Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here XJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.

low/rough idle cherokee, need help

Thread Tools
 
Search this Thread
 
Old 04-30-2015, 12:29 AM
  #46  
Junior Member
Thread Starter
 
noraayrrek's Avatar
 
Join Date: May 2014
Posts: 63
Likes: 0
Received 0 Likes on 0 Posts
Model: Cherokee
Default

Originally Posted by cruiser54
Your manifold vacuum seems a little low. Perhaps the gauge is faulty? When you get the Brick hooked up again, let's see what it says the vacuum is at.

Have you indexed your distributor?
Well according to my results the first day my map said 45kpa at idle which is about 13.5 inch hg, so I think my gauge is pretty close

Being as this engine is a complete rebuilt block from a machine shop would it be possible the timing gears are off a tooth?
I personaly wasn't there to comfirm them being spot on when my buddy swapped all my trim off my old engine to the new one.

I think I did it correct, according to your tips, I may pull it again just to tripple check, how far should the rotar be in relation with post #1 ?

Last edited by noraayrrek; 04-30-2015 at 12:25 PM.
Old 04-30-2015, 04:03 PM
  #47  
Junior Member
Thread Starter
 
noraayrrek's Avatar
 
Join Date: May 2014
Posts: 63
Likes: 0
Received 0 Likes on 0 Posts
Model: Cherokee
Default

Do you think it would be worth it to pull the timing cover and check it out?
Old 04-30-2015, 05:55 PM
  #48  
::CF Moderator::
 
cruiser54's Avatar
 
Join Date: Aug 2011
Location: Prescott, Az
Posts: 43,971
Received 1,559 Likes on 1,263 Posts
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Default

Originally Posted by noraayrrek
Do you think it would be worth it to pull the timing cover and check it out?
Not before verifying the distributor indexing.
Old 04-30-2015, 08:54 PM
  #49  
Junior Member
Thread Starter
 
noraayrrek's Avatar
 
Join Date: May 2014
Posts: 63
Likes: 0
Received 0 Likes on 0 Posts
Model: Cherokee
Default

Timing is good and on compression stroke



Old 04-30-2015, 09:34 PM
  #50  
::CF Moderator::
 
cruiser54's Avatar
 
Join Date: Aug 2011
Location: Prescott, Az
Posts: 43,971
Received 1,559 Likes on 1,263 Posts
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Default

What elevation do you live at?
Old 04-30-2015, 09:55 PM
  #51  
Junior Member
Thread Starter
 
noraayrrek's Avatar
 
Join Date: May 2014
Posts: 63
Likes: 0
Received 0 Likes on 0 Posts
Model: Cherokee
Default

Around 1800 feet
Old 04-30-2015, 10:00 PM
  #52  
::CF Moderator::
 
cruiser54's Avatar
 
Join Date: Aug 2011
Location: Prescott, Az
Posts: 43,971
Received 1,559 Likes on 1,263 Posts
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Default

Originally Posted by noraayrrek
Around 1800 feet
Well, that's not the cause of low vacuum them.

Rule of thumb is 17 to 21 inches at idle at sea level. Deduct 1" of vacuum for every 1000 feet of elevation.
Old 04-30-2015, 10:26 PM
  #53  
Junior Member
Thread Starter
 
noraayrrek's Avatar
 
Join Date: May 2014
Posts: 63
Likes: 0
Received 0 Likes on 0 Posts
Model: Cherokee
Default

Originally Posted by cruiser54
Well, that's not the cause of low vacuum them.

Rule of thumb is 17 to 21 inches at idle at sea level. Deduct 1" of vacuum for every 1000 feet of elevation.
Well I have done so much to fix this motor to get it to run properly, this extrelmly low idle and almost stalling issue started when the new block was installed. My buddy said he didn't confirm the cam timing before he put the cover on.
So I don't even know what to try anymore.
This spudder, rough idle, and miss/back fire when first starting then moves to a decent idle until the motor starts warming up, then it's just low and almost stalling at every stop, I am beginning to thing this jeep is cursed. I have spent 14k building this thing and it still runs like **** after doing the motor

I think I may just pull the cover off to confirm it my self that's its good.

But I just remembered I installed that egr block plate when I put the new block in so maybe it's leaking and sucking exhaust in ?!? I used some hitemp silicone and but fired it up 30 min after putting it on so maybe it didn't dry and seal properly?
Old 04-30-2015, 10:34 PM
  #54  
::CF Moderator::
 
cruiser54's Avatar
 
Join Date: Aug 2011
Location: Prescott, Az
Posts: 43,971
Received 1,559 Likes on 1,263 Posts
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Default

Originally Posted by noraayrrek
Well I have done so much to fix this motor to get it to run properly, this extrelmly low idle and almost stalling issue started when the new block was installed. My buddy said he didn't confirm the cam timing before he put the cover on.
So I don't even know what to try anymore.
This spudder, rough idle, and miss/back fire when first starting then moves to a decent idle until the motor starts warming up, then it's just low and almost stalling at every stop, I am beginning to thing this jeep is cursed. I have spent 14k building this thing and it still runs like **** after doing the motor

I think I may just pull the cover off to confirm it my self that's its good.

But I just remembered I installed that egr block plate when I put the new block in so maybe it's leaking and sucking exhaust in ?!? I used some hitemp silicone and but fired it up 30 min after putting it on so maybe it didn't dry and seal properly?
Spray carb cleaner around there at idle. Intake manifold fully seated on the dowels?Did you use an aftermarket header?
Old 04-30-2015, 10:39 PM
  #55  
Junior Member
Thread Starter
 
noraayrrek's Avatar
 
Join Date: May 2014
Posts: 63
Likes: 0
Received 0 Likes on 0 Posts
Model: Cherokee
Default

I didn't install the intake or exhaust manifold but they look like they are seated properly, they are stock.

If I blow smoke into the intake manifold and see if I see any smoke blow out anywhere would that work too?

I'll try the carb cleaner too!

Last edited by noraayrrek; 04-30-2015 at 10:42 PM.
Old 04-30-2015, 10:48 PM
  #56  
::CF Moderator::
 
cruiser54's Avatar
 
Join Date: Aug 2011
Location: Prescott, Az
Posts: 43,971
Received 1,559 Likes on 1,263 Posts
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Default

Originally Posted by noraayrrek
I didn't install the intake or exhaust manifold but they look like they are seated properly, they are stock.

If I blow smoke into the intake manifold and see if I see any smoke blow out anywhere would that work too?

I'll try the carb cleaner too!
I've never used smoke.

I'll tell you this though.

Many aftermarket manifolds/headers do not allow the intake manifold to seat properly as it hangs up on the dowels or near #1 and #6 cylinder. I've had to file the intake manifolds to get them to fit.
Attached Thumbnails low/rough idle cherokee, need help-intake-filing.jpg  
Old 05-01-2015, 09:11 PM
  #57  
Junior Member
Thread Starter
 
noraayrrek's Avatar
 
Join Date: May 2014
Posts: 63
Likes: 0
Received 0 Likes on 0 Posts
Model: Cherokee
Default

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?
Old 05-01-2015, 09:43 PM
  #58  
::CF Moderator::
 
cruiser54's Avatar
 
Join Date: Aug 2011
Location: Prescott, Az
Posts: 43,971
Received 1,559 Likes on 1,263 Posts
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Default

Carb cleaner bogging it down is not rich. It's a result of spraying carb cleaner into it.
Old 05-01-2015, 09:59 PM
  #59  
Junior Member
Thread Starter
 
noraayrrek's Avatar
 
Join Date: May 2014
Posts: 63
Likes: 0
Received 0 Likes on 0 Posts
Model: Cherokee
Default

Originally Posted by cruiser54
Carb cleaner bogging it down is not rich. It's a result of spraying carb cleaner into it.
Okay

Is there any way that the ignition timing can be adjusted?

I think I'm going to pull the cover and check the valve timing on of these days I get time

Last edited by noraayrrek; 05-01-2015 at 10:01 PM.
Old 05-01-2015, 10:40 PM
  #60  
CF Veteran
 
DFlintstone's Avatar
 
Join Date: Aug 2011
Location: Nor-Cal Coast
Posts: 10,489
Likes: 0
Received 18 Likes on 18 Posts
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Default

You have a piece of vacuum line on the TPS tab, to get it within spec? My intermittent stalling was solved by adjusting my TPS on my "new" renix.

Fyi, my intermittent high idle was really bugging me after cleaning the IAC a few times. (on my other Renix). Finally cleaning it's connector better is what solved it. My thought is that since the socket deal faces up coolant, or water or something got, and stayed in there and did a number.

Last edited by DFlintstone; 05-01-2015 at 10:42 PM.


Quick Reply: low/rough idle cherokee, need help



All times are GMT -5. The time now is 07:16 PM.