02 Silverado 5.3L blinking Service engine light

[Anduril]

Originally Posted By: Trav
If its bad enough to cause a P300 it doesn't really matter whats coming out the pipe, its toast.

Sadly true. Around here you could be blowing rose petals but still fail smog because of the code.

 

[Vikas]

Doesn't P300 have lot more plausible causes than the clogged converter? Were others ruled out in this particular case?

 

[Trav]

Of course it does but he has gone through the ignition and taken it to the dealer, they claim its a bad cat. He is asking them if they can find the root cause.
If they are a dealer or licensed shop shenanigans with anti foulers and deleting cat efficiency codes with a tune are out, legally they have to repair the vehicle in an approved and lawful manner or face a stiff fine and more.
That means if the threshold is 90% and this one has 89% it gets a new cat.

 

[nthach]

If he replaced the manifold on that era of Chevy truck, what was the reason for it besides Dex-Cool eating away at the OEM gaskets(which were mostly a L31 problem)?

 

[Trav]

Many GM engines had trouble with gaskets. Dex-Cool is a good coolant but GM made a mistake in using materials not fully compatible with it then in typical GM fashion dropped the ball in not addressing the problem for years.
To your question, whenever mixed metals are used next to each other gasket shifting, tearing and leakage can be a problem because of the different expansion rates of the metals, an aluminum intake on iron heads pose sealing problems for gasket manufacturers likewise aluminum head on iron block or vice versa (Vega engine being an example).

 

[clinebarger]

Originally Posted By: nthach
If he replaced the manifold on that era of Chevy truck, what was the reason for it besides Dex-Cool eating away at the OEM gaskets(which were mostly a L31 problem)?


No coolant through the intake manifold on a LM7 5.3L (LSx), Plastic frame gaskets are [censored] & cause vacuum leaks also.

I've seen L31 repeat I/M gasket failures with green coolant when using plastic frame gaskets.....Dexcool is a good coolant!

 

[Gito]

Dealer confirmed P0300, P0420

The technicians notes also read the following:
P0300, P0301, P307 misfire. Re-gapped one plug and then OK

Needs cat B-1 Low Efficiency, Re-gap plug, Gap wrong.

Thats all I got from the notes.

I requested to speak with the Tech.
The tech explained that the truck needs the drivers side Cat and wouldn't hurt to change the upstream 02 sensors on both.
He also mentioned that the passenger side Cat might be going out sooner than later, based on numbers that he saw and based on his experience.

The tech stated that he also checked compression on only one cylinder, and that was because he felt the readings didn't really call for checking the rest.
(Not sure what checking one cylinder would tell him)

Also said that Fuel Pressure Regulators are common cause for the above symptoms and codes.

$130.00 Diagnostic

 

[Trav]

Did he tell you what the fuel trim numbers were? If not you have a good right to be PO'd, the guy sounds incompetent, did he even test the fuel pressure regulator?

 

[Gito]

Did not test the fuel pressure regulator.
He did say that he had been a Chevrolet mechanic for 25 years.

I will call today and ask for fuel trim readings.

 

[Trav]

Does your pressure regulator have a vacuum hose going to it? If so remove the hose and see if there is raw fuel there.
This is why fuel trim values are so important to know, a failed pressure regulator will allow more fuel through the injectors under the same mA and pulse width and cause the ECM to remove fuel and will be seen as a minus number like -10.

Testing the compression on one cylinder when there are multiple misfires is pointless. Years of experience don't matter if you are not good at your job, the last doctor in the graduating class still gets to call himself doctor.

 

[Vikas]

If people ask for diagnostic advice here, then either they need to be able to execute themselves or have somebody else who can execute the provided instructions. Without that ability, it becomes pointless and frustrating experience.

For example, calling on the phone to get the fuel trim readings of your previous visit will make your service adviser just laugh out uncontrollably.

Once again, if you can NOT invest $15 in a Bluetooth scanner to get that data, you really are not interested in getting to the bottom it, do you?

 

[Gito]

Originally Posted By: Vikas
If people ask for diagnostic advice here, then either they need to be able to execute themselves or have somebody else who can execute the provided instructions. Without that ability, it becomes pointless and frustrating experience.

For example, calling on the phone to get the fuel trim readings of your previous visit will make your service adviser just laugh out uncontrollably.

Once again, if you can NOT invest $15 in a Bluetooth scanner to get that data, you really are not interested in getting to the bottom it, do you?


Need a scanner, want a scanner.
Any recommendations? (Makes, Model#)

 

[The_Eric]

Originally Posted By: Gito
Originally Posted By: Vikas
If people ask for diagnostic advice here, then either they need to be able to execute themselves or have somebody else who can execute the provided instructions. Without that ability, it becomes pointless and frustrating experience.

For example, calling on the phone to get the fuel trim readings of your previous visit will make your service adviser just laugh out uncontrollably.

Once again, if you can NOT invest $15 in a Bluetooth scanner to get that data, you really are not interested in getting to the bottom it, do you?


Need a scanner, want a scanner.
Any recommendations? (Makes, Model#)


Vikas is saying that with a $15.00 OBD data port adapter and a free smart phone app (or tablet or laptop), you can get fair bit of info. This is very simple and easy to do. These generic adapters will get you data and codes, as well as the ability to clear them.

Keep in mind that this will only garner a limited amount of info as they generally cover basic generic OBD info. More advanced things like ABS, SRS, manufacturer specific data and codes will not be offered as the companies that do the scan tools and adapters have to pay money to the OE for that info.

 

[Ramblejam]

Originally Posted By: The_Eric
Keep in mind that this will only garner a limited amount of info as they generally cover basic generic OBD info. More advanced things like ABS, SRS, manufacturer specific data and codes will not be offered as the companies that do the scan tools and adapters have to pay money to the OE for that info.


I have no issue pulling codes from the subsystems on these GMT-800's with a phone app. "GM (1996-2007) - Check/Clear Faults, Active Test and Enhanced Data 189 PIDS (VPW Powertrain)":

 

[Vikas]

The point is if you want, you can get a scanner/reader from $15 to $10,000 with varying degree of capability. Of course, some of you will agonize over finding the perfect scanner at excellent price for years without having even rudimentary capability to obtain any data from the vehicle.

If you happen to be one of that person, then that jab is directed at you.

I can no longer count number of scanners/readers that I have collected in the last 15 years on single hand. I spent over $100 each for my first three but the last three were much cheaper and had more capability.

If I were moderator of this forum, you will NOT be able to register without owning a reader/scanner Seriously, if you can post an issue here, you have the ability to search youtube, amazon for a decent scanner at your price point. I used to give bunch of recommendations in the past but these days those would be all stale. Just go to those site and spend couple of hours and buy something.