...because my gas mileage sucks! Here is a list of stuff already done.

1.Tune-up which included plugs, wires, new dizzy, cap and rotor.
2. Set timing to base 10*.
3. New fuel filter.
4. New 02 sensor.
5. K&N filters in a Y-intake from an '86 2.8.
6. Checked for vacuum leaks and cannot for the life of me find any.

The only thing I can think of is a plugged cat or leaky injectors. The car does run a little better than before and has'nt stalled anymore even though it sputters some. I took some Seafoam and put half in the tank and sucked the rest through the brake booster line. I let it sit for 10 minutes and cranked the car again. GEEZ!!!...talk about the smoke rolling out!! Guess it cleared off some of the carbon and crap. Thats when I decided to replace the 02 sensor and fuel filter. The cat is still stock and has never been replaced and the injectors are factory as well. I did notice where the hot lead going to the starter was a little loose and tightened it. Maybe there was my stall issues...hmmm. Anyways, you guys got any thoughts on the cat and injectors?

Ken

 

How "bad" is your gas mileage? My '92 3.1 only gets ~15 mpg in city driving, but well over 20 on the highway.

 

I had leaky injectors on my 6000. Ran ok while driving. It was really hard to start if you let it sit for a minute or longer and you could smell gasoline from the intake. Eventually it got worse and the car would not idle by itself. My furl pressure regualtor was also bad

Any other symptoms asdie from the gas mileage?

 

Hmm....nah...just the gas mileage and the little sputtering. I noticed that the car never threw a code when I had the old 02 sensor unplugged..I was getting the car hot to make removing the sensor easier. The car might have to be a certain operating temp. in order for it to throw a code. You mentioned your fuel pressure regulator. When I took off my smog pump, there was a vacuum line that came from the pump and went to the pressure regulator. I just plugged it up and really don't know if thats going to affect anything. I don't think you can replace the regulator. I believe you have to replace the whole fuel rail. If I need to replace the fuel rail, I'll throw in new injectors while I'm at it. I might have the fuel pressure checked. It might be the fuel pump getting old. Its also factory. Any ideas on this info?

Ken

 

the diaphram for teh fpr cain be replaced. you'll need the tamper proof torx bits iirc for it.

http://www.partsamerica.com/ProductL...sure+Regulator

 

Tamper proof torx bits? Where can I get those for the job to replace the diaphragm? I was thinking about getting a used fuel rail and put new injectors in it along with a new pressure regulator diaphragm. If the injectors and regulator are out of the fuel rail...what else is left in the rail? Is is just a metal housing for the injectors? I was wanting to get a used one, strip it down and soak or clean it and then install new injectors in it so when I change out the injectors in my car, I'll have the whole setup ready to go in with no downtime much. Good idea?

Ken

 

I replaced the cat on mine with a high flow model. It didn't make any noticeable difference in power, but it sounds MUCH better and the engine runs a lot cooler. I highly recommend putting a new cat on yours.

I recently installed injectors rebuilt by Cruzin Performance. They did a very professional job on them, and I think my mileage increased a little bit. Not certain how much until I take it on a long drive.

Cruzin Performance

Also, a thorough check of every component under your hood would be good. I have been gradually replacing everything under mine and my mileage seems to be improving every time. Check EVERYTHING under your hood and if it doesn't work right, fix it. Start with important parts like your PCV and EGR systems.

 

Those are like regular Torx bits except they have a little hole in the middle that fits over the tang (that is really what its called) in the tamper proof screw (I think they are actually called "safety screws", as in "its for your own safety that you don't f*** with this!" ) The bits are available at most auto parts stores and even Sears and other tool outlets should have them.

 

Ken, don't sweat the tamper-proof torx bits. Take a center punch, grind the "sharp point" off the punch so it's a flat punch, lay it on the nub in the center of the torx screw, get a big hammer, and "wham"- you'll turn them into regular torx screws.

If you want to buy tools though (and who doesn't?), source the tamper-proof-torx-bits from Lisle Corp, if you can't find them locally try toolparadise.com (or similar).

I also "second" Rich's job from cruzinperformance.com - he cleaned two sets for me and it was well worth the extra power.

 

Aaron, how much did cruzin charge to do your injectors?

 

Thanks TomP, I got some punches laying around already. I primarily used them when I am working on my 1911 or AR15. I got the punches as a set and do not us all of them so I can use one for the regulator torx. The punches are already flat on the end. I just won a fuel rail and injectors from a 91 Camaro off Ebay for 20 bucks plus s/h. I'm going to take that fuel rail, take off the fuel pressure regulator and injectors and clean/soak the fuel rail to get it clean on the inside, get a new diaphragm for the regulator and install new injectors. This will save alot of time in the long run. Besides, I can get all that ready and take my time and still have my ride for work and stuff with no downtime. Sound good?

Ken

 

Regardless of what anyone wants to say about thirdgen V6 gas mileage, the EPA ratings tell a pretty clear story...

1991 Camaro 3.1L V6 17mpg city, 27mpg highway, 20mpg combined.
1991 Camaro 5.0L V8 17mpg city, 26mpg highway, 20mpg combined.
1991 Camaro 5.7L V8 16mpg city, 24mpg highway, 19mpg combined.

All the tune ups and troubleshooting in the world aren't going to make a substantial marked improvement over the EPA ratings.

EPA mileage ratings can be found online by year here... Download the Fuel Economy Database

 

drdave88, it was $12 per injector plus return shipping. Think it came to like $78 or something for all six. He did a very professional job on them.

 

cool. i think ive gotta get mine out there, mines acting like it used to last time i had a leaking injector.