Need Tune Up Help

You posted a TECH question in Talk. This limits your chances of getting some really good advice, since most guys aren't looking for Tech stuff in the Talk forum.

My advice to you is to twofold:
1.) Send a PM to one of the moderators and have your thread moved to 5.0 Tech
2.) Next time you start a thread, think about where it goes. If you are new to Stangnet, please read the terms of service and give extra thought to where your new thread belongs. There is some help in the text below to help you find the best place to start your thread.
General tech problems go in 5.0 Tech. Tech is for suspension, electrical, brakes, body, engine repair and general troubleshooting on the computer & trouble codes

Tall tales about your 5.0 Mustang, pictures of your 5.0 Mustang project and stories about your last trip to the race track go in 5.0 Talk.

Do this and you'll get the best answers quicker and not get lost in the maze of posts about everything but the type of problem you are having.

Having said that, here’s some help…




Off the shelf performance chips don't do much but advance the spark timing. You can do that yourself with a timing light and a wrench.

Want to find any hidden problems in your car? Dump the computer codes.

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 www.midwayautosupply.com/Equus-Digital-Ford-Code-Reader/dp/B000EW0KHW Equus - Digital Ford Code Reader (3145It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $22-$36.

Cole's 1987 GT said:

I got my first car a 1987 gt about a week ago and I got a basic tune up kit plugs-wires-msd cap and rotor and wanted to know if my car would happen to have any upgrades I don't know about like a performance chip etc. would that make anything diffrent when putting the tune up kit on it like timing etc? Thanks

Click to expand...

No, change plugs wires, cap n rotor you'll be fine. As for the talk/tech thing: don't worry bout the soup nazi. You'll recieve 'bout the same amount of help in either section, as long as those find the topic interesting or reply worthy you'll get replies/help. There's more traffic in talk by the way. Remember this forums social structure and hierarchy is similar to that of a highschool. Mind your p's and q's, try not to insult the popular kids, and apologize to the teachers and principal when necessary. You'll make out just fine.

One more thing: the most common reply is "do a search"

90lxwhite said:

No, change plugs wires, cap n rotor you'll be fine. As for the talk/tech thing: don't worry bout the soup nazi. You'll recieve 'bout the same amount of help in either section, as long as those find the topic interesting or reply worthy you'll get replies/help. There's more traffic in talk by the way. Remember this forums social structure and hierarchy is similar to that of a highschool. Mind your p's and q's, try not to insult the popular kids, and apologize to the teachers and principal when necessary. You'll make out just fine.

Click to expand...

In my garage is a toolbox that stands about 5 feet high. In it is a collection of tools gathered during 48+ years of fixing things from cars to airplanes to computers. I try my best to keep it neatly organized, and everything in its proper place. There are reasons for that:
1.) If I can't find a tool when I need it, it 's the same thing as not having it.
2.) If something is missing, I want to know about it. Tearing apart an airplane or automobile to find the missing tool is not fun. Not finding the missing tool when working on machinery or electrical equipment can have dangerous consequences.

Stangnet is a lot like that toolbox. Everything has it's place, and order is essential to keeping it working like it should. If you can't find something using the search feature, it may be that it is stuck in someplace you aren't searching. Searches outside of Google are often an Easter egg hunt, and there are a lot of things to look at and consider.

@Cole's 1987 GT
Your cooperation with the order of things and rules of service works for you and it isn't here to make things harder for you. Follow them and you will be the beneficiary of some great help from some very smart and skilled people. Post count, membership time and likes received are a good clue as to who has the best information. The long timers here all have this in common: a desire to help others enjoy their Mustangs and to make Stangnet the best Mustang website on the Internet.


@Noobz347 please consider moving this to Tech and emailing Cole's 1987 GT that it has been moved.

Did ya get er tuned up?