High idle

[kevin01cobra]

When in neutral and coasting at 50 mph the engine idles at 1800 rpm. The idle seems to decrease with the MPH. Idle normally at a standstill
Just did headers and EGR delete. Running open headers until I go to an exhaust shop today. I have a tune but I'm thinking it didn't cover the EGR delete or I pulled a vacuum hose I wasn't supposed to. Any one have a detailed list of what needs to be pulled on an EGR delete? I removed the two things on the drivers side and removed the two hoses from the rear of the engine.

 

[kevin01cobra]

Also I haven't plugged any lines yet. If this is my problem I will grab some plugs on the way home. I'm hoping its just that simple.

 

[po-po 5.0]

Could easily be a vacuum leak from the EGR line. You just yanked the line off, and didn't plug the hole in the vacuum tee?

 

[MickeyD]

I don't have a list of the exacts of what needs to be removed for the EGR delete, but like you mentioned if something isn't capped off it could be causing this. Also if you have a tune I would get it adjusted for the EGR delete and the LT's if you haven't done so already. If you do this and the hanging idle continues talk to you tuner about data logging the Cobra to see what is the culprit, the Idle Air controllers may need to be tweeked.

 

[STAMPEDE3]

Idle is raised on purpose when in neutral and the VSS reads over 3 MPH.

this is called Dashpot mode and is mainly because the brakes are hydroboost and run off the P/S pump.

This is normal to make sure steering and brakes have enough RPM to work correctly.

 

[po-po 5.0]

Idle is raised on purpose when in neutral and the VSS reads over 3 MPH.

this is called Dashpot mode and is mainly because the brakes are hydroboost and run off the P/S pump.

This is normal to make sure steering and brakes have enough RPM to work correctly.

It's normal if the high idle is ~1000 rpms.

His car is idling at 1800 rpms.

 

[kevin01cobra]

I have not capped off any lines. Was waiting for my mid pipe to be put on so I could work on the car without going deaf. Tune was changed to account for EGR delete. Sometimes the increase seems dependent on speed but other times it was at 1800 rpms for all mph over 2 or 3 then it was normal.
Would definitely appreciate a legit EGR how to instead of playing the educated guessing game.

 

[po-po 5.0]

I have not capped off any lines. Was waiting for my mid pipe to be put on so I could work on the car without going deaf. Tune was changed to account for EGR delete. Sometimes the increase seems dependent on speed but other times it was at 1800 rpms for all mph over 2 or 3 then it was normal.
Would definitely appreciate a legit EGR how to instead of playing the educated guessing game.

There's only one vacuum line that actually goes to a vacuum source in the EGR sytem. I believe it's the top of the two lines running to the EGR vacuum solenoid on the driver side of the intake. The other line goes from the solenoid to the EGR valve and only has vacuum going through it when the ECU commands the solenoid to activate. If you've removed this line from the big tee at the back of the intake (on top, big rubber fitting with multiple vacuum lines going to it) and/or just simply unplugged it from the solenoid without plugging the hole left behind...you have a vacuum leak.

 

[kevin01cobra]

There's only one vacuum line that actually goes to a vacuum source in the EGR sytem. I believe it's the top of the two lines running to the EGR vacuum solenoid on the driver side of the intake. The other line goes from the solenoid to the EGR valve and only has vacuum going through it when the ECU commands the solenoid to activate. If you've removed this line from the big tee at the back of the intake (on top, big rubber fitting with multiple vacuum lines going to it) and/or just simply unplugged it from the solenoid without plugging the hole left behind...you have a vacuum leak.

Thank you! I removed the two lines going into the EGR tube but have yet to remove the T itself. I'll be picking up some caps now that I can trace back to see what sizes I will need. Much appreciation to everyone!

 

[po-po 5.0]

Thank you! I removed the two lines going into the EGR tube but have yet to remove the T itself. I'll be picking up some caps now that I can trace back to see what sizes I will need. Much appreciation to everyone!

the two lines that run to the EGR tube aren't vacuum lines.

Well, ok they're KINDA vacuum lines, but they're not INTAKE vacuum lines. Those lines only go to the DPFE sensor (box about the size of a business card bolted to the back of the upper intkae) which uses the vacuum created in one line (referenced from the other) to determine how much exhaust is actually flowing into the intake. So removing those lines withoug plugging them will give you an exhaust leak, not a vacuum leak.

 

[kevin01cobra]

Ahhh okay, I assumed there was like a third line on the connection that was vacuum. The lines are completely removed. I think I know which line you are talking about. When I take a look at the car again I feel like I should be able to find it pretty quickly.

 

[po-po 5.0]

Ahhh okay, I assumed there was like a third line on the connection that was vacuum. The lines are completely removed. I think I know which line you are talking about. When I take a look at the car again I feel like I should be able to find it pretty quickly.

Just follow the line from the EGR valve (flying saucer thing on intake) to the EGR vacuum solenoid. This one doesn't matter.

The OTHER line attached to the vacuum solenoid goes directly to the big rubber vacuum tee on the top of the intake, and must be plugged!

 

[kevin01cobra]

Cool! I can picture the lines you are talking about, just need to get to the car and fix it this afternoon.

 

[ibleedblue65]

Idle is raised on purpose when in neutral and the VSS reads over 3 MPH.

this is called Dashpot mode and is mainly because the brakes are hydroboost and run off the P/S pump.

This is normal to make sure steering and brakes have enough RPM to work correctly.

This

 

[ibleedblue65]

It's normal if the high idle is ~1000 rpms.

His car is idling at 1800 rpms.

I believe the idle on these cars while moving was set at 1500 but i could be wrong. You can change it in dash pot in the tune.

 

[kevin01cobra]

Never had the car idle above 1000 while moving. It was a vacuum plug that I did not plug. Idles fine now.

 

[ibleedblue65]

Never had the car idle above 1000 while moving. It was a vacuum plug that I did not plug. Idles fine now.

But it only did it cruising not at idle?

Edit: moving and not sitting still. Seems odd that movement of the car would affect a vacuum leak.