1990 Renix low idle and random high idle on startup
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
My grumpy idle on one of my 90's is back... In the past cleaning the socket right on the IAC, turned out to be the ticket. Tough to clean. Blast with contact cleaner, plug/re-plug, re blast, is all I got) It's a "spare" Jeep I don't use allot and it's acting up again, I should check the other connector also.
A "2 cents worth" here. If an idle problem changes, or goes away after turning the engine off, then restarting, suspect the IAC, or it's wires/connections.
A "2 cents worth" here. If an idle problem changes, or goes away after turning the engine off, then restarting, suspect the IAC, or it's wires/connections.
Thread Starter
Junior Member
Joined: Feb 2012
Posts: 38
Likes: 0
From: Washington
Year: 1990
Model: Cherokee
Engine: 4.0
[QUOTE=cruiser54;3191668]
Cleaned it twice, brushed once, second time just needed spray. Tried testing it using lungs chart with my crappy dmm seemed close.
Can't recall the numbers now.
Broke down and bought contact cleaner, cleaned all the plugs I could reach in the bay plus relays. Headlight harness plug was nasty just like you said it would be.
Can't recall the numbers now.
Broke down and bought contact cleaner, cleaned all the plugs I could reach in the bay plus relays. Headlight harness plug was nasty just like you said it would be.
Thread Starter
Junior Member
Joined: Feb 2012
Posts: 38
Likes: 0
From: Washington
Year: 1990
Model: Cherokee
Engine: 4.0
My grumpy idle on one of my 90's is back... In the past cleaning the socket right on the IAC, turned out to be the ticket. Tough to clean. Blast with contact cleaner, plug/re-plug, re blast, is all I got) It's a "spare" Jeep I don't use allot and it's acting up again, I should check the other connector also.
A "2 cents worth" here. If an idle problem changes, or goes away after turning the engine off, then restarting, suspect the IAC, or it's wires/connections.
A "2 cents worth" here. If an idle problem changes, or goes away after turning the engine off, then restarting, suspect the IAC, or it's wires/connections.
Thread Starter
Junior Member
Joined: Feb 2012
Posts: 38
Likes: 0
From: Washington
Year: 1990
Model: Cherokee
Engine: 4.0
[QUOTE=Chad'sCheep;3191719]
Cleaned it twice, brushed once, second time just needed spray. Tried testing it using lungs chart with my crappy dmm seemed close.
Can't recall the numbers now.
Broke down and bought contact cleaner, cleaned all the plugs I could reach in the bay plus relays. Headlight harness plug was nasty just like you said it would be.
Well, last night cleaned more plugs, including the distributor plug that i missed last time, had some muddy residue in it. Scraped the cap and rotor, cleaned and adjusted the iac, put my old map back in (I found a new looking one in the jy that someone had replaced recently so I grabbed it)
And it seems to have worked this time. Idles at 800 rpm in park (the line under the 1k mark, I'm assuming that's 800 rpm)
Cleaned it twice, brushed once, second time just needed spray. Tried testing it using lungs chart with my crappy dmm seemed close.
Can't recall the numbers now.
Broke down and bought contact cleaner, cleaned all the plugs I could reach in the bay plus relays. Headlight harness plug was nasty just like you said it would be.
And it seems to have worked this time. Idles at 800 rpm in park (the line under the 1k mark, I'm assuming that's 800 rpm)
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,578
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
[QUOTE=Chad'sCheep;3193574]
Well, last night cleaned more plugs, including the distributor plug that i missed last time, had some muddy residue in it. Scraped the cap and rotor, cleaned and adjusted the iac, put my old map back in (I found a new looking one in the jy that someone had replaced recently so I grabbed it)
And it seems to have worked this time. Idles at 800 rpm in park (the line under the 1k mark, I'm assuming that's 800 rpm)
Well, imagine that!!!
So Cruiser isn't full of **** when he suggests doing his Tips completely?
Well, last night cleaned more plugs, including the distributor plug that i missed last time, had some muddy residue in it. Scraped the cap and rotor, cleaned and adjusted the iac, put my old map back in (I found a new looking one in the jy that someone had replaced recently so I grabbed it)
And it seems to have worked this time. Idles at 800 rpm in park (the line under the 1k mark, I'm assuming that's 800 rpm)
So Cruiser isn't full of **** when he suggests doing his Tips completely?
Thread Starter
Junior Member
Joined: Feb 2012
Posts: 38
Likes: 0
From: Washington
Year: 1990
Model: Cherokee
Engine: 4.0
[QUOTE=cruiser54;3193753]
Well then, has anyone on here suggested that your full of shyt? Lol.
It wasn't the end all fix as I had hoped, still drops down to the first line sometimes (250?) but a marked improvement regardless.
As of now still haven't done ALL your tips. The sensor harness upgrade seems like a can of worms I'm not looking forward to, as my soldering skills are lacking.
Your insight is appreciated by all of us renix rookies, so I'm gonna keep on keepin' on as time allows.
It wasn't the end all fix as I had hoped, still drops down to the first line sometimes (250?) but a marked improvement regardless.
As of now still haven't done ALL your tips. The sensor harness upgrade seems like a can of worms I'm not looking forward to, as my soldering skills are lacking.
Your insight is appreciated by all of us renix rookies, so I'm gonna keep on keepin' on as time allows.
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,578
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
[QUOTE=Chad'sCheep;3193854]
Well then, has anyone on here suggested that your full of shyt? Lol.
It wasn't the end all fix as I had hoped, still drops down to the first line sometimes (250?) but a marked improvement regardless.
As of now still haven't done ALL your tips. The sensor harness upgrade seems like a can of worms I'm not looking forward to, as my soldering skills are lacking.
Your insight is appreciated by all of us renix rookies, so I'm gonna keep on keepin' on as time allows.
Do the sensor ground upgrade. Hone those soldering skills.
Well then, has anyone on here suggested that your full of shyt? Lol.
It wasn't the end all fix as I had hoped, still drops down to the first line sometimes (250?) but a marked improvement regardless.
As of now still haven't done ALL your tips. The sensor harness upgrade seems like a can of worms I'm not looking forward to, as my soldering skills are lacking.
Your insight is appreciated by all of us renix rookies, so I'm gonna keep on keepin' on as time allows.
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