low/rough idle cherokee, need help

Reply Subscribe

Thread Tools

Search this Thread

May 28, 2015 | 02:09 PM

#106

noraayrrek

Thread Starter

Junior Member

Joined: May 2014

Posts: 63

Likes: 0

Model: Cherokee

Well I just revived my 746 injectors in the mail, I'll install them next week and update.

May 28, 2015 | 05:41 PM

#107

cruiser54

::CF Moderator::

Joined: Aug 2011

Posts: 43,971

Likes: 1,578

From: Prescott, Az

Year: 1990

Model: Cherokee (XJ)

Engine: 4.0

Quote:

Originally Posted by noraayrrek

Well I just revived my 746 injectors in the mail, I'll install them next week and update.

I'm anxious to hear the results. Don't mess up the TB to MAP line!!

May 28, 2015 | 05:43 PM

#108

monst3r

Junior Member

Joined: Nov 2014

Posts: 53

Likes: 0

Model: Cherokee

Quote:

Originally Posted by cruiser54

I'm anxious to hear the results. Don't mess up the TB to MAP line!!

I have 746 injectors on mine with a similar problem but your problem may truely be different! Best of luck and look forward to the results.

Jun 8, 2015 | 11:36 AM

#109

noraayrrek

Thread Starter

Junior Member

Joined: May 2014

Posts: 63

Likes: 0

Model: Cherokee

new(er) injectors are in and the low hunting idle is still present

Jun 8, 2015 | 11:39 AM

#110

monst3r

Junior Member

Joined: Nov 2014

Posts: 53

Likes: 0

Model: Cherokee

Quote:

Originally Posted by noraayrrek

new(er) injectors are in and the low hunting idle is still present

I know the feeling

Jun 8, 2015 | 06:43 PM

#111

cruiser54

::CF Moderator::

Joined: Aug 2011

Posts: 43,971

Likes: 1,578

From: Prescott, Az

Year: 1990

Model: Cherokee (XJ)

Engine: 4.0

Okay you two, I'm too lazy to read 8 pages of posts and playing detective. Please, in one post each, list the things you have done to address this issue.

Jun 9, 2015 | 01:01 AM

#112

adamj

Junior Member

Joined: Jun 2014

Posts: 96

Likes: 1

From: California

Year: 1990

Model: Cherokee

Engine: 4.0L

Quote:

Originally Posted by noraayrrek

So I checks my buddies cherokee and his is pulling a vac of 14-15hg at idle and when revving it up he pulled about 19hg on my gauge
Mine is pulling about 12hg at idle with tiny needle fluctuations and when revved up pulls about 18hg. But when I let off it settles down to 14hg for a sec then returns to the 12hg

Okay I have no vacuum leaks, tried smoke and I tried carb cleaner, but I did notice that when I sprayed it into the intake the jeep bogged down, so I am guessing that means I am definatly running rich?

The egr block off plate is sealing well

I also pulled my computer down and pulled it apart, looks good as new inside, but I did notice two stray wires were there? No sure why or where they go, because I didn't see any on the harness cut any ideas where they go?

According to electrical manual, those two cut wires are for CPS Input to the ECU.
Violet w/ white tracer = C1 on ecu
White w/ black tracer = D1 on ecu

Jun 9, 2015 | 08:13 AM

#113

cruiser54

::CF Moderator::

Joined: Aug 2011

Posts: 43,971

Likes: 1,578

From: Prescott, Az

Year: 1990

Model: Cherokee (XJ)

Engine: 4.0

Those stray wires are from having the cPS bypass done at some time. No worries there.

Kinda low vacuum.

Have you ever indexed your distributor? Tip 13.

Jun 9, 2015 | 10:04 AM

#114

noraayrrek

Thread Starter

Junior Member

Joined: May 2014

Posts: 63

Likes: 0

Model: Cherokee

Quote:

Originally Posted by cruiser54

Those stray wires are from having the cPS bypass done at some time. No worries there.

Kinda low vacuum.

Have you ever indexed your distributor? Tip 13.

I found where those wires go, they pop out the the harness near the iat sensor andare connected to a female plug that doesn't plug into anything.

Yup I have done all your tips cruiser.

Jun 9, 2015 | 02:35 PM

#115

cruiser54

::CF Moderator::

Joined: Aug 2011

Posts: 43,971

Likes: 1,578

From: Prescott, Az

Year: 1990

Model: Cherokee (XJ)

Engine: 4.0

Quote:

Originally Posted by noraayrrek

I found where those wires go, they pop out the the harness near the iat sensor andare connected to a female plug that doesn't plug into anything.

Yup I have done all your tips cruiser.

I wonder why your vacuum is low.

Done the vacuum "throttle snap" test for restricted exhaust?