Screwy startup and idle after general maint. - JeepForum.com
 
LinkBack Thread Tools
post #1 of 5 Old 12-14-2019, 03:12 PM Thread Starter
Kevoo_11
Registered User
 
Kevoo_11's Avatar
1997 TJ Wrangler 
 
Join Date: Sep 2017
Location: Laporte, Indiana
Posts: 109
Screwy startup and idle after general maint.

I decided to use the 45 degree temps to do some overdue maintenance to the 2000 I bought in September, so I changed the pulgs, and cleaned the IAC and throttle body (With throttle body cleaner). After I was done I started it up and it ran like absolute garbage....I thought maybe the computer was rethinking the fuel mixture or something because I pulled the ground on the battery. I drove it around the neighborhood and eventually it threw me an error code. Misfire in cylinder 6. I pulled the plug and realized that I f'ed up the gap when i installed it as it was less than .02. I pulled all the plugs again, regapped to .035, torqued to 27lbs and put the coil back on.

Today I got in and it was throwing me a check gauges (battery voltage). I checked the voltage with a multimeter and it was 12.2 off and 14.0 at idle. I fired it back up and all was well. Well on my way to the gym I started realizing that on the go it was running great, but at red lights it was quaking and shaking with some deviations between 500 and 750 rpms..it feels like death wobble when stopped but runs smooth while driving. After I'd driven 10ish miles at 50 mph it seemed to calm down.

I'm tempted to just throw a new IAC and TPS at it, or at least go to the pick n pull and buy all of the ones on the lot to see how each reacts. What do you guys think?

Kevoo_11 is offline  
Sponsored Links
Advertisement
 
post #2 of 5 Old 12-14-2019, 03:43 PM
2oldjeeps
Registered User
2000 XJ Cherokee 
 
Join Date: Aug 2017
Posts: 1,745
dont know, but my experience as a ? new jeep guy,5-7 yrs is give them fluid changes often.
fix whats broke only, like wires.
i just got home running my 00 xj,179000 mile jeep. runs strong and so smooth it amazes me.
ive never seen a jeep spark plug. big maintenance for me is filling the tank...!
my daily driver, 99 wj,147000 miles, same thing,like new!

99wj,143,000 miles
00xj,177,000 miles
10hummer3,74,000 miles
98xj,130,000 miles
2oldjeeps is offline  
post #3 of 5 Old 12-14-2019, 06:22 PM
CJ7-Tim
Real Jeeps have dents
 
CJ7-Tim's Avatar
2000 XJ Cherokee 
 
Join Date: Apr 2002
Location: out in the garage - Minneapolis
Posts: 28,352
Disconnecting the battery can cause the PCM to re-boot, leading to an initial hard start and rough idle until the PCM re-learns the idle settings. Cleaning or changing the Idle Air Controller can confuse the PCM until it adapts to the changes. If the start and idle symptoms persist, suspect low voltage.

If the dashboard voltage gauge was showing 9 volts, that usually means alternator issues. If the gauge was showing 19 volts that usually means connectivity issues, loose or corroded battery/alternator connections, or internally corroded battery wires.

Test the TPS. If you buy any parts make sure they are genuine Jeep parts. Most auto parts stores sell cheap crappy Chinese made parts, some that even come with a "Lifetime Warranty". These parts are poorly manufactured and/or made from inferior materials. They are often out of specification, or even failed, right out of the box. The ones that are not faulty many times will have a short service life before they fail. Always buy top quality replacement parts and genuine Jeep engine sensors. Numerous threads detail long and frustrating searches for a "problem" that ended up being cured simply with genuine Jeep repair parts.
 
Cheap parts are cheap for a reason.

.
“When the people find that they can vote themselves money, that will herald the end of the Republic.”

- Benjamin Franklin
CJ7-Tim is offline  
 
post #4 of 5 Old 12-14-2019, 09:26 PM
Essrobb
Registered User
 
Join Date: Dec 2019
Posts: 9
Sound to me like you got the firing order wrong when you put the plug wires back on after changing them. Worth a look before you start throwing money at new parts that may not need to be replaced.
Essrobb is offline  
post #5 of 5 Old 12-16-2019, 01:48 PM Thread Starter
Kevoo_11
Registered User
 
Kevoo_11's Avatar
1997 TJ Wrangler 
 
Join Date: Sep 2017
Location: Laporte, Indiana
Posts: 109
Quote:
Originally Posted by CJ7-Tim View Post
Disconnecting the battery can cause the PCM to re-boot, leading to an initial hard start and rough idle until the PCM re-learns the idle settings. Cleaning or changing the Idle Air Controller can confuse the PCM until it adapts to the changes. If the start and idle symptoms persist, suspect low voltage.

If the dashboard voltage gauge was showing 9 volts, that usually means alternator issues. If the gauge was showing 19 volts that usually means connectivity issues, loose or corroded battery/alternator connections, or internally corroded battery wires.

Test the TPS. If you buy any parts make sure they are genuine Jeep parts. Most auto parts stores sell cheap crappy Chinese made parts, some that even come with a "Lifetime Warranty". These parts are poorly manufactured and/or made from inferior materials. They are often out of specification, or even failed, right out of the box. The ones that are not faulty many times will have a short service life before they fail. Always buy top quality replacement parts and genuine Jeep engine sensors. Numerous threads detail long and frustrating searches for a "problem" that ended up being cured simply with genuine Jeep repair parts.
 
Cheap parts are cheap for a reason.
I ran it for 2ish hours this weekend and now the gauges are all reading just right, and it's running much smoother than it was. It's still is doing a little jumping at idle, but is running at 500-600 rpms rather than the 1000 it was before I cleaned it out. I don't think I'm going to order a $70 part just to see if it'll be a little better, but I will go pull the sensors from a few TB's at the yard and see if any of the components solve the issue. Thank you

Quote:
Originally Posted by Essrobb View Post
Sound to me like you got the firing order wrong when you put the plug wires back on after changing them. Worth a look before you start throwing money at new parts that may not need to be replaced.
Coil pack in the 2000. No wires.
Kevoo_11 is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome