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Idle-Timing issue

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Old 08-27-2014 | 12:39 PM
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Cherokeekid4x4's Avatar
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From: Kansas
Year: 1994
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Engine: 190-hp, 4.0-liter I-6
Default Idle-Timing issue

Just recently put a crate 4.0 in my jeep and am having a couple of issues. From my understanding the 4.0 timing is not adjustable. It only has one setting. Well at idle I am having a sort of miss. It feels like the motor is pulsating. When I accelerate or decelerate it is fine. Going down the road it's fine. I am just wondering if I could have my timing set very close but it is still a little advanced or retarded. My vacuum connections are all good. It idles around 750. New plugs, wires, distributor, cap, rotor, all the goodies. It also takes a decent amount of time to crank over and start. Not sure if that's tied into the timing or not. I would assume so, just hoping someone has some advice for me before I go through the procedure of setting the timing. Thanks!
Old 08-27-2014 | 07:15 PM
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Anyone??
Old 08-28-2014 | 12:12 AM
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From: north of the Rio Grande, south of the Red, east of the Pecos, west of the Sabine
Year: 1990
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Timing's not adjustable, but you can index the distributor (not convinced that's your problem, but indexing sure smooothed out my old Renix)... Cruiser's tip #13. I'm not sure if it can be done for the HO (which I assume is the crate engine you bought), but is good on the Renix.

Last edited by Bobolink; 08-28-2014 at 12:15 AM.
Old 08-28-2014 | 12:28 AM
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You do know the books and diagrams are wrong? #1 is at 5:00 as viewed from the side, 153624 clockwise.

Like Bob mentioned, indexing the dizzy can be tricky. Cruisers tips are right on top if you click on my sig. You want the rotor tip to land ahead, almost leaving the electrode, so when the puter advances the timing the spark can still reach.

Btw, the "key trick" might work on your 94. The codes are explained in "info threads" at the top of this forum.

OBD1 Models: 1991-1995
1) Start engine (if possible). Move transmission shift lever
through all positions, ending in Park. Turn A/C switch on and then off
(if equipped).
2) Turn engine off. Without starting engine again, turn
ignition on, off, on, off and on within 5 seconds. Record 2-digit
fault codes as displayed by flashing MIL.
3) For example, fault code 23 is displayed as flash, flash,
4-second pause, flash, flash, flash. After a slightly longer pause,
other codes stored are displayed in numerical order. When MIL begins
to flash fault codes, it cannot be stopped. Start over if count is
lost. Code 55 indicates end of fault code display.

Last edited by DFlintstone; 08-28-2014 at 12:38 AM.
Old 08-28-2014 | 04:18 PM
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When I dropped the rotor down it was pointed towards cylinder one wire. No clock for me I just know when the motor is top dead center on the compression stroke that's where it should be. I was just wondering can it be advanced or retarded and still runs. Just wasn't sure if it's retarded a little but still runs. Causing a choppy idle and prolonged start.
Old 08-28-2014 | 07:21 PM
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Setting Your 4.0 at #1 TDC


With #1 spark plug removed, turn the engine over clockwise using the 3/4" front crankshaft bolt. You will see the degree marks on your front cover. Mark the 0 with chalk or white-out.You will see the timing mark on the balancer. Mark it with chalk or white-out. While turning the engine over, put your finger/thumb over #1 spark plug hole. As the mark on the balancer approaches the marks on the front cover, if you are coming up on #1 TDC, pressure in the cylinder will push on your finger. If there's no pressure, you're at #6 TDC and need to crank the engine over until you see the marks coming together and you get pressure. Set the mark on the balancer to the 0 mark on the front cover.
Attached Thumbnails Idle-Timing issue-firing-order.jpg  
Old 08-28-2014 | 07:25 PM
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Originally Posted by cruiser54
Setting Your 4.0 at #1 TDC With #1 spark plug removed, turn the engine over clockwise using the 3/4" front crankshaft bolt. You will see the degree marks on your front cover. Mark the 0 with chalk or white-out.You will see the timing mark on the balancer. Mark it with chalk or white-out. While turning the engine over, put your finger/thumb over #1 spark plug hole. As the mark on the balancer approaches the marks on the front cover, if you are coming up on #1 TDC, pressure in the cylinder will push on your finger. If there's no pressure, you're at #6 TDC and need to crank the engine over until you see the marks coming together and you get pressure. Set the mark on the balancer to the 0 mark on the front cover.
Got all that. I know how to set it, I wanna know if it can be retarded or advanced and still run.
Old 08-28-2014 | 07:27 PM
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Originally Posted by Cherokeekid4x4
Got all that. I know how to set it, I wanna know if it can be retarded or advanced and still run.
The timing is not adjustable. Only the dizzy can be indexed.

See where the rotor is pointing now on #1 by using the above method. Then you'll know.....
Old 08-28-2014 | 07:31 PM
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Originally Posted by cruiser54
The timing is not adjustable. Only the dizzy can be indexed. See where the rotor is pointing now on #1 by using the above method. Then you'll know.....
Well it must be set right then..It runs so I guess I have a different problem for the idle and starting.
Old 08-28-2014 | 08:47 PM
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Maybe......
Old 08-28-2014 | 09:50 PM
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Originally Posted by cruiser54
Maybe......
Maybe... Haha thanks for the straight answer.
Old 08-28-2014 | 10:03 PM
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The only straight thing on an XJ, is the name straight-6.

Your issue is likely related to many of the other (pretty straight) forward causes of 'missing' at idle.
For the longer starting: try the " poor man's prime" technique so see if that speeds up your starting time.
Old 08-28-2014 | 10:07 PM
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Originally Posted by Cherokeekid4x4
When I dropped the rotor down it was pointed towards cylinder one wire. No clock for me I just know when the motor is top dead center on the compression stroke that's where it should be. I was just wondering can it be advanced or retarded and still runs.
"that's where it should be." OK then. I thought it should be just bit ahead, a tad past, or just leaving the #1 electrode. Yea, it will still run a tooth off. Idk, just a thought.
Old 08-28-2014 | 10:22 PM
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Originally Posted by DFlintstone
"that's where it should be." OK then. I thought it should be just bit ahead, a tad past, or just leaving the #1 electrode. Yea, it will still run a tooth off. Idk, just a thought.
The whole reason for this question was because when I did set it I left it a tad before hitting cylinder one. Maybe making it a tad retarded and causing a long start/choppy idle. Also I was told when you drop the rotor back in it shifts a little. So I left it ahead so when I dropped it down it would face cylinder one. I simply just wanna know if it would still run if it was off by even a little bit. I know how to set the timing, I understand where it should be pointing.
Old 08-28-2014 | 10:24 PM
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Originally Posted by Roler
The only straight thing on an XJ, is the name straight-6. Your issue is likely related to many of the other (pretty straight) forward causes of 'missing' at idle. For the longer starting: try the " poor man's prime" technique so see if that speeds up your starting time.
I've tried priming the pump, doesn't start any quicker. My pressure at the rail is 40.


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