hi all, i was thinking about bumping the idle up a little on my elxr8 just to keep the volts up when the thermos turn on, im running b.p.t. underdrive pulleys. yes i have done a search and there seems to be a few different ideas as to what to do. i read in an old post that when you increse the idle the ecu will retard timing to get idle back to where its set at in the ecu, can anyone confirm this? ive got a repair manual and all it says is to get car up to operating temp, disconect isc, turn screw in until revs are where you want, reconect isc and off ya go or somthing along those lines, cant find the bastard atm. can anyone please help me out, im all confused now . thanks heaps

Last edited by millard455 on Sun Nov 11, 2007 6:48 pm, edited 1 time in total.

can anyone offer some advice, please.

For a 93 mustang but should be the same

http://forums.stangnet.com/showthread.php?t=507908

Resetting the base idle

The base idle is nothing more than the idle that the computer has learned at whatever angle your throttle body is set at when at idle. This technically shouldn't change by itself but it's always good to check it because you never know what the dealer or previous owner did to the car before you had it. Once you change the setting of the base idle you will definately want to change the tps voltage at idle as well.


How to set base idle
1. Disconnect the battery's negative terminal to reset/clear the computer's memory. Leave it disconnected for 30 minutes. WARNING: Whenever removing your battery cables ALWAYS disconnect the negative battery cable first and reconnect it last. Otherwise you could destroy your computer or cause a battery explosion.
2. Disconnect the plug going to your idle motor which is located on the front of your throttle body.
3. Reconnect your battery's negative terminal.
4. Start the engine, and set the idle to the rpm you want with the stop screw on the bottom of the throttle body.
5. Turn off the engine.
6. Reconnect the plug on the idle motor
7. Make sure all accesories (radio, blower motor, a/c, lights, etc) are off and start the engine.
8. Let engine run for two minutes.
9. Turn engine off and wait two minutes then restart engine and let idle for two minutes with all accesories on.


Setting the TPS voltage

Here's how to check and adjust your TPS voltage. You may be asking, "What is a TPS"? Simply put its the Throttle Position Sensor. The TPS is a sensor that tells the ECM (computer) how much gas you are giving it, which in turn lets the computer decide how much fuel and spark to give you.

What is needed?
- Phillips head screwdriver
- Two small straight pins
- Digital multimeter



How to do it
The TPS basically bolts to the throttle body with two screws. The holes that the screws go through on the TPS are elongated so you can twist the TPS in either direction to adjust it. To adjust the TPS all you have to do is loosen (don't take them out) both screws and move the TPS until you see the right voltage.

To hook the multimeter up you will have to pierce the green wire with a pin so you can check how much voltage is going through it. The red or positive (+) wire on your multimeter will go to the pin in the green wire. Then you'll have to either pierce the black wire and put the negative wire from the multimeter to it, or just put the black multimeter wire to a good engine ground.
Now to check the voltage turn on your multimeter and make sure all of the wires are hooked up right. Then turn the ignition key to the on position, but don't start the car. You should be getting a reading on your multimeter. It should be .98-.99 volts. If its not, then its time to loosen the screws on the TPS and move it around until you get it right. When its at the right voltage tighten the screws and re-check it.
If for some reason you cannot get the voltage reading right you have two options. Either buy a new TPS or take off the old one and elongate the holes a little more with a file or a dremel.

Last edited by Swine on Fri Oct 26, 2007 9:53 pm, edited 2 times in total.

wow thats alot of info, i best start reading. thanks heaps swine

well that sounds easy enough, now to find a multimeter. thanks mate

In simpler terms, basically let engine idle (warm) disconnect ISC, adjust idle at t/b screw, re-connect ISC, then adjust TPS to suit (0.98v @ idle, key on engine off)

yeah thats what i made of it, sounds easy as. this job will have to wait a bit cos my car is up on the hoist with the kframe, sump, timing case waterpump blah blah out of it atm and ive got to drive it 400km to the city on monday to get my new exhaust done and get detailed, its gona be a long day tomorow.

Hmm sounds hectic lol.

How come its in pieces again?

fuk where do i start. a brandnew water pump s**t the briskit seal on the inside of the pump (2km old) and while i was looking at that i found the frontmain seal leaking and while i was looking at that i found the half circle gasket between sump and timing case was leaking aswell
it was all put back together by a ford mechanic or so called ford mechanic.
so now im gona fix it myself and go to court to get my money back. all parts are under waranty still so that helps a bit.

Good info Swine, this thread is about to cop a sticky

Hey millard455 now you court battle has to be part of a sticky so hope you win

all is good now, car is going good with no leaks and i got all my money back, they gave up trying to lie to me once they realised i know more about my car than they do thanks once again for that info mate.

Just to add to that...
The reason the idle voltage needs to be under 1v is because if you're over 1v the EEC thinks it's in part throttle mode.
This is the number one cause of rolling idle and stalling after people have modified their engine because they crack the blade open further to gain a higher idle but don't realise they must elongate TPS holes to enable the correct setting. This causes the EEC to see part throttle mode when it's actually idling so the ISC control becomes erratic.
The three modes are; idle mode = less than 1v
Part throttle mode = 1v to 3.7v (WOT breakpoint is 2.7v which you add your idle voltage to)
WOT mode = anything over 3.7v
Bringing your TPS voltage to 0.98v is just a way getting as close to 1 volt without going over therefore reducing the delay in time from idle mode to part throttle mode. The performance is greater.
TPS does not in itself control fuel it is only a means for the EEC to look at certain maps that apply to that mode.
In idle and part throttle modes the EEC will look at closed loop maps for fuel and spark.
If load exceeds 70% or you hit the WOT TPS breakpoint the EEC looks at WOT maps and ignores the HEGO's ie; open loop control.

Pete.

Thought i'd add some photo's on setting tps voltage.

 

 

Attachments:

File comment: Pierce green wire on tbs with a pin. Turn key to the II mark or one before ignition Pin.JPG [ 428.92 KiB | Viewed 1042 times ]

File comment: Use a digital multimeter set at DC 20 to get readings. Red to pin black to earth. I've found one of the tps screws to be a good close earthing point volt.JPG [ 425.27 KiB | Viewed 1074 times ]

File comment: If you need to adjust the tps loosen screws and spin it clockwise to increase voltage and anticlockwise to decrease voltage tps.JPG [ 423.58 KiB | Viewed 981 times ]

File comment: Once your happy with the voltage setting start your car to see if the idle needs adjusting.Screw idle screw in to increase idle and out to decrease. If you adjust your idle you will need to set your tbs volts again. Keep adjusting both till your happy wit Idle screw.JPG [ 420.94 KiB | Viewed 893 times ]

Last edited by Swine on Wed Jun 25, 2008 9:43 pm, edited 2 times in total.

can you take some photos of the engine bay as well?