drivability problems on a stock motor...

Mar 31, 2005
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just a quick question... when my engine is "cold" it seems like i need to rev it out a lot more or it gets real choppy and wnts to stall when taking off... and in general it just doesnt have any low end grunt until about 1500 rpms compared to when its hot. also, and maybe unrelated, ive noticed that when i have a good amount of pedal applied and i am at 1500 rpms or less, my car will occasionally stutter... just really quickly, like a single hiccup, but its still there. is it a miss? an injector? a spark problem? let me know your thoughts please... it is happening more often as time goes on.
thanks,
kyle
 
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just a quick question... when my engine is "cold" it seems like i need to rev it out a lot more or it gets real choppy and wnts to stall when taking off... and in general it just doesnt have any low end grunt until about 1500 rpms compared to when its hot. also, and maybe unrelated, ive noticed that when i have a good amount of pedal applied and i am at 1500 rpms or less, my car will occasionally stutter... just really quickly, like a single hiccup, but its still there. is it a miss? an injector? a spark problem? let me know your thoughts please... it is happening more often as time goes on.
thanks,
kyle

Just a thought. Did you change the ECU when you switched from the AODE to the T-5?
 
its been about a year since ive last cleaned the MAF... ill give it a shot today, i like to periodically do that anyways and it has been a while. there are no CEL's aside from the airbag light flashing code 61 which i am also trying to get to the bottom of...(Intermittent or Repaired Diagnostic Monitor Not Mounted to Vehicle Properly) and a clock which has a bad ground or something since it flashes on and off... aside from that it runs like a champ. hmm, any new thoughts?
 
what is your timing set at?

timing was at 12 btw but i set it back a click without the light just to get a couple more mpgs and it allowed me to drop it from 93 octane to 89... ive always had ping issues and the 93 seemed to remedy that a little but its too much if i dont need it on a daily driver.


ect sensor huh? is it worth cleaning or should i just buy new? i know some things like the IAC rarely clean well and its usually just best to buy a new replacement.
 
Check to see if your TPS voltage is low. If it is use this procedure to reset your idle and TPS.

Begin with a cold vehicle. The idea here is to get the car to a firm cold idle with enough air bleed capacity left in the idle circuit for IAC adjustment.

The idle stop should be set first. Back out the idle stop screw, away from the bell crank arm, until about 1/2 turn past the point where it no longer makes contact (blade fully closed). Using a 0.010" feeler gauge, tighten until gauge just drags between screw and bell crank arm. Remove feeler gauge. Tighten screw exactly 1 1/2 turns. If the screw is very loose, put a drop of loc-tite or silicone on it, so it doesn't work out of adjustment.

Now remove the connector to the Idle Air Controller (IAC) just on the other side of the throttle body. Start the car and allow vehicle to warm for 2 minutes. Give a small "blip" to let it settle. If it is having a hard time staying running you may have to get an assistant until you can get to the front of the car. Now open or close the air bleed screw (CCW opens) next to the IAC until the car idles at 575 to 600 rpm. For guys with aftermarket cams and an EEC tuner, you might want to idle a bit more briskly, say 650 to 675.

Obviously, this rpm range is by what the car and driver wants...IE, no set idle speed, whatever works for YOU.

Turn off the car. Now count the number of turns clockwise to close on the idle air bleed screw. If it falls between 1/2 and 2, it's okay, now reverse it out the same number of turns. Log the number somewhere in case you need it for the future. Reconnect the IAC. You are done.

If the air bleed screw is above 2 turns, it's a good idea to tighten the idle stop screw another 1/2 turn, and then repeat the idle setting. If it is below 1/2 turn, then loosen the idle stop screw by 1/4 to 1/2 a turn, and repeat the idle setting. Be sure to put another drop of silicone RTV on the stop screw if it was disturbed. Reconnect the IAC.

Now remember we adjusted the set screw on the throttle body. That means that the voltage reading from the TPS sensor has changed. It should read between .96 and .99 volts. Anything outside of that range will cause all sorts of issues including misfires and rough idle.

you will have to back probe the TPS connector. With the connector attached to the TPS stick a paper clip into the rubber boot on the connector where the top and middle wires go into the connector. The rubber is very flexible the paper clip will slide in between the rubber and the wire.

Set your multimeter to volts. Turn ignition to ON. Then place your multimeter leads on the metal pins. If it comes up as a negative that is okay as long as you are -.96 to -.99. If you get this reading then great you are done and hopefully your issues are gone. If not proceed to step 9

This is where and extra pair of hands come in handy. Using a large screw driver you will need to loosen the bolts that hold the TPS. DO NOT USE A SCREWDRIVER THAT IS TOO SMALL BECAUSE YOU WILL STRIP THE BOLTS. They probably will be really tight so you have to really lean on the screwdriver and use some finesse.

Once the bolts are loose you will need to move the TPS up or down and continue to read the voltage. Once you get it to the desired setting you can retighten the bolts. What I do is I find .97 and then as carefully as possible I tighten the TPS down. what will happen is the voltage will change usually to .96 or .98 but that it okay. Once you are done with this manually open the throttle body a few times and close it then reread the voltage and make sure it is still within our desired range.

Depending upon how loose your set screw was you might want to cover it in RTV to hold your setting. At this point you have CORRECTLY reset you idle.
 
wow, thats a great write-up...its very in depth and doesnt leave me with a lot of questions which is good, im not very familiar with the process so im gonna print this out and just look at things to familiarize myself with everything before i make any adjustments. sorry for the delayed response, it doesnt mean that i dont appreciate the info. ill keep ya posted once i have time to set the idle!