86 Gt Running Rough

Jaystang73 · Mar 3, 2017

Ok here is my situation im having i got the idle pretty much wired out so i have 2 questions or more, 1st question is i have black or really dark grey coming from the exhaust more when i punch the pedal for a second, can some one tell me what is causing this issue and 2nd question underneath my upper intake can someone show me where exactly all the lines go, im second guessing myself here they all seem to be correct but i just wanna make sure ,if someone could help me thatll be great thank you very much

mikestang63 · Mar 3, 2017

black smoke is you are running which which is most likely tied to your second question regarding having a vacuum leak. Go to veryuseful.com for the vacuum diagram

90sickfox · Mar 3, 2017

Black out the tailpipes means the motor is running rich. Too much fuel. On the 86 that would be a MAP sensor problem...or timing. The MAP sensor is mounted to the firewall by the vacuum tree. It should have a vacuum line running to it from the intake.

The newer 87-93 have a sensor in the same location called a BAP sensor. Theirs doesn't have a vacuum line connected to it.

What size ( color are your injectors ) ?

Can you pull computer codes ?

Is it when first starting it or after warming up ?

There are actually quite a few things that would cause a car to run rich. One if the most overlooked is the engine coolant temp sensor or the intake air temp sensor. ECT or IAT...the computer uses both for fuel correction.

The main factor to figure it out is the temp of the engine when it does it. The computer has one strategy for when its cold ( open loop ) or warm ( closed loop )

All that to say....pull the codes !!! Do a self test...

Jaystang73 · Mar 3, 2017

My injectors are like and orange tan color and tomorrow ill look over the check list you gave i got the car from a friend the entire top end was taken apart, lower and upper intake all the hoses dismantled some vacum lines cut so i went into it not knowing what he did or didn't do, and miraculously he doesnt remember, but thank you for the advice ill keep posting the progress

Jaystang73 · Mar 3, 2017

90sickfox said:
Black out the tailpipes means the motor is running rich. Too much fuel. On the 86 that would be a MAP sensor problem...or timing. The MAP sensor is mounted to the firewall by the vacuum tree. It should have a vacuum line running to it from the intake.

The newer 87-93 have a sensor in the same location called a BAP sensor. Theirs doesn't have a vacuum line connected to it.

What size ( color are your injectors ) ?

Can you pull computer codes ?

Is it when first starting it or after warming up ?

There are actually quite a few things that would cause a car to run rich. One if the most overlooked is the engine coolant temp sensor or the intake air temp sensor. ECT or IAT...the computer uses both for fuel correction.

The main factor to figure it out is the temp of the engine when it does it. The computer has one strategy for when its cold ( open loop ) or warm ( closed loop )

All that to say....pull the codes !!! Do a self test...

Oh the smoke is constant at start up cold or hot or just sitting at idle

Jaystang73 · Mar 3, 2017

90sickfox said:
Black out the tailpipes means the motor is running rich. Too much fuel. On the 86 that would be a MAP sensor problem...or timing. The MAP sensor is mounted to the firewall by the vacuum tree. It should have a vacuum line running to it from the intake.

The newer 87-93 have a sensor in the same location called a BAP sensor. Theirs doesn't have a vacuum line connected to it.

What size ( color are your injectors ) ?

Can you pull computer codes ?

Is it when first starting it or after warming up ?

There are actually quite a few things that would cause a car to run rich. One if the most overlooked is the engine coolant temp sensor or the intake air temp sensor. ECT or IAT...the computer uses both for fuel correction.

The main factor to figure it out is the temp of the engine when it does it. The computer has one strategy for when its cold ( open loop ) or warm ( closed loop )

All that to say....pull the codes !!! Do a self test...

Oh the smoke is constant at start up cold or hot or just sitting at idle

mikestang63 said:
black smoke is you are running which which is most likely tied to your second question regarding having a vacuum leak. Go to veryuseful.com for the vacuum diagram

Thank you

Jaystang73 · Mar 6, 2017

Ok still got black smoke blowing from the exhaust. Now will the timing cause this i went over this and over this car so many times and im finally stumped, another question is my fuel supposed to be running the entire time until i shut the engine off, maybe a dumb question and i should know this but im not sure with my fox

General karthief · Mar 6, 2017

I didn't see where you ran the codes.

Courtesy of @jrichker
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 orvoltmeter 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.[/B]

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. Itcomes 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, seeActron® 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 3145.
It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $22-$36.

90sickfox · Mar 6, 2017

Yes...the fuel pump stays on the whole time the car is running. When you turn the key forward without starting it should come on for a couple seconds and cut off.

Jaystang73 · Mar 6, 2017

Sorry yes i ran the code with a scanner i bought and a code 10 came up which in my code book says it is cylinders out of balance which in turn tells me tje timing is still off

Jaystang73 · Mar 6, 2017

90sickfox said:
Yes...the fuel pump stays on the whole time the car is running. When you turn the key forward without starting it should come on for a couple seconds and cut off.

It just stays on with the key in the on position and there is a new fuel pump in it

Jaystang73 · Mar 6, 2017

I wonder if it is getting roo much fuel by the pump after intial prime doesnt cut off

Jaystang73 · Mar 6, 2017

karthief said:
I didn't see where you ran the 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 orvoltmeter 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.[/B]

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. Itcomes 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, seeActron® 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 3145.
It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $22-$36.

I picked up the exact code reader shown above i got code 10

General karthief · Mar 6, 2017

Jaystang73 said:
Sorry yes i ran the code with a scanner i bought and a code 10 came up which in my code book says it is cylinders out of balance which in turn tells me tje timing is still off

I didn't find a code 10
What kind of scanner?

General karthief · Mar 6, 2017

@jrichker?

Jaystang73 · Mar 6, 2017

karthief said:
@jrichker?

Ill message him now

General karthief · Mar 6, 2017

When you @ then the screen name it will send them a notice

90sickfox · Mar 6, 2017

The pump staying on won't flood the motor. The fuel prime purpose is to clear possible air out of the fuel line before starting. The factory doesn't let the pump run when the engine is off as a safety feature.

Black smoke is unburned fuel...but it can happen for a bunch of reasons. Contrary to belief timing should be set to between 10 and 14 degrees. Setting it at 0 is not correct. Most folks tend to go with 12 degrees on our cars.

A weak spark can cause black smoke...the coil can be easily tested. I believe you said previously that the spark was orange....it should be bright blue almost white.

I has an issue with one of my cars where the o2 sensor harness grounded to the k member. It caused the car to run rough and it did put off black smoke. It also didn't give me any codes. On my car it only happened after running the car or idling for a while. Boy did I chase my tail on that one. Lol

Have you checked the resistance on the IAT or ECT sensor ? Cold air is denser than warm air. When its cold outside the engine uses more fuel to compensate for air density. These sensors are also in use as soon as the car tries to start....unlike o2 sensors. If the car thinks it's -20° it'll dump a lot of fuel.

The MAP sensor detects changing pressure in the intake. If it thinks there is no vacuum it'll command more fuel.

A vacuum gauge is a valuable tool. It'll tell you if the timing is advanced, late, if there's a valve issue, exhaust issue, or of coarse a vacuum issue.

My advise would be to get a vacuum gauge from a local parts store. Hook it up....start the car and report what it says.

My vacuum gauge is one of the most important tools in my tool box. It verifies timing and a lot of other stuff. You can fully diag a car with a vacuum gauge, spark tester, test light, multimeter, fuel pressure tester, noid light, and a regular timing light. At Harbor Freight that might be 100 bucks.

You want one like this...

General karthief · Mar 6, 2017

From my Ford EEC code reader book: "Code 10 is not a fault code. The Vehicles computer uses code 10 to signal the Code Reader operator to perform a WOT (Wide Open Throttle) test. Quickly press and release the accelerator pedal"
That is to start the cylinder balance test

Jaystang73 · Mar 6, 2017

Ah ok ill do that tomorrow ive never used this type of code reader but ill let you know tomorrow what my findings are thank you for your help

86 Gt Running Rough

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Wasn't a pretty sight...and I've got big hands

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wonder how much it would cost to ship you a pair

Wasn't a pretty sight...and I've got big hands

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wonder how much it would cost to ship you a pair

wonder how much it would cost to ship you a pair

Member

wonder how much it would cost to ship you a pair

Wasn't a pretty sight...and I've got big hands

wonder how much it would cost to ship you a pair

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