Converting my 88 back to EFI...

[POWER302]

Converting my 88 back to EFI... Help

When I bought my 88 it had allready been setup for a carb so I ran a carbed motor in it for a while. Now Im going back to fuel injection for Boost purposes later on..

I have allready got an a9l computer and mass air wiring harness, have map sensor, egr valve, tps, and iab, I know I stilll need an efi gas tank, fuel pump, lines, etc...

Now will a mass air wiring harness work with my 88s stock headlight and dash harness... I have allready pluged them together but will they work with each other ok?

Also are there any grounds that have to be hooked up by the computer or any harnesses that need to be connetced by the computer besides the computers main connector..

Any usefull information would be greatly appreitiated...

 

[RsStanG1987]

Well it will work fine with the headlights and all.. Im not sure where all the grounds are.

 

[jrichker]

1.) The main power ground is from engine block to battery: it is the power ground for the starter & alternator.

2.) The secondary power ground is between the back of the intake manifold and the driver's side firewall. It is often missing or loose. It supplies ground for the alternator, A/C compressor clutch and other electrical accessories such as the gauges. Any car that has a 3G alternator needs a 4 gauge ground wire running from the block to the chassis ground where the battery pigtail ground connects.

3.) The computer has its own dedicated power ground that comes off the ground pigtail on the battery ground wire. Due to it's proximity to the battery, it may become corroded by acid fumes from the battery. It is a black cylinder about 2 1/2" long by 1" diameter with a black/lt green wire.

4.) All the sensors have a common separate ground. This includes the TPS, ACT, EGE, BAP, & VSS

5.) The O2 sensor heaters have their own ground (HEGO ground) coming from the computer. This is different and separate from the O2 sensor ground. It is in the fuel injector wiring harness and comes out under the throttle body. It gets connected to a manifold or head bolt.

6.) The TFI module has 2 grounds: one for the foil shield around the wires and another for the module itself.

7.) The computer takes the shield ground for the TFI module and runs it from pin 20 to the chassis near the computer.

8.) The computer's main power ground (the one that comes from the battery ground wire) uses pins 40 & 60 for all the things it controls internally.

See http://www.fluke.com/application_notes/automotive/circuit.asp?AGID=1&SID=103#volt for help troubleshooting voltage drops across grounds

Copied From bbunt302

Just for reference, here's a list of all the compatible years:

89 harness should work for 86-89 as long as you're using mass air.
90 harness will only work in a 90. (B/c of air bags and dual dash connectors)
91 through early 92 harnesses should be compatible (single dash connector, fuel pump relay under driver's seat)
Late 92 through 93 harnesses should be compatible (single dash connector, fuel pump relay under the hood)

Computers from 89-92 are all the same. Look for the A9L sticker on the back cover for a 5 speed that matches your requirements. Example: E9ZF 12A650 AA" with the A9L code.

 

[POWER302]

Well. All my wiring in the dash is still intact.. And my main engine harness had two plugs that both pluged into two more plugs coming from the drivers side firewall. So would mine work or could it still be a 1990 harness or something?

 

[jrichker]

Diagram courtsey of Tmoss & Stang&2 birds. See http://www.veryuseful.com/mustang/tech for more.

If this is what you have, you should be good to go.

 

[POWER302]

Right by the connector 31 and 30 I have an extra connector and it plugs into a connector on my headlight harness its a grey color... Is that something I dont need?

 

[Drunk5oh]

if you are running a sumped tank for the carb setup, why not just keep it and run an external pump for the efi as opposed to tearing out the tank?