Idle Issue, EGR to blame?

[Saladin45]

Hey guys

As many of you know, I have a high idle issue with my vehicle. I checked the EGR and it's not working correctly. It's not going up and down, and I'm not getting suction out of it. It's finished.

The question is, would the EGR itself cause the rpm's to shoot up to 3000-4000 rpm's as it has been doing? This car in idle in park is at 3000-3500rpm's. In drive it drops to about a little less than 3000. But that's the LOWEST it goes. WHAT THE HECK.

I've replaced Vacuum lines all over. And still the problem persists. I've had many say to clean out the throttle body and IAC. I've thought to do that, but this issue with the EGR has my attention now. Could the EGR be the main issue that's causing all of my woes? Or is it the throttle body and IAC that's causing it? Or both?

Someone-anyone, help me!

-Saladin

 

[ericmccann]

I would check the obvious first. The throttle cable. Is it bound up anywhere, it is moving freely and completely? Does the throttle body close all the way when the throttle is released? It should. Have you tried running the engine with the throttle cable disconnected from the throttle body?

Just a thought.

Eric McCann
Germantown, WI

 

[bmackinnon]

Hey guys

I've had many say to clean out the throttle body and IAC. I've thought to do that, but this issue with the EGR has my attention now. Could the EGR be the main issue that's causing all of my woes? Or is it the throttle body and IAC that's causing it? Or both?

Someone-anyone, help me!

-Saladin

Both, maybe... :biggrin: EGR must be fully closing for car to idle correctly. Likely it's not, or at least leaking, and causing the ecu to compensate to keep the car running. Need to fix the EGR problem first, and go from there. Pull the egr off and clean it and the egr passages..... you'll find a real mess there that will require heavy cleaning. Also verify that the egr diaphram isn't blown. There's an egr diagnostic procedure over on gnttype.org. Follow that. That's where I would start.... and we are going to need some scan tool numbers after that.....

 

[Saladin45]

Alright, but can't I just buy a new EGR?

Someone told me that these things go dead usually after 5 years anyway. So I guess it couldn't hurt just to replace it, right?

 

[faster]

What vacuum is it pulling at idle?

Check the egr with a hand vacuum pump. Is the diaphram leaking? Does it close correctly and seal when closed?

Check all the fittings and vacuum operated things with the hand held pump too if it won't pull a vacuum at idle.

Is the idle/air motor working correctly?

My EGR is the original from 87 and still works fine but I have never been able to get the idle/air motor to hold idle ever on my T. It rolls all over the place 675-1000 rpm and will never settle out.

Just my .02

Mikey

 

[GNTIM]

A bad EGR valve will never cause RPM's to go that high. As above suggested, check the throttle cable first but it is probably the IAC motor.