TPI Corvettes use two inputs TPI F-Bodies do not on '870 and '165 ECMs (not sure about '730):

pin C7 - A/T Overdrive Switch Signal (gear selector NOT in OD, P, N, or R)
pin C8 - 4th Gear Signal (feedback contact from TCC sol.)

Does anyone know how 'Vettes use these? Would this mean that a Corvette chip would not work in an F-Body? I don't see anything in TunerCat that sets a bit or something to differentiate between the two lock-up schemes.

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-Greg

'85 Trans Am - WS6,TPI:
Original owner, original paint/engine/interior, plus the usual bolt-ons

[This message has been edited by Greg '85 T/A (edited July 13, 2001).]

 

I'm not too sure I'm following you, but can offer this:

In all the ecms I've looked at the TCC is finally applied by the ecm grounding the circuit. The qualifiers are a brake mounted cut off switch, a pressure switch(es) in the tranny, and a coolant temp enable for the code to actually enable the grounding circuit.

 

What I'm getting at, is, there is something in the 'Vette program that looks at the inputs at C7 and C8. If you put a 'Vette PROM into a vehicle without this wiring, I would suspect TCC problems. If both Y and F cars use 700r4s, why the wiring difference?

 

My PROM was originally made for my 88 Vette. After I sold the car I found the PROM laying around and tried it in my F-Body. Its been in there now over a year with no TCC problems at all.




------------------
Mike L.
It ain't pretty.......

1987 IROC Z TPI 350 A4 3.27 Borg-Warner.

Mods: 2300-2500 Stall Converter, Shift Kit(GM parts), TPI Specialties Stage 3 PROM, Modified Airbox w/ K&N's, homemade cold air, Relocated MAT sensor, Gutted MAF, 160* thermostat, Accel 8mm Wires, bypassed TB coolant, Flowmaster 3 chamber single 3" in/out muffler, 3" MAC mandrel intermediate, custom dual !cat Y-pipe. airfoil, ported plenum. !smog

http://www.MichaelLasiuta.home.att.net

**BOYCOTT LAPEER DRAGWAY**

 

The 88vette chip is different from the 85 anyways. The 85ECM was an entirely different beast. 86+ vette and fbody chips are "basically" interchangable.

But to answer to the 85 vette chip question, I'm not sure, but I would really like to know, it may come in handy.

Brendan

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1987 IROC-Z L98,SR,EB 6085's,LPE 219/219 SR Cam, Crane 1.6RR, EB TPI Base, 58mm TB, Stock T5, ADS 24#, AFPR, K&N, EB TES, Catco Cat, 3" Borla Cat-Back, Accel cap,rotor,distro/other crap, Aluminum DS, 94 Disk Rear, Adjustable Prop Valve, Precision 3.73 Gears, Weld in Sub-Frame Connectors, Hotchkis LCA's, KYB Shocks/Struts, Poly Bushings all over the place, Moog Upper/Lower Ball joints and Tie Rods ends/Idler Arm, Big stereo, 730SD Conversion.

To see the ROC, Check out the webpage Here

 

True. Very true.

The reason I discovered the extra xmission inputs was that I was trying to see if I could slip a 85 'Vette PROM into my 'puter. One bugaboo on '85s - the 1,3,5,7 and 2,4,6,8 injector outputs are opposite at D14 and D15 from what the F-Cars are. This effectively shorts the two banks together. Could mess up the drivers (?).

Its funny. C8 for an auto car ('Vette) is the 4th gear input and for manual transmissions its the first gear signal. Oh well, better get another Helm's manual.

[This message has been edited by Greg '85 T/A (edited July 13, 2001).]

 

Oh, and just thinking out loud here -
could it have to do with the Corvette display - Overdrive light? Trip or MPG display?

 

Don't the 'vettes also have the oil pressure switch input to the ECM? What do they do with it? Anybody examined the code?

 

In the 165s, and 730s, there is just one injector driver. They tie together in the PCB. With an ohm meter you could check the 6870, and I'd imagine it's the same way.

yes, both the auto trannied, and manual tranny cars use a in gear detection switch, but that is primarily for idle speeds.

 

When I was running an 85 ECM, I blew the injector driver for my passenger side. The drivers side still fired, so I believe there are multiple injector drivers. In fact, the car RAN because the O2 sensor was on the drivers side. Only time I've ever driven a '4-cyl'... -Matt-

 

I think it was posted a while back that although there is redundant wiring, it all terminates to the same point inside the ECM. Thus, the injector driver may be working fine, yet 1/2 of the injectors aren't getting the signal.

Did you swap the ECM (nothing else) and solve the problem?

 

As it happens, I just used Craig Moates' ECMScan to image my 1227165 BIN to my HDD and then burned it to a PROM.

It's from an '86 L98 Corvette w/manual trans.

Would you like to look at it? OEM; no edits.

[This message has been edited by Sarkee (edited July 21, 2001).]

 

I'd love to poke around with it.

Email it to me?

 

You've got mail!