Cel

Pull the codes yet??? All the cel codes will be stored even when the light goes off.

Tim1995 said:

Went to the local automotive stores but I guess my obd system wasn't working.

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Try using a paper clip or piece of wire to jumper the ports and read the actual cel for codes. I thought my obd1 system didn't work either till I tried it numerous times and ended up actually cleaning the connections by repeated attempts. They get oxidation on them and don't work till you scrape it off sometimes.

I'm pretty sure you can use a paper clip or jumper wire in the test port. Then count the cel light flashes in the dash gauge cluster. Google "stangnet how to pull cel codes" and read up on all the material. Its very easy when you see it. Some youtube videos are on the web too. You don't need a code reader, you just count the flashes

I have the code reader for obd1 vehicles and the damn thing has never worked. Paper clip works every time now.

Yup big plastic black multi port and a single grey one search it on this site. Jrichker posts it often. Make sure you probe the correct ports and the wire only goes from the single grey to one slot on the multi port plug. once you see it it is easy as pie

jrichkers not mine...
its the red dashes for the location of your jumper wire

Dump the codes: Codes may be present even if the Check Engine Light (CEL) isn't on.

Dumping the computer diagnostic codes on 86-95 Mustangs

Revised 26-July-2011. Added need to make sure the clutch is pressed when dumping codes.

Codes may be present even if the check engine light hasn’t come on, so be sure to check for them.

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.

Post the codes you get and I will post 86-93 model 5.0 Mustang specific code definitions and fixes. I do not have a complete listing for 94-95 model 5.0 Mustangs at this time.

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



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. This is crucial: the same wire that provides the ground to dump the codes provides signal ground for the TPS, EGR, ACT and Map/Baro sensors. If it fails, you will have poor performance, economy and driveablity problems

Some 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.

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 clutch (if present) is pressed to the floor, 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.

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

Your 86-88 5.0 won't have a working Check Engine Light, so you'll need a test light.
See AutoZone Part Number: 25886 , $10



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 Equus - 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-$36.
http://bellsouthpwp.net/l/r/lrichker/index.htm
See my website for:
R134a conversion doc
Door lock actuator fix

89 LX 5.0 with a Tremec 3550 5 speed, King Cobra clutch, Aluminum driveshaft, Cervini Stalker hood & flowmasters.

More neat stuff sitting under my garage workbench waiting for some extra $$$ to bring it up to 1st class shape and install it...

"Before you build a house build a good foundation"
jrichker, Aug 25, 2013

Tim1995 said:

So I've read a bit on this subject, and I still have some questions that still concern me. So all i have to do is put the paper clip in like the red dotted line in the second picture shown ? then i turn the key into the on position for KOEO. Count the number of times it blinks, which should be 1-1-1. Then i follow a series of test like turn the steering wheel half a turn, pressing the break.

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I don't knoe where you got the "series of tests" but no. koeo with the jumper wire then koer with the jumper wire. When your done with koer tests and the car isn't spitting any more codes floor the accelerator for a second for the cylinder balance test.

There are 2 tests "koeo and koer" = key on engine off, key on engine running. you need to address the koeo problems first.