V6 Discussion and questions about the base carbureted or MPFI V6's and the rare SFI Turbo V6.

92 3.1 v6, any issues?

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Old Jun 27, 2009 | 08:33 PM
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//<86TA>\\'s Avatar
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Car: 86 Trans Am
Engine: 408 stroker sbc
Transmission: TKO600
Axle/Gears: Moser full floater m9, 3:70 trutrac
92 3.1 v6, any issues?

hey guys, i just bought a 92 bird with the 3.1v6, 73k miles. Are there any issues with these motors or things that i should keep an eye out for? I've never had any dealings with this engine, or a v6 for that matter.

thanks
-Phil
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Old Jun 28, 2009 | 10:31 AM
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From: Chasing Electrons
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Engine: check
Transmission: check
Re: 92 3.1 v6, any issues?

The #1 spark plug is the passenger side (right side) front. Timing is 10* BTDC with the BYAPSS open. Can clip the timing light to #4 as it is easier to reach (center cylinder drivers side).

The exhaust manifold bolts tend to break. Mostly the left front or right rear. They are small at about 5/16" (8 mm?). If those are not yet broken can help to replace them before they do.

Center front of engine, has a coolant fitting below the TB. Stock is pot metal and they leak after a while. If it hasn't been replaced may want to do that. GM has (had?) a kit that included the o-ring and clip. The replacement is steel. IIRC they are now available on Help! racks.

Expect the stock pot metal one to break off when trying to remove it. A large easy out usually works to get the stub out.

Timing chain usually gets loose at 80K miles or so. If need to do a water pump, do the timing chain at the same time.

All in all they are a decent and reliable engine. Use regular spark plugs, no fancy ones. Cap & rotor from time to time. And they run forever.

RBob.

Just to add, if it is an automatic tranny, then need to do an idle learn any time the battery has been disconnected from the ECM. Otherwise it will surge, stall, sputter and run lousy at idle.

Last edited by RBob; Jun 28, 2009 at 10:35 AM.
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Old Jun 28, 2009 | 10:53 AM
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From: N. Virginia
Car: 1988 Firebird - 1998 Z28
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Re: 92 3.1 v6, any issues?

Originally Posted by RBob
Just to add, if it is an automatic tranny, then need to do an idle learn any time the battery has been disconnected from the ECM. Otherwise it will surge, stall, sputter and run lousy at idle.
Not to hijack, but could you fill me in on what you mean by that?
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Old Jun 28, 2009 | 12:26 PM
  #4  
//<86TA>\\'s Avatar
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From: Central NJ
Car: 86 Trans Am
Engine: 408 stroker sbc
Transmission: TKO600
Axle/Gears: Moser full floater m9, 3:70 trutrac
Re: 92 3.1 v6, any issues?

Originally Posted by V6F1R3BRD
Not to hijack, but could you fill me in on what you mean by that?
yeah, me too

timing chain huh, that sucks. I assume its similar to a v8 setup? pull the cover, unbolt ect?
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Old Jun 28, 2009 | 01:28 PM
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From: Chasing Electrons
Car: check
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Transmission: check
Re: 92 3.1 v6, any issues?

Here is a decent thread on the idle learn:

https://www.thirdgen.org/forums/v6/1...dle-learn.html

It also covers the need for keeping the TB and blade clean. Note that this idle learn is only required for the 3.1l engines running the SD ECM ('7730 with MAP sensor, not MAF).

The water pump & timing chain are more like the Buick & Pontiac V8's. Where the pump bolts to the timing chain housing. With the housing being an aluminum casting. Not like the SBC V8 engines.

RBob.
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Old Jun 28, 2009 | 05:53 PM
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//<86TA>\\'s Avatar
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From: Central NJ
Car: 86 Trans Am
Engine: 408 stroker sbc
Transmission: TKO600
Axle/Gears: Moser full floater m9, 3:70 trutrac
Re: 92 3.1 v6, any issues?

so the oilpan gasket is not effected by this job? Doesn'T sound too bad, unless bolts break

are there symptoms of a loose chain? will you hear it?
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Old Jun 28, 2009 | 07:37 PM
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From: Chasing Electrons
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Re: 92 3.1 v6, any issues?

Originally Posted by //<86TA>\\
so the oilpan gasket is not effected by this job? Doesn'T sound too bad, unless bolts break

are there symptoms of a loose chain? will you hear it?
No need to disrupt the pan. Although IIRC, there are two bolts that come up from the bottom through the pan into the cover. I've done this job a couple of times and it is easy. The damper is pain, but that's about it. Note that the P/S pump pulley doesn't need to be removed. Can unbolt and set the pump to the side.

When the chain gets loose the engine just doesn't run as well as it should. There is also a plastic V-wedge shaped guide between the sprockets. This can get chipped and chewed up with a loose chain.

Can do the "pull distributor cap" trick and observe the rotor motion as the crank is rotated in one direction then the other. That will show how much slack is in the chain.

RBob.
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