JSAautomotive
Banned
- Joined
- Apr 21, 2006
ShadowII
The IAC valve is not adjustable. It moves as a function of TPS, Coolant temp, VSS (vehicle speed) MAF, etc. Changing the TPS will get the IAC to react differently. Normally you'll want to see the IAC at around 30-40 counts at idle in park. The minimum air setting should be set with the IAC driven in all the way and disconneted. Depending on the size of your cam, you should set the minimum air rate to allow the engine to idle at around 500-600 RPM. Plug it back in and cycle the key a few times to reset the computers IAC zero counts position.
Disconneting the ECM after you do work is also not ness. Just disconnect the battery and re-connect.
Now... to your problem.
If you think you have a vacuum leak somewhere... get a propane bottle with a wand probe and a button style flow valve so you can flow propane around the intake and such and see if the engine rises in RPM when you get to suspected vacuum leak area's. You can do this with a can of "flammable" carb spray too. It must be flammable though (some of the new style carb sprays are not flammable).
Can you make the engine idle decently by just holding the throttle open slightly?? Or does it take mashing the throttle and quite a bit of throttle opening to keep it running??
Would be nice if you had a scan tool. You can buy used Snap On scanners now on Ebay for as cheap as $500. That would be an excellent tool to have to see all of the data. I would like to know where you Block learn and Intergrator readings are. Plus you can see if your Coolant sensor is reporting correctly and all the other sensors as well. I've seen plenty of coolant sensors fail just 40-50 degrees out of range and will make a car run lean as hell when trying to start cold and lean pretty much all the rest of the time.
To check and see if the heads or intake are exposing vacuum to the crankcase area.....
Cap off any leaks into the crankcase at the valve covers (i.e. breathers, breather hoses). Remove your PCV valve from the valley and start your car. Get a vacuum gauge with some hole size incresers to fit the vacuum gauge to where the PCV used to plug into the valley. With the engine running, you shouldn't see any vacuum there, it should be just pressure from ring blow by. If you've got vacuum, you'd better check your intake or heads having a port area exposed to the crankcase.
Hope that helps. Here's the phone number to the shop if you need help. (818) 772-1737
The IAC valve is not adjustable. It moves as a function of TPS, Coolant temp, VSS (vehicle speed) MAF, etc. Changing the TPS will get the IAC to react differently. Normally you'll want to see the IAC at around 30-40 counts at idle in park. The minimum air setting should be set with the IAC driven in all the way and disconneted. Depending on the size of your cam, you should set the minimum air rate to allow the engine to idle at around 500-600 RPM. Plug it back in and cycle the key a few times to reset the computers IAC zero counts position.
Disconneting the ECM after you do work is also not ness. Just disconnect the battery and re-connect.
Now... to your problem.
If you think you have a vacuum leak somewhere... get a propane bottle with a wand probe and a button style flow valve so you can flow propane around the intake and such and see if the engine rises in RPM when you get to suspected vacuum leak area's. You can do this with a can of "flammable" carb spray too. It must be flammable though (some of the new style carb sprays are not flammable).
Can you make the engine idle decently by just holding the throttle open slightly?? Or does it take mashing the throttle and quite a bit of throttle opening to keep it running??
Would be nice if you had a scan tool. You can buy used Snap On scanners now on Ebay for as cheap as $500. That would be an excellent tool to have to see all of the data. I would like to know where you Block learn and Intergrator readings are. Plus you can see if your Coolant sensor is reporting correctly and all the other sensors as well. I've seen plenty of coolant sensors fail just 40-50 degrees out of range and will make a car run lean as hell when trying to start cold and lean pretty much all the rest of the time.
To check and see if the heads or intake are exposing vacuum to the crankcase area.....
Cap off any leaks into the crankcase at the valve covers (i.e. breathers, breather hoses). Remove your PCV valve from the valley and start your car. Get a vacuum gauge with some hole size incresers to fit the vacuum gauge to where the PCV used to plug into the valley. With the engine running, you shouldn't see any vacuum there, it should be just pressure from ring blow by. If you've got vacuum, you'd better check your intake or heads having a port area exposed to the crankcase.
Hope that helps. Here's the phone number to the shop if you need help. (818) 772-1737
