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 4.3 blazer p1441 
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Joined: May 27th, 2011, 7:56 pm
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Post 4.3 blazer p1441
ok i have a 4-door 1998 blazer 4x4 4.3 automatic.
engine runs good, no problems starting or running.
when i bought it 1 years ago, i was averaging 240milles per tank.
now im down to 170-180 milles per tank and i have a CEL that comes on around every 2 weeks.

p-1441
evap system flow during non-purge...
i tested my purge solenoid by removing it from the engine, creating a vaccum with my mouth(it holded) then apply 12v to the solenoid(vaccum release)

now i heard i should check my evap line from the engine to the charcoil canister in the rear bumper.
there is my question : how am i suppose to check that line ?? or what should be my next step ?

also, is that p1441 code the reason for my low MPG ?

thanks for any help, and sorry for the long post but gas is fucking expensive now and i really want to get back my milleage !


July 6th, 2011, 8:14 pm
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Location: North Port, FL
Post Re: 4.3 blazer p1441
You've probably done this, but have you checked your gas cap? A faulty seal on the gas cap can (I think) cause this trouble code.

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July 6th, 2011, 8:18 pm
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Joined: June 15th, 2011, 6:41 pm
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Post Re: 4.3 blazer p1441
ImpalaPolicePack wrote:
ok i have a 4-door 1998 blazer 4x4 4.3 automatic.
engine runs good, no problems starting or running.
when i bought it 1 years ago, i was averaging 240milles per tank.
now im down to 170-180 milles per tank and i have a CEL that comes on around every 2 weeks.

p-1441
evap system flow during non-purge...
i tested my purge solenoid by removing it from the engine, creating a vaccum with my mouth(it holded) then apply 12v to the solenoid(vaccum release)

now i heard i should check my evap line from the engine to the charcoil canister in the rear bumper.
there is my question : how am i suppose to check that line ?? or what should be my next step ?

also, is that p1441 code the reason for my low MPG ?

thanks for any help, and sorry for the long post but gas is fucking expensive now and i really want to get back my milleage !


You should make sure Slayer reads this, send him a PM. He reads these codes for a living and would probably know your problem just from that one p1441 code.

I have a evap code problem myself but it's not effecting my fuel milage.


July 6th, 2011, 8:43 pm
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Post Re: 4.3 blazer p1441
thanks for the replys, ill wait and see if slayer gets here or ill pm him.
i checked my cap visualy, o-ring looks a little cracked but my problem started within a tank of gas. so i dont think its from there...

i always checked my milleage from day one, and within a week it dropped from 240 to 180milles.

i noticed that if i fill the tank to the cap, it triggers the CEL faster...


July 6th, 2011, 9:19 pm
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Post Re: 4.3 blazer p1441
ImpalaPolicePack wrote:
thanks for the replys, ill wait and see if slayer gets here or ill pm him.
i checked my cap visualy, o-ring looks a little cracked but my problem started within a tank of gas. so i dont think its from there...

i always checked my milleage from day one, and within a week it dropped from 240 to 180milles.

i noticed that if i fill the tank to the cap, it triggers the CEL faster...


I know that you shouldn't top off the tank - it can definitely cause CELs. Not that it would cause a drop in mileage, but...

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July 7th, 2011, 6:25 am
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Post Re: 4.3 blazer p1441
Don't see too many Blazers with evap codes myself, but the system shouldn't even be running any tests at a full tank, all the evap diag I've done requires the tank to be from 20% - 80% full to run the test.
But if you see any cracking on the fuel cap o-ring you should replace that first with one straight from GM.
Evap shouldn't hit your mileage, even a full vented system is only leaking fumes...
When you apply 12V to that valve it should click sharply on and off, look inside and see if there's any corrosion, that's usually what makes the valves go bad.
When I do evap I have a smoke machine specifically for that, if I can't find a broken line or bad valve right off the bat... I use the Snap-On scan tool to command the valves on and off but they are 12V so you can just use a batt an jumper wires with the valve unplugged from the harness.
It could also be a fuel tank pressure sensor that's on the fritz, that's how the PCM detects leaks from pressure changes in the tank, don't happen too often tho.
There's alot of shit that can cause evap codes but I'd start with a fuel cap.


July 7th, 2011, 10:41 am
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Post Re: 4.3 blazer p1441
evap codes are some of the toughest to diagnose... but when you bring up poor mileage - that makes me think tank pressure, if GM uses that sensor. Tank pressure is one of those issues that can trigger open loop operation.. ie: warm up or enrichment mode... it won't always throw a code, but will show up on a diag tool when running (should switch over to closed loop when the coolant temp hits about 125.)

open loop has the car running off pre-set values, instead of changing the values dynamically based on the various sensors (o2, iat, maf/map, etc) and mileage takes a nose dive when that happens.

good luck.


July 7th, 2011, 1:42 pm
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Post Re: 4.3 blazer p1441
SLAYERDUDE

1- ill check for a replacement gas cap from the dealer.

2- i tested the purge valve solenoid with 12v and it holds vacum and ''clicks sharply'' when releasing. i didnt saw any corosion but i noticed the tube fits a little loose on it...

3- i dont have access to a smoke machine, and dont think i could.

4- FTP, hum, could be that, how can i test it ? i only have a basic CEL scanner.

thanks.


Last edited by ImpalaPolicePack on July 7th, 2011, 9:22 pm, edited 1 time in total.



July 7th, 2011, 9:16 pm
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Post Re: 4.3 blazer p1441
Goatcrapp

FTP sensor, i know from another forum that blazers have it, somewhere around the fuel tank.

how can i test/know if its running in closed/open loop ?
that sounds like it may be the problem, i noticed the tailpipe gasses really smells bad/strong, almost like a vinegar odor...

could it be running overly rich ?
again, how can i test that sensor ?

thanks a lot to everyone thats helping !


July 7th, 2011, 9:22 pm
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Post Re: 4.3 blazer p1441
Pretty much you need a scan tool that shows live readings to see FTP pressure and open/closed loop operation, evap is actually fairly easy to diag once you have the right tools for the job. (that cost thousands of dollars)

If I have a chance later I'll see what common things go bad on Blazers for evap, I gotta be OCB right now. :roll:


July 8th, 2011, 8:29 am
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Post Re: 4.3 blazer p1441
Here's some info from a resource I have here at work.

Quote:
Trouble code P1441.
Tests/Procedures: 1. Scan test the fuel tank pressure sensor to be 1.3v-1.7v with no vacuum or pressure on the fuel tank (gas cap removed).

2. If the value is out of range, verify the 5v reference and the ground at the sensor on top of the sending unit.

3. Start and run the engine and the fuel tank pressure sensor should not move.

4. If the value changes, disconnect the purge solenoid on the engine and verify no vacuum is passing through the solenoid.

5. If vacuum is passing through the solenoid, replace.

6. If no problems are found, check the current calibration installed in the Vehicle Control Module (VCM). TSB #00-06-04-039 is related to a calibration update.


Quote:
Confirmed Fix
3 - Fuel Tank Pressure (FTP) Sensor
2 - Evaporative Emissions (EVAP) Canister Purge Solenoid/Valve



Quote:
Confirmed Fix
2 - Charcoal Canister, Evaporative Emissions (EVAP) Canister Purge Solenoid/Valve
1 - Charcoal Canister, Evaporative Emission (EVAP) System Hose(s)/Line(s)
1 - Evaporative Emissions (EVAP) Canister Purge Solenoid/Valve


Quote:
1996 Chevrolet Blazer, 4.3L *
Replaced Evaporative Emissions (EVAP) Canister Purge Solenoid/Valve
- P1441.Both evap vent solenoid and purge solenoid were stuck open.Replaced Purge and vent solenoids. Evaporative Emissions (EVAP) Canister Purge Solenoid/Valve


Guess the FTP sensors do go bad on these trucks..
And the FTP sensor should be in the top of the fuel tank.

Here's a pic of where the purge valve is on the frame.

And the solenoid on the intake.


Attachments:
File comment: purge solenoid
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58847702.gif [ 10.35 KiB | Viewed 637 times ]
File comment: purge valve
78731498.gif
78731498.gif [ 26.78 KiB | Viewed 637 times ]
July 8th, 2011, 9:11 am
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Post Re: 4.3 blazer p1441
well thanks for the replys and infos !
for the open/closed loop, theres nothing i can do without a scan tool ?

tomorow ill work on it and let you know what i find...
thanks again !

Anthony


July 8th, 2011, 9:40 pm
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Post Re: 4.3 blazer p1441
Only way I know of seeing if your PCM/ECM is working on closed/open loop is from a scan tool.
I'm far from a diagnostic wizard, I had to learn enough to get by when our diag guy quit so don't quote my info by any means.
Duaynehydro would be the man in this area. ;)


July 8th, 2011, 10:37 pm
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