SILVER2000SVT
07-09-2007, 10:08 AM
My truck has developed a problem in the past few months and I could use some help figuring out what is wrong.
Current Mods: 4lb lower, full exhaust (krooks longtubes, magnaflow cats & mufflers), JDM CAI w/ 90mm Mass air, Predator tuned by RWTD
Note that no modifications or changes have been recently made immediately preceding to the problems I’m having. I’ve been running the setup for over 3 years.
Major Symptoms:
Significantly down on power at WOT. (A Honda Civic was keeping up with me the other day):nono:
Very little SC wine at WOT
Other Symptoms(may or may not be related):
1. A/F is now running down to around 10 at WOT when it used to run at 11.8ish on the same tune when it was running good. (WBC Sensor in drivers side collector)
2. #7 plug appears to be burning a little oil (not a lot, just enough to be able to tell a difference on the plug tip when compared to the rest of the plugs, I think it’s just a valve guide leaking)
3. Compression check showed all cylinders in the 160-165 range except for #7 at 180psi and #8 at 150 psi. (Higher compression in #7 probably due to carbon buildup from leaky valve guide?)
4. Recent plug change (TR6’s gapped at 0.035) installed but no change.
5. Fuel pressure is good both at idle (28psi) and WOT (50 psi).
6. No Engine codes.
7. Vacuum good at idle 18” (it’s always been at 18”)
8. Good part throttle power and feel.
9. Sounds funny at WOT (different from before) but doesn’t sound like detonation (I’ve heard detonation before, this sounds more like a small water pump trying to pump air, sort of a swishing sound)
10. Idle is smooth 95% of time except:
11. Sometimes when truck is completely warmed up after driving when I come to a stop the idle will get really rough for just a moment (I notice when this happens that the WBC goes all the way lean). Only last about 15-20secs then goes back to normal.
My current thinking is that it may be the following but I would think I should be getting a code for most of these:
COP failing under load.
Dirty (clogged) fuel injector.
Dirty (bad) MAF
Current Mods: 4lb lower, full exhaust (krooks longtubes, magnaflow cats & mufflers), JDM CAI w/ 90mm Mass air, Predator tuned by RWTD
Note that no modifications or changes have been recently made immediately preceding to the problems I’m having. I’ve been running the setup for over 3 years.
Major Symptoms:
Significantly down on power at WOT. (A Honda Civic was keeping up with me the other day):nono:
Very little SC wine at WOT
Other Symptoms(may or may not be related):
1. A/F is now running down to around 10 at WOT when it used to run at 11.8ish on the same tune when it was running good. (WBC Sensor in drivers side collector)
2. #7 plug appears to be burning a little oil (not a lot, just enough to be able to tell a difference on the plug tip when compared to the rest of the plugs, I think it’s just a valve guide leaking)
3. Compression check showed all cylinders in the 160-165 range except for #7 at 180psi and #8 at 150 psi. (Higher compression in #7 probably due to carbon buildup from leaky valve guide?)
4. Recent plug change (TR6’s gapped at 0.035) installed but no change.
5. Fuel pressure is good both at idle (28psi) and WOT (50 psi).
6. No Engine codes.
7. Vacuum good at idle 18” (it’s always been at 18”)
8. Good part throttle power and feel.
9. Sounds funny at WOT (different from before) but doesn’t sound like detonation (I’ve heard detonation before, this sounds more like a small water pump trying to pump air, sort of a swishing sound)
10. Idle is smooth 95% of time except:
11. Sometimes when truck is completely warmed up after driving when I come to a stop the idle will get really rough for just a moment (I notice when this happens that the WBC goes all the way lean). Only last about 15-20secs then goes back to normal.
My current thinking is that it may be the following but I would think I should be getting a code for most of these:
COP failing under load.
Dirty (clogged) fuel injector.
Dirty (bad) MAF