LOOOOW idle

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Laurent Wagoneer

NAXJA Forum User

Location

Boyle Heights,CA

• Nov 6, 2013

• #1

Really LOW idle. Talking 250 here. 90 wagoneer 4.0
I give it gas and hold it at 750 for about 5 sec and when I let go it drops to the point of hevy shaking.



Changed IAC and no diference.
Noticed this after a sea foam treatment.
New O2 sensor after the sea foam as well as a new CAt.

 

xjtrailrider

NAXJA Forum User

NAXJA Member

Location

Roanoke VA

• Nov 6, 2013

• #2

Check and make sure the rear CCV orifice is clear. I found on my 90 Laredo I had put on a 96 valve cover with a 96 CCV orifice, it turns out I had to drill out the orifice to allow it to run leaner at idle(think controlled vacuum leak) It went from idleing at 600rpm to 750rpm easily. This same result will happen if the stock rear CCV tube is stopped up.

 

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Laurent Wagoneer

NAXJA Forum User

Location

Boyle Heights,CA

• Nov 6, 2013

• #3

I'll take out the VC and clean it out along with the tube

 

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Runnin'OnEmpty

NAXJA Forum User

Location

Southeast USA

• Nov 6, 2013

• #4

Laurent Wagoneer said:

........Changed IAC and no diference.......

Click to expand...

Check to see if you actually have power at
the IAC plug. That is about what the idle speed
would be if the IAC is inoperative.
(Blown fuse?)

 

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Laurent Wagoneer

NAXJA Forum User

Location

Boyle Heights,CA

• Nov 6, 2013

• #5

There is power going to the IAC
I unplugged it and started the car, high idle.
Plugged it in and idle fixed

 

xjtrailrider

NAXJA Forum User

NAXJA Member

Location

Roanoke VA

• Nov 6, 2013

• #6

Laurent Wagoneer said:

I'll take out the VC and clean it out along with the tube

Click to expand...

While you are at it go ahead and do the valve cover mod to prevent all of the oil being sucked up into the filter box and CCV tube. Search, you will find the write up on here

 

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Laurent Wagoneer

NAXJA Forum User

Location

Boyle Heights,CA

• Nov 6, 2013

• #7

ok, so i inspected the CCV and there in no signes of it being plugged. i also took the valve off and no signs of it being clogged either.
i took the intake hose from the air box and there is no suction... on the norm, there would be enough to suck my hand in ...... at idle.... took it off to expose the TB and still... not enough suction... TB and intake are clean, i sea foamed it last month. bolts are tight....

 

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cruiser54

NAXJA Forum User

Location

Prescott, Az

• Nov 7, 2013

• #8

How much vacuum do you have from the hose that runs to the rear grommet? I've seen the intake manifold fittings get crudded up with carbon.