'89 will work fine also. You will need an O2 sensor. The Knock sensor is optional - install it later after the vehicle is running on the TBI.
Jerry (DIY autotune) emailed me to get the adapter boards ordered. So in about 4 weeks they will be ready.
Whats needed:
TBI
GM ECM for the harness connector
GM ECM harness and fuel pump harness (get the entire wiring harness - don't chop anything)get all the control relays that are attached to the ECM harness.
TBI fuel pump - if your existing tank can accept the intank pump this is a better route to take.
Get ALL the sensors (coolant, TPS, MAP, MAT or IAT).
Reccomend that you buy a new aftermarket wideband O2 kit - it will make tuning a lot easier.
Also get another GM harness from an EFI vehicle - you will use this as a source of the correct color and size wire to extend the good harness as needed. This keeps the harness stock GM colors - you will be thankfull that you did later as it makes troubleshooting much easier.
Get a wiring diagram for the donor vehicle. If a wire passes through the firewall bulkhead going to the ECM then make sure you don't damage it during removal. Mark each connector where it goes e.g. coolant sensor.
From the wreckers get 2-3 spare 12V relays and sockets ( some FWD GM cars have a nice mounting bracket to hold 3-6 relays). Also get 3-6 sealed fuse holders.
If the donor vehicle is still running check the spray pattern on the TBI injectors to see if they are conical (good) or dripping ( bad).
From the auto parts get:
- A TBI overhaul kit and clean up the TBI (easier than a carb rebuild).
- electrical heat shrink that has sealer in it ( melts and seals to the wire).
(MS == megasquirt)
From DIY autotune order the following:
MS 3.00 main board ( if you have never done any electronic assembly before then get a pre-built board).
MS II processor
MS to GM TBI adapter board
MS stim board
D9 serial cable
Then get a PC laptop that has a serial port on it or a suitable USB to serial convertor - check the MS site for reccomendations.
Basic vehcile requirements:
1) must be 12v with a 50 to 60 amp min. alternator 85 to 100 amp with Air conditioning.
2) ideally electronic ignition - just makes it easier to do the install. Optimally an aftermarket ignition box - nothing fancy MSD6a or equiv. is fine.
3) room to install the MS controller inside the operator compartment.
4) the ignition switch must have a wire that is hot in run and start. If it doesn't then the ECM will need a seperate switch.
Vehicle prep:
A) phsically mount the tbi on the intake - sort out the throttle cable and kickdown cable if needed.
B) install the high pressure fuel supply and return lines. The supply needs to be 3/8" and the return 5/16 or 3/8". I have used both hard line and braided line for the job. Braided is so much easier. Earls makes adapters to convert the -6 line to the GM TBI fittings. Install a new fuel filter between the pump and the tbi unit.
C) make sure the tank pick up has a filter sock on it.
D) make sure that the return line ends max. 1" off the bottom of the tank. This ensures that the return fuel is kept in liquid state and doesn't build pressure up in the tank.
Wiring harness prep:
Throw the whole harness into the laundry sink with a strong detergent (liquid Tide works well) and let it soak at least for 24 hours giving it a stir once in a while. Then using a scrub brush clean the convoluted tubing.
Once dry - remove the convoluted tubing and use twist ties (or cable ties) to hold the harness together - keeps it from turing into a jumble...
where ever the harness splits off put a cable tie. Lay the harness out flat and sort out which wires are not needed. Tag the ones not needed with masking tape.
Then take the hrness out to the intended vehicle and lay it out in the engine compartment - the idea here is to find out where the EFI sensor and output wires need to go. Tag the wires that are too short and note how much longer they need to be. Find a suitable location where to put the firewall bulkhead pass through and cut the hole.
Install the required sensors on the motor.
Feed the ECM connectors through the firewall and install the bulkhead pass through. Now extend the wires that are to short ONE AT A TIME so the connectors have 2-3" slack and connect them to the correct sensor. ( you did mark them right
Connect the harness grounds to the block.
The donor vehicle used a 7 pin HEI distributor. If using an aftermarket ignition - connect the "distributor reference high" wire to the tach output on the ignition box or to the "-" side of the coil if using a pertronix conversion kit (this wire goes to pin B5 on the ECM connector. DO NOT remove or connect any of the remaining wires that orginally went to the donor HEI dist.
Once the vehicle is running on the TBI you can convert to control the timing later. Doing both at once is really harder for a first time EFI conversion.
Now remove the unneeded wires ( starter, alt. etc.) and put the convoulted tubing back on the harness. If your not sure and the wire is not connected to anything then just bury it in the harness - you can remove it later.
The Injectors need a 10 amp fuse, the MS a 2 amp fuse, and the fuel pump needs a 20 amp fuse.
Check your work using an ohm meter between the ECM connector and the other end e.g. TPS connector. Correct any wiring ooops.
Finish hooking up the fuel system to the tank, pump, fuel filter, TBI etc. Then apply 12V to the pump and check for leaks. I usually install a fuel pressure gage permanently in the fuel preussre feed line.
Now take the GM ECM apart - don't worry about static zaps - your going to hack at it anyway. Remove the 2 aluminum side rails holding the board to the case - remove any electronic parts attached to the RH side rail ( holding the ECM connector up).
Now remove the ECM harness connector from the GM ECM - you can use a heat gun to do the job - clamp the connector in a vise and apply heat to the back side of the board - wear a vapour mask ( suitable for painting). The idea here is to get the connector off with out damaging it - the GM board will be damaged but we don't care. Once you have the connector off using a pencil soldering iron clean each connector pin that went into the GM board one at a time to remove excess solder ( get this solder wick 473-1063-ND from
www.digi-key.com). To use the wick you press it against a pin to be cleaned and heat it with a soldering iron on the opposite side - the braided wick soaks up any solder present. After a couple of pins you'll get the hang of it.
Once the connector is clean install it onto the GM -TBI adapter board you bought from DIY autotune. Be carefull not to bridge the connector pinse with solder. Use only ROSIN core solder.
Complete installing the adapter board into the GM case - you will need to snip a hole on the back side of the case for the MS computer connector.
Read the MS manual.
Configure the MS board - not hard once you read the manual or when you order it ask DIY autotune to do it for you - I think they have a small fee for this service.
From here on it follow the proceedure for initial start up outlined on the MS site - too much to repeat here.
Once someone does a stock 250 conversion then they can share their MS setup file with the rest of the inliners which will make it so much easier - it'll almost be plug and play.
