g60 rough idle when cold/ runs rich

[jetta-j2]

My g60 Corrado has 98,000 on it. i just did the following :
Fuel Filter
Spark Plugs
Wires
Cap
Rotor
Timing Belt
Water Pump
Thermostat
ISV Reroute


Im running a stock airbox with the K&N Drop in.
I had this problem prior to doing all of this work and i did all of these things because of mileage. When the car starts say first thing in the morning or when its been sitting a while, It idles really rough almost to the point of stalling. Also i can smell and see that the car is running really rich. Once the car warms up, it idles beautifully and drives good with no issues. Doesnt over heat or anything. I noticed that my supercharger is slightly leaking oil so i got a Rebuild kit that is on its way but this wouldnt cause a rough idle..

1. I noticed that when i unplug my ISV, nothing changes ( possibly a sign that the valve isnt working?)
2. I was going to pull my plugs to see which cylinder is running rich ( if any )
3. I replaced the vacuum line going to my FPR because it blew. Possibly damaged the FPR?

Like i said earlier once the car is at operating temperature it runs great. Could it be that something is keeping the engine at open loop?

These are the next things im going to check:
-Coolant Temp sensors
-PCM Grounds
-02 Sensor
- Ignition Timing? although i dont see how this could change with the temperature.
- ISV
- Vacuum lines

if anyone has any input on whats going on please let me know because this car runs great. i just want it to run great all the time especially with winter on its way.
Thanks!

[crazynorweegian]

My g60 Corrado has 98,000 on it. i just did the following :
Fuel Filter
Spark Plugs
Wires
Cap
Rotor
Timing Belt
Water Pump
Thermostat
ISV Reroute


Im running a stock airbox with the K&N Drop in.
I had this problem prior to doing all of this work and i did all of these things because of mileage. When the car starts say first thing in the morning or when its been sitting a while, It idles really rough almost to the point of stalling. Also i can smell and see that the car is running really rich. Once the car warms up, it idles beautifully and drives good with no issues. Doesnt over heat or anything. I noticed that my supercharger is slightly leaking oil so i got a Rebuild kit that is on its way but this wouldnt cause a rough idle..

1. I noticed that when i unplug my ISV, nothing changes ( possibly a sign that the valve isnt working?)
2. I was going to pull my plugs to see which cylinder is running rich ( if any )
3. I replaced the vacuum line going to my FPR because it blew. Possibly damaged the FPR?

Like i said earlier once the car is at operating temperature it runs great. Could it be that something is keeping the engine at open loop?

These are the next things im going to check:
-Coolant Temp sensors
-PCM Grounds
-02 Sensor
- Ignition Timing? although i dont see how this could change with the temperature.
- ISV
- Vacuum lines

if anyone has any input on whats going on please let me know because this car runs great. i just want it to run great all the time especially with winter on its way.
Thanks!

To be perfectly honest, you should be doing the temp sensors, cleaning the grounds, adding grounding wires, and replacing the vac lines with all of the other stuff you did anyhow.

Also, ignition timing is PART of the timing belt change procedure... so why are you trying to troubleshoot before you finish your timing belt job? Adjusting the idle screw is also technically part of this.

Unplug the o2 sensor and see if the idle changes. Also, it is safest to unplug or plug in the ISV with the battery disconnected as far as I have heard (though others have told me that the key just needs to be out, but do you really want to gamble with the ECU)?

A bad G60 could add drag or reduce the air in the mix and create a weird idle until the computer kicks in after it reaches temp... I suppose. It would have to be pretty shot though.

Keep in mind the computer is basically blind and deaf on a cold start, so it takes certain conditions for granted. It is programmed to be generous in order to get your car the fuel, etc that it needs on a cold start, even if your car is a bit off or you are in a weird climate. However, it is still assuming that you are not going to exceed those maximum or minimum variable values that are programmed into the mapping for the cold start. If something is pretty far off, it might have a hard time on a cold start but then sortof recover once the sensors are all working together to make adjustments, though they are maxing out their adjustability so to speak. I just had this type of situation happen with my AFR, it would only normalize once the sensors were warmed up and the computer knew to basically open everything up all the way.

[jetta-j2]

the timing belt job has been done and i didnt move the ignition timing. I checked it with a light ( through the hole in the trans ) and the ignition timing is on. As for the G-Lader i dont have any issues with boost or low rpms or anything like that, once i get moving it runs fine. Its just at cold idle and sometimes when i come to a stop ill get hit with the smell of rich, unburned fuel. Since im working today and there isnt **** to do ill pull my car in and check the grounds and vacuum. It doesnt help that the people that owned the car before me tried turning it into a race car and hacked the hell out of it. This car has come a long way since i first bought it. Also im going to pull my plugs. Thanks man, ill def check out/ do what you suggested.

[jetta-j2]

Also, I did adjust the Idle screw in the back of the throttle body.

[jetta-j2]

so i just cleaned and relocated the ground strap going from the ignition coil to the block, i rewired the ISV because the white wire leading to the ISV was attached by a strand and i adjusted the throttle valve again and its idling better ( at about 1,000 rpms ) and it doesnt hesitate quite as much but it still has a slight studder and the rpms will surge between 800-1000. If im not mistaken, when the engine is trying to " hunt " for a clean idle it could be the ISV.

[G0to60]

Along with what was mentioned above (blue temp sensor, O2 sensor, vacuum hoses, wiring) one thing that helped me with a similar situation was cleaning out the ISV. Disconnect the battery and remove the ISV from the car. I ran some carb cleaner through mine and some nice black junk came flowing out. It didn't totally fix my problem (it was the BTS) but it did help.

[jetta-j2]

awesome, yeah ill try that as well. thanks