Was just curious who has removed their throttle control (TSC, TCS...never can remember which...)

I know Chuck did this. What was your reasoning for getting rid of it? Just the finicky PFC idle control?

I recently removed mine and now it's a real struggle to keep it idling until everything is warm. Is this normal, or can the fuel be tweaked in the PFC to alleviate this? I'm just getting tired of heel-toeing everytime I come to a stop... Once it's warm, it idles well.

Thanks

 

Most common things that can be removed and why:

(1) AWS (accelerated warmup system) solenoid under UIM. It causes the 3000rpm warm up. Not really needed and revs engine high when it is still cold. Was there to help warm up the pre-cat and cat. Removeal also clears up the area between the throttle body and firewall.

(2) FPR (fuel pressure regulator) solenoid. When starting the engine it is suppose to slightly increase fuel pressure to prevent vapor lock by preventing the FPR from sensing cranking vacum. DOH! With an in-tank pusher electric fuel pump, it would never happen. If it fails, the FPR may only see 0 psi boost under all conditions.

(3) AST (air seperation tank) has been proven that it isn't really needed by many of us EXPERIENCED and RACER owners. Requires changing/modding some other parts. Clears up the area in front of the engine also.

(4) Vacum operated double throttle control and butterflys. More of a racer mod to reduce weight and air flow restriction in the throttle body for the secondary high speed ports.

(5) ISC (idle speed control) controls those three idle speeds you can set in the PFC. Works in conjuntion with the O2 and TIMING idle control functions that you can turn on/off When engines are modded a lot, it sometimes does not work very well or at all. This is because the program for it can't handle the new range of idle conditions the engine is experiencing. That is why it is disconnected by many. When disconnected/turned off, you also HAVE to turn off the O2 idle control!!!

If you MONITOR your idle timing, you will see that it does not match the timing in the IGL/IGT map for the idle area. If you use the DATALOGIT to change all three idle speeds to 0, it will actually run the idle timing from the IGL/IGT maps.

Thus you can have direct fuel, timing, and rev control for the idle area which before you did not have That is why it is now posible with a well modded engine running a cat to pass gas analysis emmissions testing if you know how to tune.
Also allows a smoother idle.

 

Thanks for the great post, as always, Chuck.

While I was installing the KG secondary rail, I removed everything from the intake and replaced with block-offs. But I'm leaning toward putting the AWS and ISC back in place, since this is a daily driver and it's such a PITA right now to drive when it's cold.

Did you get yours to behave while it's warming up, or does it try to stall? Wasn't sure if I might be able to tweak settings in the PFC (mainly the cold water fuel/ignition) to get it to behave better, or if it's a lost cause. I currently have my warm idle at about 1100, so I really don't want to crank it up any higher than that.

 

You do not need the AWS solenoid for winter.

Even though I have the AWS and ISC solenoids removed and blocked off, I still have the cold start hot wax rod unit installed and working as it increases idle speed until the engine warms up. I did not discussed this one as it is benefitial and works even with a very modded engine. Removeal is one of those race types mods but does not affect HP.

My cold start revs to about 1500rpm then drops down slowly to my summer idle of 1100rpm as the engine warms up. Since I only have one idle speed which is mechanically adjusted, I set it to 850 rpm with full electrical and A/C load which turns into 1100rpm with no load. For winter I turn the idle down to 850rpm.

 

Perfect! Sounds like I need to take a look at the wax rod as it doesn't appear to be functioning.

Thanks again for your replies!

 

I pulled off all that stuff including the wax rod and coolant lines to the TB and had zero idle issues, always rock solid with cold or warm engine. Do as chuck suggested and set your idle rpms in the PFC to zero, it will help your idle quite a bit. I did have to run the dashpot all the way in to keep the idle rpms from falling too much when lifting throttle. And you will likely find a need to readjust the idle bleed as the ambient temps change with the seasons.

 

Great! That's talking me into just leaving things the way they are. I, too, removed the coolant lines. If I can just adjust the dashpot or wax rods then that's good enough for me. I never liked the finicky PFC idle anyway...

I'll give the PFC 0rpm suggestion a try this afternoon. As always, thanks a million for you guys' responses. I value the advice of you two more than anyone on the forum.

 

Just wanted to follow up and thank you for the PFC idle setting idea. By doing nothing more than setting my idle down to 500 (haven't hooked the datalogit up yet to set it to 0), I have a rock-solid idle. For some reason, despite having ignition and 02 control turned off, when I had the idle set at 1100 (both mechanically and on the PFC), it was still bouncing a little, and trying to stall a lot...

Anyway, fantastic tip! Thanks again!

 

how did you cap off the thermostat housing and the rear iron? any more advice or info on the removal of the wax rod and the two rubber lines and hardline?

 

anyone???

 

Some have just pulled the hoses for the hot wax rod unit plumbing and capped off the pipes. Others have physically removed, the pipes and tapped and plugs the souce.

 

thats what i was thinking of doing acually sealing off the rear iron and thermostat housing. i just wanted to make sure that it wasnt a bad move.

ALSO im glad YOU chimed in here since your a great tuner . do you think its a bad idea to take this out? does it really affect the idle and or drivablilty? im running the pfc and trying to see if its worth keeping to make things better or if its better off gone. please reply i value your posts.

-Lance