So I asked my shop to put in a plastic kit to fix the fuel line but they just patched the leak instead. Ordinarily I'd be fine with that but I was hoping to eliminate a possible leaky vapor line as a problem source. I'm still I'm still getting hard start when cold, smelling fuel in exhaust, obviously very rich, seems fine once warm. Tried clearing the only code, P0172, comes back, and...

NEW issue, fairly loud clacking noise, 2-3 per second, for about 5-10 seconds on startup, hot or cold. Noise seems to emanate from inside dash, and also same or similar clack each time I press the brake pedal. That also stops after a similar amount of time. !??? (What's the best way to share a video with the noises?)

1st O2 sensor voltage bounces all over the place, even after warmup. The #2 is steady. Short term fuel trim (STFT1,) I have no idea how to interpret. I assume the ecu is trying to compensate for a rich mix.

Thinking I need to get a fuel pressure gage.

 

If this is your SS or LS , then please verify as repairs could be model specific.

the vapour line leaking vacuum can be the cause of the P0172, so could the flex pipe!

 

#1 O2 sensor is supposed to jump up and down, that is the short term fuel trim mechanism. The #2 O2 sensor is supposed to be rock steady. You need to get a fuel pressure gauge, the OBD does not report it.
Kinda looks like a leaky injector. Clacking when hitting brake pedal usually stems from weak battery.

 

This is the 2011 LS, 2.2, mentioned in #175 but I'll keep mentioning it, because who wants to scroll all over the place? Auto, 75k miles, well maintained.

Fuel pressure checked, 59 psi, immediately dropped to 54 psi upon shutoff and didn't budge from that for 5 minutes.

Trying to decide whether to figure out how to test the vapor line for leaks or send it back to the shop for a new vapor line.

If the was a leak in the flex pipe would I hear it?

 

The clacking noise from pressing the brake is clearly the interlock for the shifter. Never noticed it that loud before. Ignoring it. The other clacking is a bit different I now realize, and louder, and from a different place, and seems loud at the vent ducts, so maybe something in that system. Did do it again when last driven on cold start, but not upon warm startup. We'll see.

 

It’s a brand-new battery, but the cranking seemed a little sluggardly.

Forgot to mention the car got driven about 120 miles yesterday, in four legs, warm start each time was uneventful, even with pending P0172. Seemed to run great, fuel economy was great, but after a hard start this morning the CEL came on and P0172 was set. Still no other codes. Wanted to monitor fuel mix and whatever but the battery died in the old phone I had to use with OBD Link LX and Torque Lite. Still working on understanding how to set up the gages on Torque Lite and also how to use the OBD Link app.

Flex joint seems too quiet to be leaking enough to cause this much trouble, if anything at all. Have no idea about the fuel vapor line though.

 

The fuel vapour line will usually leak up above the rear axle just into the insulation sleeve or above the drivers rear tire, you might see fuel dripping in that area. Sometimes the insulation is wet with fuel from the condensation of the fuel vapour.

 

I need to figure out how to do that.

Using OBDLink XL and Torq Lite.

 

The best you can do is reboot the computers with a lobotomy. both of those parameters are dynamic. You might argue that LTFT can be somewhat static because it is a long term running average. but that is a weak argument.

 

The update is that I replaced the evap purge valve because it was easy. On a 40F morning it started grudgingly and ran rich based on smell until it went into closed loop at 105F or so and then ran fine. So, no change. That was a few days ago.

Just now started at 23F, more or less the same drill. Starts grudgingly without touching the throttle. But, run for a couple minutes to let the coolant come up to 60F and turned off, won’t start without throttle. This seems to eliminate a leaky injector. Warmed it up to full temp, runs beautifully, turn it off, restarts instantly without any hint of rich mix.

Don’t know if above eliminates leak in vapor line. Also don’t know if a bad gas cap could cause this because I don’t really understand what goes wrong when it won’t hold pressure.

Tomorrow I will perform a battery disconnect lobotomy.