moleyman

I am finishing my 57 Corvette. I have converted the Rochester fuel injection to efi. I am using a FAST XFI 2.0 ecu and a FAST dual sync distributer. I have a 2010 LS3 6 pin throttle body, and a Lokar dbw pedal. The FAST ecu does not support dbw, so I am planning on using a 2004 corvette TAC module to drive the servo in the throttle body. ecu will get TPS data from sensor on the throttle body. Has anyone done a stand alone dbw system. Any input on how I should be proceeding will be appreciated.
Thanks

Old Geezer

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LT4T56Monte

I suspect your idea will not work without a lot of additional work. In a 2004 Corvette, the ECM (a 1M 411) communicates with the TAC module by it's own serial data link (not the OBD serial link). Without a 411 ECM, the TAC won't have a clue what to do, it wants more information than just TPS and pedal position. What might work: I am running a '91 Vette stock TPI motor using a 411 ECM and a modified dual sync distributor. It runs great but that is a whole different story, what is relevant is that I was able to keep the Vette's stock dashboard, ABS, and all other 'normal' '91 Vette operations by leaving the '91 TPI ECM in the car, relocated to under the left headlight. But to keep all the functions I had to feed the old ECM several signals. Some are fake, like substituting a fixed resistor for the IAT, ECT and the O2 sensor. The TPS signal is fed to both ECMs. The two ECMs did not like being connected together for the MAP sensor. I built an electronic buffer; you could just add a second MAP sensor. My modified dual sync provided a 1/2 RPM signal so I built a RPM doubler. The TPI ECM 'thinks' it is controlling the engine when in fact the injector and ignition outputs are not connected to anything. In your case you might be successful feeding similar dummy signals to a 411, let it control the throttle and let the FAST controller control the engine. Oh buy the way, I'm fairly sure that neither of the TPS signals from the electronic throttle are a match for a cable TPS signal. They start at a higher voltage and ramp up slower to a lower final value. So you might need a second TPS sensor. Also, I suspect the FAST ECM and TAC will not like their TPS signal together in what amounts to a parallel connection. I recently tried to add a Speed Hut wide band gauge to a car with electronic throttle. It had a warning light for AFR at WOT. When ever I connected the gauge TPS sensor wire to the electronic throttle, I would instantly get a Fault Code.
While it appears to be late in your effort, it sounds to me like you are going around the tree the hard way. Why not use a cable throttle body? The big thing that the electronic throttle adds is built in cruise control. There are plenty of good aftermarket cable operated cruise control systems. Trust me, just because you ask for 100% throttle with the pedal, does not mean you get 100% throttle opening as quickly as you ask for it. And remember Toyota had a bunch of trouble (or was it just rumor) with their early electronic throttle.

LT4T56Monte

A bit more research finds that in Mike Noonan's book on GEN III engines, the 411 ECM will not support electronic throttle when used in a 1 coil configuration because GM never offered it that way. So if I'm right about needing RPM and other engine sensor signals, you would have to come up with a 24 tooth reluctor wheel-like signal. EFI Connection has some 24 tooth stuff that fits under the timing cover. Maybe I'm wrong - I wish you luck. Try to find a vehicle with electronic throttle and a single coil. Use that ECM and operating system configuration.

Project GatTagO

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You can always swap to a Holley Dominator ECU.

Andrew

stevieturbo

With an ecu that is capable of doing it.

s30.hybrid

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Krom

run the factory throttle body, pedal, cable, rig a tps (gets my vote for the look)

or switch to an ecu that supports dbw

moleyman

Thanks for the feedback. It sounds like it is going to be far more difficult than I thought. I have already had the car running with a cable throttle body. I will keep you posted

G Atsma

The whole idea of a DBW throttle is to integrate it with an ECU so idle, cruise control, etc. is centrally controlled. A stand alone DBW throttle is like a stand alone transmission. It needs something to drive it.

JoeNova

The only time I've ever considered making a stand alone DBW controller was for an RV that had the engine in the rear and was having major throttle issues.

G Atsma

That WOULD be a worthy calling for one! lol Did you come up with anything?