IAT Sensor...

usamarshal · #1 10-29-2006, 05:44 PM

Does anyone know if there is an IAT Sensor on a 2000 Tahoe Z71 4x4 with a 5.7 Vortec? Vehicle is running rich and was thinking this may be the problem from the research I've done. I've already replaced the gaskets, FPR, oxygen sensors, and a tune up...thanks for any help, Skip

maxwedge · #2 10-29-2006, 06:55 PM

What is the running fuel pressure? have you scanned it and looked at the coolant temp sensor and iat sensor readings? Replaced what gaskets?

GMMerlin · #3 10-30-2006, 05:17 AM

Quote:

Originally Posted by usamarshal

Does anyone know if there is an IAT Sensor on a 2000 Tahoe Z71 4x4 with a 5.7 Vortec? Vehicle is running rich and was thinking this may be the problem from the research I've done. I've already replaced the gaskets, FPR, oxygen sensors, and a tune up...thanks for any help, Skip

My first question would be how do you know it is running rich?
What are the O2 readings, fuel trims?
Any codes?

usamarshal · #4 10-30-2006, 08:21 AM

Thanks for the response...I forgot to mention that I did check the fuel pressure and its fine...I think when I checked it it was running 70 psi...also replaced the fuel pump, which is a pain in my you know what...also replaced the thermostate and temp sensor because they weren't good anymore...the gaskets I replaced were the upper gaskets...I did that after replacing the FPR....I'm also thinking that if the gaskets are leaking then I'd get a lean condition...but when I have the check engine light come on its showing a rich condition...thanks!!!

Quote:

Originally Posted by maxwedge

What is the running fuel pressure? have you scanned it and looked at the coolant temp sensor and iat sensor readings? Replaced what gaskets?

usamarshal · #5 10-30-2006, 08:28 AM

Thanks for the response...the reason I know its running rich is because I'm getting a code for it...not sure what the O2 readings are, but I did have a mechanic check that...he said everything was fine, except the thermastate readings...thats when I replaced the thermastate and sensor...the only code I'm getting right now is the rich code...I'll find out what the code number is when I get home...thanks!!!

Quote:

Originally Posted by GMMerlin

My first question would be how do you know it is running rich?
What are the O2 readings, fuel trims?
Any codes?

usamarshal · #6 10-30-2006, 08:37 AM

I'm getting a 172 and 175 code.

GMMerlin · #7 10-30-2006, 09:06 AM

Could this be a 99 model carry over truck? Tahoe Limited?
70psi fuel pressure is this with the engine running? Either way this is too high and could cause the DTCs to set for a rich condition.
A rich condition may result from the fuel pressure being above 455 kPa (66 psi). A rich condition may cause a DTC to set.
If this thing is throwing a rich code then the O2 readings and fuel trims will indicate a problem...maybe your mechanic doesn't know what he is looking at.
I would start with fuel pressure.

usamarshal · #8 10-30-2006, 09:33 AM

I'll check the fuel pressure again...if the reading does turn out to be that high what options do I have to correct the problem? But yes, this is the old body style with the 350...its the Z71 series, which I think is the same as the Tahoe Limited series....whats a DTC? Anyway I took it the GM dealer...lol...maybe I should try a different place..thanks again.

Quote:

Originally Posted by GMMerlin

Could this be a 99 model carry over truck? Tahoe Limited?
70psi fuel pressure is this with the engine running? Either way this is too high and could cause the DTCs to set for a rich condition.
A rich condition may result from the fuel pressure being above 455 kPa (66 psi). A rich condition may cause a DTC to set.
If this thing is throwing a rich code then the O2 readings and fuel trims will indicate a problem...maybe your mechanic doesn't know what he is looking at.
I would start with fuel pressure.

usamarshal · #9 10-30-2006, 09:36 AM

Alright...checked a past post and found out its running between 60-70 psi the last time I checked...I will check it again today for a more precise reading.

usamarshal · #10 10-30-2006, 06:20 PM

Ok, I put seafoam in the gas tank, in the oil, and through the PVC valve and intake...three cans worth in all....running very well now...drove it around and put fresh gas in her....will change the oil tomorrow and see if I get the check engine light to come...should be interesting...my buddy bet me that it wouldn't come on again...I doubt it though...lol...also checked the fuel pressure....it runs exactly 59-60 and when I turn the engine off it holds at 55-60 without going down....I'll keep everyone informed...thanks again for the help, Andrew

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