maf conversion on 86 GT - misfire

[gxnos]

I just converted my 86 GT to MAF using the 4 wire harness and A9P. I just started it up and it misfires. It isnt random and is consistent on 1 or 2 cylinders. I havent had time to diagnose anyting, I was hoping this may be a common thing and somebody could suggest something.

For the MAF wires - I ran the power (red) into pin 57 (there wasnt one at 37), ground (black) to pin 60 (there wasnt one at 40), signal ground (brown) to pin 9, and signal (blue) to pin 50. I plugged the vacuum line for the map, and left the map sensor plugged in (also tried it unplugged)

The instructions I have say to move pin 51 to 38 and 11 to 32 for the thermactor pump. I pulled pin 51 out and I didnt have anything in pin 11. I didnt think these would matter anyways.

Also want to note that I started it with the maf sensor unplugged and it ran the same. Anybody have any ideas? I was hoping this was going to go smooth and easy!

 

[jrichker]

Dumping The computer diagnostic codes on 86-95 Mustangs

Revised 19-May-2009 to update drawing for dumping the codes on 86-88 Mustangs with no check engine light.

Dump the codes and see what the computer says is wrong…Codes may be present in the computer even if the Check Engine light isn’t on.

Here's the way to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.

Be sure to turn off the A/C, and put the transmission in neutral when dumping the codes. Fail to do this and you will generate a code 67 and not be able to dump the Engine Running codes.

Dumping the Engine Running codes: The procedure is the same, you start the engine with the test jumper in place. Be sure the A/C is off and the transmission is in neutral. You'll get an 11, then a 4 and the engine will speed up to do the EGR test. After the engine speed decreases back to idle, it will dump the engine running codes.

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.

See Troublcodes.net Trouble Codes OBD & OBD2 Trouble Codes and Technical info & Tool Store. By BAT Auto Technical

If your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.

89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.

The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.


WARNING!!! There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.

What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

Alternate methods:
For those who are intimidated by all the wires & connections, see Actron® for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.

Or for a nicer scanner see Digital Ford Code Reader (3145) – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.

 

[gxnos]

a faulty maf sensor or bad wiring to it can cause the misfire problem i listed above. my problem is fixed but i am curious about the vss. the car stalls sometimes on decel, im assuming because i dont have a vss. anybody know any way to get by this?

 

[v8only]

wire in the vss circuit.

you can get a vss at fordfuelinjection.com or ron morris site

 

[gxnos]

thanks for the info. i am doing more and more reading, and i found out i might actually have a vss.

my car is an 86 GT with cruise control. I heard the cruise control vehicles have a VSS. i do not have any wires going to pins 3 and 6 on the ECM though. Also, I dont remember seeing a VSS when I had the trans out. From what I am reading, I just need to run wires from the vss to the pins on the ECM. Can anybody give me more info on this?

 

[gxnos]

ah ha! this is what i found:

"You can hook the VSS signals up to the EEC-IV connector by connecting the input pins of the EEC to the appropriate wires on the cruise control module (located just to the left of the clutch/brake pedals). You need to hook the dark green/white wire going to the speed control to pin 3 of the EEC, and the orange/yellow wire to pin 6 (these are the colors for an '88, anyway). These positions on the EEC connector are empty and will require 2 EEC-IV connector pins."

 

[v8only]

I've done the mass air conversion on my 86, and I hooked up the vss to the ecu

 

[gxnos]

I've done the mass air conversion on my 86, and I hooked up the vss to the ecu

ok help me out here. where is the vss exactly? i do not have a sensor where the speedo cable plugs into the trans. also, did you run directly to the sensor, or did you tap into the wires at the cruise control module?

 

[v8only]

the vss is at the speedo cable at the trans. I'm surprised you don't have one....was your car an original aod car??

If you don't have one down there, get this one
Ron Morris Performance: VSS Connector & Wiring

and wire it in.

I tapped directly into the vss wires that came into the tunnel from the vss sensor directly.

 

[gxnos]

you know what, i gotta have one. the car is an original 86 GT with a T5. it has cruise and it works... so i have to have one. maybe i just didnt notice the wires goin to the trans when i did the clutch.

i am going to tap into the cruise module and see if that works. thanks!

 

[v8only]

there is a mass air conversion article here on stangnet. that's the one I went off of.. it told me exactly where to tap into.

just be aware, the plug drawing they have for the eec is backwards per their numbering order.

 

[oldskolbus]

I don't think mine had one when I did it. I think I had to buy a new cable.

 

[gxnos]

i DO have a vss!

i found the wires behind the radio, T-ed off them and ran them to the EEC pins 3 and 6. it runs awesome!