High idle after throttle body cleaning

[BrianXJ]

I cleaned my TB on Tuesday. Now I have high idle. I didn't touch the tps. I took the IAC out and cleaned the tip. It idles so high that when I put it in drive the rpm's drop. What did I do to me TB???? It runs great just hgh rpm's @ idle.

[bluedragon436]

So just keep the pedal to the floor... then you don't have to worry bout the idle part... LOL... Nah... something I would look into is making sure all connections are good for any lines in the area... then reset your ECM so that it can relearn with the clean sensors and such... and hopefully that will take care of your high idle issue... figure it got used to running with the gunked up TB and sensors...

[default83]

make sure you check the vacuum lines, vacuum leaks can cause high idles.

[oderdene]

make sure you check the vacuum lines, vacuum leaks can cause high idles.

2X;

[steph74]

yep 3 thigs can have happen....
you knocked a vacuum line
you didn't bolt your TB back tight enough and have a leak
Definitely recheck your IAC

You might want to try to reset your computer as well

(what do you call idle High by the way ?)

[BrianXJ]

ok I reset the ECM and installed a new oring on the IAC, now it is running richer then before, but no high idle. I am going to check the voltages on the TPS and make sure it didn't slip during cleaning. Man do I have a headache from driving it.

[BrianXJ]

OK I have drove about 60 miles since the last ECM reset. seems to be doing better but it still runs rich.

[BrianXJ]

I found this on How to adjust the TPS.


Turn the ignition switch to the ON position.
Find the Four-way TPS connector and insert the black lead of the voltmeter into the back side of terminal (D). Insert the red lead of the voltmeter into the back side of terminal (A). Make sure that the throttle plate is completely closed against the throttle stop. Note the voltage reading of the voltmeter as it is connected across these two terminals, this reading is the input voltage.
Remove the red lead of the voltmeter from the back side of terminal (A) and reinstall it into the back side of terminal (B). Make sure that the throttle plate is completely closed against the throttle stop. Note the voltage reading of the voltmeter as it is connected across terminals (B) and (D), this reading is the output voltage.
Divide the output voltage reading by the input voltage reading. The ratio should be between .825 and .835 (.830 optimum).
If the voltage ratio is not within this range, adjustments can be made using the two mounting screws. To make large adjustments, loosen the bottom mounting screw and pivot the sensor. To make small adjustments, loosen the top mounting screw and pivot the sensor.
Disconnect the voltmeter, and tighten the mounting screws securely.

[BrianXJ]

The difference in my reading is .79.... Looks like I have some fine tuning to do.

[BrianXJ]

ok tuned the TPS, checked all grounds, cleaned the C101 connector on firewall, ran better for about 60 miles now it is back to sputtering when idling. When you get out of the road it runs fine.

[bigjim350]

To me it sounds like either a vacumm leak or a malfunctioning fuel pressure regulator. the best bet is just throw 100 dollar bills at it till it starts running right, thats what i have to do.

[Outlaw]

To me it sounds like either a vacumm leak or a malfunctioning fuel pressure regulator. the best bet is just throw 100 dollar bills at it till it starts running right, thats what i have to do.

Hey Thats what I do!! :smiley-laughing021:

[BrianXJ]

Well interesting. I went out to get lunch and I couldn't believe it it was back to high idle. I will check the ECM connections this weekend, as I have already cleaned the C101 connector under the lid.

[BrianXJ]

I think I have found the solution. My head gasket is blown not bad but blown. doesn't show up on dipstick but it does in the blow-by.

[BrianXJ]

Now we are back to rough idle here is a short video I took with my phone. Any Ideas??

http://www.youtube.com/watch?v=bJag20_G8jo

[BlueXJ]

Brian if you replace the head gasket also have the head rebuilt and a valve job done. Make sure they resurface the head. For about $40 you can replace the oxygen sensor, then you will have covered all the inputs to the computer which concern idle and acceleration response.

[BrianXJ]

Roger

[BrianXJ]

I think I have found the solution. My head gasket is blown not bad but blown. doesn't show up on dipstick but it does in the blow-by.


May not be blown. I will have to double check. then recheck.

[OverEasy]

May not be blown. I will have to double check. then recheck.

I absolutely hate trying to diagnose a blown head gasket. Unless its completely noticeable. Good luck with figuring it out.

[BlueXJ]

Compression check will tell him alot.

[Outlaw]

Now we are back to rough idle here is a short video I took with my phone. Any Ideas??

http://www.youtube.com/watch?v=bJag20_G8jo

That sounds alot like a vacuum leak. There is a somewhat hidden vacuum line that plugs into the TB on the backside. I almost missed putting mine back when I took my TB off and cleaned it. There is a small rubber plug with two hole in it that a plastic vacuum line goes in. Might check it.

[BrianXJ]

That sounds alot like a vacuum leak. There is a somewhat hidden vacuum line that plugs into the TB on the backside. I almost missed putting mine back when I took my TB off and cleaned it. There is a small rubber plug with two hole in it that a plastic vacuum line goes in. Might check it.


:notworthy:


I decided to take another look for a vacuum leak. And low and behold I ran that line up to the MAP sensor and I'll be a monkey's uncle. When I was cleaning the C101 connector I must have pulled it a little to hard and crack that line. I ran some tape around the crack and this is what I got.

http://www.youtube.com/watch?v=Sbqk-7TgEa4


It still has a surge but after the few days of running rough the plugs are almost shot so. I will keep you guys updated

[4x4Dalton]

Wow bro dont even sound like same XJ glad ya found that crack. Still sounds like theres a small leak somewhere in one of the vac lines. Nothin major but its there.Plus like ya said the plugs are about shot so that to has to some to do with it still sounding a lil rough. Good luck in yer dealin with this. Keep us posted.

[BrianXJ]

The idle is better then that now I took and tape that line to the MAP sensor from one end to the other and I now have my TPS adjusted to .829 Still getting a small drop out and seems to be a little high idle, but that may be due to the engine needs a tune up. I can't tell you the rpm's as there is no gauge. I will shoot a video later on how it is running now.

[BrianXJ]

Is there any vacuum lines that can be done away with? The less I have, maybe the easier to find the leaks.