What's Wrong?

[D.J. Aranda]

My '89 Supra isn't idling correctly. When I first start it up in the morning it'll idle @ 600-750 RPM... But when the engine is at operating temp., it's idling @ 1100-1300 RPM. The valve clearances are correct, the vaccum hoses are in good cond., the EGR vaccum modulator filter WAS dirty (I'd removed it and drove around... There isn't much of a change), the air filter's new, the ignition timing is set (10 degrees before TDC w/ the advance off and the engine hot & idling @ 850 RPM), the injectors are more or less clean, and the ign. components (plugs, wires, coil, distributor) are in good cond. if not new. What's wrong with my Supra? I'd really appreciate it if someone who knows what might be wrong could w/b.

 

[Highnitro]

does it run normally other than the idle?

 

[Moy]

Are you getting any codes?

 

[D.J. Aranda]

does it run normally other than the idle?

Yeah, the trottle response is great, the engine's powerful, but it just idles weird.

 

[D.J. Aranda]

Are you getting any codes?

The only thing I'm getting from the OBD is the a/c or nuetral start switch, (the a/c's disconnected) but other than that there are no other codes.

 

[rayall01]

After I rebuilt my engine, (7MGTE), it had a rough idle. I replaced the coil pack and wires, problem gone. That being the case, I'm gonna say it's probably ignition related. Plugs, wires distributor cap and rotor. Or an improperly connected vacuum line could do it as well. I had an 82 Celica GT back in the day, that had a bad idle from the get-go. One day I started switching vacuum lines around. Bang! Hit the correct connection, car ran perfect till I sold it.

 

[D.J. Aranda]

After I rebuilt my engine, (7MGTE), it had a rough idle. I replaced the coil pack and wires, problem gone. That being the case, I'm gonna say it's probably ignition related. Plugs, wires distributor cap and rotor. Or an improperly connected vacuum line could do it as well. I had an 82 Celica GT back in the day, that had a bad idle from the get-go. One day I started switching vacuum lines around. Bang! Hit the correct connection, car ran perfect till I sold it.

Hey, is the coil wire (from the coil to the distributor) supposed to make a pulsating electrical 'zapping' sound?

 

[jetjock]

The only thing I'm getting from the OBD is the a/c or nuetral start switch, (the a/c's disconnected) but other than that there are no other codes.

You're kidding right?

 

[D.J. Aranda]

You're kidding right?

...No.

 

[JDMMA70]

id check the TPS and CPS

 

[rayall01]

Hey, is the coil wire (from the coil to the distributor) supposed to make a pulsating electrical 'zapping' sound?

NO! It's not supposed to do that.

 

[D.J. Aranda]

NO! It's not supposed to do that.

...wait, i dnt think i worded that last question right.
ok, would the coil wire makes that sound if you was listenin w/ your ear about 1'' away from it w/ the engine runnin. It's not very loud, but @ 1-2'' away you can hear it.... Is it still supposed to do that???

 

[CRE]

A/C.... start with fixing the codes.... sheesh.

 

[jetjock]

^ Indeed. And he needs to get closer with that ear...one inch is too far

 

[D.J. Aranda]

Ok, i've ruled out the TPS, plugs, wires, coil, valve clearances, and injectors. Could it just be the fuel filter? Or might it be as serious as the ECU -(the Supra manual says that the ECU on '83 and later models controls the idle.) This problem just started all of the sudden, not progressively... I've already tried to see if it was just an error in the computor by disconnecting the battery for about 5 min. it didn't change anything.

 

[D.J. Aranda]

A/C.... start with fixing the codes.... sheesh.

well, i recharged my a/c a couple months ago, but 2 months ago it started leaking a/c oil. so to make sure that the compressor wouldn't seize up like the last one, i cut the main wire to the a/c and taped the ends together (so they'd be together but not making contact)

 

[JDMMA70]

dunno if anyone asked but have you checked for codes first? jumping the terminals in the diag box?

 

[D.J. Aranda]

dunno if anyone asked but have you checked for codes first? jumping the terminals in the diag box?

yea, i've already done that.

 

[supradragontoy]

yea, i've already done that.

Isn't there an idle adjust screw on the throttle body? I know some things are different from ge to gte, so I dunno. If there is, try backing it off 1/4 turn or 1/2, but keep track so you can put it back just in case. Last time I had idle issues after warming up it was the TPS and a bad brake booster grommet and check valve. Just a thought

 

[3p141592654]

Here's a hint. You could remove the compressor and dump it into the trash can and it would not cause code 51. You need to understand what code 51 is telling you, and fix it.

well, i recharged my a/c a couple months ago, but 2 months ago it started leaking a/c oil. so to make sure that the compressor wouldn't seize up like the last one, i cut the main wire to the a/c and taped the ends together (so they'd be together but not making contact)