2003 Tahoe starts.... and dies

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Matahoe

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I guess im the only one not too lazy to type Fuel Pressure Regulator. Really.


And a bad fuel pump and/or fuel pressure regulator would stick out like a sore thumb when you stick a damn fuel pressure gauge on the rail.

Yes young padawan. You will learn quickly that a lot of newbies aren't going to have much experience with any type of gauge, let alone a fuel pressure gauge. Unfortunately we need to resort to jedi mind reading. Caution. It can be lethal in some instances!
 

rockola1971

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Yes young padawan. You will learn quickly that a lot of newbies aren't going to have much experience with any type of gauge, let alone a fuel pressure gauge. Unfortunately we need to resort to jedi mind reading. Caution. It can be lethal in some instances!
Im guessing my original star wars figures that I got in 1977 when I was 6 are older than you are...and yet you are trying the star wars lingo with ME. Thats almost laughable.
If any given person doesnt know how to operate a fuel pressure gauge, find a youtube vid on it or even where or how to find the schrader valve on the fuel rail then they probably shouldnt be working on their own vehicle.
 
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brasil

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I think that a temp sensor could be involved... For example if the coolant temp sensor shows 30 deg F but in the reality the outside temp is around 75 deg F then the ECU "thinks " the engine is ICECOLD and throws a lot of fuel into the engine. So at the end the engine is flooded. And the only possibibility to get the car runnin again - is to use the PEDAL TO THE METAL procedure.... while cranking the the engine for 2-5 sek for a couple of times. After some minutes the engine starts... and runs as if nothing happend.
And again the "mistake /Error " only occurs when the engine is cold. When the engine just ran...or is warm /hot no issues

Greeetings Juergen
 

M1Gunner

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I think that a temp sensor could be involved... For example if the coolant temp sensor shows 30 deg F but in the reality the outside temp is around 75 deg F then the ECU "thinks " the engine is ICECOLD and throws a lot of fuel into the engine. So at the end the engine is flooded. And the only possibibility to get the car runnin again - is to use the PEDAL TO THE METAL procedure.... while cranking the the engine for 2-5 sek for a couple of times. After some minutes the engine starts... and runs as if nothing happend.
And again the "mistake /Error " only occurs when the engine is cold. When the engine just ran...or is warm /hot no issues

Greeetings Juergen

Would the ECM not then look at the IAT and default the coolant temp to its last known good reading. Then set a code for ECT sensor error and stay in open loop?
 

rockola1971

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Would the ECM not then look at the IAT and default the coolant temp to its last known good reading. Then set a code for ECT sensor error and stay in open loop?
I dont believe so. I seem to remember this ECT Temp Sensor causing this same issue in the past on a K chassis. The PCM has no way to tell if the ECT is reporting a correct value or not. Now it might enter a default value if it wasnt getting any sensor data or possibly an extreme negative/positive value(-100 deg or 150deg) Easiest way to tell is hookup a scanner and see what value is being reported to the PCM.
 

M1Gunner

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I dont believe so. I seem to remember this ECT Temp Sensor causing this same issue in the past on a K chassis. The PCM has no way to tell if the ECT is reporting a correct value or not. Now it might enter a default value if it wasnt getting any sensor data or possibly an extreme negative/positive value(-100 deg or 150deg) Easiest way to tell is hookup a scanner and see what value is being reported to the PCM.

Sorry but that's incorrect. PCM/ECM's actually do have the capabilities of determining if the ECT input data is fouled or the circuit is faulty. There are checks and balances that are done to verify readings from sensors that throw up red flags.
 

rockdenhorst

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Hello

I’m Marco and im from Germany and yes I have actually the same kind of problem with a 2003 Tahoe.
It starts when it’s in the warm Garage 70 Degrees . But it doesn’t start when it’s outside and cold 40 Degrees.
Fuel Pump, Relais, All Grounds are Checked. No Trouble Codes on the BCM or PCM. No solid or flashing Security Light.

The funny thing is, it starts after I disconnect the Battery for 15 Seconds.

I ordered a New BCM in US, hopefully that will solve the issue. Otherwise I will try to get rid of the VATS on the PCM.

Sadly it’s very difficult here in Germany to get parts or people who can program a PCM.

How was this Problem solved from Brasil?

Excuse some grammatical errors, I’m normally not writing much in English



Best regards from Germany
 

strutaeng

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Hello

I’m Marco and im from Germany and yes I have actually the same kind of problem with a 2003 Tahoe.
It starts when it’s in the warm Garage 70 Degrees . But it doesn’t start when it’s outside and cold 40 Degrees.
Fuel Pump, Relais, All Grounds are Checked. No Trouble Codes on the BCM or PCM. No solid or flashing Security Light.

The funny thing is, it starts after I disconnect the Battery for 15 Seconds.

I ordered a New BCM in US, hopefully that will solve the issue. Otherwise I will try to get rid of the VATS on the PCM.

Sadly it’s very difficult here in Germany to get parts or people who can program a PCM.

How was this Problem solved from Brasil?

Excuse some grammatical errors, I’m normally not writing much in English



Best regards from Germany
You should start a new thread on your issues. Link this thread if you want.

It's likely OP hasn't been back in years, and probably won't chime in to say if the issue was resolved...
 

strutaeng

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Exactly. I understand your teaching him. But since it's his first ever post...maybe give him a break and tell him at the end?
Apologies. I wasn't trying to be rude or anything...and I missed he was a new member..doh!

@rockdenhorst Welcome to the forum. You will find a lot of knowledge and guys trying to help diagnose your truck.
 

Fless

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Hello

I’m Marco and im from Germany and yes I have actually the same kind of problem with a 2003 Tahoe.
It starts when it’s in the warm Garage 70 Degrees . But it doesn’t start when it’s outside and cold 40 Degrees.
Fuel Pump, Relais, All Grounds are Checked. No Trouble Codes on the BCM or PCM. No solid or flashing Security Light.

The funny thing is, it starts after I disconnect the Battery for 15 Seconds.

I ordered a New BCM in US, hopefully that will solve the issue. Otherwise I will try to get rid of the VATS on the PCM.

Sadly it’s very difficult here in Germany to get parts or people who can program a PCM.

How was this Problem solved from Brasil?

Excuse some grammatical errors, I’m normally not writing much in English



Best regards from Germany

Welcome to the forum!

You will likely need a decent scanner that will read live data so you can see what the individual sensors are reporting. Tell us more about your Tahoe -- which engine, how many miles or Km on it, and what's been done to it lately.

When did this trouble start? Was it after any repair or other issue?

Can you describe what happens when it doesn't start? Does it crank over fine, but not ignite? Or does it not crank?
 

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