Stroker up and running.......NOT!

Well, finally got my stroker in and fired up. Had a couple of initial problems......fuel lines reversed, distributor 180* out, and then missed it by one tooth, but it finally fired and ran for 40 min to break in the cam. Oil pressure is good, over 60 lbs (pegs the gauge) until warm and then runs between 35 and 55lbs.

Developed a slight miss with no load, but it was a bad miss when under a load driving it. First drive it still had more power than my old motor, even with a bad miss. In only a couple of drives and starts the miss has become very bad under load, and is very noticeable at no load (sitting in neutral) most of the time, but not all of the time. A couple of times it had started and no miss could be detected, but then it would gradually start to miss again. Under a load it has always missed bad, but now it seems worse than it did at first.

A tester showed a problem with one cylinder......a special tester that measures the current flow of each plug wire, which showed one cylinder (no 4) taking less current to fire. This would normally relate to less compression, a plug not gapped enough, or something like that. We replaced the plug wires, the cap, the plug in that cyl, and the injector in that cyl, and sprayed brake cleaner around the manifold and vacuum lines looking for a leak, but none of this made any difference.

I need to do a compression test, and pull the valve cover to see if anything isn't right. Has anyone experienced something similar that had an easy fix that we're missing? I've already run it with ATF to unstick a sticky lifter, with no improvement. I'm afraid that a lifter is just bad or the cam lobe has gone flat.

If you have a stuck lifter or flat cam lobe, you'll hear loud tappet noise from that cylinder as well as having a loss of compression.
Are you getting any fault codes on your PCM? I just wonder if your problem's sensor related e.g. MAP sensor. Also check your distributor again to make sure it's correctly indexed. I've written a page on how to do this procedure:

http://www.angelfire.com/my/fan/dist_index.html
___________________________________________________________
1992 XJ Laredo - 4.6L I6 HO Stroker - 175k miles - AX15, NP231, D35c, D30
Estimated 261hp/322lbft, best 1/4 mile [email protected] with modded 4.0L I6
Websites - Jeep 4.0 Performance, 4.6L Stroker Build-Up, Dino's Jeep Tricks

Already set the distributor right, it was off one tooth and ran very badly. Now, it has a miss consistant with a dead hole......only one cylinder misfiring. This doesn't point to a sensor, unfortunately. There is a slight tapping noise in the motor, but deeper in the motor, not on top like inside the valve cover. But, noises can telegraph, and I haven't properly listened for the source of the noise yet. It does not have a typical lifter clack, any noise is much quieter and can only be heard when next to the vehicle, not inside or even standing in front when normal engine and exhaust noise drowns it out.

Goatman said:

Already set the distributor right, it was off one tooth and ran very badly. Now, it has a miss consistant with a dead hole......only one cylinder misfiring. This doesn't point to a sensor, unfortunately. There is a slight tapping noise in the motor, but deeper in the motor, not on top like inside the valve cover. But, noises can telegraph, and I haven't properly listened for the source of the noise yet. It does not have a typical lifter clack, any noise is much quieter and can only be heard when next to the vehicle, not inside or even standing in front when normal engine and exhaust noise drowns it out.

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So, No more impromptu drag races from the food joint to camp???? You will kick my butt this time ....the 91's a dog....... Even ricks is faster than mine......


Joe

FlexyJOE said:

So, No more impromptu drag races from the food joint to camp???? You will kick my butt this time ....the 91's a dog....... Even ricks is faster than mine......


Joe

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Yeah, it should run good........once I get it running right. I'm having to ride in a CJ for this weekends Swamp Lake run, but I'll have a good time. I can jump out and see more of what's going on, and it may be a more relaxing trip overall. I'll get back to figuring mine out next week. I have to get it ready for the 'Con trip in a month.

Now it's running! Finally got the time to get it checked out, and it was a bad injector. I had replaced the injector in cyl 4, but I had the wrong cyl, it was number 5. The motor runs strong, a big difference from my old motor. I've only driven it a few miles, so I need to spend some time in it to see what it really does, but I'm very happy with the first impression.

Welcome to the stroker club...... You will really love it on the trails. It pulls so nice at low rpms. Are you running an auto or manual tranny?

Auto.......with 5.13's and a 4 to 1, and 37's. I'll really need to get that 2nd gear lock switch done on the tranny now. Actually, I've never felt a need for more power on the trail, so we'll see how it feels. I mostly wanted more power to go fast to and from the trail, to keep ahead of CRASH, Jes, and Hinkley. I also wanted more power for the highway, especially those long trips to Moab and CO, and to the 'Con, but now I've started trailering so that's not such a big deal any more. Still, having much better highway performance will be very nice.......and I can already tell there's a major difference.