Fast Idle

[coze]

Hi, I have a 97 grandam 3.1 Sometimes when you start it, it idles too fast. I changed the IAC and cleaned the port it sets in, this worked for only a short while. Now that it is getting colder out this problem happens more often. If I turn the ignition on and off a few times it will idle normally. Will the TPS cause this to happen or could the main computer be doing this. Thank you for any help.

[skeeter123]

You could check the ETC:

http://www.automotiveforums.com/vbul...d.php?t=660655

Hope this helps....

[coze]

Thank you skeeter123, I tested the sensor and plug connector and they checked out fine. Whats next ????

[3100]

how fast is the idle in rpm? for your engine it will start at 900 -1000 and go down to 650-700 once it warms up, however it should not ever go over 1100 even when it's very cold.

Also just for the testing purposes, use can of coke or any type of can and cut same shape gasket as the one used for EGR, You can use regular scissors for this, but don't make any holes for the egr passages. Make holes only for the mounting bolts. Then install the gasket that you just made instead of the egr gasket. It will work better if you make it double gasket like that. If after this you don't have any problems with idle, you will know that the egr is getting sometimes stuck open. Or you can try to clean egr.

also check that you did not install egr backwards (egr connector plug should face engine radiator not windshield)

[coze]

Originally Posted by 3100

how fast is the idle in rpm? for your engine it will start at 900 -1000 and go down to 650-700 once it warms up, however it should not ever go over 1100 even when it's very cold.

Also just for the testing purposes, use can of coke or any type of can and cut same shape gasket as the one used for EGR, You can use regular scissors for this, but don't make any holes for the egr passages. Make holes only for the mounting bolts. Then install the gasket that you just made instead of the egr gasket. It will work better if you make it double gasket like that. If after this you don't have any problems with idle, you will know that the egr is getting sometimes stuck open. Or you can try to clean egr.

also check that you did not install egr backwards (egr connector plug should face engine radiator not windshield)

When the engine fast idles it is between 1000 to 2200 rpm's. Sometimes the engine will not idle fast at start up, but after you have driven it for several miles. Usually if it idles fast at startup or later on, most of the time if you turn the engine off and back on it will idle normally. This kind of makes me think it is an electrical/sensor problem. I will take a look at the EGR ,clean it and try a solid gasket. I hope this works. Especially the wife since this is her car. Thank you for your reply 3100

[3100]

any pcm codes?

[coze]

Originally Posted by 3100

any pcm codes?

None

[3100]

Originally Posted by coze

None

OK. still try solid egr gasket that I explained in my previous post. I Also recommend that you change pcv valve since it is very inexpensive. And pcv valves sometimes can do crazy things and idle will bounce up and down.

[xeroinfinity]

Originally Posted by coze

Hi, I have a 97 grandam 3.1 Sometimes when you start it, it idles too fast. I changed the IAC and cleaned the port it sets in, this worked for only a short while. Now that it is getting colder out this problem happens more often. If I turn the ignition on and off a few times it will idle normally. Will the TPS cause this to happen or could the main computer be doing this. Thank you for any help.

Welcome to AF !

When you removed your IAC, did you move the pintal(the tip)?

Also have you actualy tested the IAC ?

If thats good then I'd say you have a bad vacum leak under the hood.

[coze]

Originally Posted by xeroinfinity

Welcome to AF !

When you removed your IAC, did you move the pintal(the tip)?

Also have you actualy tested the IAC ?

If thats good then I'd say you have a bad vacum leak under the hood.

Hello, I put a new IAC on it. I measured the pintal and it was 1 1/8 inches I also checked the old and new one with an miltimeter they checked out ok per your instructions. If it is a vacuum leak would it not idle fast all the time ? Also when it is idling fast, most of the time if you turn the ignition off and on a couple of times it will idle fine

[3100]

Next time when it starts to idle fast, try wiggling the IAC connector and its wiring to see if that will make any difference and bring idle down.

[coze]

Originally Posted by 3100

Next time when it starts to idle fast, try wiggling the IAC connector and its wiring to see if that will make any difference and bring idle down.

Thanks I will try that , I have not had a chance to check the egr yet. Thanks again