White Diamond '03 DHS (with DTS floor shift)
Run the engine to heat the exhaust system. The thermal expansion might help loosen it.
Great! good to know I don't have a mysterious passage somewhere inside.The oil fill cap is on the clean air side (atmospheric) of the PCV system. The rattle valve or orifice is the dirty side. Regardless, a smoke test pressurizes the entire inside of the engine - remember that the cam covers have wide open drains to the oil pan, so the PCV dirty air line is equalized between the crankcase and the cam cover - it's restricted only into the intake manifold full vacuum line.
The old rattle valve slammed shut in the event of an intake manifold backfire - and the Northstar has an intake manifold overpressure valve built-in.
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Thank you! Nice lookin engine!The thingy on the top of the throttlebody is the MAP (Manifold Absolute Pressure) sensor. Manifold vacuum signal.
#3 is the AIR system vacuum - secondary air that sends fresh air to the exhaust manifolds in order to quickly light the cat on cold start. You (should) have it. The relay is clipped to the right strut tower - blue connector.
#2 is the AIR valve for Bank 1 - the right (rear) bank, on top of the cam cover. #8 is the AIR valve for Bank 2 - the left (front) bank, near the lower radiator hose.
B2S1 is in the left bank exhaust collector - left bank mixture sensing
B1S1 is in the top of the right bank exhaust manifold - right bank mixture sensing
B1S2 is the after-cat sensor - exhaust/converter total mixture efficiency sensing
Click to enlarge, use the < > to scroll pictures, click the little grid right lower for full view.
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Thanks for the suggestion. I'll have to get help for that one. My scanner only shows trouble codes, not real time pressure readings or trim levels. However, the car runs fine. I would expect hesitation, missing, or other symptoms if the injectors or fuel pressure were not functioning properly. I was getting @ 19 mpg in the city before I forgot to reconnect the MAF sensor before my last test drive. That senior moment caused mpg to drop to @15. Thought I finally fixed the "leak" issue because only 1 code came up (p0102). But, how could the pcm tell if the engine was running lean if the MAF was unplugged? So, fixed that, cleared the code and going for another test drive.... At least I was able to get a 30 day temporary registration while we sort this out...What if your fuel pump pressure is low, or your injectors plugged? At idle, you should get sufficient flow, but as the engine requires more and more fuel, you should eventually run out of fuel trim adjustment. Other GM injectors have a habit of being sticky, pulse them open and they delay closing, setting P 0172 & P 0175 rich codes. These tend to set at idle, where the engine uses less fuel than you can prevent coming through the injectors. Fuel Trims show as -30, typically.
Hi Guys;Late to this thread.
When chasing rich/lean, Need to focus on items that are common unique.
If you receive rich/lean for both sides of the engine, then focus on items common to both. Ie fuel pressure/supply, air supply/vacuum leaks, map/mag, throttle,
If on one side only, then focus on items unique to that side, plugs, injector, o2 sensor, cylinder mechanical, orings, seals.
For the O2, You can hook up the scanner, check that O2 is creating voltage cycles (reflecting the computer is constantly adjusting up and down), and then check the STFT/LTFT to see how the computer is resPonding to the o2 sensor.