new motor runs bad above 1k

Just fired my fresh remanned motor and it idles at 500 rpm and from idle to 1000k it revs but as soon as it gets above 1000k it starts to cut out and back fire real bad.I pulled a plug out and it was wet.

The only sensors I have not replaced are the cam sensor,iac,map and tps.everything else is new,injectors are new from five-o motorsports(19lb).The old motor didn't run this bad so I'm thinking I did something wrong.....

I did have the dist installed 180 deg out and it wouldn't fire at all,so I reinstalled it and it fired up but runs like $hit.It's almost like the ignition isn't advancing when you open the throttle.

If I have the dist installed one or two teeth off would it make it run so bad or would the computer compensate?I only hope they installed the timing set right......,I'll put a timing light on it just in case.

any help?I'm very frustrated!!

The symptom you outline is most likely caused because you don't have the distributor indexed correctly. You are off by one tooth.

I just installed a remanufactured motor in my '91 XJ, and I had the same problem. It was difficult to start, and had a hard time revving.

It was the distributor. I was off by one tooth, and then I had the wires installed incorrectly in the opposite direction. Since the distributor was installed wrong, the wire posts on it *looked* like number 1, number 2, etc. But after I rotated the distributor one tooth, I realized that the proper post positions were different from what I thought.

It was an easy fix, and from your description, I'd bet that's your problem. Good luck.

Thanks guys...that is what I suspected,although I've been told that even if the dist is one or two teeth off that the computer would compensate?Rule #1 don't believe everything you hear......

The thing that baffles me is when I installed the dist the first time I did it by the chilton manual and it ended up being out 180 so I reinstalled the way the book said using my compression gauge to find tdc on #1 and made sure the timing marks on the pulley said tdc.Then I made sure the rotor was pointing at #1.

Is there a step I'm missing here?What is the easiest way to index this thing?

I know you've got a Renix, but this is what I could find
http://www.angelfire.com/my/fan/dist_index.html
Finally got that block out of the back of my MJ. Looking for a 258 crank. Got my budget put together for the stroker. Less than $1k to build it proper. Little bit more to put on an HO head, intake and exhaust.
Good luck with the XJ. Can't wait to come down there and beat on it

1000?that sounds good...maybe I should have stroked it....

yea I came across that link for the ho indexing after some searching.I'm going to put the timing light on it tomorrow and fiddle with the indexing some more.So after I get this little gremlin fixed I'll be looking at getting all my armor on and I'll see you on the trail!!

pull it back out rotate 1 more tooth and test. If that doesn't fix it, pull out and rotate opposite direction 2 teeth and test.

I've had this issue before (being 1 tooth off) on a 91 cherokee. The optimum position is for the trailing edge of the rotor to be pointing at your plug 1 position on the cap. I had set mine at the leading edge and it also ran horribly. If you continue to have this issue after resetting the position then you might want to check out the link below.
I ran into a bad misfire issue on my 90 XJ, but unfortunately I replaced ALL sensors, the distributor, coil, ECM and plenty of other things, I even had it in three shops with no cure, until a mechanic friend of mine got this tech bulletin through a research service. cure.http://www.asashop.org/autoinc/feb99/techtotech.htm
Good Luck!

Welcome to naxja.....
That was a very interesting article....it answered alot of my questions.I do have another question concerning this part:
quote:
A misindexed distributor may exhibit surging, light bucking or intermittent engine misfiring. This will most likely occur when the vehicle is at operating temperature and under a light load at approximately 2,000 rpm. This condition may be caused by a misindexed distributor

I've had the exact same problem for the three years I've owned this xj,so I think this has been my problem all along.My question is about those distributor gears I heard about that were installed at the factory of the wrong tooth count.What years are affected?and what should the tooth count on the dist gear on my 89 ? I'm making sure I rule that out......

T.I.A

Thanks for everyones help.I finally got the dist. stabbed right and she purrs like a kitten....or uhh I mean she roars like a tiger,ha that sounds more manly.

Now I have to get a new tps because I found dead spot in this one while I was adjusting it.....damn it never ends does it?

I owe you all a cold one!
thanks again,
Mike

jeepdeepfreak said:

Thanks for everyones help.I finally got the dist. stabbed right and she purrs like a kitten....or uhh I mean she roars like a tiger,ha that sounds more manly.

Now I have to get a new tps because I found dead spot in this one while I was adjusting it.....damn it never ends does it?

I owe you all a cold one!
thanks again,
Mike

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