Crappy idle (VIDEO)
 

Ever since I touched my TPS screw my car has been idling like shit. I can't seem to get it down. Regret ever touching that screw. Reason for messing with it was because my idle was a bit too high (900) I though messing with it would help out my idle but instead I just dug myself in to a hole.

I got a multimeter to adjust my TPS to 1K OHM on a fully warmed engine but that didn't help out. I tried adjusting the idle screw and variable resister but that did nothing. I checked for vacuum leaks and used a compressor to hear for leaks, nothing. I checked timing twice and they were both on the yellow mark. I don't know what else to do. I swapped out the TPS for 2 other "used" TPS's and they all gave me the same conclusion. I tried testing the TPS 3 prong green connector(near airbox) to simulate the "2 light bulbs". Voltage in one side but not the other. I only get 10.8 volts... I thought it was suppose to be 12V? Every TPS that I've installed does not increase in resistance when I open the throttle. It'll be at 1K OHM then 1.900 as I open the throttle and then drop to .5 OHM's at mid throttle. and stay there at WOT(The 3 TPS's that I have does this). In the video my temp gauge is at the highest it goes. If it goes higher then that my car starts overheating(change for Mazda thermostat soon, using Napa). I would have videotaped longer but my cam ran out of battery's. You cant really hear but my car idles like it's hesitating/fluctuating. Also above 900-1000 RPM's I can hear this whistle or a slight metal on metal contact(not sure if it's actually metal on metal though, just sounds like it...lol) sound coming from where the CAS area is, may be to the right of it, looking at it from drivers fender.

http://www.youtube.com/watch?v=-JrXawfEsbA

Oh yea when I was testing for vacuum leaks I pulled the hose going to the brake booster and noticed what I cousin said to be a check valve inside the hose.

Is that suppose to be in there?...


If there's anyone located near me (Hayward, Bay Area CA) that wouldn't mind helping out I'd appreciate that too. I'm starting to run out of ideas.:icon_no2:


Cliffs... Messed with TPS now car idles like crap, checked timing, vacuum leaks, adjusted tps, idle air screw, variable resister...ect. I did jump the green connector next to the battery before messing with idle screw and variable resister.

Every things all out of spec now. :(

Try setting the TPS by monitoring voltage at the "A" wire (http://howto.globalvicinity.com/gv_w...i=58&co=1&vi=1). That is if you're talking about an S4. You want to see 1.0V between the TPS and the battery ground w/ the engine fully warmed.

And yes, the brake booster vac line has a check valve on all turbos, and some NAs. It's kind of useless on NAs though since it's there to prevent the booster from seeing positive pressure.

Just tried measuring voltage"key on engine off".

Voltage was at .5 and I adjusted the TPS screw counter clockwise which raised the voltage to 1.0Volt. I started it up and it seemed to worse...:scratch:

It's not enough to set the volts to 1.0 you also should use a voltmeter or LED setup to finish adjusting the TPS. You should have only 1 LED on (or voltage) to ONE of the test connector terminals when it's set correctly. After the TPS is properly set, use propane from an unlit torch to search for vacuum leaks at idle. Trace all vacuum hose connections with the propane as well as all intake boot joints.

Adjusting the voltage at the TPS is the essentially the same as the 2-light method, except for the fact that it's FAR more accurate. I've had just 1 LED light up when the TPS was completely out of whack, so I don't trust it at all. Testing directly at the TPS or even ECU is going to the source. Everything else is indirect.

Tried measuring voltage at the TPS. Then I checked the TPS check coupler and none of the prongs had a singnal/voltage meaning no light bulb would light.

It's weird If I adjust the TPS voltage to 1Volt the check coupler will not be in spec and if I adjust OHM's to 1K, TPS voltage won't be in spec.

Motor is always fully warmed.

I just adjusted my TPS using OHM's to 1K and tried messing with my idle speed and fuel mixture screw. RPM would bounce 1000 to 1500 at most, if I mess with the idle speed screw and variable resister I can get my idle to somewhat stabilize(no more bounce but still kind of rough and idle too high) I tried messing with it fallowing the FSM but no luck. I run out of adjustment and can't lower my idle anymore when it gets too high.

Already searched for vacuum leaks and timing has always been right. I even checked it again a few times while making adjustments and it was dead on.

sounds like you could be letting in air from somewhere after the afm...........