Please help me find a problem to my idle/RPM problems...

[KJSupra]

Hello everyone,

I have a 7M-GTE (Automatic) 140,000 miles. My car is completely stock aside from Blitz BOV. My car is having these symptoms and I was wondering if anybody is kind enough to give me some hints;

1) When coasting at around 2500RPM at around 65MPH, the car seems to run fine. However, when pushing gas to accelerate (ie:freeway ramps), at around 3000 RPM, there's blackish smoke coming out of the exhaust. I'm assuming its' burning fuel. The car doesn't want to accelerate any further. The car simply loses power and boggs.

2) However, when decelerating to come to a stop, the RPM needle lopes up and down from about 200RPM~800RPM...My car used to recover fine without stalling but just yesterday, my car actually stalled while coming to a complete stop. I started the car again right away and the car would sometimes lope and stall.

Things I've checked;
1) No codes
2) Briefly checked vacuum hoses.
3) Checked O2 sensor connection.

What else can the problems be? I tried looking for the solutions but I can't quite pin-point the problem... Thank you everyone in advance!!!

 

[USPturbo89]

i would say just change all the O2 sensors just to be on the safe side... that way you can rule out them immediately.. but thats just me.

 

[KJSupra]

^ Thank you for your quick response. I actually changed the O2 sensor about a month ago and the black smoke problem went away (although it did lope once in awhile). I changed the O2 sensor that's attached to the turbo. There's another O2 sensor??

 

[SideWinderGX]

There's only one O2 sensor.

For the loping, check your TPS (throttle position sensor) and make sure it is adjusted properly. It's a bit of a pain to fiddle with it and get it where it needs to be but worth doing.

I want to say the BOV could be causing the loping when coming to a stop, but that's only if it's venting to the atmosphere.

 

[CajunKenny]

You're in socal...? IF your car is a california car you DO have a second O2 sensor, though I doubt it's your problem. Here's a link for reference.

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=118

What does the car do at WOT?

Venting to atmosphere will cause exhaust pops between shifts and an occasional stall when letting off the throttle.

 

[jetjock]

According to his profile he's GTE. That means one sensor even in Cali. Regardless, throwing parts at the car is dumb...

 

[CajunKenny]

Ha....missed that one. I stand corrected. Good catch jj!

 

[jetjock]

Eh, stuff happens. At least you're more on track than your Cajun brother

 

[KJSupra]

Thank you everyone for your input!

So I should check with the TPS first?

Could anything else be a problem? When I floor it, things seem fine until the RPM reaches about 3000-ish and it reaches around the speed of 65MPH. It seems like the more the engines tries to work (for example uphill), the more black smoke comes out.

Is this a common problem for our cars? Thanks everyone!

 

[Gunnar]

Check for a boostleak.

 

[rayall01]

^^ +1 on the boost leak!

 

[cordoba]

how does it behave while in neutral/park, at idle?

 

[KJSupra]

how does it behave while in neutral/park, at idle?

The car usually idles at around 900RPM-1000RPM when warm.

The car idles at around 1300RPM when cold or just starting up...

 

[thevork]

high idle = +1 on the boost leak.

 

[jetjock]

^ Induction leaks do not raise idle speed on L Type EFI systems. They only effect idle quality.

 

[KJSupra]

^ Induction leaks do not raise idle speed on L Type EFI systems. They only effect idle quality.

So could it be the TPS and not boost leak?