cold idle - Northern California Ford Owners

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Posted by Holmes88GT (Member # 1096) on :

When i first start the car at any time it has a fluctuating idle after a few seconds it idles ok all sensors are new ,tps, idle control,and the orignal maf is back on.Could any other sensor cause that or is it just my cam B303 motorsport.

could anyone tell me what my timing is supposed to be at and how far I can advance it. GT40crate motor aluminum gt40 heads and B303cam.

Posted by st5150 (Member # 51) on :

No clear cut answers to these problems. Try tightening the idle screw a bit and lowering the TPS voltage to compensate or vise versa. As for timing... 14ish is the ballpark. Each car is different. Do you know which GT40 heads you got? The ones with a smaller combustion chamber volume will have a higher compression ratio and "take" less timing.

Posted by Holmes88GT (Member # 1096) on :

tps sensor is set at 0.95 and my idle is set at 950-1000rpms it only does it when I first start the car each time

I dont know what type of heads they are.There not gt40x or gt40p heads

Posted by st5150 (Member # 51) on :

quote:
Originally posted by Holmes88GT:
tps sensor is set at 0.95 and my idle is set at 950-1000rpms it only does it when I first start the car each time

I dont know what type of heads they are.There not gt40x or gt40p heads

Lower your TPS to somewhere in the 0.80 volt range. Remmeber when you change the idle screw, the TPS setting is also changed as well. When I had this problem it was a combonation of two things.... improper idle screw/TPS setting....this fixed almost all of the problem, then it turned out that my MAF was also bad thanks to a cleaning job by me gone bad.

Posted by 66 InjectedCobra (Member # 819) on :

I just installed a 70mm TB and I had to tighten the idle screw like 1 1/2 turns to get the car to hold an idle. I set the idle by taking out my chip and unpluging my IBP valve, then set the idle. Now how do I set my TPS correctly? What wires do I check and cross?
Oh I unpluged the batterie for 20 min before running the car again. My idle still is fucked up [Frown]

Posted by 66 InjectedCobra (Member # 819) on :

Alil help please [Frown]

Posted by 66 InjectedCobra (Member # 819) on :

HI [Confused]

Posted by st5150 (Member # 51) on :

Leave the chip in there when you set the idle. You only need to disconnect the battery for 20 seconds, not 20 minutes. Try tightening or loosening your idle screw a bit, yet make sure your TPS doesn't go over 0.90ish volts. Get the idle as good as you can this way. Now try clocking your MAF to get the last bit of idle out of it. Clocking = loosening the two clamps holding it down and rotating the MAF so the electronics point at an angle like hands on a clock.

Posted by 66 InjectedCobra (Member # 819) on :

Thanks, but why would I leave the chip in since that will want to change idle on it's own? I know where the chip wants to hold the idle,so my goal is to get just the computer idle close to where the chip wants to hold it. Now that my idle is set what wires do I check for properly setting my TPS setting? MY goal is .8-.9 right? Thanks

Posted by st5150 (Member # 51) on :

quote:
Originally posted by 66 InjectedCobra:
Thanks, but why would I leave the chip in since that will want to change idle on it's own? I know where the chip wants to hold the idle,so my goal is to get just the computer idle close to where the chip wants to hold it. Now that my idle is set what wires do I check for properly setting my TPS setting? MY goal is .8-.9 right? Thanks

You tweak, race, idle and drive the car with the chip in there, it only makes sence that you set the idle with the chip in there. Chances are Byron tweaked it to compensate for the less than perfect readings the large MAF gives under low flow conditions (idle). You have an E cam right? It shouldn't idle that rough at all.

Check the green and brown/black wire for your TPS voltage. I'd aim closer to 0.80 volts. Make sure you try the clocking of the MAF as well.

Posted by 66 InjectedCobra (Member # 819) on :

I don't understand what Clocking the MAF exactly is?
Plus it's mounted face down and fixed mounted.

Posted by 66 InjectedCobra (Member # 819) on :

Oh, I can check either one "Green or Brown" or do I need to use both in making a complete circuit?
If I need to use both then which is positive and negative?

Posted by gr40coupe (Member # 698) on :

quote:
Originally posted by 66 InjectedCobra:
Oh, I can check either one "Green or Brown" or do I need to use both in making a complete circuit?
If I need to use both then which is positive and negative?

pierce the green wire. put + voltmeter lead to it. ground negative on chasis or similar. the setting you actually want is 0.98 volts if you can get it there. throttle seems to react the best. any questions [Confused]

or need help call me, my boy can help you. [dance]

Posted by st5150 (Member # 51) on :

quote:
Originally posted by gr40coupe:

quote:
Originally posted by 66 InjectedCobra:
Oh, I can check either one "Green or Brown" or do I need to use both in making a complete circuit?
If I need to use both then which is positive and negative?
pierce the green wire. put + voltmeter lead to it. ground negative on chasis or similar. the setting you actually want is 0.98 volts if you can get it there. throttle seems to react the best. any questions or need help call me, my boy can help you.

Actually chassis ground isn't the same as what the EEC uses as reference to ground. From what I can tell, the EEC uses a ground plane above chassis ground to ride above the noise. The 0.98 volt thing is also a crock developed by redneck magazine writters. It doesn't help you at the track and often causes idle problems. 0.80ish volts is a great number to keep it around.

Here is a good web site with pictures on how to set your TPS:

http://www.promustangs.com/tps.html

Posted by st5150 (Member # 51) on :

quote:
Originally posted by 66 InjectedCobra:
I don't understand what Clocking the MAF exactly is?
Plus it's mounted face down and fixed mounted.

Unless you have a '94+ style MAF, your MAF is connected to the tubings on each end by two large hose clamps. Loosen both clamps and rotate the MAF while the car is on. Listen for a better, smoother idle and tighten the clamps. Its a long shot, but definately something to try. If you have bends in the tubing shortly before or after the MAF, this can help a lot.

Posted by 66 InjectedCobra (Member # 819) on :

Thanks a lot [Smile]

Posted by st5150 (Member # 51) on :

quote:
Originally posted by 66 InjectedCobra:
Thanks a lot

Make sure you come back and post your results.

Posted by 66 InjectedCobra (Member # 819) on :

That link you gave me was great [Eek!]

I'm still not sure if it is better to use the ground from the TPS or engine ground? [Confused]

I guess I will just try both!

Posted by Holmes88GT (Member # 1096) on :

so if my idle is high the tps should be at stock for smog 0.86v and my idle will improve

Posted by st5150 (Member # 51) on :

quote:
Originally posted by 66 InjectedCobra:
That link you gave me was great I'm still not sure if it is better to use the ground from the TPS or engine ground? I guess I will just try both!

Use the ground from the TPS. After all, it's what the EEC uses to measure readings from the TPS [Smile]

Posted by st5150 (Member # 51) on :

quote:
Originally posted by Holmes88GT:
so if my idle is high the tps should be at stock for smog 0.86v and my idle will improve

Regardless of high idle or smog time, leave your TPS at 0.86ish volts.

Remember, if you adjust the idle screw, the TPS will also be adjusted and needs to be re-measured.

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