What are my options on this configuration?

[doug70]

What I am considering doing;

Run a 91 Suburban TBI on a 97 F350 351W.

Truck/Powerplant info

1973 F100 Being converted to a 1979 F250 4x4 (frame and differentials are from a 79.
Motor 97 F350 351W F4TE (EFI cam) using a 1970 4V intake manifold. Ford EFI distributor.
Trans 95 Chevy NV4500 manual 5 speed with BW4401 Tcase has VSS
Stock 1979 Dana 44 up front Dana 60 rear 3:54 Gears
TBI parts from a 1991 Suburban 1500 (ECM, harness, Throttle body, sensors)
Fuel tank from 1995 K3500 with internal TBI fuel pump 15lb
Custom Exhaust with welded in Bung for O2 sensor (Mustang Shorty Headers)


Problems I see and questions.

Will the Ford EFI distributor work with the GM TBI? (H.A.M.B has a solution)
Speedometer is cable drive in cab and Tcase is VSS. There is an after market solution.
Accelerator pedal setup. I assume I can use the one from the suburban.
Cruise control. I would like to use the one from the suburban, but don't know what is involved.
Steering Column. I have a manual floor shift column from an 87 F250 or should I use the suburban.

I am no electrical wizzard, is this something I should attempt? Should I use the GM ECM or Megasquirt? Why?

Doug

[Matt Cramer]

I can't answer for the GM ECM side, but I can cover the MegaSquirt. Perhaps this should be moved to the OEM EFI hardware section as your question is as much about the GM ECM as the MS. Although if you go with the MS, I would probably use the 351W EFI intake instead; putting a TBI on it sounds like a step backwards.

Will the Ford EFI distributor work with the GM TBI? (H.A.M.B has a solution)

MegaSquirt can accommodate just about any mix and match of fuel parts and ignition parts out there; a Ford TFI distributor and a GM TBI in the same installation is no problem. (The GM ECU may need a locked out Duraspark instead. Not sure on that point.)

Accelerator pedal setup. I assume I can use the one from the suburban.

Just about any cable setup should work there, and it sounds like the Suburban's a handy donor. You might even be able to get the Suburban throttle cable onto your stock pedal depending on what you have now.

[Six_Shooter]

To use the full benefits of the GM EFI, there is an easy solution to interfacing the Ford the dizzy with the ECM, and that is to use the GM ICM (Ignition Control Module).

What you would do is remove the Ford TFI module, connect the reluctor trigger (magnetic trigger inside the dizzy) to the magnetic input on the GM ICM, that would have been used in the donor Suburban.

This does a couple things for you, it provides the ECM with the "REF HI" (purple/white wire), which is basically a tach signal, and also allows the ECM to control timing, through the "REF LO" connection (white).

I used this very connection scheme on my 1973 Datsun 240Z when I was running a dizzy in it on a 1981 Datsun L28 I6, I'm still running a GM ECM, just with DIS now.

In this configuration, with the TBI and other EFI related sensors, you should be able to start and run the engine on stock GM calibration.

As Matt said, you should be able to get a throttle cable to connect between the Ford throttle pedal, and the GM TBI, there's really no magic there, just make throttle blade open.

Using the original steering colum would be easiest, this will have no effect on getting the GM ECM to work, this is strictly a connection to the steering and if there is an auto shifter to the shifter mechanism of the tranny.

The easiest way to get a VSS signal to the ECM is to use something similar to the screw on VSS that Painless Wiring or other companies sell.

Just for reference, in my Datsun I couldn't use one of the Painless VSS, because the output of the tranny doesn't use a square tang, I had to come up with another solution. What I did was use a later speedo mead, that had a split magnet, as opposed to the early one that came in my car with a continuous (round) magnet. I fitted an optical VSS from an '86 to '90 S-10, and because of the split magnet it worked just like it would in the S-10, by reflecting the Infrared light back to the detector. The Suburban might use the same VSS.

If you are saying that the tranny only has an electronic VSS, then you may be able to use that for the ECM, though the PPM may not be correct.

The GM ECM will definatly work.

Mega Squirt will also work.

[fury fan]

Lots of good answers so far and saved me a bit of typing.

One thing I must add -
The Ford distributor will have a Hall Effect sensor in it (squre wave), not a magnetic trigger (AC sine wave). I don't know what the GM stuff uses, but research both dizzys and see how they compare. Fordfuelinjection.com is a good resource for the Ford.