolts, torqued to spec, pretty simple stuff really, re installed everything, fired it up, ran like a damn clock, perfectly smooth, had great acceleration, took it down the road and by the time i was back i had a skip so bad it barely drove, and check engine light was on and flashing, Found number 2 misfire, I had bought aftermarket injectors and went with an upgrade, yup DUH, ok so put the old fuel injectors back in, Mind you i repalced them because 2 had started to burst from inside from rust and were splitting the plastic outsides, but they worked, i reinstalled them, took a test drive same exact thing, started and ran fantastic, within a few minutes skipping and popping through the air horn now?, WTH LMAO, so i ordered another set of injectors basically without thinking, in the mean time i said lets check it all out, i started testing stuff, boy that was a mistake, i found NOTHING, NO CODES, even after shaking so hard and almost stalling to popping through the air horn it still would not kick a code, it was running so lean and timing had to be off,
This is where is starts to get fun, of course i suspected every single thing i touched, i went over EVERYTHING one more time, did a compression test, good, fuel pressure test, good, tested and cleaned IAC, tested TPS it was good, tested the MAP tested good,{ i replaced it anyway} replaced the coil pack, just because i could, did nothing, i ohmed out the ambient air temp the coolant temp, all tested good, i then decided to replace all 4 oxygen sensors, bought all NTK, made no difference, had a buddy of mine who owns a shop bring over his brand new snapon scanner, it comes with little folks that jump out and run wire leads to stuff for you, hell i think its got a coffee warmer, We ran the scanner on the jeep, found the cam sensor was not syncing, it would go off and on, repeatedly, so the crank sensor was original, i replaced it, still no cam sync, so we replaced the cam position sensor, did nothing, its actually getting worse, now its getting spark pinging even at idle, actually sounds like a lifter, pulled the valve cover, all rockers move when its turning over, none can be depressed, the lifters are ok, put it back together, did another compression test, i got 135 to 150 across the board, nothing we have done seems to have changed anything, now my next logical steps would be cam shaft end play or excess crank shaft end play, sloppy as heel timing chain, or PCM?. for a while this thing would run perfect at cold start them you could literally here it start to get worse by the minute by the time it gets to 160 its skipping like hell, now that happens within a minutes of starting up,

ANYONE, HAVE ANY IDEAS???? LMAO, im kinda stumped,

4.3L XJ

I think this might be similar to getting the distributor in correctly. So here is the procedure for correct installation of the cam sensor assy.INSTALLATION—OIL PUMP DRIVE AND SENSOR

(1) Clean oil pump drive mounting hole area of

engine block.

(2) Install new oil pump drive-to-engine block gasket.

(3) Temporarily install a toothpick or similar tool

through access hole at side of oil pump drive housing.

Align toothpick into mating hole on pulse ring (Fig.

34).

(4) Install oil pump drive into engine while aligning

into slot on oil pump. Rotate oil pump drive back

to its original position and install hold-down clamp

and bolt. Finger tighten bolt. Do not do a final tightening

of bolt at this time.

(5) If engine crankshaft or camshaft has been

rotated, such as during engine tear-down, CMP sensor

relationship must be reestablished.

(a) Remove ignition coil rail assembly. Refer to

Ignition Coil Removal/Installation.

(b) Remove cylinder number 1 spark plug.

(c) Hold a finger over the open spark plug hole.

Rotate engine at vibration dampener bolt until

compression (pressure) is felt.

(d) Slowly continue to rotate engine. Do this

until timing index mark on vibration damper pulley

aligns with top dead center (TDC) mark (0

degree) on timing degree scale (Fig. 35). Always

rotate engine in direction of normal rotation. Do

not rotate engine backward to align timing marks.

(e) Install oil pump drive into engine while

aligning into slot on oil pump. If pump drive will

not drop down flush to engine block, the oil pump

slot is not aligned. Remove oil pump drive and

align slot in oil pump to shaft at bottom of drive.

Install into engine. Rotate oil pump drive back to

its original position and install hold-down clamp

and bolt. Finger tighten bolt. Do not do a final

tightening of bolt at this time.

(f) Remove toothpick from housing.

(6) Install sensor to oil pump drive. After installation,

the CMP sensor should face rear of engine 0°.

(7) Install 2 sensor mounting bolts and tighten to

2 N·m (15 in. lbs.) torque.

(8) Connect electrical connector to CMP sensor.

(9) If removed, install spark plug and ignition coil

rail.

To verify correct rotational position of oil pump

drive, the DRB scan tool must be used.

WARNING: WHEN PERFORMING THE FOLLOWING

TEST, THE ENGINE WILL BE RUNNING. BE CAREFUL

NOT TO STAND IN LINE WITH THE FAN

BLADES OR FAN BELT. DO NOT WEAR LOOSE

CLOTHING.

(10) Connect DRB scan tool to data link connector.

The data link connector is located in passenger compartment,

below and to left of steering column.

(11) Gain access to SET SYNC screen on DRB.

(12) Follow directions on DRB screen and start

engine. Bring to operating temperature (engine must

be in “closed loop” mode).

(13) With engine running at idle speed, the words

IN RANGE should appear on screen along with 0°.

This indicates correct position of oil pump drive.

(14) If a plus (+) or a minus (-) is displayed next to

degree number, and/or the degree displayed is not

zero, loosen but do not remove hold-down clamp bolt.

Rotate oil pump drive until IN RANGE appears on

screen. Continue to rotate oil pump drive until

achieving as close to 0° as possible.

The degree scale on SET SYNC screen of DRB is

referring to fuel synchronization only. It is not

referring to ignition timing. Because of this, do

not attempt to adjust ignition timing using this

method. Rotating oil pump drive will have no effect

on ignition timing. All ignition timing values are controlled

by powertrain control module (PCM).

(15) Tighten hold-down clamp bolt to 23 N·m (17

ft. lbs.) torque.

Crabbi

Awesome right up, thank you 4.3L XL, i saved it and will try it again, however both the original and the replacement are doing the same exact thing, and the original did not test bad, and neither did the cam position sensor, we used a snapon brand new, literally, 6 months old, system for diagnostics, it showed the exact same results prior to cam sensor replacement, the crank will sync, but the cam will not, when we first hooked up the scanner, it said it was out of sync, it had never come out before, we adjusted it now it flashs on and off lost sync then sync lost sync then sync, it keeps repeating, then we pulled the lower shaft assembly of the cam sensor, basically the bottom half of a distributor, we set it per factory instructions which are available on the scanner, we then set it at 0 using the scanner, both the old cam sensor and the new cam sensor do the same thing, and they both tested good on the jeep, as a note not once has the check engine light come on for misfire, thats despite it almost stalling and sputtering and running lean as hell, not one check engine light has come on,
the question then becomes, whats next? PCM? timing chain?, if a 16k scanner cant find anything it leads me to believe its mechanical or a PCM, any ideas?

4.3L XJ

The reason I suggested to start there is that it seems to be an alignment issue. Works the same with the regular distributor. If you verify it is aligned properly, then yes I would start looking at an ECM, or a connection problem there. One thing to consider with the connections is having a good connection. There is a product called OxGuard. It is not like dielectric grease. This stuff conducts electricity so don't just smear it on. You apply it inside the pin connectors with a toothpick. It has abrasives in it, so you plug and unplug a few times. I have saved some plugs that way, including the remote on my Warn Winch

Crabbi

Thanks again 4.3L YJ,
I will have to look for that stuff, what else could it be? timing chain? the crank is in sync the cam will not, and with it flashing in sync lost sync in sync lost sync, something is moving, when we had the cam sensor shaft assembly out we spun it, it seemed smooth no burs, i put a lab scope down the cylinders, i have a nice one, cylinders looked good, can still see crosshatch on cylinder walls, valves looked ok plugs looked funny, 5 and 6 had some minor black on them, 3 had white minor flakes 2 was clean as a whistle, 1 was clean as a whistle, and 4 had minor tan, the PCM is not in control of the timing, but its showing it can communicate with the cam sensor, but the cam sensor wont sync is telling the scanner it wont sync the engine,
whats next lol.

4.3L XJ

You could suspect a timing chain, but you would notice a difference in performance at low and high rpm, so I would rule that out. We are starting to get to my expertise limit.

4.3L XJ

One thing I would do after thinking about it is unplug the harness at both ends and ohm each wire involved to see if there is any resistance that shouldn't be there

lawsoncl

Running okay until it warms up doesn't really point to a distributor issue to me. No codes for O2 sensors? What happens if you unplug them or the temp sensor and force it to stay open loop?

Crabbi

I tried unplugging the 02 sensors,made no difference, if it did it was hard to tell, no codes at all, i did make sure it would actually show a code, thinking PCM so i unplugged a sensor started it got a check engine light , plugged it back in cleared it, restarted and no codes
im thinking remove lower cam sensor assembly again, look more for side to side play, i had a 140hp mercruiser boat that baffled me for a while, one day while changing points i wiggled it and nothing, another time i was trying points AGAIN, wiggled it around a bit and found a notch it would settle in, pulled it and sure enough the bushing had wore and it had side to side play but only when it got stuck in that spot, long story, lol, i fixed it,
this one has me stumped

4.3L XJ

I am wondering if it is temp related. Try unplugging the temp sensor and see what happens. See if you can keep it in open loop mode

Crabbi

Tried the temp sensor, also bench tested it, it changed how it ran when unplugged but made no change in the original problem, still on the scope shows lost sync syn lost sync sync lost sync, i went and inspected the lower shaft assembly were the cam position sensors mounts today, we had it all the way out previously didnt see anything major, today with it installed, i tried wiggling the half circle of metal inside were the cam sensor sits, it has play in one direction actually front of jeep to back of jeep but side to side of the jeep it is solid, almost like it has a worn bushing inside, its about 1/16 to 1/8 inch of play with zero pay the other way, like its play in the bushing, but im not sure how much play is acceptable,

Crabbi

Anyone have any ideas? i pulled it out today and replaced the syncronizer assembly, it did not fix the problem, but the old one did have side to side play,

So what now? timing chain or PCM ?, i did ohm the signal wire and verified i had 5 volt reference at the cam sensor, still shows lost sync in sync lost sync in sync on the scanner

Dave51

Can your scanner actually read the CKS/CPS signals? They should look like this:



Did you check to see if the flex plate is broken, shifted, installed upside down, etc.?

After that, I'm thinking it's time to pull the timing cover and check timing chain and gear.

bluejeep2001

Step 1 verify cam sensor is installed correctly...my synchronizer had a installation cap that would hold the rotating part in proper position, no toothpicks needed. Remove all spark plugs and rotate engine until you feel pressure buildup with your finger in #1 cyl. You should be somewhat close to 0 mark on timing index. If so rotate to exactly zero. Now the tricky part...your end result wants the arrow on test cap pointing straight back to the firewall . see the angle the flat oil pump drive is compared to the arrow remember it. When you slide the synchronizer in it will rotate slightly ( 10 -15 ) degrees as the shaft gear and cam gear mesh you need to account for this rotation during final install so figure where you need to start your rotation so it ends up facing back. Note where the flat oil drive is as you start the install...make sure the oil pump slot is at that same angle and it should all slide together smoothly and the arrow should be facing mostly straight back. The angle of the gears may make it off a little. Try several times w and get it as close as possible...it will work well enough as is but you can adjust perfect with your scanner. While the synchronizer is out check your cam gear well. I had a stroker that died because the brass distributor gear completely ate the cam gear until it wouldn't spin the shaft...with NOdamage to the distributor gear

Crabbi

Hi thanks for the reply
We can see both on the scanner, it looks ok, but it keeps flashing lost sync then sync then lost sync then sync, and of course with nothing controlling timing and injectors it is popping through the intake and running lean as hell,
Makes no sense really, unless it is PCM or endplay on the cam, when i rotated the cam sensor there was not much moving of the crank before it moved, i know i was looking for that and when it moved pretty quick i decided thats not much play, i have a PCM coming but im trying to make sure by testing it down to PCM, theres 3 wires on the cam sensor, i have ohmed 1 back to the PCM its tested good, i dont know were on the PCM to check for the other two wires and ohm them to make sure i have no wiring issues,
any ideas