89'S 07 Tahoe 350K 5.3 P2135 & P2176 Limp Mode/No crank

[89Suburban]

End of work day normal routine lock up the office then pull my truck into the back warehouse to check on the truck loaders and see them out the door and lock up.

I went to leave, started up fine, pulled outside, closed the warehouse bay door, got in truck, put into gear, pulled away, immediate shut down. Truck made it 25 feet before rolling to a stop. traction/stability warning, engine light. Put it in park. Got my bearings. Tried to restart several times, no crank at all. I would hear the relay and lights would dim, but no crank. All lights nice and bright, don't believe it was a battery issue.

I popped the hood to check the battery cables anyway, they were nice and tight. I gave them a yank for the hell of it. Got back in truck, still no crank. So my next animal instinct was to shift through all the gears and back to park. Once I did this it fired right up.

I started to drive up our access road, after a few hundred feet right back into limp. However this time it did not shut down, once I came to a slow enough roll it would get moving again. It was starting to act like if I gave it too much gas it was starving for fuel. I pulled into another parking lot to investigate. This time however it shut off and I rolled to a stop again.

I did not try to restart, I immediately got my poor man's scanner to read the codes and started googling and reached out to @iamdub via bat phone text. I saw these codes deal with the TB and/or TAC sensor or related wiring? I gave the throttle pedal a few good hard flops full travel. Went and check the plug on the TB and gave it a push. Didn't feel like there was an issue. Didn't pull the plug off to investigate, dark as hell and freezing out.

I got back in, fired it up. Gave it a few good throttle blips, seemed ok. I cleared the codes out. Manned up and headed out to the main roadway. Truck ran fine, stopped for gas, ran over to the next town to pick up dinner, came home. Probably about a 20+ mile trip, rural road and highway mix speeds. Ran fine. No CEL.

Started fine this morning and drove to work fine. What y'all suggest I do now?

TB replaced with a off the shelf Pep Boys unit about 45,000 miles ago. Once I replaced it I had to limp it to the shop for a forced idle relearn. Lifetime warranty but now that they shut down their retail stores that warranty is probably screwed.

 

[Geotrash]

Whoa...glad you made it home and back to work okay. If you haven't replaced the TPS or gas pedal assembly yet, those would be next on my list. I initially assumed you replaced the TPS on yours when you replaced the TB, but if not it might be wise to replace the whole assembly. I used the Dorman part on my '07 30K ago and it's been fine.

 

[George B]

TPS is an easy swap but… Watch a video and do it on the bench. I lightly clamped my TB in the vise with soft jaws and rags to hold it.

 

[89Suburban]

Whoa...glad you made it home and back to work okay. If you haven't replaced the TPS or gas pedal assembly yet, those would be next on my list. I initially assumed you replaced the TPS on yours when you replaced the TB, but if not it might be wise to replace the whole assembly. I used the Dorman part on my '07 30K ago and it's been fine.

TPS is an easy swap but… Watch a video and do it on the bench. I lightly clamped my TB in the vise with soft jaws and rags to hold it.

The TPS came installed on the replacement TB.

 

[George B]

The TPS came installed on the replacement TB.

I figured but I thought you wanted to put a new TPS on your 45K mile TB from Pep Boys to solve your current issue.

 

[89Suburban]

I figured but I thought you wanted to put a new TPS on your 45K mile TB from Pep Boys to solve your current issue.

Oh ok I misunderstood .

 

[iamdub]

Reading the whole story gives me a different vibe than the texts. I can't think of a correlation between the shifting through all the gears and the TAC-to-TB system. Might be purely coincidental. The starter relay clicking and lights dimming as if the battery is under a heavy load is confusing, too. Anything the PCM does to keep the engine from starting would kill the relay so none of that even engages.

How old is that battery? I know you said the lights and all were bright and when it did fire up, it fired right up. But, it could still have an intermittent internal open circuit or even a short. You giving it throttle and it acting like "it was starving for fuel" could be weak fuel supply, which could be low voltage to the pump, caused by a weak battery. Maybe the modules making up the throttle system is just what's feeling the effects? Did you check the rest of the battery cables other than the terminals on the battery? The ground is on the front of the passenger head.

But, then, if the PCM doesn't know where the pedal and/or throttle blade is, that could cause a bog from an opened throttle and no correlating fuel supply.

Aside from checking the freebies and before you load the parts cannon, a scan tool that can display live data and/or freeze frames would be really helpful. Otherwise, we're all just taking stabs.


Oh- and your '07 doesn't have a 5.7

 

[89Suburban]

Reading the whole story gives me a different vibe than the texts. I can't think of a correlation between the shifting through all the gears and the TAC-to-TB system. Might be purely coincidental. The starter relay clicking and lights dimming as if the battery is under a heavy load is confusing, too. Anything the PCM does to keep the engine from starting would kill the relay so none of that even engages.

How old is that battery? I know you said the lights and all were bright and when it did fire up, it fired right up. But, it could still have an intermittent internal open circuit or even a short. You giving it throttle and it acting like "it was starving for fuel" could be weak fuel supply, which could be low voltage to the pump, caused by a weak battery. Maybe the modules making up the throttle system is just what's feeling the effects? Did you check the rest of the battery cables other than the terminals on the battery? The ground is on the front of the passenger head.

But, then, if the PCM doesn't know where the pedal and/or throttle blade is, that could cause a bog from an opened throttle and no correlating fuel supply.

Aside from checking the freebies and before you load the parts cannon, a scan tool that can display live data and/or freeze frames would be really helpful. Otherwise, we're all just taking stabs.


Oh- and your '07 doesn't have a 5.7

Could the ignition switch in the column be an issue? I got this gut feeling it is tired.

 

[Trey Hardy]

Could the ignition switch in the column be an issue? I got this gut feeling it is tired.

Sounds more like a battery issue or possibly the throttle position sensor in the throttle body
I never had to do a relearn on mine when I replaced it? I don’t remember doing it anyways…
I did clear the codes though I ported the crap out of it and was worried I went to far but it and the one I ported in my white truck has held up great
I do remember I got a bad dorman throttle body TWICE from different advance auto stores because after installing I ended up robbing my white trucks throttle body until I could find another throttle body nearby

Like @iamdub said check the battery if it’s old replace it for ***** and giggles or swap one out another car you got sitting around
Check the ground straps and make sure there not corroded
I would have all kinds of electrical issues in my 07 until I finally got a new battery and did the BIG 3 Upgrade they’ve seemed to disappear

 

[iamdub]

Could the ignition switch in the column be an issue? I got this gut feeling it is tired.

It could be tired and I could be wrong. But, I ruled that out based on your relay clicking and lights dimming when you turned the key to crank it. Next time it happens, don't clear the codes and try to get your hands on a scanner that will display the freeze frame(s). They could be vital to catching this ghost. I would say to try to check the battery gauge as quickly as you can but it doesn't respond quickly enough nor has enough resolution to be much of a diagnostic tool in this case.

And +1 to the Big 3 (or 4 or 5) Upgrade.