Tried Everything Still Have Iac Problem

[white90gsx]

OK my 95 tsi is having a case of idle surging between 1k and 2500k and on startup it revs to 4k then to its surging up and down my computer is spitting the code p0505 idle air controller system so i went and bought a new isc i put it in and still doesn't fix anything and the computer spits the same code. I read up and searched around and found how to test the ohms my buddy tested them and everything is fine he said and also i tried cleaning the tb i got all my info from this http://dmtalon.v8eaters.com/ISC.html plus i tried the surging troubleshooting i even put a different ecu in it and it still not working i dont know what to do can someone please help me.

 

[DirtyBirdRacing]

Hi,

Have you done everything on this page from vfaq:

http://www.vfaq.com/index-main.html

If that doesnt work, then maybe you could look into a FIAV block off plate.

Bill

 

[white90gsx]

Just about, but would my biss make it idle like that and plus would it make the computer spit the code p0505 idle air controller system?

 

[DirtyBirdRacing]

Honestly I do not know about the computer code. I would check the BISS o-ring and make sure its set right, I wouldnt think it would make it surge that much but its another possible cause you know.

Bill

 

[white90gsx]

The biss is real loose but i dont think that could be it because like i said im still getting the check engine light.

 

[white90gsx]

I screwed the biss screw all the way in and when I start it it dont idle so high but I think that just masked the problem I changed plug wires today but still the same because im out of options..

 

[Ceddy]

You need to set your base idle speed if you put a new ISC in.

On a 95 this involves grounding the Timing Terminal in the engine bay and Pin 1 of the OBDII Connector underneath the steering wheel.

Have you done this yet?

Turning the BISS screw when the car isn't in diagnostic mode is just going to make idle surge worst.

 

[white90gsx]

No...I haven't I never even heard of that before but i will def do it. Is there a how to or maybe you can be specific for me pics would be great I would greatly appreciate it...


Thanks a lot.

 

[Ceddy]

The Chilton book for 1990-98 Eclipses, has the procedure in it. You should be able to get it for less than $20. The other books should have it also.

Basically,
Make sure timing is set at 5 degrees.
Let car warm up.(Coolant gauge near middle)
Ground Pin 1 of OBD connector.
Ground Timing Adjustment connector.
Adjust BISS screw for 750 rpms.
Turn ignition OFF.
Remove ground jumpers.

Hope that helps, I would buy the book lots of good info in it.

 

[linksys42]

The Chilton book for 1990-98 Eclipses, has the procedure in it. You should be able to get it for less than $20. The other books should have it also.

Basically,
Make sure timing is set at 5 degrees.
Let car warm up.(Coolant gauge near middle)
Ground Pin 1 of OBD connector.
Ground Timing Adjustment connector.
Adjust BISS screw for 750 rpms.
Turn ignition OFF.
Remove ground jumpers.

Hope that helps, I would buy the book lots of good info in it.

I was under the impression that this only works for the 1g obdI. I have never heard of being able to ground pin 1 on the obdII connector on the 2g's 95-99 I thought you have to have the mut III diagnostic handheld to properly put the iac into open loop so that it takes the control away from the ecu so you can set the idle speed.

 

[Ceddy]

I was under the impression that this only works for the 1g obdI. I have never heard of being able to ground pin 1 on the obdII connector on the 2g’s 95-99 I thought you have to have the mut III diagnostic handheld to properly put the iac into open loop so that it takes the control away from the ecu so you can set the idle speed.

95-96 use grounding of test terminals to set timing and idle. (like 1Gs)
97-99 require the dealership MUT tool.

 

[white90gsx]

I allready have the chiltons book. What is the procedure called so I can look for it thanks?

 

[Ceddy]

I allready have the chiltons book. What is the procedure called so I can look for it thanks?

Idle Speed and Mixture Adjustments.
On page 1-52 in mine.

 

[white90gsx]

well i found it in the book but it talks about using the code reader i have one of those but i dont understand how to do it

 

[white90gsx]

Ok....Sorry to keep posting but im on my pda and I cant search but I found out that when the code reader is pluged in it grounds out the obd2 so I dont need a jumper wire...So my question now is I dont know were the other wire is that i have to ground out could i possibly get a photo to help.....

thanks chris

 

[Ceddy]

The Code Reader is being used to ground pin 1. Just ground pin 1 yourself.
Be aware not all scan tools will ground pin 1.

Its easier just to use a piece of wire or alligator clips.

Like this:

You must be logged in to view this image or video.

 

[white90gsx]

ok..what about the one in the engine bay?

 

[white90gsx]

Ok..Well I tried that but it didnt work while it was in limp mode it still was surging...Man im fed up with this thing!!!!


Anyone any other ideas????

 

[DirtyBirdRacing]

Ok..Well I tried that but it didnt work while it was in limp mode it still was surging...Man im fed up with this thing!!!!


Anyone any other ideas????

And you grounded both the timing adjustment connector and the OBD connector while you tried to adjust it?

Bill

 

[white90gsx]

I grounded the obd2 pin 1 and the blue connector underneath the hood against the fire wall. But i think my problem lies elsewere.

 

[Ceddy]

I grounded the obd2 pin 1 and the blue connector underneath the hood against the fire wall. But i think my problem lies elsewere.

The blue connector is just the Tach output. You need to use the brown plug.
And you need to check your timing first.
Read your Chiltons more closely.

 

[white90gsx]

So I have to ground the brown one not the blue one?

 

[DirtyBirdRacing]

Have you resolved your problem yet? Just wondering how you fixed it.

Bill

 

[vol96]

Bet you sold it, huh?