Gas tank is acting like tank is full when it isn't.
#1
09-04-2009, 10:57 AM
Gas tank is acting like tank is full when it isn't.
I have been lurking on this site for a while now but the most recent problem with my monte is frustrating me to no end. I recently attempted to fill up my tank but the pump was acting like my tank was full and was cutting off. I just assumed it was a bad pump and after $15 worth of gas I said forget it and let. A few days later I went to go put gas in again, this time at a different fueling station though. The same problem occured, this time ending with me stopping at $2.26 as I was too frustrated to continue. The pump would cut off almost every few pennies worth of gas. It was then that I realized I had a problem.
Since my speedo gauge is only working intermittingly, I just figured that I did in fact have a full tank of gas and this was just a sign that my gas gauge was going out. So I decided to wait a couple days until I knew I had used up some gas. I raced a BMW M3 after he cut me off, knowing that this would surely lead to fuel consumption and after 278 miles I went to the pump again. Ten minutes and $2.23 later I realized that the gauge is fine and something else is screwed up. I tried pulling out the nozzle half way, tried just squirting the gas in without the nozzle in the tank at all, and nothing worked. The gas would just sit there at the top of the tank where the cap goes or spew back out at me. I had to sit there and watch money literally pour onto the ground as I became increasingly irate.
Does anyone know what is causing this? I have heard possibly the filler pipe, charcoal canister, etc.. but I don't want to have to take it to the dealership as they want $90 just to look at it and an additional $90 per hour of labor, not including parts. I have a shade tree mechanic who is a certified GM mechanic that works on cars after hours for supplimentary income but I would like to try and diagnose the problem before I bring it to him so I can have an idea what to expect.
This is just one of the many problems this car has brought me and although I love the car to death and have always owned chevies, I'm starting to think Chevy is the wrong way to go. In the past few months my a/c started to go out when I hit a bump and then back on when I hit another one before finally going out completely. I still have cold cold and hot hot air but it doesn't blow out, only "seeps" out with zero force at all. My PCM apparently went bad per dealership as it is telling my IACV to go into full throttle at all times. I have the IACV unplugged until I can afford to drop the $600 on parts and labor for the PCM. and now the fuel problem.
BTW, it is a 2005 monte carlo ls with 100,000 miles. ( I work 60 miles from my house so all highway miles)
Since my speedo gauge is only working intermittingly, I just figured that I did in fact have a full tank of gas and this was just a sign that my gas gauge was going out. So I decided to wait a couple days until I knew I had used up some gas. I raced a BMW M3 after he cut me off, knowing that this would surely lead to fuel consumption and after 278 miles I went to the pump again. Ten minutes and $2.23 later I realized that the gauge is fine and something else is screwed up. I tried pulling out the nozzle half way, tried just squirting the gas in without the nozzle in the tank at all, and nothing worked. The gas would just sit there at the top of the tank where the cap goes or spew back out at me. I had to sit there and watch money literally pour onto the ground as I became increasingly irate.
Does anyone know what is causing this? I have heard possibly the filler pipe, charcoal canister, etc.. but I don't want to have to take it to the dealership as they want $90 just to look at it and an additional $90 per hour of labor, not including parts. I have a shade tree mechanic who is a certified GM mechanic that works on cars after hours for supplimentary income but I would like to try and diagnose the problem before I bring it to him so I can have an idea what to expect.
This is just one of the many problems this car has brought me and although I love the car to death and have always owned chevies, I'm starting to think Chevy is the wrong way to go. In the past few months my a/c started to go out when I hit a bump and then back on when I hit another one before finally going out completely. I still have cold cold and hot hot air but it doesn't blow out, only "seeps" out with zero force at all. My PCM apparently went bad per dealership as it is telling my IACV to go into full throttle at all times. I have the IACV unplugged until I can afford to drop the $600 on parts and labor for the PCM. and now the fuel problem.
BTW, it is a 2005 monte carlo ls with 100,000 miles. ( I work 60 miles from my house so all highway miles)
#2
09-04-2009, 11:43 AM
"I have the IACV unplugged until I can afford to drop the $600 on parts and labor for the PCM. and now the fuel problem."
you don't have to spend that much for a PCM, you can buy one for $100 +$100 refundable core charge.
http://www.zzperformance.com/grand_p...=182&catid=107
or
http://intense-racing.com/Merchant2/...tegory_Code=IE
sorry, i cant help with your current issue, but im sure the members here will chime in with some advice.
you don't have to spend that much for a PCM, you can buy one for $100 +$100 refundable core charge.
http://www.zzperformance.com/grand_p...=182&catid=107
or
http://intense-racing.com/Merchant2/...tegory_Code=IE
sorry, i cant help with your current issue, but im sure the members here will chime in with some advice.
#3
09-04-2009, 11:52 AM
Join Date: Sep 2008
Location: Southeast PA
Posts: 25,136
I've had that happen to me, but never in a row. And usually just pulling the gas pump out a little bit fixed it, and never happened again.
Sorry I'm unsure about this one.
Sorry I'm unsure about this one.
#5
09-04-2009, 12:42 PM
I tried bringing a "refurbished" PCM I bought to the dealership to have them put it in but they turned me down, stating they could "only install brand new GM parts ordered through them to ensure reliability". They wanted $300 for the PCM and $300 to put it in which made my eyes almost jump out of their sockets as I have disconnected the battery, unbolted the safety bar, removed air filter box, removed old PCM and installed new one like 5 times in under ten minutes each time. The only reason I even went to the dealership is because after I installed the new PCM, the car wouldnt start-probably related to the damn PASSLOCK. I tried the PASSLOCK reset but the security light never flashed on and off after ten minutes, it always stayed on constantly throughout the whole 45 minute process. The place I bought the PCM from "supposedly" programmed it to my car as I supplied him with the VIN but I haven't had any luck yet with it. I'm thinking about trying it again tomorrow but I work 100 hours a week so my chances to screw with my car are far and few between.
As far as the fuel dilemma goes, I have never had a problem with it before but I googled it and some people claim it can be caused by filling tank past the point where the pump stops iself- a habit I have always had as it made it seem like the car would go longer without going below the full line. I'm currently sitting on a low fuel light at work-60 miles from my house and 20 miles from the nearest gas station.
so far my speedo has failed-it works unless I have to break hard or come to a stop. If I do, it starts back from below zero and increasing gets further and further from the real speed I'm driving. dealer wants $500 to replace it even though I've heard that a $5 stepper motor is the cause.
My Fuel Pressure regulator leaked- replaced it.
Car was idling at 2000 RPM, so I replaced the throttle body, IACV, TPS, MAF and MAP sensors, and both o2 sensors. I checked for vacuum leaks via propane, carb cleaner, and UV dye. finally had a dianostic ran, which cost $70. The guy hooked it up and five minutes later told me my PCM was sending "false reading" to the IACV, causing it to go to full throttle all the time so he told me to disconnect it until I could get it replaced. Before I found this out, I had to ride brakes 24/7 as car was accelerating by itself due to the false IACV readings- resulting in 4 warped rotors and four destroyed brake pads.
Replaced headlights 3 times, each time with the expensive sylvania 9600 ones that are like $30 a piece.
Front hub asssemblies both got cracked.
Studs broke off on rear on both sides. IDK if I can just replace the studs or if I have to get two new assemblies- have been told both by different people.
Blower motor has a faulty connection I assume as it sporadically works, or at least did. now it doesnt work at all but for the past few months it would go on if I hit a bump and then back off next time I hit a bump.
cat went out at like 30k miles, luckily was still under warranty.
As you can tell, this car has been a never ending problem. Even though I have all these problems, I still love it to death and wuldnt trade it for the world, I just wish it drove properly.
I've owned a 72 monte, 84 monte, 88 monte, 91 caprice classic, 93 camaro (i think it was a 93), 96 impala ss with a ls2 in it, a 2000 impala and now my 2005 monte. I'm obviously a chevy man til I die but I can't afford a new 'maro right now so I just have to fix what I got. Any help would be greatly appreciated.
As far as the fuel dilemma goes, I have never had a problem with it before but I googled it and some people claim it can be caused by filling tank past the point where the pump stops iself- a habit I have always had as it made it seem like the car would go longer without going below the full line. I'm currently sitting on a low fuel light at work-60 miles from my house and 20 miles from the nearest gas station.
so far my speedo has failed-it works unless I have to break hard or come to a stop. If I do, it starts back from below zero and increasing gets further and further from the real speed I'm driving. dealer wants $500 to replace it even though I've heard that a $5 stepper motor is the cause.
My Fuel Pressure regulator leaked- replaced it.
Car was idling at 2000 RPM, so I replaced the throttle body, IACV, TPS, MAF and MAP sensors, and both o2 sensors. I checked for vacuum leaks via propane, carb cleaner, and UV dye. finally had a dianostic ran, which cost $70. The guy hooked it up and five minutes later told me my PCM was sending "false reading" to the IACV, causing it to go to full throttle all the time so he told me to disconnect it until I could get it replaced. Before I found this out, I had to ride brakes 24/7 as car was accelerating by itself due to the false IACV readings- resulting in 4 warped rotors and four destroyed brake pads.
Replaced headlights 3 times, each time with the expensive sylvania 9600 ones that are like $30 a piece.
Front hub asssemblies both got cracked.
Studs broke off on rear on both sides. IDK if I can just replace the studs or if I have to get two new assemblies- have been told both by different people.
Blower motor has a faulty connection I assume as it sporadically works, or at least did. now it doesnt work at all but for the past few months it would go on if I hit a bump and then back off next time I hit a bump.
cat went out at like 30k miles, luckily was still under warranty.
As you can tell, this car has been a never ending problem. Even though I have all these problems, I still love it to death and wuldnt trade it for the world, I just wish it drove properly.
I've owned a 72 monte, 84 monte, 88 monte, 91 caprice classic, 93 camaro (i think it was a 93), 96 impala ss with a ls2 in it, a 2000 impala and now my 2005 monte. I'm obviously a chevy man til I die but I can't afford a new 'maro right now so I just have to fix what I got. Any help would be greatly appreciated.
#6
09-04-2009, 12:48 PM
Join Date: Sep 2008
Location: Southeast PA
Posts: 25,136
Try the security relearn procedure for your PCM.
As for the idling, it could also be a PCV valve.
As for the idling, it could also be a PCV valve.
#7
09-04-2009, 12:53 PM
If the security relearn is to install new PCM, try to start it, keep in on position for ten minutes, turn off for ten seconds, try to start it again and then repeat that 3 times- I already have to no avail. The 2k idle was apparently related to the PCM giving the IACV false readings because when I disconnect the IACV it doesn't do it. It idles at 500 RPM and gets crappy gas mileage but it doesnt idle at 2k RPM or accelerate by itself with it disconnected, so I just unplug the IACV.
#8
09-04-2009, 12:57 PM
Join Date: Sep 2008
Location: Southeast PA
Posts: 25,136
You can try to disconnect the battery, and then try that security relearn procedure
Or try this way of security relearn:
1. Disconnect battery for 10 sec.
2. Reconnect battery
3. Turn key to ON position
4. Do not try to start vehicle, just quickly click to RUN position to engage security light
5. Let vehicle sit with key ON for 35 min.
6. Attempt to crank vehicle. Once vehicle is running, the security light may still be on
7. If security light is still on, turn key to OFF position for 5 sec.
8. Turn key to ON position and security light should turn off
9. Start vehicle
Or try this way of security relearn:
1. Disconnect battery for 10 sec.
2. Reconnect battery
3. Turn key to ON position
4. Do not try to start vehicle, just quickly click to RUN position to engage security light
5. Let vehicle sit with key ON for 35 min.
6. Attempt to crank vehicle. Once vehicle is running, the security light may still be on
7. If security light is still on, turn key to OFF position for 5 sec.
8. Turn key to ON position and security light should turn off
9. Start vehicle
#9
09-04-2009, 12:57 PM
just read online that someone who had the same fuel problem as me noticed it didn't happen if he refueled with car on so I'm driving 20m to the gas station on my lunch to try it. It isn't a perm. fix but will at least allow me to keep from running out of gas. he said the mechanic said some "mechanism" inside gas tank failed and complete new tank would be needed or in other words $1400 job for parts and labor. I sure hope not.
#10
09-04-2009, 12:59 PM
blacksheep- you are a life saver, I'll try it in the morning, hopefully it works. If it does, I'll figure out a way to buy you a beer. lol