hey everyone im new here this is my first post. i was just wondering if you guys knew how i could adjust the air/fuel mixture in my lo3? i get a horrible raw fuel stench from my car. i guess that 177,000 miles on dont help either. i got a 350 tbi from a '93 silverado and i think i might just swap it in. but i am still going to rebuild my lo3. i just dont know if i can make the kind of power i want from the 305.any info on the air fuel mixture will be a help.
Moderator
If it's an otherwise stock LO3, and you're running rich, then I'd check two things first: the TPS sensor, and the OČ sensor. If the OČ sensor has never been replaced before, that's probably it, since OČ sensors are recommended to be changed at 30,000 miles or sooner if you're consistently running rich or use a lot of additives.
A good starting point for you would be to set the timing, then the minimum air, then the TPS voltage if your TPS is adjustable; in that order. Then before you run it after setting all that, remove your ECM fuse long enough to clear the memory so that it starts fresh on the AF ratio correction and drive it around town at moderate throttle speeds for about 20 minutes (long enough for it to "relearn" your driving habits and the engine's internal characteristics) Also check for vac leaks. Vacuum leaks typically make the car run leaner, but sometimes they're only there long enough for the computer to want to compensate for it, then go away making it run richer (like rotted hoses that actually seal when they're bent just so). A bad culprit is the hose that is actually connected to the intake manifold in the back by the distributor. That 1/4" hose really likes to rot about now right where it meets the inlet.
I know it's chinsey but cars are like that and no one else was answering you..
Hope you get it sorted out TEXAS89RS, and welcome to Thirdgen.Org.
A good starting point for you would be to set the timing, then the minimum air, then the TPS voltage if your TPS is adjustable; in that order. Then before you run it after setting all that, remove your ECM fuse long enough to clear the memory so that it starts fresh on the AF ratio correction and drive it around town at moderate throttle speeds for about 20 minutes (long enough for it to "relearn" your driving habits and the engine's internal characteristics) Also check for vac leaks. Vacuum leaks typically make the car run leaner, but sometimes they're only there long enough for the computer to want to compensate for it, then go away making it run richer (like rotted hoses that actually seal when they're bent just so). A bad culprit is the hose that is actually connected to the intake manifold in the back by the distributor. That 1/4" hose really likes to rot about now right where it meets the inlet.
I know it's chinsey but cars are like that and no one else was answering you..
Hope you get it sorted out TEXAS89RS, and welcome to Thirdgen.Org.thanks i will check that out. what do you think about the 350 swap. its only got about 80,000 on it. do you happen to know what the truck motor was making in terms of horsepower in '93?
Senior Member
wasp
Senior Member
close
- Join DateFeb 2002
- Locationsaugerties new york
- Posts:885
- iTrader Positive Feedback0
- iTrader Feedback Score(0)
- Car91 firebird,mint
- Engine305 tbi,lots of work done
- Transmission700-r4 built by level 10 in nj
- Axle/Gears3.73, auburn , precision
- Likes:0
- Liked:0 Times in 0 Posts
your running rich for a fact? or you just think you are cuz you smell gas? check your vapor canister it may be shot and the source of the smell..........its the tall black canister should be on drivers side right behind headlight
the can is fine so are all the hoses going to it. could it be the small valve that connects to the fuel tank. how would i check that??
Member
well, i'd check the o2 sensor first, they are bad to cause that, and watch your cat if its running rich cuz she'll stop up on ya, did it to me...
anyway, I don't know about everyone else, but I want to hear about the:
1986 ASC McLaren Z28 convertable SE #41
anyway, I don't know about everyone else, but I want to hear about the:
1986 ASC McLaren Z28 convertable SE #41
Senior Member
Quote:
Originally posted by TEXAS89RS
thanks i will check that out. what do you think about the 350 swap. its only got about 80,000 on it. do you happen to know what the truck motor was making in terms of horsepower in '93?
According to Edmunds.com,Originally posted by TEXAS89RS
thanks i will check that out. what do you think about the 350 swap. its only got about 80,000 on it. do you happen to know what the truck motor was making in terms of horsepower in '93?
210hp @ 4000 rpm
300lb-ft @ 2800 rpm
I have seen lower than 210hp (like 195, 200, etc.) and I've also seen more than 300lb-ft (310....). I also don't know if that torque peak RPM is right. These numbers are ballpark figures, to be sure...HTH
Senior Member
You say it only smells like gas but are there any problems in performance? Like does it have an erratic idle, boggs shoots smoke. Or what? If it is shooting smoke and actually is burning rich you might also want to check the coolant temp sensor.
how does the cts make the engine burn rich? i will go ahead and change that too. idle is fine. it blows smoke under heavy throttle, but that is probably worn piston rings. might the smell be coming the exhaust? maybe a leaking exhaust manifold. oh bye the way any tips for changing the cts?
Senior Member
The CTS is a primary sensor for our TBIs. It needs that and the MAP sensor to run. The CTS obviously reports to the ECU how warm/cold the engine is (via coolant temp) so the ECU can adjust fuel flow accordingly. And guess what? More fuel when cold. So a malfunctioning CTS that is always reporting cold would make the car run too rich when it warmed up. Make sense?