JohnRich 4 #1 February 25, 2008 My 2001 Chevy Blazer started acting funny a few days ago. I want to challenge you "Click & Clack" people out there to diagnose what could be wrong with my vehicle. (Click & Clack are the nicknames for the two guys that do a call-in radio show diagnosing automobile problems.) The problem: When accelerating from a stop, the engine stalls out. It can be immediately re-started, but may cut out several more times before acceleration is achieved. Being very light on the gas pedal helps - so light that you almost aren't accelerating at all (and that's really difficult for me). When on cruise control and hit a hill, the engine cuts out repeatedly for about a second at a time as it attempts to climb the grade. And these engine stalls only happen when the gas tank is less than half-full. It runs fine on the first half of the tank. That little tidbit really sweetens the mystery. So, do any of you professional or backyard mechanics have an idea what could be going on here? My thoughts: 1) A bad tank of gas? This started happening after a top-off at a very remote national park (Big Bend, Texas), which doesn't have much gas turnover at the camp store. However, several tank re-fills since have failed to clear the problem. 2) There is also a lot of fine powdery sand through which I was driving on dirt roads. The air filter was not clogged. Could it have gotten into the gas tank? I welcome informed thoughts. Attached: Photo of "Big Red" next to the stone ruins of an old ranch home in the Texas desert. Quote Share this post Link to post Share on other sites
jcd11235 0 #2 February 25, 2008 I once had a similar problem on a much older vehicle, sans the "only on the last half of the tank" bit. It turned out to be a length of rubber fuel line had weakened, and was collapsing upon acceleration, restricting fuel flow to the carburetor. On newer vehicles, I'm not sure if or how fuel level can affect pressure in the fuel line, but id it can, and pressure reduces with fuel level, that might explain that. Not to say there aren't knowledgeable DZ.commers, but I have found Click and Clack's website (cartalk.com, I think) to be helpful in the past.Math tutoring available. Only $6! per hour! First lesson: Factorials! Quote Share this post Link to post Share on other sites
ifall 0 #3 February 25, 2008 Shall we assume that the "check engine" light never came on at one point or another? I had a similar problem with a Jeep Wrangler. Only happened though after the engine warmed up. After months of not knowing what it was (I didn't drive it daily) and trying several different things it ended up being my rear O2 sensor. Quote Share this post Link to post Share on other sites
turtlespeed 212 #5 February 25, 2008 It sounds like a fuel pump/filter problem. If you can - check the fuel filter - if there is water or sand in the gas tank it willl have found it's way into the filter.I'm not usually into the whole 3-way thing, but you got me a little excited with that. - Skymama BTR #1 / OTB^5 Official #2 / Hellfish #408 / VSCR #108/Tortuga/Orfun Quote Share this post Link to post Share on other sites
JohnRich 4 #6 February 25, 2008 QuoteShall we assume that the "check engine" light never came on at one point or another? I had a similar problem with a Jeep Wrangler. Only happened though after the engine warmed up. After months of not knowing what it was (I didn't drive it daily) and trying several different things it ended up being my rear O2 sensor. All gauges and warning lights were normal while this was going on. O2 sensors... Ack! I just had two of those replaced six months ago, and they ain't cheap! Quote Share this post Link to post Share on other sites
quade 3 #7 February 25, 2008 I'm gonna go with fuel tank pressurization.quade - The World's Most Boring Skydiver Quote Share this post Link to post Share on other sites
BillyVance 34 #8 February 25, 2008 Quote Quote Shall we assume that the "check engine" light never came on at one point or another? I had a similar problem with a Jeep Wrangler. Only happened though after the engine warmed up. After months of not knowing what it was (I didn't drive it daily) and trying several different things it ended up being my rear O2 sensor. All gauges and warning lights were normal while this was going on. O2 sensors... Ack! I just had two of those replaced six months ago, and they ain't cheap! I HATE those O2 sensors too. Had one replaced last fall. Had to pay full price. The same one that needed replacing 3 previous times. Luckily those were covered under warranty, just not the labor. "Mediocre people don't like high achievers, and high achievers don't like mediocre people." - SIX TIME National Champion coach Nick Saban Quote Share this post Link to post Share on other sites
jkm2500 0 #9 February 25, 2008 John, That year of Blazer is notorious for developing weak fuel pumps. If the thing has over 100K miles, the probability is high. It can be tested to see if the pump is developing enough pressure. The less than half-tank thing could have something to do with the bypass line. I don't know all of the intricacies of it. When was the last time that the fuel filter was changed? Another thing could be sediment in the fuel tank. When the tank is full the sediment has more area to float around. But as it empties the sediment will start to collect around fuel pump and restrict the flow. The blazer has an in tank fuel pump, so there are a lot of possibilities. But, in order to check many of them you have to drain the tank and drop it. A huge pain in the ass. I would start by replacing the fuel filter. When you replace the filter look and see if there is a bunch of sediment in the filter. If that is the case then you might need to flush the tank. If not, then the pump may be on its last leg. Let me know if any of this works...The primary purpose of the Armed Forces is to prepare for and to prevail in combat should the need arise. Quote Share this post Link to post Share on other sites
ifall 0 #10 February 25, 2008 Well, thats why I asked if the check engine light came on at any point. Usually the O2 sensors will throw a code. One thing that pointed me away from the O2 sensor on mine at first was the person who read the code read it wrong. Now I have my own reader. I've gotten codes though when the light hasn't been on. Quote Share this post Link to post Share on other sites
BillyVance 34 #12 February 25, 2008 Never had a fuel pump problem. Just bad O2 sensors... I even drove around for 25K miles with the check engine light on just because I didn't want to have the damn sensor replaced (and I knew what was causing the light on). I finally had it replaced because my truck was over 140K miles and due a major service."Mediocre people don't like high achievers, and high achievers don't like mediocre people." - SIX TIME National Champion coach Nick Saban Quote Share this post Link to post Share on other sites
Spizzzarko 0 #13 February 25, 2008 This could be caused from a multitude of problems. 1. The fuel air mixture could be lean or rich. If you have smoke coming from the exhaust it is indicative of a rich mixture. If you pull the plugs and inspect them and they are white or ashy then teh engine is running lean. The vehicle uses a series or thermometers in the intake system to adjust the fuel air mixture. 2. You could have a clogged fuel filter or fuel supply line that may be robbing the engine of fuel. Conversely if your vehicle has a fuel pump go out then you may not get enough fuel during accelleration. Hope this helps. Quote Share this post Link to post Share on other sites
BIGUN 1,053 #14 February 25, 2008 2001 Chevy Blazer started acting funny a few days ago... 2001 Chevy Blazer told to straighten up. Suggestions: 1. Fuel filter (think they're supposed be checked every 15,000 miles?) I hate when Dodge changed from an inline fuel filter to inside the damn tank. 2. Fuel pump 3. Injector cleaning Nobody has time to listen; because they're desperately chasing the need of being heard. Quote Share this post Link to post Share on other sites
pre7117 0 #15 February 25, 2008 Fuel pumpHELLFISH 429 POPS 11113 Quote Share this post Link to post Share on other sites
BikerBabe 0 #16 February 25, 2008 gonna go with fuel pump for $1000, Alex. Had a very similar issue with my old car (before my husband blew it up), turned out to be a bad fuel pump. I would get the entire fuel delivery system checked just in case, though.Never meddle in the affairs of dragons, for you are crunchy and taste good with ketchup! Quote Share this post Link to post Share on other sites
IanHarrop 37 #17 February 25, 2008 Feul Pressure Regulator"Where troubles melt like lemon drops, away above the chimney tops, that's where you'll find me" Dorothy Quote Share this post Link to post Share on other sites
warpedskydiver 0 #18 February 25, 2008 Don't know which your car has but it sounds like either a MAP, or Mass Airflow Sensor. I say this because if you had your O2 sensor go bad more than once, it may have been due to the MAP or Mass Airflow sensor running your vehicle rich. Quote Share this post Link to post Share on other sites
warpedskydiver 0 #19 February 25, 2008 QuoteQuoteShall we assume that the "check engine" light never came on at one point or another? I had a similar problem with a Jeep Wrangler. Only happened though after the engine warmed up. After months of not knowing what it was (I didn't drive it daily) and trying several different things it ended up being my rear O2 sensor. All gauges and warning lights were normal while this was going on. O2 sensors... Ack! I just had two of those replaced six months ago, and they ain't cheap! Yeah and btw they can be cleaned Quote Share this post Link to post Share on other sites
warpedskydiver 0 #20 February 25, 2008 If it is the fuel pump, you can take out the rear frame to chassis bolts, and raise the rear of the body so that you can remove the pump without having to drop the tank. At least you could on the older models. Quote Share this post Link to post Share on other sites
ypelchat 0 #21 February 25, 2008 Quote My 2001 Chevy Blazer started acting funny a few days ago. I want to challenge you "Click & Clack" people out there to diagnose what could be wrong with my vehicle. (Click & Clack are the nicknames for the two guys that do a call-in radio show diagnosing automobile problems.) The problem: When accelerating from a stop, the engine stalls out. It can be immediately re-started, but may cut out several more times before acceleration is achieved. Being very light on the gas pedal helps - so light that you almost aren't accelerating at all (and that's really difficult for me). When on cruise control and hit a hill, the engine cuts out repeatedly for about a second at a time as it attempts to climb the grade. And these engine stalls only happen when the gas tank is less than half-full. It runs fine on the first half of the tank. That little tidbit really sweetens the mystery. So, do any of you professional or backyard mechanics have an idea what could be going on here? My thoughts: 1) A bad tank of gas? This started happening after a top-off at a very remote national park (Big Bend, Texas), which doesn't have much gas turnover at the camp store. However, several tank re-fills since have failed to clear the problem. 2) There is also a lot of fine powdery sand through which I was driving on dirt roads. The air filter was not clogged. Could it have gotten into the gas tank? I welcome informed thoughts. Attached: Photo of "Big Red" next to the stone ruins of an old ranch home in the Texas desert. I would check for a corroded rotor in the distributor. You may also need a new distributor cap. I would check for both, if i were you. Yves. Quote Share this post Link to post Share on other sites
airdvr 197 #22 February 25, 2008 You can spend a ton of money hanging parts in an attempt to solve the problem. Take it to a qualified mechanic who can scan the system and tell you what's wrong. Or...you can hang the roughly $800 worth of parts your friends suggested and still not solve the problem.Please don't dent the planet. Destinations by Roxanne Quote Share this post Link to post Share on other sites
bloody_trauma 2 #23 February 25, 2008 You have to blow into the tube everyonce in a while so the truck knows your sober... Fly it like you stole it Quote Share this post Link to post Share on other sites
skybytch 259 #24 February 25, 2008 Quote I'm gonna go with fuel tank pressurization. You're wrong. It's slider rebound. My experience probably doesn't apply because it was all with pre-fuel injected and computer controlled engines, but every time I had the issues you described it had something to do with the fuel delivery system. Fuel pump, fuel filters, fuel lines, screen in the gas tank... I'd start with the filters since they're the cheapest to replace. Quote Share this post Link to post Share on other sites
ryoder 1,384 #25 February 26, 2008 When the problem starts happening, try stopping and opening the fuel cap. Listen for the sound of a suction being released. I'm thinking it could be a problem with the fuel vent system that is preventing air being able to get in to replace the fuel being drawn out, resulting in a partial vacuum forming in the tank that opposes the effort of the fuel pump to pull it out."There are only three things of value: younger women, faster airplanes, and bigger crocodiles" - Arthur Jones. Quote Share this post Link to post Share on other sites
