pinging on 87 octane
#1
10-17-2014
#2
10-17-2014
If you are not getting any EGR codes then yes, you may need to replace knock sensor, which is under the upper intake and can be a PITA to replace.
EGR system adds exhaust gases to intake when engine is under load, this cools the cylinders which reduces NOx emissions but also reduces pinging because of the lower cylinder temperature.
Octane is a heat rating, 87 octane will self ignite at a lower temp than 89 octane, which will self ignite at a lower temp than 91 octane........ect
Pinging is fuel self igniting prior to spark plug firing, the computer can change the spark timing, so if knock sensor is working the ping is detected, before you even hear it, and computer changes spark timing so spark plug ignites the fuel before it can self ignite.
This produces a loss of power
But because you have pinging it means the knock sensor is not working in any case.
You could check the connector, but I would think if it was the problem you would get a code for that.
EGR system adds exhaust gases to intake when engine is under load, this cools the cylinders which reduces NOx emissions but also reduces pinging because of the lower cylinder temperature.
Octane is a heat rating, 87 octane will self ignite at a lower temp than 89 octane, which will self ignite at a lower temp than 91 octane........ect
Pinging is fuel self igniting prior to spark plug firing, the computer can change the spark timing, so if knock sensor is working the ping is detected, before you even hear it, and computer changes spark timing so spark plug ignites the fuel before it can self ignite.
This produces a loss of power
But because you have pinging it means the knock sensor is not working in any case.
You could check the connector, but I would think if it was the problem you would get a code for that.
Last edited by RonD; 10-17-2014 at 09:41 AM.
#4
10-19-2014
pinging
If you are not getting any EGR codes then yes, you may need to replace knock sensor, which is under the upper intake and can be a PITA to replace.
EGR system adds exhaust gases to intake when engine is under load, this cools the cylinders which reduces NOx emissions but also reduces pinging because of the lower cylinder temperature.
Octane is a heat rating, 87 octane will self ignite at a lower temp than 89 octane, which will self ignite at a lower temp than 91 octane........ect
Pinging is fuel self igniting prior to spark plug firing, the computer can change the spark timing, so if knock sensor is working the ping is detected, before you even hear it, and computer changes spark timing so spark plug ignites the fuel before it can self ignite.
This produces a loss of power
But because you have pinging it means the knock sensor is not working in any case.
You could check the connector, but I would think if it was the problem you would get a code for that.
EGR system adds exhaust gases to intake when engine is under load, this cools the cylinders which reduces NOx emissions but also reduces pinging because of the lower cylinder temperature.
Octane is a heat rating, 87 octane will self ignite at a lower temp than 89 octane, which will self ignite at a lower temp than 91 octane........ect
Pinging is fuel self igniting prior to spark plug firing, the computer can change the spark timing, so if knock sensor is working the ping is detected, before you even hear it, and computer changes spark timing so spark plug ignites the fuel before it can self ignite.
This produces a loss of power
But because you have pinging it means the knock sensor is not working in any case.
You could check the connector, but I would think if it was the problem you would get a code for that.
#5
10-20-2014
DPFE sensor would see a bad EGR valve, it measures pressure difference in the exhaust manifold in two places, one near EGR inlet and one farther away.
With EGR valve closed pressure difference would be 0, as computer opens EGR valve the DPFE feedback tells it the pressure difference between the two hoses, this allows computer to open the EGR valve more or less based on engine load.
A clogged or restricted EGR valve would show up on the DPFE sensor as less change in pressure than expected.
With EGR valve closed pressure difference would be 0, as computer opens EGR valve the DPFE feedback tells it the pressure difference between the two hoses, this allows computer to open the EGR valve more or less based on engine load.
A clogged or restricted EGR valve would show up on the DPFE sensor as less change in pressure than expected.
#8
10-21-2014
DPFE = differential pressure feedback
It is a sensor that reads the pressure difference between two locations in the exhaust manifold.
In this case one location is near the EGR valve, when the EGR valve opens the pressure near it will drop as the intakes vacuum pulls in the exhaust.
Computer uses this pressure difference to calculate the amount of exhaust entering the intake.
Knock sensor info at this link: SOHC V6 knock sensor replacement - Ford Explorer and Ranger Forums "Serious Explorations"®
It is a sensor that reads the pressure difference between two locations in the exhaust manifold.
In this case one location is near the EGR valve, when the EGR valve opens the pressure near it will drop as the intakes vacuum pulls in the exhaust.
Computer uses this pressure difference to calculate the amount of exhaust entering the intake.
Knock sensor info at this link: SOHC V6 knock sensor replacement - Ford Explorer and Ranger Forums "Serious Explorations"®
#11
10-21-2014
#13
10-22-2014
#14
10-22-2014
Pinging/knocking is from gasoline self-igniting slightly before spark plug can ignite it.
Octane is a heat rating, lower octane number means lower self-ignition temperature
Compression is heat, under 9.5:1 compression ratio engine will usually run fine on 87 octane
4.0l SOHC runs 9.7:1 so can ping on 87 octane which was why they added the Knock Sensor
So here is the basic issue.
The Knock sensor is there to detect pinging and then retard(or advance depending on your point of view, lol) the spark timing to prevent it, spark ignites fuel before it can self-ignite, no ping.
There may be an underlying issue that can cause the pinging, carbon build up, EGR fault, cooling system problem, and that would be important to find.
But the main issue is that the Knock Sensor or Computer is not correcting for the pinging, so that would be the first issue to address.
A Knock Sensor detects pinging before you can hear it, the symptom with an engine issue if knock sensor is working is loss of power.
The pinging from carbon buildup or EGR issue makes the computer retard spark timing which causes a loss of power, so pinging is never heard, just loss of power.
Your symptom is pinging, so computer or knock sensor problem, because it shouldn't ping
Octane is a heat rating, lower octane number means lower self-ignition temperature
Compression is heat, under 9.5:1 compression ratio engine will usually run fine on 87 octane
4.0l SOHC runs 9.7:1 so can ping on 87 octane which was why they added the Knock Sensor
So here is the basic issue.
The Knock sensor is there to detect pinging and then retard(or advance depending on your point of view, lol) the spark timing to prevent it, spark ignites fuel before it can self-ignite, no ping.
There may be an underlying issue that can cause the pinging, carbon build up, EGR fault, cooling system problem, and that would be important to find.
But the main issue is that the Knock Sensor or Computer is not correcting for the pinging, so that would be the first issue to address.
A Knock Sensor detects pinging before you can hear it, the symptom with an engine issue if knock sensor is working is loss of power.
The pinging from carbon buildup or EGR issue makes the computer retard spark timing which causes a loss of power, so pinging is never heard, just loss of power.
Your symptom is pinging, so computer or knock sensor problem, because it shouldn't ping
#16
10-22-2014
The kind that makes the computer ignore knock/ping???
Not trying to be trite but automotive computer technology is a mystery even to the Ford Techs I know(when sober they deny it, but after a few beers the truth comes out, lol)
There is no way to check Ford's EEC computers outside of a live scanner and all that tells you is the parameters the computer is seeing, the knock sensor data should be available, so it would tell you if computer is detecting a knock.
In your case it isn't since you hear the knock, but that won't tell you if it is the sensor that's bad or the computer circuit for that sensor.
My guess would be the sensor
Not trying to be trite but automotive computer technology is a mystery even to the Ford Techs I know(when sober they deny it, but after a few beers the truth comes out, lol)
There is no way to check Ford's EEC computers outside of a live scanner and all that tells you is the parameters the computer is seeing, the knock sensor data should be available, so it would tell you if computer is detecting a knock.
In your case it isn't since you hear the knock, but that won't tell you if it is the sensor that's bad or the computer circuit for that sensor.
My guess would be the sensor
#17
10-22-2014
The kind that makes the computer ignore knock/ping???
Not trying to be trite but automotive computer technology is a mystery even to the Ford Techs I know(when sober they deny it, but after a few beers the truth comes out, lol)
There is no way to check Ford's EEC computers outside of a live scanner and all that tells you is the parameters the computer is seeing, the knock sensor data should be available, so it would tell you if computer is detecting a knock.
In your case it isn't since you hear the knock, but that won't tell you if it is the sensor that's bad or the computer circuit for that sensor.
My guess would be the sensor
Not trying to be trite but automotive computer technology is a mystery even to the Ford Techs I know(when sober they deny it, but after a few beers the truth comes out, lol)
There is no way to check Ford's EEC computers outside of a live scanner and all that tells you is the parameters the computer is seeing, the knock sensor data should be available, so it would tell you if computer is detecting a knock.
In your case it isn't since you hear the knock, but that won't tell you if it is the sensor that's bad or the computer circuit for that sensor.
My guess would be the sensor
#18
10-22-2014
Look for "KS" or PID "16E6"
Live scan(engine running and driving) would be best
Number should change while driving, negative numbers are usual, in this case it means advanced spark, the computer pushes the spark after TDC(advances it) until it gets a ping(knock sensor detects it), then computer retards the spark a bit.
It continues to do this as long as the engine is running, this is how it can get the best power from the octane of the fuel being used.
Similar to how computer and O2 sensors work, computer adds more fuel and less fuel continually to get the best power and MPG based on O2 sensor feedback.
Live scan(engine running and driving) would be best
Number should change while driving, negative numbers are usual, in this case it means advanced spark, the computer pushes the spark after TDC(advances it) until it gets a ping(knock sensor detects it), then computer retards the spark a bit.
It continues to do this as long as the engine is running, this is how it can get the best power from the octane of the fuel being used.
Similar to how computer and O2 sensors work, computer adds more fuel and less fuel continually to get the best power and MPG based on O2 sensor feedback.
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