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Back on the street!!!

KANE

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3,244
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KY
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Dark Blue 1982 Trans Am(s): Polo Green 1995 MN6
Back on the street!!! UPDATED BELOW-

So, she's got her plate and back on the road again!

It is painfully obvious that I still have some minor tuning issues and little things to work through.

- I'm sure the plugs could stand to be replaced. I'll pull them out and replace them. I've got a new set in the garage. She's not missing- but she seems to lack some consistency at low RPMs and at idle.
- I also need to adjust the detent cable. It isn't dropping to first gear the way I want it too.
- The speedometer cable needs to be adjusted. I don't think the cable is seated properly on the back of the speedometer. It was a **** to get the new cable on the back of the speedometer (had to get a new cable- not using the cruise control system).


She screams between 3500 and 5000 RPM. No issues with WOT in terms of fuel or starvation thankfully.

Note to self- when setting the minimum idle with bad gas still in the tank, expect to do it again with new gas.
 

Bill75

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Jan 1, 2004
Messages
698
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Somers CT
Corvette
75 Coupe ZZ4, Brodix IK-180's, Headers,TK0-500
I bet that feels good huh! I've been following your interesting posts, glad you're back on the road.
:beer
 
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KANE

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Joined
Mar 2, 2002
Messages
3,244
Location
KY
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Dark Blue 1982 Trans Am(s): Polo Green 1995 MN6
Thanks for the interest, Bill!

Put in the new plugs last night. The AC Delco Rapid fire plugs were fouled out to say the least. I think the previous owner ran far too rich a mixture. That did make a big difference- off idle performance is greatly improved, although still not perfect. She's got a smoother transition from 1k to 5k now. I'm still perplexed by the minimum idle.

I reset the TPS to .5 yesterday with the throttle blades nearly shut. No luck. She wouldn't even start until I brought her to around .55 on the TPS. Athough not correct GM service procedure, I may look at tuning the TPS to the minimum idle; essentially pulling the TPS to .5 when it is really at .55 based upon the relative position of the blades. She seems to want more air than the idle air curcuit provides at stock tuning.

I'm begining to think some of my issues are from the limp home mode. It may very well be running too rich. I still have to weld in my O2 sensor bung. I realize the 02 sensor will help- but in my experience with TPI swaps, this doesn't equal the idle quality issue. Overall, S/D systems don't have the flexability that MAF does. Once I get the O2 sensor in, and if I haven't resolved these nuances, I'll move to data logging.
 
P

Piet

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Congrats!

My '78 just passed our Provincial Safety Check. She is on the road legal like. This year... I am just going to drive.
 
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KANE

Moderator
Joined
Mar 2, 2002
Messages
3,244
Location
KY
Corvette
Dark Blue 1982 Trans Am(s): Polo Green 1995 MN6
....This year... I am just going to drive.

Sounds like a great idea Piet!!! I'm almost there too.

Well, the 02 sensor is in. I'm using a three wire variant normally found on an L35 4.3 V6. Seems to have cleaned up the idle as it can now go into CLOSED LOOP. Yippee!!

It was throwing code 13 (02 sensor) and a code 43 (knock). I still need to clean it up. Maybe I'll revisit the base timing (it is at 6 degrees). I need to adjust the throttle and detent. We'll see.
 
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KANE

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3,244
Location
KY
Corvette
Dark Blue 1982 Trans Am(s): Polo Green 1995 MN6
... I'm almost there too...

Well, I'm getting a little closer still.

I checked TH350's Lokar detent cable, and what do you know... it slipped about an inch down from where it needed to be for WOT passing gear shifts.

Oops. :chuckle


That would explain my theory of a lack of power at the (upper) low end to mid range- it wasn't downshifting or holding gears for long enough. Where it should have been downshifting, it was getting bogged in a gear and simply staying there.

To recap, I'm convinced the ECM was going into "limp home" mode without the 02 sensor. It seemed to run beter when it was cold. As soon as it warmed up, the idle would seemingly fallen apart.
 
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KANE

Moderator
Joined
Mar 2, 2002
Messages
3,244
Location
KY
Corvette
Dark Blue 1982 Trans Am(s): Polo Green 1995 MN6
Tuning Done!

UPDATE:
She's SCARY FAST!

:eek:hnoes

So, I think I picked the winning combination for my L82- HEI with 8.8mm wires, 24lb injectors, SLP runners, ported plenum, and a custom chip brings her to 5k RPM in a hurry.

She doesn't seem to have quite as much low-end torque as the LM1/TPI I built in my 1978... but I'd make the trade off any day for the acceleration and top end HP I'm getting with the L82/TPI.
 

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