Ford Techs: Diagnostic Help Please TPS Issue
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I didn't look at the long term trims. I will check that out tomorrow. It seems like #7 comes back with misfires first. On my last test drive although I didn't feel the stutter I got 2 misfires on #7. Other times I've seem three misfires on #7 and #7 alone. I wonder if if could be a cascading thing where the computer tries to compensate and causes misfires on the other cylinders on that bank.
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From: St. Peter
If you are stopped put your truck in drive, foot on the brake and give it gas (as if to do a brake stand)(I call it "Loading it") will it misfire on you? If so then chances are it is just a coil and plug. I would replace #7 and #7 plug.
That or if anyone has just washed the engine it WILL cause problems. I cant tell you how many ford misfires on these engines i've had to chase because the detail guys at our shop get water in the boots of the coil.
On these trucks the PCM uses the CKP sensor to pick up changes in crank speed, and that is how it determines misfire. It is usually accurate however it is still possible that it is mistaking surrounding cylinders.
That or if anyone has just washed the engine it WILL cause problems. I cant tell you how many ford misfires on these engines i've had to chase because the detail guys at our shop get water in the boots of the coil.
On these trucks the PCM uses the CKP sensor to pick up changes in crank speed, and that is how it determines misfire. It is usually accurate however it is still possible that it is mistaking surrounding cylinders.
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So after a longer drive today the miss is not completely gone but it definitely seems less pronounced, doesn't happen as frequently and when it does happen its less severe.
I'm not getting as many misfires and when I do they only come up on #7. I did a loaded test and I believe I could feel a misfire but the component test did count any misfires. Here are the long term fuel trims
FT1
Idle 1.6
2500 RPM 13.3
FT2
Idle -0.8
2500 RPM 13.3
I'll see if I can get a new coil on #7 this week. yippee
I'm not getting as many misfires and when I do they only come up on #7. I did a loaded test and I believe I could feel a misfire but the component test did count any misfires. Here are the long term fuel trims
FT1
Idle 1.6
2500 RPM 13.3
FT2
Idle -0.8
2500 RPM 13.3
I'll see if I can get a new coil on #7 this week. yippee
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I had about 20 minutes waiting for a contractor to arrive at my house this morning so I ran to the autoparts store and bought one new coil. I installed it on #7, but the problem is still there. Doesn't feel quite as bad though. And no misfire counts.
I just ordered new plugs and the special tool required due to the plug design(breaking plug design). I also looked through my paperwork on the truck and the OASIS report I asked for when I bought it shows that all 8 plugs were replaced with the "updated" plugs, so hopefully they will come out.
I still can't quite resolve the TPS spike. Could the spike be a result of back charging the ECM following a failed spark signal to the coil?
I feel like if it was the phasers the thing would run lousy all the time. Although it probably could run better, the only real issue is this sputter.
I just ordered new plugs and the special tool required due to the plug design(breaking plug design). I also looked through my paperwork on the truck and the OASIS report I asked for when I bought it shows that all 8 plugs were replaced with the "updated" plugs, so hopefully they will come out.
I still can't quite resolve the TPS spike. Could the spike be a result of back charging the ECM following a failed spark signal to the coil?
I feel like if it was the phasers the thing would run lousy all the time. Although it probably could run better, the only real issue is this sputter.
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OK at this point I've replaced all the plugs and the problem seems to have been resolved. Also, the Performance Engines and Troubleshooting forum seems to have beat this issue to death. I guess my symptoms are pretty typical when the plugs start to go. I think that the codes and the TPS spike was related to misfires. The 30 or 40K volts trying to seek ground when the plug couldn't fire.
I was able to get all 8 plugs out without breaking them.
I was able to get all 8 plugs out without breaking them.
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I thought the trims looked ok. The only thing that seemed strange was the peeks when driving. I'm gonna change the fuel filter this weekend and I'll take another look. But I think you're right as soon as you have uncombusted air fuel mix in the exhaust stream from misfires, its going to result in a rich reading in the O2 sensor. But I would think that would cause a lean trim.
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From: St. Peter
The fuel trim at 2500 is a positive 13.3%, which indicates the engine is running lean, mainly because you have more o2 in the exhaust gas. Remember the only thing the o2 picks up is oxygen. During a misfire event you will have more o2 in your exhaust. I would say that it is not a vacuum leak because it would be high during idle, and closer to normal at 2500 rpm's if that was the case. It is probably something like unmetered airflow between the MAF and TB, or a bad MAF sensor. Otherwise you could be on the right track with the fuel filter, or just low fuel PSI in general. Now that it seems to be running better, it may be a good idea to re-check your fuel trims and see where they are at. 13.3 is not that far out of range. However it may be an indicator of a potential problem in the future.
Good Luck, Hope Its fixed
Good Luck, Hope Its fixed
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I just took another look at the Long Term Trims. The RH side is around 10% and the LH side is still around 13%(both at 2500 RPM). I'll do the fuel filter this weekend and I need to check my IWE system because I have a problem there. But...
Would a bad cam phaser impact the trims? Why would it be different from left to right? From what I've been able to find about the long term trim it does not rely on the O2 sensor while the short term does.
Thanks
Would a bad cam phaser impact the trims? Why would it be different from left to right? From what I've been able to find about the long term trim it does not rely on the O2 sensor while the short term does.
Thanks
Tuned
Joined: Sep 2005
Posts: 331
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From: Charlton, NY
OK at this point I've replaced all the plugs and the problem seems to have been resolved. Also, the Performance Engines and Troubleshooting forum seems to have beat this issue to death. I guess my symptoms are pretty typical when the plugs start to go. I think that the codes and the TPS spike was related to misfires. The 30 or 40K volts trying to seek ground when the plug couldn't fire.
I was able to get all 8 plugs out without breaking them.
I was able to get all 8 plugs out without breaking them.
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They were Motorcraft with about 30,000 on them. The original plugs were replaced at the dealer by the PO of the truck. These were supposed to be the upgraded Motorcraft Plugs. They were definitely fouled. The markings inlude;
PZT
14F
7C
PZT
14F
7C
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I don't know if this applys to you but a friend just had almost the same syptoms, a few differnt codes with intermitent misfires,and because of the drive by wire it's hard to get a real time feel for the problem, his truck is a 3 valve 04 150 4x4, turned out his intake gaskets were bad, some days they were really bad other days not so bad, keep it in mind.his truck just turned a hundred thousand miles
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OK I changed the fuel filter and rechecked my trims everything seems to be in order now. Long Term is around 3% at 2500. I also did a propane test looking for vacuum leaks and nothing going on. It was either the fuel filter, or the trim tables got reset when I disconnected the battery. Either way I'm a happy camper now.
Thanks for everyones Help!
Thanks for everyones Help!
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