• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

High Idle

luvme88xj

luvme88xj

NAXJA Forum User
Location
North Mankato, MN.
While out of town, a friend delivered my `88 renix blessed xj to my son so he would have a vehicle to drive while home on leave from his 2nd tour in Iraq. His Blazer was being eqpt. with a 383 stroker. Anyway. My friend got to experience my off and on, 2700 rpm idle. As the xj was idling high, he shut the ignition switch off. Just before it died, he turned the key back to the on position. This dropped the idle down to around 750 rpm's and it ran fine. But as most high idle issues go it was a short lived fix. Any ideas as to what would trigger the idle drop? A brief history of other temporary fixes: New TPS, IAC and Map sensors also replaced the ECU and tightened the exhaust and intake bolts.
 
my 89 did that after i replaced and installed the tps to specs. i believe it was from the moisture build up over night. i readjusted the tps to specs and it never happened again.

could also be the new IAC got stuck or you may have the wrong one, maybe one from an 91 and up, which has a longer pintle.
 
Just a thought... Have you tried the SeaFoam intake cleaning thing? It's a cheap stab at a fix and won't hurt anything even if it doesn't fix this issue. :dunno:
 
Learning to live with it. It really sucks this time of year with icy roads. I have to put it in 4hi just to keep from doing brake stands when the roads are wet and icy. I will look into the IAC possibly being for an 89 vs. an 88. It seems to go away when the temp is below 20 degrees F and above 50 F...if it is dry weather!
 
luvme88xj said:
Learning to live with it. It really sucks this time of year with icy roads. I have to put it in 4hi just to keep from doing brake stands when the roads are wet and icy. I will look into the IAC possibly being for an 89 vs. an 88. It seems to go away when the temp is below 20 degrees F and above 50 F...if it is dry weather!
Click to expand...
88-89 IAC are the same

if you have no vacuum leaks, it could be a misadjusted tps. did you adjust the tps to specs? ive heard of people installing the tps with the arm on the wrong side of the throttle lever.
 
Have yet to try seafoam. Have used it in other applications with success. Got some at home and will try it tonight. Is it like fogging an engine. Do I just pour a little in the throttle body? Or just add it to the tank?
 
luvme88xj said:
Have yet to try seafoam. Have used it in other applications with success. Got some at home and will try it tonight. Is it like fogging an engine. Do I just pour a little in the throttle body? Or just add it to the tank?
Click to expand...

As the engine is running, pour the SeaFoam into the TB/intake until the engines dies. I usually pour about 1/2 of a can in. I then pour the rest into the gas tank. Some folks go ahead and pour the whole can in the TB after it dies.

Either way..... Let the thing sit from anywhere between 30 minutes and all night. Then once you fire her up, watch out for all that white smoke!!! I mean a LOT of white smoke!!! Run it (or drive it around the block) until the smoke stops.

Good Luck!! :cheers:
 
I have seen the cloud! Use to work at a marina and come fall, it was time to FOG engines. We'd pour a can in the carb and rev it up and shut`er down the cloud would carry all the way across the lake. Come next spring we fire up an boat that had been in storage and send another cloud across the lake. Im headed home now and gonna give it a shot. Also will mess with the TPS some more. I fried my volt meter so I have to get a new one. Thanks to all for the input. I'll post any successful results, and any unsuccessful...How many ways did Thomas Edison find out how Not to make a light bulb? So is the worn path of the Renix High Idle. Live Long and Idle High
 
After following the Renix posts, I took my 90 to the mechanic. He changed the CPS, MAP and the ECU connection was not good. This was also a full time high idle problem not sporadic.
 
just so I don't start a new thread for this...

My '90 idles high on startup... it'll idle high for quite some time, then after about a half hour of driving it will calm back down to a normal range... any ideas what this could be? maybe my intake? and as it gets hot, it swells, and tightens? any help is appreciated, thanks...
 
tayman said:
just so I don't start a new thread for this...

My '90 idles high on startup... it'll idle high for quite some time, then after about a half hour of driving it will calm back down to a normal range... any ideas what this could be? maybe my intake? and as it gets hot, it swells, and tightens? any help is appreciated, thanks...
Click to expand...

could be intake, tighten the intake/exhaust manifold bolts.

could also be sticky IAC and dirty throttle body.
 
I'll give it a try. Thanks.
 
You must log in or register to reply here.

Similar threads

V
High temp woes
2
Replies
21
Views
414
Vitzaa
V
I
High idle, smells like gas, running out of things to replace
Replies
2
Views
2K
Inverhyt
I
F
Stumped on this one!
2
Replies
29
Views
4K
Bent
Bent
O
0331 Strikes Again...?
Replies
11
Views
301
Ol Blue
O
O
2000 XJ Failed Colorado Emissions high CO
2
Replies
27
Views
2K
Ken M
K
Back
Top