Cold idle stalls, Q45 related?

[KFred 513]

What's up guys. A little different situation here. I bought my car a month before I came into the Air Force so I haven't seen it in a few months, and it will be a few more before I see it again.

My problem is that the car will not idle at all under 106*. I have to pedal it up to around 1500 to keep it alive. Once it hits 105~108* it will purr until it runs out of gas.

Since the PO put the Q45 on, I'm missing a lot of the stock idle controls. It's been a long time but I think my tps volts are simulated via V3 lite. I also may have a boost leak helping contribute but I also run speed density so a boost leak shouldn't hurt idle.

I don't know how other people get their Q45 setup to work but I'm thinking I want to go to a 1g TB when I get done with training.

My questions are, does anyone know what could be causing this condition? What issues will I run into going back to a 1g TB. I know I need to make sure my uicp is the right dia, and I'm going to order a flange from extremepsi for my JMF smim->1g. I also want to send the tb to throttlebodies.com to get rebuilt. Do you have advise on what to do about the biss, coolant lines ect?

I think the 1g tb will be a lot more street friendly and hopefully cause less problems. If everyone thinks its worth it to try to fix the Q45 ill give it my best shot.

 

[Blurred Talon]

This is a common issue with the Q45.
If your are has no FIAV (Fast Idle Air Valve) or ISC then it will have trouble with cold starts and idle.

 

[mondale]

I use a q45 and experience a similar issue when cold. Try to up the idle a bit on the throttle body. Also if you can, check the simulate idle switch on link. This might help the driveability a bit.

 

[KFred 513]

Thanks for the replies. Mine has some sort of fast idle but it doesn't seem to work. It's got coolant lines running to it, and everything I read says it has a was stat that should open the throttle plate a bit until the car warms up. It seems that most people eliminate this whole mechanism, but for me it seems I need that to work and it's not.

My idle is already at around 1k once warm so I don't really want to raise it any more to control a cold start situation.

Mondale, when you say yours has similar issues when cold, are you talking cold ambient temps or when the motor is cold (first start of the day)? Mine will not idle on its own at all until the engine reaches temp regardless of the outdoor temps.

I also just looked back at an old log and noticed that the GMiat is stuck at 77* and never changes. Could that have anything to do with the car not idling with a cold motor?

 

[mondale]

My car does not idle well whenever the engine is below operating temp, regardless of ambient temps. There is a detailed write up on how to properly set idle with the coolant lines on one of the dsm forums, I can't seem to find it right now though unfortunately.

 

[KFred 513]

My car does not idle well whenever the engine is below operating temp, regardless of ambient temps. There is a detailed write up on how to properly set idle with the coolant lines on one of the dsm forums, I can't seem to find it right now though unfortunately.

A rough idle I'd be fine with. I have to keep my foot on the gas though. A combination of the cams, Q45, and lightened flywheel make it hard to hold a steady rpm so I end up revving between 1000-2000 and I look like a jackass haha. It's hard to find much on this issue with the q45. As I said most ppl seem to have a high idle when starting and eliminate the waxstat system.