Bouncing Idle!?!?!

Final13 · 12-08-2007, 04:31 PM

So im coming home last night and i notice that when I push in the clutch and come to a stop that the idle bounces b/w 1 and 2 grand. Kinda like im bliping the throttle but im not even touching it. it doesnt do this when driving down the road, just when the clutch is in or its at idle...This very strange and I have never experienced this before on any car. I have been thinking that a new O2 sensor is in order for a couple of weeks now. (since I put the new 5s in its been running a little rich) Could that be the problem?

Gairloch · 12-08-2007, 06:21 PM

There are a lot of possible explanations for this problem. Unfortunately unstable idle is really common with the 5sfe.

If you have the ability you might want to test your O2 sensor. If that tests out good another possible explanation is the coolant temp sensor.

LordNikon · 12-08-2007, 06:47 PM

What about in a 16V. I have a similar prob. but it only does it occasionally. Then some times it drops down to about 500.

Final13 · 12-09-2007, 03:31 AM

Previously the idle seemed to stay at about 1250 after warming up...I kinda played with the tps and got it to hold rpm at 2 but I noticed that if I just slightly touched the gas and held it there the bounce would return, and normal driving didnt feel as....."spirited" Also once I shut the engine down and come back to it later the bounce is still there. I dont think that I have a way to test the O2 sensor, I guess buying one is in order. Hopefully that will be the answer to my problems.

Gairloch · 12-09-2007, 03:38 AM

You do not want to just start throwing parts at this problem or you could end up buying a new engine piece by piece. See if you can get your hands on a multimeter; that's what you need to be able to test the O2 sensor. Maybe you could get a shop to run the test for you. The details are in the BGB.

Final13 · 12-09-2007, 04:02 AM

I took a look in the book and makes mention of a CEL, and checking the specific code. I dont currently have a CEL at all. Could there still be a code logged despited the fact that I havent thrown a code yet. (at least on the dash)

Gairloch · 12-09-2007, 06:00 AM

Yes. Not all codes result in a CEL.

Georgeorge · 12-10-2007, 03:42 PM

I have the same problem on my '91. At first when I pushed in the clutch it would bounce from about 1200 to 1800 about 5 times, then settle at about 1200. If I left the clutch out until the rpm was about 1000, then it would not bounce. Now it bounces but doesn't stop at the 5 times, it just keeps bouncing, even if I leave the clutch out until the rpm is about 1000. I'm interested it what others have done that has worked.
Thank you

LordNikon · 12-10-2007, 05:14 PM

Could this possiably be a vacume prob. mine seems to bounce when comming to a stop. Once stopped it stops bounceing.

Gairloch · 12-10-2007, 05:27 PM

Yes, it can be a vacuum problem.

Final13 · 12-15-2007, 10:29 PM

Ok, cant find vac leaks, cant test o2 cause I cant keep the motor at 2500 rpms long enough to test for the code...Could it be the AC Idle up valve, I kinda had to rig it back together when I put the motor back in? (although it looks ok and the screw seems to be working fine) what about bubbles in the coolant, I know that can trip out the water temp sensor sometimes, but I didnt know if this would cause the bad idle?

Gairloch · 12-18-2007, 07:24 PM

How did you test for vacuum leaks?

You don't have to run the motor and try to get it to throw a code. Find someone that's got access to a multimeter and look in the BGB for the testing process.

Final13 · 12-19-2007, 02:11 AM

The test process says to hold the engine at 2500 rpm and look for voltt changes...there is a flow chart to lead you to the prob. (at least for the O2 sensor) as far as the vac leaks i only really double checked the accessories and vaccum fittings. I have had no time to see what the problem is this week, but I got to get the problem fixxed so I can get it to pass MARTA

Firechixen · 12-20-2007, 05:55 AM

i also had the bouncing idle last week, the vacum hose on the AC VSV was crack underneath and it only made problems when at rest. i tried adjusting the AC idle up screw while it was cold becuase my startup/cold idle was 2200rpms and i noticed the bounced idle rpm range changed as i turned the screw. just my last poor idle experience hope it helps.

Gairloch · 12-20-2007, 06:26 AM

Quote:

Originally Posted by Final13

The test process says to hold the engine at 2500 rpm and look for voltt changes...there is a flow chart to lead you to the prob. (at least for the O2 sensor) as far as the vac leaks i only really double checked the accessories and vaccum fittings. I have had no time to see what the problem is this week, but I got to get the problem fixxed so I can get it to pass MARTA

Here's a trick to find vacuum leaks.

Take an UNLIT propane torch (brake cleaner works too but I don't like getting that **** all over my engine) and as your car idles slowly wave it over the vacuum lines. If you have a leak the motor will rev when it starts to suck in the propane.

12-08-2007, 04:31 PM	#1 (permalink)
Final13 Cage Fighter Join Date: Nov 2006 Location: Tennessee Posts: 377 Thanks: 6 Thanked 9 Times in 9 Posts iTrader Rating: (0/0% )	Bouncing Idle!?!?! So im coming home last night and i notice that when I push in the clutch and come to a stop that the idle bounces b/w 1 and 2 grand. Kinda like im bliping the throttle but im not even touching it. it doesnt do this when driving down the road, just when the clutch is in or its at idle...This very strange and I have never experienced this before on any car. I have been thinking that a new O2 sensor is in order for a couple of weeks now. (since I put the new 5s in its been running a little rich) Could that be the problem?

12-08-2007, 06:21 PM	#2 (permalink)
Gairloch Dreaming of apexes Join Date: Aug 2005 Location: Minneapolis, MN Posts: 4,426 Thanks: 114 Thanked 219 Times in 192 Posts My Google Map iTrader Rating: (7/100% )	There are a lot of possible explanations for this problem. Unfortunately unstable idle is really common with the 5sfe. If you have the ability you might want to test your O2 sensor. If that tests out good another possible explanation is the coolant temp sensor. __________________ "Inside the car, the world beyond the driver's immediate horizon ceases to exist. Alone with the solitude of his desire, survival sense numbed by the speed, he's outrun the mediocrity of the outside world, slipped the shackles it tries to clamp on us all. He is running free, chased only by a fear of failure, for failure is to risk ejection into the real world." ~Mark Hughes

12-10-2007, 03:42 PM	#8 (permalink)
Georgeorge No Skills Join Date: Nov 2007 Posts: 8 Thanks: 4 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	bouncing idle I have the same problem on my '91. At first when I pushed in the clutch it would bounce from about 1200 to 1800 about 5 times, then settle at about 1200. If I left the clutch out until the rpm was about 1000, then it would not bounce. Now it bounces but doesn't stop at the 5 times, it just keeps bouncing, even if I leave the clutch out until the rpm is about 1000. I'm interested it what others have done that has worked. Thank you

12-20-2007, 05:55 AM	#14 (permalink)
Firechixen No Skills Join Date: Mar 2007 Posts: 7 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	i also had the bouncing idle last week, the vacum hose on the AC VSV was crack underneath and it only made problems when at rest. i tried adjusting the AC idle up screw while it was cold becuase my startup/cold idle was 2200rpms and i noticed the bounced idle rpm range changed as i turned the screw. just my last poor idle experience hope it helps. Last edited by Firechixen; 12-20-2007 at 06:09 AM.

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12-08-2007, 06:47 PM	#3 (permalink)
LordNikon ProjectMadMR2 Join Date: Nov 2007 Location: Ft. Hood TX Posts: 145 Thanks: 1 Thanked 4 Times in 4 Posts iTrader Rating: (0/0% )	What about in a 16V. I have a similar prob. but it only does it occasionally. Then some times it drops down to about 500.

12-09-2007, 03:31 AM	#4 (permalink)
Final13 Cage Fighter Join Date: Nov 2006 Location: Tennessee Posts: 377 Thanks: 6 Thanked 9 Times in 9 Posts iTrader Rating: (0/0% )	Previously the idle seemed to stay at about 1250 after warming up...I kinda played with the tps and got it to hold rpm at 2 but I noticed that if I just slightly touched the gas and held it there the bounce would return, and normal driving didnt feel as....."spirited" Also once I shut the engine down and come back to it later the bounce is still there. I dont think that I have a way to test the O2 sensor, I guess buying one is in order. Hopefully that will be the answer to my problems.

12-09-2007, 03:38 AM	#5 (permalink)
Gairloch Dreaming of apexes Join Date: Aug 2005 Location: Minneapolis, MN Posts: 4,426 Thanks: 114 Thanked 219 Times in 192 Posts My Google Map iTrader Rating: (7/100% )	You do not want to just start throwing parts at this problem or you could end up buying a new engine piece by piece. See if you can get your hands on a multimeter; that's what you need to be able to test the O2 sensor. Maybe you could get a shop to run the test for you. The details are in the BGB.

12-09-2007, 04:02 AM	#6 (permalink)
Final13 Cage Fighter Join Date: Nov 2006 Location: Tennessee Posts: 377 Thanks: 6 Thanked 9 Times in 9 Posts iTrader Rating: (0/0% )	I took a look in the book and makes mention of a CEL, and checking the specific code. I dont currently have a CEL at all. Could there still be a code logged despited the fact that I havent thrown a code yet. (at least on the dash)

12-09-2007, 06:00 AM	#7 (permalink)
Gairloch Dreaming of apexes Join Date: Aug 2005 Location: Minneapolis, MN Posts: 4,426 Thanks: 114 Thanked 219 Times in 192 Posts My Google Map iTrader Rating: (7/100% )	Yes. Not all codes result in a CEL.

12-10-2007, 05:14 PM	#9 (permalink)
LordNikon ProjectMadMR2 Join Date: Nov 2007 Location: Ft. Hood TX Posts: 145 Thanks: 1 Thanked 4 Times in 4 Posts iTrader Rating: (0/0% )	Could this possiably be a vacume prob. mine seems to bounce when comming to a stop. Once stopped it stops bounceing.

12-10-2007, 05:27 PM	#10 (permalink)
Gairloch Dreaming of apexes Join Date: Aug 2005 Location: Minneapolis, MN Posts: 4,426 Thanks: 114 Thanked 219 Times in 192 Posts My Google Map iTrader Rating: (7/100% )	Yes, it can be a vacuum problem.

12-15-2007, 10:29 PM	#11 (permalink)
Final13 Cage Fighter Join Date: Nov 2006 Location: Tennessee Posts: 377 Thanks: 6 Thanked 9 Times in 9 Posts iTrader Rating: (0/0% )	Ok, cant find vac leaks, cant test o2 cause I cant keep the motor at 2500 rpms long enough to test for the code...Could it be the AC Idle up valve, I kinda had to rig it back together when I put the motor back in? (although it looks ok and the screw seems to be working fine) what about bubbles in the coolant, I know that can trip out the water temp sensor sometimes, but I didnt know if this would cause the bad idle?

12-18-2007, 07:24 PM	#12 (permalink)
Gairloch Dreaming of apexes Join Date: Aug 2005 Location: Minneapolis, MN Posts: 4,426 Thanks: 114 Thanked 219 Times in 192 Posts My Google Map iTrader Rating: (7/100% )	How did you test for vacuum leaks? You don't have to run the motor and try to get it to throw a code. Find someone that's got access to a multimeter and look in the BGB for the testing process.

12-19-2007, 02:11 AM	#13 (permalink)
Final13 Cage Fighter Join Date: Nov 2006 Location: Tennessee Posts: 377 Thanks: 6 Thanked 9 Times in 9 Posts iTrader Rating: (0/0% )	The test process says to hold the engine at 2500 rpm and look for voltt changes...there is a flow chart to lead you to the prob. (at least for the O2 sensor) as far as the vac leaks i only really double checked the accessories and vaccum fittings. I have had no time to see what the problem is this week, but I got to get the problem fixxed so I can get it to pass MARTA