Xj dies at idle

When I did mine, I lined up using the marks on the harmonic balancer, and used a probe in the spark plug hole to make sure I was at #1 TDC instead of #6. (that took me a minute to get right)

Cruiser's tip says to line up with the trailing edge of the rotor departing the #1 terminal (the other thing I had to do twice) - if that's not working for you I think you could try bringing it back a bit (so you have more overlap between the rotor and #1 terminal).
 
Got it running again, adjusting the distributor did not help the idle. With a vacuum gauge hooked up and the brake booster vacuum unhooked the needle stays steady at 16 or in the red zone saying LATEING TIMING, with all vacuum lines hooked up it bounces around 10 just past the red zone saying LATE VALVE TIMING OR LEAK AT INTAKE MANIFOLD OR HEATRISER.
 
I don't know if it'll help, but you can tweak the ignition timing a little by moving the crankshaft position sensor along its bracket...I don't know much at all about valve timing, but with your low RPM I doubt you have an intake leak.
 
Unfortunately I've already done that. I originally thought that would help. I read somewhere about advancing timing when using a bigger cam.
 
Similar issues from this old thread, some reasonable suggestions to run through

shortxjdoug

Thread 'Help me PLEASE 4.7 stroker wont idle or run right....'

ok here it goes. Purchased a 4.7 stroker block running a 12w 258 crank and what looks to be the KB dished aluminum pistons. Unsure of cam specs but its similar to the xtreme 4x4 cam for these motors. Stock refurbished HO head and intake running 24lb ford injectors and controlled by factory renix junk. heres the issue im at right now.

will start and idle rough when revved you can hear it missing by way of lowered rpm but its running smooth and no smoke or any other ugly symptoms. once the tps is calibrated right it will idle very rough and very low, it will then begin to cycle idling very...
 
I put an hold timing light on it just for the hell of it guess since you can't really adjust timing but its not even registering on the timing cover scale. The scale is at like the 2 o'clock position in reference to the harmonic balancer and my light is reading the mark on the balancer at the 12 o'clock position. It does move closer to the scale when I rev it abit.
 
So my solution is going to be a new stock cam. Hopefully I can go back to stock springs even though the spring seats were cut to accommodate stiffer ones.
 
Without going back through the whole thread (I see no mention of it in your initial post), have you run a compression check?
 
I realize it is a new build.

If you are at the point of thinking of replacing the cam, before going to that extent, I would run a compression check. You might glean an insight into the issue.
 
So dang it. New is not a good reason to not run test. Compression is terrible. Oh the frustration.
1. 39
2. 39
3. 39
4. 40
5. 60
6. 60
 
What do you get if you add a bit of oil (maybe Marvel Mystery Oil) to each cylinder?

There is some time required for rings to "seat" in. How much time do you have on this motor?

There are a number of variables to consider at this point.

How did you set the cam timing?
 
I have 20 miles on the engine and idk how many times at idle. So yeah the rings probably aren't set yet. I was told by the machine shop " two years ago" that I would have high compression at 10:1. Woud rings that aren't set yet allow that much to leak past? Keith at Newcomer Racing says my cam is bigger than he likes on this platform. Degreeing a cam is out of my wheel house.
 
I would get both sets of compression numbers (dry and wet) and discuss those as well as the cam numbers (lift, duration, overlap) with a good engine builder (Keith, Russ Pottenger...) before tearing into the engine.

It could be just a matter of this being part of the break-in process.

It could be that your cylinders were not honed properly for the metallurgy of the rings (Do you know what ring type you are running? Was the machinist apprised of that?)

The list of ways to get things wrong is a long one. Best to get the diagnosis refined before you fire the parts cannon.
 
So alittle progress maybe. I did the wet compression test and numbers are much better.

Also, way back at the beginning of this thread I said adjusting the butterfly didn't work, well maybe I didn't do it enough because I just maxed it out and I've got idle. It actually stays idling when I come to a stop sign. It did rev kinda high once at stop but maybe that will work itself idle. I wish I would of checked the butterfly again after mewz99 suggested it.
 
Ryn89xj said:
Also, way back at the beginning of this thread I said adjusting the butterfly didn't work, well maybe I didn't do it enough because I just maxed it out and I've got idle. It actually stays idling when I come to a stop sign. It did rev kinda high once at stop but maybe that will work itself idle. I wish I would of checked the butterfly again after mewz99 suggested it.
Click to expand...
Well, at least it's more driveable now, and you've got ideas on the other stuff.

You said you replaced the intake with HO, so I'm assuming you are running HO throttle body...I don't know if it has an idle adjustment screw (under a cap on the driver's side) but that's worth adjusting so you can bring the butterfly back a bit. If it doesn't have it, then butterfly is your only option
 
I have switched TB's and haven't noticed another screw adjustment but I'm damn sure going to double check at this point. Its a stock TB off a 96. The TPS was a pain. Thanks for everyone's help.
 
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