Idle, Idle Surge, Timing Adjustment and heat...

tpunx99GSX · 05-14-2010

Ok so i think all three of these are related but i want to ask your opinions.

Idle:
The car idles at 1200-1300 when cold and warming up. very smooth.
Idle Surge:
After the car is fully heated it starts idle surging slowly. Drops to 900 rpms, then climbs very slowly up to 1300 then drops back down to 900. If i push in the clutch it will climb even slower.
Base timing Adjustment:
When i first got the car running and was setting the base timing, i ended up setting it to around 2 degrees BTDC. Mainly because if i set it to 5 or 10 degrees BTDC it would idle surge and idle really high, like around 2000 rpms. Granted this was when the new head gasket was just installed and the motor only had 25 miles on it. Im going to attempt to readjust today.
Heat:
Currently i have no thermostat in. The car warms up and sits right in the middle. but after driving for a bit when i get to the lower speeds it starts to head towards the H and get hot, it never gets past that first line but gets hot enough to make me worry.

My theory on how these are all related:
My belief is that being that the Base timing is set so close to TDC its causing the heat issues, but also with that the thermostat being uninstalled is constantly flowing the coolant through the system and not allowing the coolant to get much time in the radiator to cool down before getting thrown through the system again. And while on the highway it says perfectly in the average range, but this is likely caused by the airflow that is reaching the radiator is cooling the coolant more rapidly.
The Idle surge and Idle i think are related to the base timing as well. but how would i go about adjusting the timing down to 5 deg BTDC without it raising the idle to 2k rpm? Should i maybe try the green cap CAS and see if its maybe a faulty CAS?

What do you all think?

**Kracka** · 05-14-2010

Get a thermostat back in there and flush the cooling system; it's very likely the radiator is full of gunk/corrosion/who knows what. Get your base timing set correctly and perform a boost leak test. Once those are good if it still idle surges then you're going to want to look at the throttle body and clean/rebuild if needed.

**Halon** · 05-14-2010

You don't adjust your idle by adjusting your base timing. Set your base timing to 5, that's where it's supposed to be. Adjust your idle with the BISS screw. And like Chris said, verify no boost/vacuum leaks as those only enhance idle problems.

tpunx99GSX · 05-14-2010

I know theres no leaks in the system, i have already performed a boost leak check. It only happens when the system is heated up.
ill try the biss screw. but i think he threw a bolt where the biss screw should be so ill have to see if that works like a regular one.

**Kracka** · 05-14-2010

...and that didn't raise a red flag as potentially the issue to you? Get the bolt out of there and replace it with a new BISS screw, o-ring, and cap.

**Halon** · 05-14-2010

That's gotta be a nice contributor to your idle issues...

And you understand there is a difference between a cold and warm car right? You have a bypass built into your TB (FIAV) that allows extra air in when cold to keep your idle up. Once the car is warm that closes off.

You need to set your idle once it's warm.

tehehodi · 05-14-2010

He blocked those FIAV lines off.

**Kracka** · 05-14-2010

Do you have a coolant run to your TB?

**Halon** · 05-14-2010

Quote:

Originally Posted by tehehodi

He blocked those FIAV lines off.

Did he use a block-off platetoo? Or just not hook up the lines?

tehehodi · 05-14-2010

Plugged the coolant lines that go to the TB. Thats all i know of.

tpunx99GSX · 05-14-2010

no no no. When i did the head gasket i used a blockoff plate on the TB. originally i had just not hooked up the lines, but i found that to be the idle surge issue when it was surging all of the time.

**Kracka** · 05-14-2010

Quote:

Originally Posted by tehehodi

Plugged the coolant lines that go to the TB. Thats all i know of.

That is [at least part of] the issue right there unless he also got a block-off plate.

**Halon** · 05-14-2010

Tom chime in here? Did you just block off the lines without running a block-off plate? If so, you have a bunch of extra air sneaking past your throttle plate that isn't supposed to be.

*edit - oops didn't see your responce. Good that you used a blockoff plate. I'd get that BISS situation fixed though. That's how you adjust the idle.

**Kracka** · 05-14-2010

Quote:

Originally Posted by tpunx99GSX

no no no. When i did the head gasket i used a blockoff plate on the TB. originally i had just not hooked up the lines, but i found that to be the idle surge issue when it was surging all of the time.

OK, now put an actual BISS screw with new o-ring and cap in there. Total it will probably be under $15 from the dealership.

tpunx99GSX · 05-14-2010

You must have been typing when i posted that i had used a blockoff plate.

tpunx99GSX · 05-14-2010

Ill have to go grab one today then.

**asshanson** · 05-14-2010

Having base timing not at exactly 5* btdc will not cause your overheating issue. Also I disagree with your theory that not having a thermostat will cause the overheating, it's not going to heat soak the radiator. No thermostat is the coldest your car is going to run, and it's not really good to run without one.

Get a stock fan with shroud and install that. The little single slim fan probably isn't flowing enough air at low speeds. I know my single slim fan did nothing compared to my stock one.

1QUICK4 · 05-14-2010

Quote:

Originally Posted by asshanson

Get a stock fan with shroud and install that. The little single slim fan probably isn't flowing enough air at low speeds. I know my single slim fan did nothing compared to my stock one.

This ^^^ Also, make sure your fan is coming on.

Set timing at 5* when warm, then adjust your idle down.
(make sure the ECU is grounded when you set your timing too)