Misfiring/popping Issue?

[antnvlz1294]

Hey everyone,

I currently have an 88' Mustang 5.0 Lx. I've had this misfiring issue but it progressed. I don't really understand if it is progressing because it is simply cold outside (17 degrees) here in NJ or if its because of an idling issue or what. I've included a video below showing the issue (you might have to turn up your volume) and You can actually hear the misfiring/popping sound. A little bit of information: My oil pressure psi was about 47 psi, my water temperature was at about 180(its usually between 180-195, not really sure what it is suppose to be around). My gas was full and my battery was normal it was at the 13v mark I believe(its the longest "-" about 1/4th of the way up from the bottom). I bought the car back in November from an older guy who took pretty good care of it but when I called him he "didnt know anything about it" of course. The car is completely stock besides the BBK Cold Air Intake, short throw shifter, BBK headers, Mac x pipe and I believe mac mufflers. The previous owner said also that the engine had only 100k miles but it just rolled over again and I personally believe it is on 200k but theres no way to tell. I've replaced the Egr valve and position sensor, the fuel filter, the sparkplugs with motorcraft coppers, replaced the igniton wires with auto lights, replaced the distributor cap and rotor with msd and even did a 3g alternator 130 amp swap with the bigger power wire that connects from the alternator to the ignition system. I went to clean out the Idle Air Control valve and it looks almost brand new and didnt have any buildup although i still sprayed it with carb cleaner. I have the speed density system not MAF and i currently have a MAP sensor. The car was in 3rd gear in the video, I was doing 35mph at about 1700rpm and It started misfiring/popping. It used to only do this with the headlights on but now its most of the time, at least once a day. Please ignore my stupid talking toward the end of the video. I included two videos, one while driving and another one with my idle moving around while i was at a stop light.

Thank you for your input.

Video 1:
View: http://www.youtube.com/watch?v=lG-ChzZHPAo


&

Video 2:
View: http://www.youtube.com/watch?v=MeMgbrSHe3E

 

[2000xp8]

Which of those repairs were done before the misfire and after?

As for mileage, if it was inspected in NJ at an inspection station, simply run a carfax on it.

 

[antnvlz1294]

Which of those repairs were done before the misfire and after?

As for mileage, if it was inspected in NJ at an inspection station, simply run a carfax on it.

I did all of those repairs to try to get rid of the problem. These repairs where done after I recognized the problem. My next time I plan on doing is to replace the O2 sensors with Bosch.

 

[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 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.

 

[antnvlz1294]

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.

 

[antnvlz1294]

I own and used an obd1 coder. I did all the tests on it and I got no codes. System pass.

 

[jrichker]

I own and used an obd1 coder. I did all the tests on it and I got no codes. System pass.

You got a code 11 and no other codes?

Does this happen only on a warm engine?

 

[antnvlz1294]

Yes only on a warm engine. If I do a KOEO with a cold engine I get code 24. Although I heard that is a common code to get put out when the engine is cold.

You got a code 11 and no other codes?

Does this happen only on a warm engine?

 

[jrichker]

Yes only on a warm engine. If I do a KOEO with a cold engine I get code 24. Although I heard that is a common code to get put out when the engine is cold.

Time to start looking at the TFI or PIP. Both are prone to problems on a warm engine. The hotter the engine gets, the more noticeable the problem.

 

[antnvlz1294]

Time to start looking at the TFI or PIP. Both are prone to problems on a warm engine. The hotter the engine gets, the more noticeable the problem.

Okay that makes sense because when my engines cold it really isn't noticble. What is a pip? I know the TFI module is on the distributor but I've never even heard of a pip?

 

[jrichker]

PIP Sensor functionality, testing and replacement:
The PIP is a Hall Effect magnetic sensor that triggers the TFI and injectors. There is a shutter wheel alternately covers and uncovers a fixed magnet as it rotates. The change in the magnetic field triggers the sensor. A failing PIP sensor will often set code 14 in the computer. They are often heat sensitive, increasing the failure rate as the temperature increases.

Some simple checks to do before replacing the PIP sensor or distributor:
You will need a Multimeter or DVM with good batteries: test or replace them before you get started.. You may also need some extra 16-18 gauge wire to extend the length of the meter’s test leads.
Visual check first: look for chaffed or damaged wiring and loose connector pins in the TFI harness connector.

Check the IDM wiring – dark green/yellow wire from the TFI module to pin 4 on the computer. There is a 22K Ohm resistor in the wiring between the TFI and the computer. Use an ohmmeter to measure the wire resistance from the TFI to the computer. You should see 22,000 ohms +/- 10%.
Check the PIP wiring - dark blue from the TFI module to pin 56 on the computer. Use an ohmmeter to measure the wire resistance from the TFI to the computer. You should see 0.2-1.5 ohms.
Check the SPOUT wiring – yellow/lt green from the TFI module to pin 36 on the computer. Use an ohmmeter to measure the wire resistance from the TFI to the computer. You should see 0.2-1.5 ohms.
Check the black/orange wire from the TFI module to pin 16 on the computer. Use an ohmmeter to measure the wire resistance from the TFI to the computer. You should see 0.2-1.5 ohms.
Check the red/green wire; it should have a steady 12-13 volts with the ignition switch on and the engine not running.
Check the red/blue wire; it should have a steady 12-13 volts with the ignition switch in Start and the engine not running. Watch out for the fan blades when you do this test, since the engine will be cranking.
If you do not find any chaffed or broken wires, high resistance connections or loose pins in the wiring harness, replace the PIP sensor or the distributor.

The PIP sensor is mounted in the bottom of the distributor under the shutter wheel. In stock Ford distributors, you have to press the gear off the distributor shaft to get access to it to replace it.

To remove the gear, first you drive out the roll pin that secures the gear to the shaft. Then you get to press the gear off with a hydraulic press or puller. When you go to press the gear back on, it has to be perfectly lined up with the hole in the gear and shaft. I have been told that the hole for the pin is offset slightly from center and may require some extra examination to get it lined up correctly.

Most guys just end up replacing the distributor with a remanufactured unit for about $75 exchange
PIP problems & diagnostic info
Spark with the SPOUT out, but not with the SPOUT in suggests a PIP problem. The PIP signal level needs to be above 6.5 volts to trigger the computer, but only needs to be 5.75 volts to trigger the TFI module. Hence with a weak PIP signal, you could get spark but no injector pulse. You will need an oscilloscope or graphing DVM to measure the output voltage since it is not a straight DC voltage.

See http://www.wellsmfgcorp.com/pdf/counterp_v8_i2_2004.pdf and http://www.wellsmfgcorp.com/pdf/counterp_v8_i3_2004.pdf for verification of this little detail from Wells, a manufacturer of TFI modules and ignition system products.

 

[antnvlz1294]

PIP Sensor functionality, testing and replacement:
The PIP is a Hall Effect magnetic sensor that triggers the TFI and injectors. There is a shutter wheel alternately covers and uncovers a fixed magnet as it rotates. The change in the magnetic field triggers the sensor. A failing PIP sensor will often set code 14 in the computer. They are often heat sensitive, increasing the failure rate as the temperature increases.

Some simple checks to do before replacing the PIP sensor or distributor:
You will need a Multimeter or DVM with good batteries: test or replace them before you get started.. You may also need some extra 16-18 gauge wire to extend the length of the meter’s test leads.
Visual check first: look for chaffed or damaged wiring and loose connector pins in the TFI harness connector.

Check the IDM wiring – dark green/yellow wire from the TFI module to pin 4 on the computer. There is a 22K Ohm resistor in the wiring between the TFI and the computer. Use an ohmmeter to measure the wire resistance from the TFI to the computer. You should see 22,000 ohms +/- 10%.
Check the PIP wiring - dark blue from the TFI module to pin 56 on the computer. Use an ohmmeter to measure the wire resistance from the TFI to the computer. You should see 0.2-1.5 ohms.
Check the SPOUT wiring – yellow/lt green from the TFI module to pin 36 on the computer. Use an ohmmeter to measure the wire resistance from the TFI to the computer. You should see 0.2-1.5 ohms.
Check the black/orange wire from the TFI module to pin 16 on the computer. Use an ohmmeter to measure the wire resistance from the TFI to the computer. You should see 0.2-1.5 ohms.
Check the red/green wire; it should have a steady 12-13 volts with the ignition switch on and the engine not running.
Check the red/blue wire; it should have a steady 12-13 volts with the ignition switch in Start and the engine not running. Watch out for the fan blades when you do this test, since the engine will be cranking.
If you do not find any chaffed or broken wires, high resistance connections or loose pins in the wiring harness, replace the PIP sensor or the distributor.

The PIP sensor is mounted in the bottom of the distributor under the shutter wheel. In stock Ford distributors, you have to press the gear off the distributor shaft to get access to it to replace it.

To remove the gear, first you drive out the roll pin that secures the gear to the shaft. Then you get to press the gear off with a hydraulic press or puller. When you go to press the gear back on, it has to be perfectly lined up with the hole in the gear and shaft. I have been told that the hole for the pin is offset slightly from center and may require some extra examination to get it lined up correctly.

Most guys just end up replacing the distributor with a remanufactured unit for about $75 exchange
PIP problems & diagnostic info
Spark with the SPOUT out, but not with the SPOUT in suggests a PIP problem. The PIP signal level needs to be above 6.5 volts to trigger the computer, but only needs to be 5.75 volts to trigger the TFI module. Hence with a weak PIP signal, you could get spark but no injector pulse. You will need an oscilloscope or graphing DVM to measure the output voltage since it is not a straight DC voltage.

See http://www.wellsmfgcorp.com/pdf/counterp_v8_i2_2004.pdf and http://www.wellsmfgcorp.com/pdf/counterp_v8_i3_2004.pdf for verification of this little detail from Wells, a manufacturer of TFI modules and ignition system products.

So do I ground the negative multimeter wire and use the positive on the TFI pins or do I have to do that to the computer as well?

 

[jrichker]

All the wiring resistance checks are one end of the wire to the other end of the same wire.

All the voltage checks are done using the battery ground post as the negative or ground for the meter

 

[antnvlz1294]

Alright I'll have to get some wire and do these test when I get home. I'll pose the results later on today.

 

[antnvlz1294]

All the wiring resistance checks are one end of the wire to the other end of the same wire.

All the voltage checks are done using the battery ground post as the negative or ground for the meter

So I measured the voltage in the Red/green and Red/Blue wires and I got around 11.98 volts for both. As for the resistance I just couldnt get that whole thing to work. I tried that a few ways Adapter<- 16 gauge<- Negative & positive cable(tried both at different times) <- voltmeter->Negative & positive cable(tried both at different times) -> wires. I even tried using the pins on the adapter and then connecting them to the 16 gauge wiring and then connecting the wire to the multimeter. Do you think I should just get a new distributor?

 

[jrichker]

So I measured the voltage in the Red/green and Red/Blue wires and I got around 11.98 volts for both. As for the resistance I just couldnt get that whole thing to work. I tried that a few ways Adapter<- 16 gauge<- Negative & positive cable(tried both at different times) <- voltmeter->Negative & positive cable(tried both at different times) -> wires. I even tried using the pins on the adapter and then connecting them to the 16 gauge wiring and then connecting the wire to the multimeter. Do you think I should just get a new distributor?

Not unless you are reasonably sure that you have eliminated everything else.
Be sure that you can return the distributor if it doesn't fix you problem, makes it worse, or introduces new problems.

 

[antnvlz1294]

Not unless you are reasonably sure that you have eliminated everything else.
Be sure that you can return the distributor if it doesn't fix you problem, makes it worse, or introduces new problems.

I'm not 100% positive. Should I just start by replacing the o2 sensors and the ignition coil first?

 

[jrichker]

I am not a fan of throwing parts at things in a wild effort to fix a problem. The O2 sensors are not likely to cause a miss such as you described. Plus at $35-$45 each, they are expensive to replace if it isn't indicated by codes 41/91 or 42/92.

If you just want to spend less than $20 on a wild guess, I probably would do the coil first.

 

[antnvlz1294]

I am not a fan of throwing parts at things in a wild effort to fix a problem. The O2 sensors are not likely to cause a miss such as you described. Plus at $35-$45 each, they are expensive to replace if it isn't indicated by codes 41/91 or 42/92.

If you just want to spend less than $20 on a wild guess, I probably would do the coil first.

Would the msd ignition coil be okay for a replacement? I believe it's around $55?

 

[antnvlz1294]

I am not a fan of throwing parts at things in a wild effort to fix a problem. The O2 sensors are not likely to cause a miss such as you described. Plus at $35-$45 each, they are expensive to replace if it isn't indicated by codes 41/91 or 42/92.

If you just want to spend less than $20 on a wild guess, I probably would do the coil first.

Tomorrow i'm going to go to advanced auto and pick up 8 new Motorcraft copper spark plugs, a gapper, msd ignition wires, possibly a new tfi module(will probably try to get if none of the other parts I pick up remove the issue) and a msd ignition coil. I already have an msd distributor cap and rotor that is on the vehicle that is pretty new that I put on back in November that I will just continue to use. I also plan on picking up dielectric grease to put on the new coil, will use to clean and expand the salt and pepper pins. Should i use some on the distributor cap prongs and the spark plugs? I also plan on picking up some sea foam to clean out my fuel system because god only knows how clogged it is after 24 years. I also plan on getting a new oil filter and oil for a change. I was thinking royal purple for oil? 10w40? Thanks.