C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

1992 LT1 trouble codes

Thread Tools
 
Search this Thread
 
Old 04-01-2015, 08:07 AM
  #21  
1stVetteFinally
Pro
Thread Starter
 
1stVetteFinally's Avatar
 
Member Since: Sep 2014
Location: Smithfield VA
Posts: 588
Received 33 Likes on 30 Posts
Default

Originally Posted by 1stVetteFinally
After driving the car for a few more hours, it started throwing the 44 and 55 codes again. Went to Harbor Freight, got a fuel pressure gauge, and checked my fuel pressure.



turn key on- jumps to around 35 PSI and then drops to 10 PSI in about 5-7 secs

start car and drive- still unable to actually drive the car as Harbor Freight also didn't have a fuel pressure gauge with a long enough hose, but on idle and putting the car in gear and giving gas, 35-36 PSI.

IIRC, my fuel pressure should be around 43-45 PSI. What could be causing this? Car has a new fuel filter and pump. No kind of damage to the fuel lines that I can see. My racing season starts in 5 weeks, practice in 3. PLEASE HELP
replaced the fuel regulator yesterday afternoon, still only getting 35 PSI on the fuel rail. New fuel pump, filter, regulator, no visible damage or wear on the fuel lines, and I'm still only getting 35 PSI. Please, anyone have any ideas as to what may be causing this?
Old 04-01-2015, 04:40 PM
  #22  
Ozzstar
Pro
 
Ozzstar's Avatar
 
Member Since: Mar 2009
Location: Middletown Delaware
Posts: 702
Received 256 Likes on 75 Posts

Default

Originally Posted by 1stVetteFinally
replaced the fuel regulator yesterday afternoon, still only getting 35 PSI on the fuel rail. New fuel pump, filter, regulator, no visible damage or wear on the fuel lines, and I'm still only getting 35 PSI. Please, anyone have any ideas as to what may be causing this?
Post #4 , but that's how it goes sometimes. Engine OFF key ON , called EOKO. Try clamping the rubber return fuel line back at the tank and see if the static pressure goes above 43psi. Then if it does not hold high pressure it's possibly the small rubber hose inside the tank connected to the pump that could be cracked, dislodged, leaking or missing, like a check valve. This is called dead head pressure.

You said the fuel pump has been replaced, wonder why? Did you check the voltage or amp draw on the pump? Old and new?

How much fuel is in the tank? Is it more than a quarter tank?

Does the engine have to crank a lot when starting? I assume its not firing right up like it should.

Have you OHM tested the fuel injectors? No? you will need to do it. Even if they check out okay further testing may be needed to check for a leaking injector (stuck open). Temperature will effect the ohm reading, do them all at once (cold and then hot) is good practice.

Try this test real quick, unplug the vacuum line at the regulator, do you see any wet fuel or smell strong vapors inside the hose? If so the "new" regulator could be defective. Can't trust the made in China stuff much these days.

Make sure that the small plastic black cone shaped vacuum diaphram near the regulator (passnger side on my '93) isn't cracked if your car has one. LOOK at the BACK of it...it may appear on the front as good but they can split open in the back where you can't see it installed! Get a vacuum pump and test it off of the car. Replace if necessary.

Report your findings. Parts chasing is not the way to solve an issue. Find the evidence to the problem then repair. Good luck

Last edited by Ozzstar; 04-01-2015 at 04:56 PM.
Old 04-01-2015, 05:15 PM
  #23  
1stVetteFinally
Pro
Thread Starter
 
1stVetteFinally's Avatar
 
Member Since: Sep 2014
Location: Smithfield VA
Posts: 588
Received 33 Likes on 30 Posts
Default

Appreciate the reply. Spent the day working on it and talking with some of the guys I'll be racing with. After all the trouble shooting, it seems the regulator I got from advance was bad. Got a different brand name regulator and the appears to be running right now. No codes and no stuttering when pedal is floored
Old 04-02-2015, 03:37 PM
  #24  
Ozzstar
Pro
 
Ozzstar's Avatar
 
Member Since: Mar 2009
Location: Middletown Delaware
Posts: 702
Received 256 Likes on 75 Posts

Default

Originally Posted by 1stVetteFinally
Appreciate the reply. Spent the day working on it and talking with some of the guys I'll be racing with. After all the trouble shooting, it seems the regulator I got from advance was bad. Got a different brand name regulator and the appears to be running right now. No codes and no stuttering when pedal is floored
"Try this test real quick, unplug the vacuum line at the regulator, do you see any wet fuel or smell strong vapors inside the hose? If so the "new" regulator could be defective. Can't trust the made in China stuff much these days."

Glad you got it fixed. Check out my youtube channel Ozzstar, you may like some of the repairs I do. Take it easy - Ozz



Quick Reply: 1992 LT1 trouble codes



All times are GMT -4. The time now is 06:38 PM.