1G how to set idle with 272 cams

[fast90eclipse]

Hey I've got a built head with 272 bc cams. I wanna kno how to set the idle to were its stable at 900 rpm's. 750 rpm's. Seems alil low for the cams.

 

[92AWDHX40]

Do you have a tuning device, did you try to set idle at all since the install?

 

[fast90eclipse]

I have no tuning devices I've tryed to set the idle to 900 rpm's since I've installed. Every time I set the idle shut it off an start it back up an its back at 750 rpm's

 

[92AWDHX40]

Cant help you there only used stock cams so far.

 

[keith2g]

I'm assuming your using the BISS screw on the throttle body to adjust the idle? If not, try it. If your are using the BISS and it's still going back to 750 rpm, the computer is probably compesating for a vacuum leak somewhere.

 

[XiKeiyaZI]

I'm assuming your using the BISS screw on the throttle body to adjust the idle? If not, try it. If your are using the BISS and it's still going back to 750 rpm, the computer is probably compesating for a vacuum leak somewhere.

This is negative. Adjusting the BISS without being able to log is a no-no as you will set your FIAV off and can cause stalling at low RPMS or idle surge.

 

[BoosteDsm1993]

Get the car tuned. Problem solved. Why would you spend money on a set of cams when you could have tuned the car instead? Not flaming, just curious.

 

[kchaazz]

Actually, the FIAV in a 1g stops doing its job once the car is warmed up. The problem with adjusting the idle via the biss, is that the ECU has a map for the idle, based on coolant temp. When the car is cold on initial startup, the ecu targets idle at just over 1000 rpms. This is done in order to help the engine warm up faster so that efficiency and optimum performance and fuel mileage can be achieved as quickly as possible. At operating temp, the ecu targets 750 rpm idle; no matter what you do with the biss, it will try to correct the idle via the ISC motor. Yes, you will experience stalling and idle surge and possibly burn up the ISC and the ISC driver in the ECU. The only real solution is one of two things, depending on whether youre using an eprom: change the idle map to 900 rpms if thats what you want. Link: set the idle to whatever you want.

One more thing, like a couple others stated before me, you really shouldnt put cams in without other supporting mods or any tuning capability. That said, since you already have the cams installed, IF you have adjustable cam gears, take the car to a shop (preferably one that knows how to work on a 4G63 because you will need at least 2 modified lifters for what Im about to tell you) and have them degree your cams. Installing cams straight up by just using stock or adjustable gears and lining up the factory timing marks will work, but aftermarket cams are ALWAYS machined a couple or a few degrees off, and degreeing your cams will not only increase vacuum and idle stability, but will also insure you are getting maximum performance out of your cams.

 

[fast90eclipse]

When I got the car the cams were already in it I had to fully rebuild the head to were its now a built head. My factory Ecu is a prom Ecu. I haven't had time to go out n spend 100's of dollars on other mods yet but its my daily driver. I just hate trying to take off at a stop light when it idles at 750 rpm's. I wanna drop a bigger fuel pump n full 3inch exhaust n tune. An maybe bigger turbo.

 

[kchaazz]

Hmm. Well, I would just say to send off your ECU to get it socketed and have a custom chip burned, but since its your DD, youre going to have to buy another ECU to run the car while the EPROM is being worked on. If youre good at soldering, there is a VFAQ on socketing your own ECU, but its easy to screw it up and I dont recomend it when its only 50.00 to have it done professionally. One quick solution which MAY work, is to unplug the ISC motor. This will disable the ECU's capability to control the idle and you can then use the biss to try and set the idle where you want it. You may experience problems if you do this. Idle surge and stalling are two main things that can happen and it may even cause the ISC driver on the ECU to fry because the ECU will just keep trying to utilize an ISC that is no longer plugged in (the ECU has no feedback from the isc as to what position it is in, if its plugged in, or if its even working at all). Try it and see what happens but keep in mind it would only be a temoprary solution.