will not run
Thread Starter
Drifting
Joined: Feb 2013
Posts: 1,464
Likes: 48
will not run
Hello everybody. I own a 1984 4 plus 3 Corvette. A couple of weeks ago I ported the manifold. Car ran great. Today it ran AWFUL. I can start the car and when it is at operating temperature and 900/1000 rpm it is pulling 20 inches of vacuum. When I start to go it stalls out. It can idle for ever but once I start driving it wants to stall and usually does. The TPS is at 0.5 volts at idle. Any ideas. I am thinking fuel pump but I put one in about 800 miles ago. Regulators? I have a shop manual. Thank you
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
Start by pulling the codes
http://www.corvettephotographs.com/c4vettes/codes.htm
Check the fuel pressure
http://www.corvettephotographs.com/c4vettes/codes.htm
Check the fuel pressure
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
Does the light come on when you 1st turn the key on?
Does the bulb work?
You say you have the shop manual .The correct test procedures are documented there
Does the bulb work?
You say you have the shop manual .The correct test procedures are documented there
Thread Starter
Drifting
Joined: Feb 2013
Posts: 1,464
Likes: 48
thank you
Burning Brakes
Joined: Sep 2004
Posts: 1,130
Likes: 19
From: Arkansas
I had an 84 and the cat converter clogged up. The car would idle fine but barely moved, it was really smothered down.
Look to see if it glows red after the car runs for a few minutes. This will not set a code.
Shawn
Look to see if it glows red after the car runs for a few minutes. This will not set a code.
Shawn
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Drifting
Joined: Feb 2013
Posts: 1,464
Likes: 48
car won't run
So I located the diagnostics in the shop manual. It said to apply 12 volts to terminal G on the ALDI. So I did that. and the pump did not run. But when I apply 12 volts to the pump connector the pump runs. The fuse is good. I seperated the connector at the relay under the hood and put a test lamp to the leads. I get a completed circuit but no pump running.
Thread Starter
Drifting
Joined: Feb 2013
Posts: 1,464
Likes: 48
So I decided to see if the car would run. I poured gas into the TBIs and the car ran and the TBIs pulsed.
Could the poor performance be the IACs reacting to the porting.
But then why didn't the pump run when I used the OBD1 connector port to power the pump
Could the poor performance be the IACs reacting to the porting.
But then why didn't the pump run when I used the OBD1 connector port to power the pump
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
You may have a fault/ break in the wiring from the fuse to the tank
If the fuse is confirmed good , put a DVM between each of the fuse terminals and the tank connector and see if you get continuity.
If not you know where your problem lies
Thread Starter
Drifting
Joined: Feb 2013
Posts: 1,464
Likes: 48
The ALDL terminal uses the same wiring back to the pump , all it does it let you run the pump with the key off.
You may have a fault/ break in the wiring from the fuse to the tank
If the fuse is confirmed good , put a DVM between each of the fuse terminals and the tank connector and see if you get continuity.
If not you know where your problem lies
You may have a fault/ break in the wiring from the fuse to the tank
If the fuse is confirmed good , put a DVM between each of the fuse terminals and the tank connector and see if you get continuity.
If not you know where your problem lies
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
Thread Starter
Drifting
Joined: Feb 2013
Posts: 1,464
Likes: 48
Circuit 120 runs from ALDL terminal G to the pump. The fuse is that fuse the fuse box or inline. What is between the fuse and the pump. Fuse able link. Sorry I just don't yet understand electronic short hand.
thank you
thank you
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
Drifting
Joined: Jun 2013
Posts: 1,590
Likes: 60
From: ft myers FL/Munising MI
Hello everybody. I own a 1984 4 plus 3 Corvette. A couple of weeks ago I ported the manifold. Car ran great. Today it ran AWFUL. I can start the car and when it is at operating temperature and 900/1000 rpm it is pulling 20 inches of vacuum. When I start to go it stalls out. It can idle for ever but once I start driving it wants to stall and usually does. The TPS is at 0.5 volts at idle. Any ideas. I am thinking fuel pump but I put one in about 800 miles ago. Regulators? I have a shop manual. Thank you
Thread Starter
Drifting
Joined: Feb 2013
Posts: 1,464
Likes: 48
you didn't indicate what the fuel pressure was or if it stayed up...I had a similar problem....went through the same trouble shooting guide...I also had recently installed a new pump...if pressure is an issue...look where it says to pinch off the pressure and return lines at your tank...I had a loose connection between pump and pulsator...started/ idle ok...wouldn't go....that part will tell you whether it's the pump or regulator...if your pressure stays up, ignore my 2 cents....