Ok I bought a mechanics stethoscope today from Harbor Freight for $5(good deal). I checked all my injectors and they are working properly. I poked around to listen for vacuum leaks. The only hissing/whining I found on the line from the intake to the vapor management valve. I've never used a mech. stethoscope before so I am not sure what I am supposed to be looking for. If I stuck the scope on a line and heard a hissing/whining sound, does that mean its a vac. leak in that line? Or would the line going to the vapor manage valve make that sound anyhow? I sprayed the ever loving crap out of that line with ether and it didnt affect the idle.

 

A mechanics stethoscope, you lucky dog!

If you can blow air thru your stethoscope with the probe removed then don't put the end of your stethoscope directly on the end of a vacuum line. I don't want you to get your eardrums sucked out!


Remember that You are supposed to remove the steel probe and only use ONLY the hose on the stethoscope to check for leaks. Have a friend act like they are going to whistle but have them suck in air instead. Put the hose of the stethoscope near their mouth and listen to what it sounds like. You are hoping to hear air sucked into a hose or gasket area by placing the stethoscope hose near those places in the engine compartment.

You could even remove a vacuum hose while the engine is running and put the end of your stethosope near it to get a feel for what it sounds like.

See vacuum leaks here...

http://brickboard.com/FAQ/700-900/En...mLeakDiagnosis

If you make PHYSICAL contact with engine parts (especially when using the stethoscope probe) then you could hear any variety of noises and even normal air movement within parts of the engine (like the throttle body).

Your ear will become trained over time and you may even start hearing sounds coming from your vehicle that have always been present. You may start hearing them because you are waking up your sound awareness.

Have fun with your new toy!



http://www.valvoline.com/carcare/art...=res20020801dt

http://remanufactured-engines.com/pa...iagnosis%20101

http://www.imperialclub.com/Repair/Engine/noise.htm

 

You know now that I think about it my P0171/P0174 problem started after I had changed my COP's, I changed them right before going on a trip to Florida and while I was down there the check engine light came on. hmmmm strange.

 

Ok my CEL is gone. I replaced the line from the intake to the VMV.
New problem now. It idles like crap and feels sluggish. I drove around for about 45 min and no check engine light. I don't know what it can be. Unless I can figure it out in the morning, its going to the shop. Damn what a pain in the a$$ just to change spark plugs.

 

VMV???

Are you sure the CEL is off for good? I could unhook the battery and mine would go off for a while but then come back, one time it came back on the same day but another time it took it a few days to come back on.

 

VMV is the Vapor Management Valve. Its up near the brake booster on the fire wall. The check engine light came on on my way to the shop. The said its a vac leak, just have to find it.

 

So far I have managed to stump the mechanics with my problem. They get the same lean bank codes and cant figure out where the problem is. He mentioned something with the lower intake being plastic. I thought it was alum. Do the 5.4L's have a TSB out for the intakes???

 

Over inside the passenger side fender is a vacuum canister. make sure it doesn't have a pinhole leak. Coming of the TB elbow should be a connector for a group of vacuum lines. One of these lines goes to the canister. Follow it to the canister and check it for leaks.

JMC

 

My lower is plastic. I'm not sure about the TSB. It seems like we have the same problem and if it's a vacuum leak it may be like JMC said the vacuum canister in the fender. I know I have sprayed carb cleaner all around the intake and inlet tube and found nothing so I'll check the canister in the fender.

 

So far my truck has been at the shop two full days and they havent found the vac. leak. He said its coming from somewhere on the right side. He did say I had a small exhaust leak, but that wouldnt cause a dual lean bank code.

 

It sounds like the shop is saying that a vac leak exists but they can't find it yet?

Here is a diagnosis link for p0171/p0174 again...

http://www.v8sho.com/SHO/TSB0197HO2SServiceTips.htm

Fuel System:
· Contaminated fuel injectors
· Low fuel pressure or running out of fuel (fuel pump, filter, fuel supply line restrictions)
· Vapor recovery system (VMV)
Induction System:
· MAF contamination
· Air leaks between the MAF and throttle body
· Vacuum leaks
· PCV system concern
· Improperly seated engine oil dipstick
EGR System:
· Leaking gasket
· Stuck EGR valve
· Leaking diaphragm or EVR
Base Engine:
· Exhaust leaks before or near the HO2S
· Secondary air concern
Powertrain Control System:
· PCM concern

 

Yeah the shop cant find it. They are thinking right now that it might be a cracked spark plug.

 

That would be funny if it is a cracked spark plug for codes p0171 and p0174.

Wait, I know what it is... You left one of the valve stem covers off a wheel!

Sorry, I forget that these vehicle problems are a bummer...

 

Yeah sorry but there's no way it's a cracked spark plug, I've had a cracked sparkplug before and you would have a severe mis if that was it. They must be out of ideas also Yesterday I changed out my DPFE sensor with the one from my cobra to see if that makes a difference since I don't want to buy a new one if it's not the problem. I'll have to drive it a few days to see if the check engine light comes back on, I'll keep you posted.

 

I'm gonna give them till Monday afternoon. If they cant figure it out, I'm gonna bite the bullet and take it to the dealership.