BSeery

Where did you mount your computer for your fuel injection?

And where is the best place on the firewall to bring out the wiring?

AZSwede1960 and I took the glove box out and looked back there - nothing but A/C ducting in the way.

We were thinking of mounting it in place of the e-brake (I don't use it and don't like it) but the wiring won't reach. Under the radio looks good, but finding a place to take the wiring out to the engine compartment is hard to find.

Any ideas ??

EDIT: I asked this once before, but was looking to see if there were any other ideas. Damn, with the A/C ducting behind there, it is tight.


[Modified by BSeery, 1:30 AM 8/16/2003]

mrvette

OK, best spot I found was in line with about the pass side of the console, if you pull the map pocket, you can then remove center cluster, and the rear most a/c distribution duct coming back across the rear side of the main blower box, this will reveal a 'notch' about 1.5 inches wide in the top sections between the main blower box and the air diverter valve/door/flapper controll box...the one that decides where the air goes..right there n the crotch of that notch I went through the firewall with a hole saw....it lands just to the pass side and down below the distributor cap height....so it's a great location, much better than anything under the driver's side, beleive me....

OH, BTW, I used a bunch of pipe wrap to seal it up pretty tight, aded RTV...

GENE

PatsLs1vette

i did mine behind the map pocket just above the heater box,also brought it in in the wiper cowl area and sealed it but since you have a glove box then genes idea would be better for you.or how about the other computer thats weatherpacked and mount it under the hood somewhere.

mrvette

Pat, I know that's where GM mounts a lot of computers, but in fact, it's very poor practice.....no EE or ET for that matter thinks a whole lot of putting a computer out in the weather and water, and most of all 200F HEAT....to me that's very poor practice, especially if the car is stuck in traffic on a hot day....
never met an electron that loved heat....

GENE

flynhi

I've tried two locations on my 71: on the drivers side behind the left front wheel just below the vac reservoir and inside on the pass side behind the map pocket.

I ran the first location for a year or so with no problems (I run a weatherproof 727 speed density computer). However, in an effort to reduce engine bay heat, I relocated it to the area behind the map pockets to open up the air flow route out the drivers side gill louvers.

On the 71, the area behind the map pockets is pretty tight on an AC car and I ended up installing it three times and Dremeling the back of the lower dash panel to make it fit. It's do-able but not easy.

I think it will be easier on your 80 C3. Pay attention to routingfor the ECM wire bundles - they occupy more space that you would think.


[Modified by flynhi, 9:03 AM 8/17/2003]

Budman68

Gene disagrees with me, but mine is mounted under the windsheild water bottle. It's a 27 series ECM. i.e. 90 to 92.

The other system you could install it under the radio in 78 -82. Just pull the wires through the vacuum gromet.


[Modified by Budman78, 8:24 AM 8/16/2003]

mrvette

Well aside from the theory of mounting, the 727 computer is more rare in junkyards than the 730, and I used a 730 since for ten bux ea....I have about 5 of them, keep rotating them around so I know they are all active and well...

in for the long haul??? yeh, I guess.....

GENE

SuprJames

My DFI computer was small enough to fit in my glovebox (though I had to do some slicing on the glovebox). It required two holes in the firewall to run the wires efficiently. I used two stock holes. One was a large grommet with 3 small vaccum hoses going through it on the passenger side behind the glove box, and the other was on the driver's side. Since the 82' was equipped with throttle body injection I took all the wires that had to do with the computer out, and used that on the driver's side above the fuse box. My system has a ton of fuses and relays bunched together in the wiring bundle and I used the large amount of space behind the radio to place these.

I doubt this helps you much, but thought I'd share just in case.

mrvette

I have often wondered how easy it would be in reality to do a changeover from the TBI to say a TPI system...the wiring is allmost in place, just a few changes here and there, and I"d imagine it's done....

only thing is....I would never mount any electrical/electronics in the battery box....very poor practice with battery fumes....

GENE

markdtn

I ran mine in near the accelerator cable and then above the tunnel and put the ECM in the jack storage compartment. If you use a sealed battery, I don't see why you should have any problems. I am running a 7730 ECM for what it's worth.

mrvette

mark, in my first install I ran the wiring near the gas pedal and it was a huge problem for me, the computer was attached to the map pocket, vertically...fit well, 7730 indoor computer....thing was routing all that wiring over the radio turned out to be a HUGE PIA over time....hated that install....so I rewired the entire car about 2 years ago or so...and that time got it right, and now the computer is under a modded brace for the front console, flat enough on the tunnel, and under the radio, more or less....with the wiring routed as described above...making the entire car much easier to work on....I can just drop the front pass side panel off the console, and slip the computer outta there....OH, I also modded the heater blower output box on bottom slightly for extra room....allways something....

too much time on my hands....

GENE

flynhi

Is the 727 ECM functionally equivalent to the 730? Will the plug ins fit?

markdtn

The 7727 is functionally the same as a 7730, the PROMs interchange. The 7727 is weatherproof and has 3 rounded plugs. The 7730 is not weatherproof and has 3 rectangular plugs. So no, they wre not a direct interchange in that sense.

I like the idea if the ECM under the radio. I did have the car apart to install the harness and it is tight near the rear fiberoptic panel on mine. If I ever do another one I'll put the ECM under the radio and then just the fuel pump and battery hot leads to the back.