Gas Mileage shifty again

[JoshBarber]

Anyone have quick suggestions on things to check if I smell a faint smell of gas in the cab after filling up?

[BlazerBoyLT98]

Hole in the filler neck? Maybe a hole in the tank itself? Maybe a fuel line is slowlt leaking? Also could just be the vapors getting in. Good luck

[JoshBarber]

I've looked for external leaks underneath the vehicle and have found none. The mpg has gotten really bad like it was before I replaced the fuel spider. I hate to tear the engine cover off again if I dont have to.

another symptom I've noticed:
when I start up, and reverse out of a parking spot...my blazer will occasionally stall. I'll have to restart and then its fine.

-I know we all have the gas gauge deal where when you back up the dial drops lower, and rises back up once you're moving forward....any ideas why it would stall though? I would imagine its connected to the poor gas mileage. Some kind of pressure drop when you reverse?

[BlazerLT]

Have you actually checked the fuel economy?

You know fuel economy will drop this time of year seeing the air is getting colder and the ECM compensates by dumping in more fuel.

[JoshBarber]

How's 12-13mpg sound?

Originally Posted by BlazerLT

Have you actually checked the fuel economy?

You know fuel economy will drop this time of year seeing the air is getting colder and the ECM compensates by dumping in more fuel.

[BlazerLT]

Are you basing this off of real number or inferring from the tank level on the dash?

[JoshBarber]

not sure what you mean by "inferring from the tank level on the dash" but...no I'm telling you my gas mileage is about 12mpg by miles driven vs. gallons put in. You can't get much more precise than that.

Something is obviously wrong again. It's gotten as bad as it was before I replaced the fuel spider a few months ago. Gas mileage had gotten a LOT better after replacing the spider (which includes a new fuel pressure regulator)...but its gone to shit again. Not sure what I can do short of tearing the cover off again and looking for signs of leak.

It's too sudden and drastic of a change for it to not be a significant problem. I can't find ANY external signs of leak like in the fuel line or tank. My guess is that its either the regulator suddenly leaking, or the injectors getting stuck open. Either way...its F&CKING rediculous after only months of use on a new DEALER part.

Ready to toss the car for another volvo that gets 25mpg year round...and goes clear past 250-300,000 miles without issue.

Originally Posted by BlazerLT

Are you basing this off of real number or inferring from the tank level on the dash?

[BlazerLT]

How old are the O2 sensors?

[JoshBarber]

probably original as far as I know. but without getting a trouble code indicating it, I'm not going to waste money replacing things if I don't have a near positive idea that its causing it. its not like you can return them after the install. I also think my CATConveter is fried...it rattles like theres loose pieces inside...but thats been like that for months and months.

But again...this is a drastic sudden change in mileage...like all of a sudden something failed...whether it was a mechanical part that is now leaking fuel, or an electronic sensor that regulates fuel economy.

Originally Posted by BlazerLT

How old are the O2 sensors?

[JoshBarber]

No suggestions from anyone? I'm not going to find a problem by running a computer test if I have no engine light on correct?

[AJT1961]

My guess would be that your new spider went bad. I just did mine a couple of weeks ago (2000 Blazer 4wd) and I'm just waiting for that number 3 injector hose to start leaking (or kink shut) because of the unnatural bend you have to put into it to comply with the MFI Coversion Bulletin No. 00-06-04-003B. Or you just got unlucky and the new regulator went bad already. My old CSFI system was leaking gas like crazy into the manifold but I never smelled it in the cabin, so that's an odd symptom. It would bleed off the fuel pressure almost instantly after shutting off the ignition. (Have you checked the fuel pressure yet?) The only time I ever smelled gas in the cabin is when the person filling up before me spilled some on the ground and I inadvertantly stepped in it. Good luck, and when you nail down the problem, please let us know. These Blazers sure keep you busy. Having already ventured far down the slippery slope, I'm hoping that I get at least another 90,000 trouble free miles now that I have relaced almost everything that typically goes wrong with a 2000. For awhile there it was really discouraging.

[JoshBarber]

I'm not really smelling the gas that often...so it just may have been from the outside fumes when I filled up. I'm leaning towards agreeing with you here. Either the Spider shit the bed already..WHICH IS REDICULOUS...or the included regulator did...WHICH IS ALSO REDICULOUS. Its always been discouraging. I'll never buy another American vehicle again. First and Last.

Originally Posted by AJT1961

My guess would be that your new spider went bad. I just did mine a couple of weeks ago (2000 Blazer 4wd) and I'm just waiting for that number 3 injector hose to start leaking (or kink shut) because of the unnatural bend you have to put into it to comply with the MFI Coversion Bulletin No. 00-06-04-003B. Or you just got unlucky and the new regulator went bad already. My old CSFI system was leaking gas like crazy into the manifold but I never smelled it in the cabin, so that's an odd symptom. It would bleed off the fuel pressure almost instantly after shutting off the ignition. (Have you checked the fuel pressure yet?) The only time I ever smelled gas in the cabin is when the person filling up before me spilled some on the ground and I inadvertantly stepped in it. Good luck, and when you nail down the problem, please let us know. These Blazers sure keep you busy. Having already ventured far down the slippery slope, I'm hoping that I get at least another 90,000 trouble free miles now that I have relaced almost everything that typically goes wrong with a 2000. For awhile there it was really discouraging.

[blazes9395]

Put a pressure guage on it an see what you get. If its bleeding down, you know something is going on. throwing a scanner on it and seeing what its doing will give you an idea of whats going on too with the system(electronics). Your cat is probably dead, and since you mention its rattling, it probably is no good. That doesn't help performance, and if its starting to clog the exhaust, it will cause a series of problems, such as poor gas milage, and generally poor performance. Usually for a cat to go bad, it is usually because the truck is running rich, or misfiring, either of which cause the unburnt gas to be burned inside the cat, overheating the convertor and causing it to fail. If it is your injector spider, and if you bought it from a dealer, its warrentied for a year. Either way, take some time to do some diagnostics and see what you get.

[BlazerLT]

Smell of gas in the cab is normal to and extent.

If you are overfilling it and not just topping off to the next dollar after it clicks off, you will be flooding the Charcoal canister with fuel which is not good.

I was overfilling and causing the smell.

[Blue Bowtie]

I have overfilled at Taco Johns and had a similar problem...

To expound, if the truck isn't driven at light-load, full temperature, and medium highway speeds periodically, the EVAP canister may never purge, aggrevating the fuel vapor problem.