- May 3, 2015
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Please Help I Have Searched For An Answer Everywhere
- Thread starter purplefox93
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- May 3, 2015
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Replaced tps since problem started. A friend suggested that it could be the gear in the distributor badly worn. But on an efi car the computer controls total timing so I am thinking it's got to be in the tune. Just wandering if anyone else has ever seen this problem
Set your timing back to what it was when the car was tuned (usually 10* BTDC). Pull the chip from the computer, clean the contacts with contact cleaner and reinstall.
We can look for more after that.
We can look for more after that.
- May 3, 2015
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- 0
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Tried that already in a way. Ordered a tune from bama tune thinking maybe I had a bad chip i cleaned contacts when installing it and had the same problem sent that chip back to them lesson learned never order a boxed tune for a car with mods other than simple cold air and stuff like that.
- May 3, 2015
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Just to be sure though I will pull the chip and make sure contacts are clean on both the chip and the ecu in the morning
- May 3, 2015
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The previous owner did run a nitrous kit and is the one who had car tuned by Tony gonyun could it be that it's a nitrous tune that I'm running on and the computer is pulling total timing? But if that is the case would the timing advance higher before falling back
That tune should still work. A trigger is set to let the tune when nitrous is on or off. When not triggered, it should run that car perfectly without nitrous.
On Fox Mustangs, the timing is sent to the computer by a sensor in the distributor. Others may have a crank or cam position sensor, but not with EEC IV computers.
- May 3, 2015
- 8
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About ready to just go carb.. just like the throttle response and driveability of fuel injection
squeak93
15 Year Member
I would take it for a retune long before swapping to carb etc. As stated, ensure all parts are in working order and no wires are broken/bent or pinched and then spring for a new tune (maybe a new chip depending on what the tuner says). Throwing money at it only make you hate it that much more (man, I should listen to myself lol)
Do some simple diagnostic work before you spend money on a new tune & chip.
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) 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.
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) 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.
I would be most curios to check the Mass Air voltage first. This isn't something that you can easily do yourself, but I've seen quite a few bad mass air sensors in the last year or so... We use zedtronic data logging software to log these cars in the shop and it has proven to be one of the most helpful tools we have. I would find a competent shop and let them take a look at things, don't go to the extreme of a carb setup when the fuel injection can be fixed and allow the car to run as it should
What mass air meter do you have?
If it's calibrated for the 24's, just pull the chip out.
You don't have any parts that absolutely need a tune.
If it still has issues, you know that it's not the tune itself.
I'd also bypass the msd (separately from pulling the chip).
If it's calibrated for the 24's, just pull the chip out.
You don't have any parts that absolutely need a tune.
If it still has issues, you know that it's not the tune itself.
I'd also bypass the msd (separately from pulling the chip).
