Topic: Running rich
in Forum: C3 Engines
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Former Member
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Phoenix, AZ - USA
Joined: 6/12/2011
Posts: 139
Vette(s): 1982 corvette crossfire production numer C5101985. Color is silver and claret. All original numbers match. slight mods to crossfire for better efficiancy and power balanced and added fuel pressure assembly between throttle bodies,
Ok, so I am going to be running the car at a much lower altitude. last time i drove it, it smelled rich after i shut it down.
any thoughts on how to tune it to a phoenix altitude from the Idaho altitude?
I know if i mess with the sensors im going to get a code thrown. Im not sure how to lean out the duel throttle bodies, now on a carburetor with the mixture dial no problems.
I wont honestly know if it will need it or not until i get it down here. It was at one time a Vegas car and passed smog at 47k (carfax)
Marcus
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Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
The ECM should automatically adjust the fuel mixture, as long as the MAP/Baro sensor is connected, and working properly. The MAP(manifold absolute pressure) sensor is basically a vacuum sensor, but it is usually also used as a barometric pressure sensor, so it will read both vacuum and pressure. As the altitude goes up/down, the baro sensor will see it, and adjust the fuel mixture accordingly.
Joel Adams
C3VR Lifetime Member #56 
My Link 
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Former Member
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Phoenix, AZ - USA
Joined: 6/12/2011
Posts: 139
Vette(s): 1982 corvette crossfire production numer C5101985. Color is silver and claret. All original numbers match. slight mods to crossfire for better efficiancy and power balanced and added fuel pressure assembly between throttle bodies,
runs like crap with the E10 fuel. I put a stablizer in the tank and it runs better, but the smell of it running rich is something im not use to.
I will check my map sensor connection as well as any air leaks on the manifold and other areas.
thanks
Lifetime MemberLemon Grove, CA - USA
Joined: 10/17/2007
Posts: 2041
Vette(s): 1982 C3 Collectors Edition 44000 miles, sat in the sun most of its life, My wife purchased it for me for Father's Day in 2007 from her girlfriend that had it for 19 years. It is on the road again. I'm retired but it is now my daily driver.
I had that problem and I had to take it in to get if fixed. $1300 later it passed smog. The did a lot of things to it and I have a large box of stuff they replaced. It came down to a lot of thing but the big ones were vacuum leak intake manifold bottom where it bolt to the engine not the top plate. Not much mind you but enough. The temperature sensor (relatively new) was also not providing a consistent reading. It was not enough for me to see on the temp gauge but it confused the computer. At least that is what they told me. That part did not cost a lot so I would assume it was correct. It seems that it would indicate cold every now and then.
I could not get my car to come close to passing smog. Now it is running really clean without any smog issues except I have a spark plug wire that is shorting out. They replaced them and put in some heat shields so I should get it back Tuesday and then I will see what kind of shape it is in.
By the way you cannot reduce the fuel through the injectors. You can cut the pressure some but that is all. If they are pumping to much fuel it is the duration that they are on that is the cause and that is determined by the computer.
Former Member
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Phoenix, AZ - USA
Joined: 6/12/2011
Posts: 139
Vette(s): 1982 corvette crossfire production numer C5101985. Color is silver and claret. All original numbers match. slight mods to crossfire for better efficiancy and power balanced and added fuel pressure assembly between throttle bodies,
with my insurance and the Phoenix area I dont have to go pass smog. but im going to get it checked out any ways just to see where it stands.
State Farm Antique insurance by the way.
agreed value- and i really dont drive it all that much anyways
Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
Marcus, does it have any codes stored in it? If it's running super rich it should have at the very least an O2(oxygen sensor) code. Then again, a flaky O2 sensor can make them run rich....as can a flaky coolant temp sensor. Seems like we've been down this road before.....was that you? Might have been a feller on the C4 site.....I can't remember.
But......might just need to take that thing out on the hiway and blow the soot out!
But......might just need to take that thing out on the hiway and blow the soot out!
Joel Adams
C3VR Lifetime Member #56
My Link
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Former Member
Send PM
Phoenix, AZ - USA
Joined: 6/12/2011
Posts: 139
Vette(s): 1982 corvette crossfire production numer C5101985. Color is silver and claret. All original numbers match. slight mods to crossfire for better efficiancy and power balanced and added fuel pressure assembly between throttle bodies,
na, wasnt me, It was running rich after i had it stored for awhile with the bat disconnected, ran it for awhile and it corrected itself.
no codes stored on the computer. its about time to replace sensors though- i dont know when they were replaced.
I still need to get the car from Idaho though.
Im looking into grayhound not my best option but it will get me their.
Marcus
in Forum: C3 Engines
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