I have a 90 Vette and plan on putting my Accel DFi in shortly as I put in the new engine. I plan on still running the stock dash, and I know part of my issues here with the Tach, and the Guages. I do not really want to leave the stock computer in there (Actually would love to eliminate it completly) Is this possible, and still be able to run the 90 Dash? I plan on getting rid of the VATS and doing some additional wiring to make thing work, but want to get rid of the stock computer, but do not really want to build a dash with guages to make it all work.

Anyone done what I am about to do with good results? I have read quite a few nightmare stories that people have had to go in and reworks someone elses work, but on mine, since I have some background on the Electronics end of it, and have no worries about having to rewire something, I am confident I can do it. Just not sure what electronics I need to worry about. I rewired my 935 because of harness conditions, and had a 1954 Ford that I got that had no wire at all when I got it, and I scratch did the Harness it in, but in both cases there is not much to these cars. This POS seems to really love its computer, and pulling out the computer and going conventional wiring, and running some things from the outs of the DFi seems pretty straight forward. For me if it looks that straight forward I feel like I must be missing something.

Opinions?

 

Its a cake walk, the hardest thing to do is to find a location for mounting the ECM. I would use a flying lead harness and piggy back the DFI box to the stock system. That way the stock ECM thinks its there and the CCM is all happy. You share the signals between the boxes and that is all that is to it. The VATs will be a thing of the past because all fuel and ignition will be handled by the DFI box.

 

Sounds good to me. My goal is to put all the electronics on the back side of the firewall behind the glove box area, and have the computer cable rolled up and stored in the glovebox that I will hook to the laptop as tuning is needed. Most everything else I want to appear stock as possible, so that a person that does not really know what they are looking at will never notice I have changed much. I want to pass all Smog stuff here in utah as I plan on still driving this on the streets.

 

I installed an Autronic SMC standalone DFI in my -90. Put it in the glove box compartment. It was a couple of years ago and if my memory serves me right I did have some trouble getting the fans to work in the beginning. Therefore, I was forced to keep the OEM computer (controls the AC and fans only). I feed a rpm signal and a simulated narrow band lambda signal (from my Innovate LC1) to the OEM ECU, without these the ECU "thinks" the engine is not running (thus not turning on fans etc). THe TPS is also feeding both ECU´s.

I don´t know about the Accell but the Autronic is running sequential -mode only so I was forced to modify the distributor; one additional Hall sensor for the cylinder 1 position signal while keeping the OEM magnetic sensor to get a rpm signal to the stock ECU. Found one pic:


If the Accell is running batch/bank mode it´s likely you will have an easier situation. Since I don´t know the details of the OEM ECU "logic" it might work without one or more of the sensors I still have connected but since it was fairly easy work I just connected them anyway.

BTW, I did this installation like 4-5 years ago and it still works-even my backyard style cranktrigger/distributor modification

I can send you some pics if you are interested.

 

I appreciate it. Any help here and there will be a big help. I plan on doing quite a bit of photo work as I go and if I run into trouble I can refer to them as to what was stock and what is now, and can try to be able to go back and trace problems.

 

Mine's mounted under the passenger seat.

 

I've got an old fashioned accel gen 6 in my 84. The stock ecm is in a cabinet. The accel computer is in the old computer location under the passenger kick panel. The dash still works except for the mph (didn't get a box since this is a race car) and the mpg readout. All the other functions work. Took some wiring, and time, but definitely doable. I am running a stand alone TCI computer for the 4l60e.

 

A recent pic of the glovebox. It´s a little difficult to see it (in the process of tidying up the wiring) but the ECU is the box to the left (with a small tube attached to it). The harness goes down to the passenger side footwell where it goes through the firewall and exits just under the heater box. Only thing that´s not working is the mpg display.