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Unread 05-03-2013, 09:02 PM   #1
brewcity1
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Did tune-up and injector swap...ZJ running terrible! :(

Hey guys...I just did a tune up (Kolak's injection upgrade w/ new Camshaft Position Sensor) and did the 703 injector swap all about a week ago. I figured it would take a bit for the PCM to re-learn everything...but my Niner is running like ars!
I also put in a new TPS, IAC, cleaned the Throttle Body, and have a Durango air hat now.
Since all this...the Jeep has a really rough idle, and it has worse gas mileage than before. It also seems more sluggish, and has a loss of power. It hasn't died on me though.
I have NO idea what to even check now, as all the threads on this say to put in new spark plugs, wires, cap, rotor and coil...which I did...and to clean the IAC, which mine is new.
Can someone shed some light on what else would cause my issues, and what I should do or check. I would greatly appreciate it.
Thanks a lot!!

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Unread 05-03-2013, 09:19 PM   #2
tbax94
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I had the same issue with my tune-up last month. My problem was that one of the spark plugs got damaged during installation, the ground electrode was bent, and it closed the gap. It may not be the solution for you but its worth taking a peak
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Unread 05-03-2013, 09:27 PM   #3
zander21510
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Were the injectors new? Are they all tested? It sounds pretty similar to problems a lot of people have with leaky injectors from JYs.
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Unread 05-03-2013, 09:32 PM   #4
brewcity1
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Quote:
Originally Posted by tbax94 View Post
I had the same issue with my tune-up last month. My problem was that one of the spark plugs got damaged during installation, the ground electrode was bent, and it closed the gap. It may not be the solution for you but its worth taking a peak
Thanks...I didnt think of that. I will take another look and make sure they are all gapped the same, and report back.

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Originally Posted by zander21510 View Post
Were the injectors new? Are they all tested? It sounds pretty similar to problems a lot of people have with leaky injectors from JYs.
The injectors were not new, but were cleaned, re-built and tested before going in. Is there a way to test for a leaky injector while on the manifold?? Or do I have to yank them out to test them?
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Unread 05-03-2013, 09:40 PM   #5
dnuccio
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had a problem like that with mine after the injector swap. one of them was leaking and dumping fuel. swapped it out and she ran/has run perfect/better since.
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Unread 05-03-2013, 10:00 PM   #6
brewcity1
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Originally Posted by dnuccio View Post
had a problem like that with mine after the injector swap. one of them was leaking and dumping fuel. swapped it out and she ran/has run perfect/better since.
Thanks...sounding like its a injector issue. I'll double check the plugs 1st...then tackle the injectors if that doesnt clear up the issue.
Exactly what am I looking for with a leaky injector? How do I find out one is leaking?
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Unread 05-03-2013, 10:15 PM   #7
zander21510
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I listed an easy way to test on the OP of my injector swap thread (in my sig) you can try that.
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Unread 05-03-2013, 10:38 PM   #8
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Are they copper plugs?
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Unread 05-03-2013, 10:44 PM   #9
Uniblurb
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When I put new 703's in my 96 it was running like crap with idle going up/down. Someone mentioned to drive it at 50+mph for a while and sure enough after about a week of occasional driving it eventually smoothed right out. Rpm's were still going up/down at idle and about another week it leveled out. Don't know why it took the PCM so long to learn the new injectors and make adjustments but it finally did.
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Unread 05-04-2013, 07:44 AM   #10
brewcity1
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Quote:
Originally Posted by Uniblurb View Post
When I put new 703's in my 96 it was running like crap with idle going up/down. Someone mentioned to drive it at 50+mph for a while and sure enough after about a week of occasional driving it eventually smoothed right out. Rpm's were still going up/down at idle and about another week it leveled out. Don't know why it took the PCM so long to learn the new injectors and make adjustments but it finally did.
Huh...I was thinking it may take a awhile...but I have not taken the Niner for a drive around 50+ sunce the swap. Guess I'll try that now.
Thanks a lot!
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Unread 05-04-2013, 07:44 AM   #11
brewcity1
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Quote:
Originally Posted by xrunndonex View Post
Are they copper plugs?
They are the plugs that Kolak suggested for his ignition tune up....so no...they are platinum.
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Unread 05-04-2013, 07:56 AM   #12
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Quote:
Originally Posted by brewcity1 View Post

They are the plugs that Kolak suggested for his ignition tune up....so no...they are platinum.
.I know my 4.0 likes copper and wormy run good on any other
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Unread 05-04-2013, 08:15 AM   #13
brewcity1
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Originally Posted by xrunndonex View Post
.I know my 4.0 likes copper and wormy run good on any other
Thanks...I have read the same. However, Kolaks ignition tune up is well proven, and if he has platinum plugs with his kit, I trust that choice, in combination with the other parts in his kit. I will just have to double check that each one is gapped at .040, and that some are not off.
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Unread 05-04-2013, 10:13 AM   #14
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Take off the air hat and throttle body then unbolt the fuel rail and gently pry the injectors up one side at a time while leaving them on the fuel rail. Put some paper towel under them and have someone turn the key to cycle the fuel pump on. That's how I checked for a leaky injector. If it leaky it will drip on the paper towel when the fuel line is pressurized.

To listen if the injectors are working just put the tip of a long dowel rod on the injectors while it's running and put the other end to your ear to listen. You will hear them clicking away if they are working. They should all sound the same.
Good luck.
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Unread 05-04-2013, 10:45 AM   #15
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Quote:
Originally Posted by brewcity1 View Post
Thanks...I have read the same. However, Kolaks ignition tune up is well proven, and if he has platinum plugs with his kit, I trust that choice, in combination with the other parts in his kit. I will just have to double check that each one is gapped at .040, and that some are not off.
I would throw the old copper plugs in as a test. Rule out the easier stuff before you start pulling injectors and whatnot.
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