I'm wondering if the the PCM controls the Fuel Tank Pressure Sensor on a 1997 K1500?
Thanks,
dave w
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I'm wondering if the the PCM controls the Fuel Tank Pressure Sensor on a 1997 K1500?
Thanks,
dave w
P0452 Evaporative Emission Control System Pressure Sensor Low Input
P0453 Evaporative Emission Control System Pressure Sensor High Input
Are both listed in 1997 Vortec cal and both unchecked for no reporting.
I think P codes are from PCM, then there's B codes which are Body Control Module, and C codes which are ABS/Suspension... there's a pattern but some codes overlap like these Fuel Sender is in B and Fuel Tank Pressure in B on later vehicles...
Then U codes is missing data stuff.
That has me thinking, I need to find the published technical material to figure out if the fuel tank pressure sensor is an input / output to the Evaporative Emission Purge Valve (which is controlled by the PCM). I'm thinking most likely an input, but where? The fuel tank is from a single tank system, so is the fuel tank pressure system used by the fuel pump balance system? The vehicle is a daily driver, that has to pass emissions, so I need to get my homework done correctly.
dave w
so..... are you looking for wiring diagrams, or just how it functions?
and what is needed to pass in Wa? Is it a plug in OBDII test?
I'm just not sure? Even single tanks have the pressure, although I don't know what code my kid used to find them all the time when he worked at Oriellys. Loose gas cap after fill up will cause it.Quote:
Originally Posted by dave w
This will be helpful!
Quote:
Originally Posted by 1project2many
I'm some what new to OBDII fuel tank emission requirements, so I'm wondering what the theory of operation is fuel tank pressure sensor... what does it input / output to (PCM controlled), is what I'm wanting to figure out. I can find the wiring schematics.Quote:
Originally Posted by RobertISaar
dave w
NM. much better explanation Robert.
from a very condensed point of view:
normally, the PCM allows the engine vacuum that would normally draw fumes from the CCP and allow the tank to vent as necessary. it also controls a solenoid that prevents the tank from venting vacuum. so the solenoid is switched when the engine is creating vacuum, causing a vacuum to exist in the tank. the tank pressure/vacuum sensor is read to determine if there is enough vacuum to consider it a pass. this tests a couple of things at once, mostly CCP and fuel tank integrity.
i might be able to grab a better explanation, but that's essentially how it all works.
This is for 1996 and 1997 ONLY!
Evaporative Emission Control System
Purpose
The Evaporative Emission (EVAP) control system limits the fuel vapors from escaping into the atmosphere. The EVAP transfers the fuel vapor from the sealed fuel tank to an activated carbon (charcoal) storage device (EVAP canister). The EVAP canister stores the vapors until the engine is able to use the extra fuel vapor.
When the engine is able to use the extra fuel vapor, the intake air flow purges the fuel vapor from the carbon element, and then the normal combustion process consumes the fuel vapor.
The fuel tank is sealed with a fuel cap that is not normally vented to atmosphere. The fuel tank cap has a safety valve which allows for both pressure and vacuum relief.
Operation
Fuel vapors from the fuel tank purge and flow into the EVAP canister tube labeled Tank and the carbon absorbs the vapors. The canister purges when the engine is able to use extra fuel vapor. A vacuum source is applied to the EVAP canister tube labeled Purge to draw fresh air through the top of the canister. The air mixes with the fuel vapor and the mixture is drawn in the intake manifold to be consumed in the normal combustion process.
While the canister is purging, fresh air is drawn in through the air inlet at the top of the canister. Air flows to the bottom of the canister and forces the vapors out the Purge tube.
The EVAP system in some applications uses an electrically controlled solenoid to cycle the vacuum to the purge canister. The control module cycles the solenoid when the engine coolant temperature is greater than 45°C or the Short Term Fuel Trim counter is less than 122.
A vacuum switch in the purge line detects when the system is purging. The normally closed switch will open when less than 1 inch Hg is present in the purge line.
EVAP Canister Location
The canister is located in the left front fender well.
1998 on up use FTP Sensors
Hey Dave I posted the Schematics for you
Thanks, for posting the wiring diagrams!:thumbsup: http://www.gearhead-efi.com/Fuel-Inj...9545#post29545Quote:
Originally Posted by Caleditor
Seems like I can't find the wiring schematic for the Fuel Tank Pressure Sensor show in post #1.
dave w
It was not used in 1997Quote:
Originally Posted by dave w
I have a 97 Express 1500 and can confirm no FTP sensor in my application and can also confirm with the sensor codes turned off I still get the monitor to show "Ready" status.Quote:
Originally Posted by Caleditor
Maybe California Emissions for 1997? The vehicle owner lives in Oregon. Very common to find California emission vehicles in Oregon.Quote:
Originally Posted by Caleditor
dave w
Dave, have you confirmed 97 Model year vs 97 manufacturing year? Emissions label will provide all needed answers here... "Vehicle conforms to Federal (or Federal and California) emissions standards for 199X model year."
Dave I have a 1997 and I think it has a sensor. I just did a 0411 swap and I think the wires were in place. I was going to look over the weekend and never made it out to the truck. I will look tonightQuote:
Originally Posted by dave w
I have worked on plenty of 1997 GM's and they have the vacuum sensing switch.
I was thinking my 1997 S10 SS had a vacuum sensor. I kind of remember thinking it was odd for a 1997.
I checked at lunch and my truck does have a FTP Sensor. Then I checked the Production Date 6/97. I will look for the correct documents for you.
The dealership get the next model year usually starting in June/July. Most of the time when they come before July the vehicle has been redesigned. 1998 S10's had a few changes, but not like going from a GMT-800 to the GMT-900 models
We got 2014 Silverado's in this year in June.
The vehicle emission lablel is not available. Earlier this summer, I helped with a diesel to gas conversion http://www.gearhead-efi.com/Fuel-Inj...7-Vortec-4L80EQuote:
Originally Posted by 1project2many
The donor vehicle was a 1997 Suburban. I sent the PCM to eaglemark to reflash, so maybe he can post the file he read from the PCM, so we can see what the original VIN was? Most everything needed to swap from diesel to gas was removed from the Suburban motor, PCM, and wiring harness. Some details, like the fuel tank pressure sensor were not important at the time the fuel tank from the Suburban was removed.
The vehicle is up and running, no issues. The vehicle owner is not 100% satisfied because the fuel tank pressure sensor is not wired in. I've researched the Mitchells Manuals at my public library, but I could not find the wiring diagram I was looking for. I'm thinking the fuel tank pressure sensor is not directly wired to the PCM like 1998 and newer?
dave w
I will check the pin-out again, but I am 100% sure the FTP sensor was wire to the VCM on my truck and now to the 0411 PCM.
Here's the one that came out of donor ECM, before we changed it to 4l80E trans.
This is how that app I was talking about will help. The FTP sensor signal wire goes to C2 (RED) terminal 25 per GM's engineering documents.
That's very interesting. I checked both the schematics that have been posted, and C2 ~ pin 25 is blank or not listed. What I'm thinking is, C2 ~ pin 25 did not have a wire when I got the harness.Quote:
Originally Posted by Caleditor
dave w
At C2 pin 25, 1997 is a blank hole. 1998 has the fuel tank pressure wire.Quote:
Originally Posted by dave w