Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner

1 - 7 of 7 Posts

·
Registered
2002 chevy trailblazer_lt
Joined
·
15 Posts
Discussion Starter #1
Hey all,

Been a while since I've posted. Happy New Year, and Merry belated Christmas!!!

If some people would read this and reply if you have suggestions, that WOULD BE AWESOME!!! But please read before, because I have done work and I don't wanna read suggestions I've already tried/done.

So a while back, like late 2011-2012, I was getting crappy mpg; usually I could get 16-18 city, 18-20 combined and 20+ for highway, usually 20-23 mpg. I really liked that and considered it nice mpg for a mid-size SUV. So it was getting noticeably different mpg and was smelling gas upon start-up, and it was a little hard starting. Didn't really run rough or idle rough. The dealership at the time replaced the fuel pressure regulator as it was leaking really bad. So the mph improved for a little bit but then went down.

I had a tune-up done last year and haven't yet gotten to the point where I need another one. They replaced the fuel pressure regulator last year in January, as they smelt gasoline on the vacuum hose. I just did a whole bunch of work to try and solve what still might be a fuel leak/bad mpg problem...

That work included doing my temp sensor/thermostat, as my engine has been running cool since July of 2012, cool enough to warrant replacing it. I heard that if the engine runs cool then the computer will feed more fuel to the fuel injectors and therefore runs rich...so I did some fuel injector cleaner because of this and also because they hadn't been cleaned in a while...we did my fuel vent because a trusted mechanic said those can get clogged up...mine wasn't too bad but still a little clogged nonetheless. Also did the charcoal canister and when we took it off it was saturated with gasoline. Replaced the air filter, too. And cleaned the throttle body. That's pretty much it for the mpg related stuff...we also did power steering pump, master cylinder, passenger side front hub (did the driver side last fall, it was making a lot of noise...replaced this one as it was getting kinda old and bad, too), oil pressure sending unit...:crazy::crazy:

So I know that obviously the fuel injector cleaner will take a while to clean (I've heard anywhere from one tank to a few times) and I'm going to track my mileage. When I started my car yesterday and this morning, however, I noticed again, as I have been noticing for a while still, there is a strong smell of gas. I noticed it right outside of the driver door (don't know if that helps), as I didn't notice it inside the car. I had forgotten to unplug the cord for the block heater and stepped back out after starting it up. It was definitely gas and I know that it's not really normal to be smelling that. I noticed my mileage is still kinda where it was before, getting like 12-15 city/combined and only as high as 17-18 mpg highway. Like I said, I know that the injector cleaner will take a little while to clean. Before it seemed like my acceleration was sluggish and had to really kick it down to get going, especially uphill. Everything seems ok now, it seems to run great...only thing is the gas smell and the mpg, which I think the mpg will be improving with the cleaner unless there is still a bad leak.

What do you think? Where else would have I have to look? I know I've read about looking at the rail, but as far as I know, we didn't see any gas. I don't think it would be leaking fuel injectors just because it seems to run fine...but I could be wrong.

Any advice would be nice, as I love higher mpg and I don't know where else to look or what else to do :bonk::bonk::bonk::thx:thx:confused:
 

·
Registered
2006 saab 9_7x
Joined
·
450 Posts
I am not sure if you are aware that winter blend gasoline makes quite a difference in MPG, but it does. Usually longer warm up time, adds to fuel consumed, again not knowing your preferences. Some people say, get in, start up and take off. I operated heavy equipment for over 50 years and just can't seem to do that. Not saying that is your problem, just giving you some things that might be.
 

·
Registered
2002 chevy trailblazer_lt
Joined
·
15 Posts
Discussion Starter #3
I have heard that before...I'm just not sure it's the winter blend because I've been having bad mpg for a while...my dad thinks that since I have over 180,000 miles on it that it's an older engine and older engines seem to have lower mpg. One other note is that at one point a while ago the dealership had to take apart the cam actuator and clean it/replace it or whatever. During that time it had been running kinda rough and it did throw a code. They had done it twice. It was right around that time of the actuator and the FPR my mileage dropped and hasn't returned since...:ugh::ugh:
 

·
Registered
2003 chevy trailblazer_ls
Joined
·
1,236 Posts
With 180K on the engine, I would suggest that you are seeing the effects of wear. Try a compression test to see what cylinder pressures are, and if you have leakage past the valves. That would be normal for an engine with that many miles. They DO wear even though they will continue running for a long time in worn state.

Here is a video:

http://www.youtube.com/watch?v=X_tbksFYhl4
 

·
Registered
2002 chevy trailblazer_lt
Joined
·
15 Posts
Discussion Starter #5
With 180K on the engine, I would suggest that you are seeing the effects of wear. Try a compression test to see what cylinder pressures are, and if you have leakage past the valves. That would be normal for an engine with that many miles. They DO wear even though they will continue running for a long time in worn state.

Here is a video:

http://www.youtube.com/watch?v=X_tbksFYhl4
Yeah I'm kinda feeling that it's wear, unfortunately :sadcry:

However last night I noticed one little thing that could possibly be a huge problem...I was plugging the cord for my block heater back in and noticed that when my dad put the air intake resonator back on, he kind of forgot to hook the crankcase ventilation hose to the valve cover plug. I've read on this and it can present some problems...possibly why I may be continuing to notice bad mileage? I have already driven 210ish miles and the gas tank is already empty, amounting to 12-14 mpg, kinda what I was getting before only a little worse. :bonk::bonk:
 

·
Registered
2003 gmc envoy_slt
Joined
·
1 Posts
bad mpg and gas smell

Well i am pretty sure your gas smell is your fuel pump leaking and possibly the bad mpg. The top part of your fuel pump is exposed to the elements and will start to rust thru if you live in the rust belt. There are two small steel tubes on the top part of the pump, these are connected to your fuel lines that run up to the motor and will rust right thru at the 90 deg bend and you will need to replace the whole fuel pump. There are several good posts on here on how to do that. Good luck.
 

·
Registered
2003 chevy trailblazer_ls
Joined
·
1,236 Posts
Not sure the ventilation hose would cause much of a mileage difference.

I'd be looking to other issues, including just plain winter. My own has dropped several mpg also. Just more difficult to pull good numbers when it is cold and the gas is blended for cold temps.
 
1 - 7 of 7 Posts
Top