tps failing emissions?

[jvamps]

haven't found a specific thread on this just yet. so decided to make one.

I took my car in for emissions...failed misserably. HC was around 3.78 CO was around 82 and NOx was around 3 something.

replaced the cat, O2 sensor, spark plugs, and cleaned my filter.. took it in again. and got HC was around 2.60 CO was around 20 and NOx passed

I was having problems with my idle. its either two high or it tends to rev on me.

could my problem be the tps? or is that just some vacuum leak? I've checked all my vacuums and it seems fine.

Also, the chick at the emissions said it was probably just me running too rich.



any comments?

 

[CRE]

Nope, the TPS wouldn't cause that. Have you checked for error codes? http://www.cygnusx1.net/Supra/TechTips/engine_error_codes.aspx

 

[jvamps]

yeah, only error code was 51. it used to throw 41, 21, and 51 but replacing the o2 solved the first two

 

[cuel]

Tps is a possible cause for the 51. If you have a volt meter these are the readings you should test for. Leave the sensor on the t.b., and the harness plugged in. With key on engine off, test through the back of the plug. E2 is your ground, and you should test with your ground lead there.
The pin id is here Don't use the ohm tests, as this is more accurate.

E2 ecu ground
IDL .029v closed, 11.99 open(batt. was a little low)
VTA .536v closed, 3.5v open
VC 5.01v closed, 5.01v open

Your readings might differ slightly, but should be close. Post back with what you find.

Edit: Oh yeah. VTA should rise smoothly from .5 or so to almost 4v. Move the throttle slowly to check this as well.

 

[jvamps]

I'll check it out soon. sadly it turns out my alternator died and a few other crap decided to go wrong. so emissions is second on my list.

quick question though. you mentioned testing the tps with the harness plugged in? did I read that right? and how do you do that, I found it extremely difficult to get anywhere with the harness still attached.

 

[cuel]

You either probe each wire individually through the insulation(if your probes are sharp enough), or you Carefully slit the boot on the back of the harness plug, and peel it off. To reseal the wires, put some waterproof dielectric grease in the back of the plug.

 

[jvamps]

my tps seems fine. sorry it took so long to reply. Haven't taken it to emissions again since then though. ran into a bad alt. bad fuel sender and a few other things.

thanks for the advice on how to check the tps though, worked great.