So I replaced the Q-jet with a Holley... which means the ECM no longer will lock up the converter in 4th.

So I get a TCI (or whatever) vacuum lockup switch. I have only installed the vacuum swtitch and harness that go inside the tranny... not the one that plugs in outside the tranny, that is still pluged in like stock (to what's left of the computer?).

Now I notice that when I hit 4th on the highway, the rpms drop about 200rpms right after I shift into 4th. This is just like it is locking up... right? So I tap the brake, but it doesn't disengauge and bump up briefly to a few higher rpms... almost like it locks and stays locked in 4th. Is this possible?

This is a 89 700r4 which was rebuilt with a Fairbanks kit and I have had no problems in the last 4 years with it. I still don't... especially if I don't have to crawl under there and install that external vacuum switch!

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

 

OK, it took me a little bit on that one. You mean you installed the pressure switch and internal wiring harness and haven't install the external harness yet. If the existing harness is giving the solenoid 12V and a ground, yes it will lock up when it shifts into 4th. The existing brake cut-out for the lock-up may or may-not work, since it's not designed to work with the TCI kit. The TCI kit isn't designed to be used with a brake cut-out. All the vacuum switch does is ground a wire that goes into the tranny, which locks the Torque converter when it's in fourth gear. I did't like the vacuum switch, so I just have a toggle switch on the ground wire. When it's on, the TCC locks in 4th gear. When it's off, the TCC won't ever lock.

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350 with stealth intake, holley carb, 470 lift cam. 700r4 with .5 boost valve, vette servo, tci lock-up kit, B&M megashifter. Richmond 3.73 gears, powertrax locker, timkin bearings, synthetic lube. Custom 3 inch single into 2 2.5 pipes. 1 1/2 drop springs, 1 5/16 solid front sway bar, 1 inch rear bar, custom subframe connectors, custom LCA relocation brackets. Kobel ground FX, current red metallic paint. Lots of other stuff...
82camaro

 

The TCI kit works fine with the brake switch.

 

Since all the control needed to run the TCC is turning the ground on and off, I'm sure the TCI kit will work with a brake switch. TCI just doesn't show you how to hook it up in the instructions. Sorry if I mislead anyone.


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350 with stealth intake, holley carb, 470 lift cam. 700r4 with .5 boost valve, vette servo, tci lock-up kit, B&M megashifter. Richmond 3.73 gears, powertrax locker, timkin bearings, synthetic lube. Custom 3 inch single into 2 2.5 pipes. 1 1/2 drop springs, 1 5/16 solid front sway bar, 1 inch rear bar, custom subframe connectors, custom LCA relocation brackets. Kobel ground FX, current red metallic paint. Lots of other stuff...
82camaro

 

OK, but I didn't do anything to the outside harness. It just locks up in 4th. I rev up in 3rd... shift... revs in 4th then drops a few hundred rpms almost immedieately after the shift.

Another thing, I seem to be able to hit full throttle in 4th as well (doesn't kick back down to third at WOT). Is this a benefit I was unaware of (never really tried to go 130+mph before) with the Fairbanks kit?

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

 

If your existing harness applies 12V and a ground it will lock in 4th gear.

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350 with stealth intake, holley carb, 470 lift cam. 700r4 with .5 boost valve, vette servo, tci lock-up kit, B&M megashifter. Richmond 3.73 gears, powertrax locker, timkin bearings, synthetic lube. Custom 3 inch single into 2 2.5 pipes. 1 1/2 drop springs, 1 5/16 solid front sway bar, 1 inch rear bar, custom subframe connectors, custom LCA relocation brackets. Kobel ground FX, current red metallic paint. Lots of other stuff...
82camaro