2008 Trailblazer SS

[wxo]

Look what just turned up:

I arrived home last night with 111110 on the clock so I only had to go less than a mile before it turned over for the photo shoot.

[Maverick]

Goes well with the address on your mail box.

[Basement Paul]

I JUST missed the 111111 on my Ranger last weekend. I saw it at 111114... too late. 222222 can't come soon enough. Life's little amusements!

-BP

[MostMint]

121212 and 123321 will come lots sooner

[wxo]

Within the last 5 days, I noticed a change in behavior at startup. Normally, I do a quick hit with the key and the engine fires and runs instantly. Recently, however, it has been stumbling to life. This stumbling lasts only 1 or 2 seconds then it appears to run normally. it happens intermittently. I have 117K on the odometer and it is an LS2 6.0 liter. I plan to hook up my Hptuners equipment and run some scans to see if I can notice anything that might be causing this. Fuel pressure?

[MostMint]

Dirty MAF? How old are plugs?

[wxo]

I recently (about 17k miles ago) replaced the plugs and cleaned the MAF. This thing appears to be related to sitting for some time. Once it starts, I need to wait for a while (maybe an hour or two or overnight) before I can make it happen again. Restarting, it starts quickly (no stumble). It also runs normally after starting. Also, there are no pending codes recorded.

[Maverick]

Maybe a fuel check valve leaking? Maybe try leaving the key on for a few seconds before cranking to see if that fixes it.

[wxo]

Maybe a fuel check valve leaking? Maybe try leaving the key on for a few seconds before cranking to see if that fixes it.

Yes. That appears to allow it to start normally. Although, now I have to wait for a few hours to do more testing on that.

[MostMint]

good call Maverick

[wxo]

Took the TBSS out for the day yesterday and the starting issue seems to have gone away (for now, at least). I'm wondering if I have an injector intermittently leaking fuel pressure. If the problem comes back I'll have to get serious about understanding my fuel system.

[wxo]

Another thing popped up on my trip yesterday. It was a hot and humid day and the AC suddenly stopped cooling. Then I glanced down at the dash and saw an icon lit in the shape of an analog gauge. I had seen this before in the past and it reminded me that I could circumvent it by resetting the code.
I pulled over and used my UltraGauge to do just that. My buddy and I were pleased to feel the cool air flowing again. Then about 20 minutes later it happened again. Again, I reset it and we were cool again. When I got home, I did a bit of research and came up with this thread which describes what is going on: https://www.chevymalibuforum.com/thread ... ail.12036/

[wxo]

Took the TBSS out for the day yesterday and the starting issue seems to have gone away (for now, at least). I'm wondering if I have an injector intermittently leaking fuel pressure. If the problem comes back I'll have to get serious about understanding my fuel system.

It came back yesterday. It seems to start normally if I turn the ignition on for a few seconds before starting. Time to dig a bit deeper.

[wxo]

I did a bit of research and came up with this thread which describes what is going on: https://www.chevymalibuforum.com/thread ... ail.12036/

This issue also came back yesterday. I believe the original thermostat is currently in the engine now. I have a new thermostat on the work bench ready for an opportunity to install it. Hopefully, according to this thread, it will cure the problem.

[wxo]

I drove the truck and made some observations today. I watched the engine temperature display on my UltraGauge. It wasn't long before I noticed that the temperature had not increased above 96.8°. It stayed that way for the 20 minute drive. I also noticed that the ECM stayed in open loop mode the whole time. Usually it goes into closed loop mode (using the MAF for airflow readings) within the first mile of driving (controlled by engine temp). Obviously the original factory thermostat was sticking open. I plan to get it changed within the next few days.