High idle in cold temps
12-16-2016, 09:41 AM
#11
Senior Member
Thread Starter
Yeah wasn't my issue they are completely removed right now, leaving out until I get it sorted out. Really leaning towards something with the wastegates at this point, read for hours last night. Going to try and do some testing on them this weekend.
I keep confusing myself on the boost control solenoids though...those lines add pressure to the waste gate actuator to help it stay closed until target boost is reached, correct? I keep wanting to think of them as a vacuum line but my understanding is as boost increases it adds more and more pressure to the actuator to help keep it closed.
So if you blow air into that line...it should hold pressure and shouldn't leak at all. If it does, that means its not staying closed at lower boost levels like it should
I keep confusing myself on the boost control solenoids though...those lines add pressure to the waste gate actuator to help it stay closed until target boost is reached, correct? I keep wanting to think of them as a vacuum line but my understanding is as boost increases it adds more and more pressure to the actuator to help keep it closed.
So if you blow air into that line...it should hold pressure and shouldn't leak at all. If it does, that means its not staying closed at lower boost levels like it should
12-20-2016, 04:49 PM
#12
Senior Member
Thread Starter
We had a 60 degree temp swing from Sunday morning to today, -25 to 35 degrees. Truck went back to running poorly, idle dropped a little, air leaking sound is back, and the cat efficiency code reappeared on the drivers side bank.
I dunno I gotta keep looking things over, I didn't notice anything looking under the hood today except for me breaking a t fitting as I was inspecting lines
I dunno I gotta keep looking things over, I didn't notice anything looking under the hood today except for me breaking a t fitting as I was inspecting lines
12-28-2016, 10:18 PM
#13
Senior Member
Thread Starter
So after breaking that t connection behind the boost control solenoid, I decided to drive it a few days to see how the wastegates reacted with no pressure added to help keep them closed.
Does anybody know what these have for stock springs? Aftermarket wastegates come with 5 psi for these trucks so I'm assuming that's a stock spring.
With the solenoid not adding pressure I was able the get the wastegates to flutter at 2-3 psi. I'm assuming the 5 psi spring should hold the wastegates closed up to 5 psi, if anyone knows differently please chime in.
This would kind of make sense because down low it feels lacking and higher gears you can feel the power coming on, presumably from more exhaust flow sending more pressure through the solenoid to help keep them closed, whereas down low it's not building enough pressure for the solenoid to help out and exhaust is getting bypassed.
Guess I am going to continue the experiment and disconnect one wastegate at a time and see if one side holds better than the other
Doesn't really explain the change in idle though, with 170,000 miles it's entirely possible I have several issues. I have what sounds like an air leak under the hood but on further inspection it is air traveling through the catch can hose from the passenger side valve cover to the can. If anyone knows if it's normal to hear air traveling through there let me know...Otherwise I am concerned it is sucking in excess air through the valve cover or area around the PCV valve. I already replaced the gaskets on that side 2 years ago
Does anybody know what these have for stock springs? Aftermarket wastegates come with 5 psi for these trucks so I'm assuming that's a stock spring.
With the solenoid not adding pressure I was able the get the wastegates to flutter at 2-3 psi. I'm assuming the 5 psi spring should hold the wastegates closed up to 5 psi, if anyone knows differently please chime in.
This would kind of make sense because down low it feels lacking and higher gears you can feel the power coming on, presumably from more exhaust flow sending more pressure through the solenoid to help keep them closed, whereas down low it's not building enough pressure for the solenoid to help out and exhaust is getting bypassed.
Guess I am going to continue the experiment and disconnect one wastegate at a time and see if one side holds better than the other
Doesn't really explain the change in idle though, with 170,000 miles it's entirely possible I have several issues. I have what sounds like an air leak under the hood but on further inspection it is air traveling through the catch can hose from the passenger side valve cover to the can. If anyone knows if it's normal to hear air traveling through there let me know...Otherwise I am concerned it is sucking in excess air through the valve cover or area around the PCV valve. I already replaced the gaskets on that side 2 years ago
03-13-2017, 01:54 PM
#14
Just researching about a few things about some issues on my truck, and I swear we have identical trucks. I never went with cutting out the cats, because I felt like that wasn't the issue. The other day, truck was idling high (800-900) and I couldn't understand why. Truck was warmed up, etc. I get a weird 'whooshing' sound occasionally also, can never pinpoint it either. Was thinking manifold leaks (no evidence of soot), etc. Sometimes when I come to a stop, my RPM's will bounce from 500-800. I've just about given up and said heck with it.
Now I'm getting an A/C compressor whine, so I believe my compressor is on the way out. Was thinking it was just the clutch, but I don't believe that's the issue.
Now I'm getting an A/C compressor whine, so I believe my compressor is on the way out. Was thinking it was just the clutch, but I don't believe that's the issue.
03-13-2017, 08:06 PM
#15
Senior Member
Thread Starter
Ya I got some actual data this weekend since it cooled down. Fully warm after idling then driving 15 min, foot on the brake in drive it will idle at 740-790 rpms, vacuum is only 16 at temps below 15 degrees ambient. When temps warmed up into the 20's, idle was around 580 rpms and vacuum about 17.4.
Sure seems like a vacuum leak caused by expanding/contracting materials, but where? IWE's were one thought but I'm not getting the intermittent engagement like when they were cracked before. Only other place I can think of is intake manifold...Maybe that explains why I hear the air leaking sound under boost.
I'm going to order a new gasket and do it on a Saturday so if the manifold is cracked I can run to the dealer and get one. Only problem is it probably won't get below 15 degrees again this winter to know if it fixes anything.
If anyone has any other ideas I'm all ears. Trying to get this thing running right before I hit the 200,000 mile mark haha
Sure seems like a vacuum leak caused by expanding/contracting materials, but where? IWE's were one thought but I'm not getting the intermittent engagement like when they were cracked before. Only other place I can think of is intake manifold...Maybe that explains why I hear the air leaking sound under boost.
I'm going to order a new gasket and do it on a Saturday so if the manifold is cracked I can run to the dealer and get one. Only problem is it probably won't get below 15 degrees again this winter to know if it fixes anything.
If anyone has any other ideas I'm all ears. Trying to get this thing running right before I hit the 200,000 mile mark haha