Fuel Pressure - Fuel Pump
Thread Starter
Pro
Joined: Jan 2005
Posts: 579
Likes: 0
From: Denton Texas
Fuel Pressure - Fuel Pump
95 LT1
Hard Starting Condition
Intermittent Rough Idle
When the ignition is turned on (not started) the fuel pressure jumps to 44 PSI then reads: 41 PSI
When the engine is running the fuel pressure reads: 36 PSI
When the engine starts to stumble the pressure gauges jumps just a needle width on either side of 36 PSI. Maybe down to 35 PSI.
When the engine is revved the pressure jumps to 44 PSI then drops back to 36 PSI
When the car is turned off then immediately started,it starts with no problem.
Car has been sitting for 15 minutes & no sign of the pressure dropping.
Can I assume the injectors are good?
Is this a sign that my fuel pump is going out?
Fogot to list the error code that I have stored on my original post.
Code 64 - Bank 2 (Right Front) Heated Oxygen Sensor (HO2S) #1 Circuit - Lean Exhaust Indicated
Hard Starting Condition
Intermittent Rough Idle
When the ignition is turned on (not started) the fuel pressure jumps to 44 PSI then reads: 41 PSI
When the engine is running the fuel pressure reads: 36 PSI
When the engine starts to stumble the pressure gauges jumps just a needle width on either side of 36 PSI. Maybe down to 35 PSI.
When the engine is revved the pressure jumps to 44 PSI then drops back to 36 PSI
When the car is turned off then immediately started,it starts with no problem.
Car has been sitting for 15 minutes & no sign of the pressure dropping.
Can I assume the injectors are good?
Is this a sign that my fuel pump is going out?
Fogot to list the error code that I have stored on my original post.
Code 64 - Bank 2 (Right Front) Heated Oxygen Sensor (HO2S) #1 Circuit - Lean Exhaust Indicated
Last edited by DG'sVette; May 22, 2006 at 07:13 PM.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
Your pressure sounds good, assuming it does drop rapidly, or far down.
If it doesn't it means neither the injectors, regulator or FP are leaking. As to the health of the injectors...you should ohm them, warm and cold. And at this point, I wouldn't worry about the fuel pump.
If it doesn't it means neither the injectors, regulator or FP are leaking. As to the health of the injectors...you should ohm them, warm and cold. And at this point, I wouldn't worry about the fuel pump.
Instructor
Joined: May 2006
Posts: 202
Likes: 16
Don't suppose you can get the fuel trim #s??
Ck for vacuum leaks.
Ck for exhaust leaks near or before the sensor.
No test equip? Swap the O2s Rt to Left, clear the code, & run it. When the MIL comes back (With a B1S1 or B1S2 code) you will know if you have a bad sensor or an engine (drivability) problem.
Ck for vacuum leaks.
Ck for exhaust leaks near or before the sensor.
No test equip? Swap the O2s Rt to Left, clear the code, & run it. When the MIL comes back (With a B1S1 or B1S2 code) you will know if you have a bad sensor or an engine (drivability) problem.
Melting Slicks
Joined: Oct 2002
Posts: 3,193
Likes: 1
From: Cincinnati Oh
Sounds to me like your fuel system and all components are working spot on. Everything you said (except the code) sounds normal.
You may want to try other things like checking for vacuum leaks, checking the coolant and oil for contamination, and asking yourself if the oxygen sensor isn't due for replacement? Can you get a scanner to see if it's "lazy?"
Also, sometimes just unplugging the battery can reset the codes and miraculously solve all your problems.
You may want to try other things like checking for vacuum leaks, checking the coolant and oil for contamination, and asking yourself if the oxygen sensor isn't due for replacement? Can you get a scanner to see if it's "lazy?"
Also, sometimes just unplugging the battery can reset the codes and miraculously solve all your problems.
Thread Starter
Pro
Joined: Jan 2005
Posts: 579
Likes: 0
From: Denton Texas
Heres the deal. The hard start is prior to my otpi (MSD Cap & Rotor Only) / waterpump install last week.
The idle problem is new.
I replaced all the vacuum lines except the lower line coming from the cruise control to somewhere behind the break booster. I replaced the TPS & coolant temp sensor as well.
I'm stumped.!
I guess I'll run it down to corvettes of Dallas tomorrow so they can take a look at it.
Could this be a problem with the EGR system?
Also, on the driverside coming from the exhaust manifold, I believe it is part of the EGR system. The pipe comes to a "T", then follow the hose down, there is a small "T", I do not have a hose connected to this "T".
Any ideas on this connection?
Should there be another hose connected here?
If so, where does it run?
The idle problem is new.
I replaced all the vacuum lines except the lower line coming from the cruise control to somewhere behind the break booster. I replaced the TPS & coolant temp sensor as well.
I'm stumped.!
I guess I'll run it down to corvettes of Dallas tomorrow so they can take a look at it.
Could this be a problem with the EGR system?
Also, on the driverside coming from the exhaust manifold, I believe it is part of the EGR system. The pipe comes to a "T", then follow the hose down, there is a small "T", I do not have a hose connected to this "T".
Any ideas on this connection?
Should there be another hose connected here?
If so, where does it run?
Thread Starter
Pro
Joined: Jan 2005
Posts: 579
Likes: 0
From: Denton Texas
How can I check the spark from the OPTI without removing the plugs?
I was thinking about this code 64 (Lean HO2S) sensor. This would be like the passengers side is not getting enought fuel, correct?
I'd like to rule out my decission to only go with the cap & rotor on my initial repairs last week.
I was thinking about this code 64 (Lean HO2S) sensor. This would be like the passengers side is not getting enought fuel, correct?
I'd like to rule out my decission to only go with the cap & rotor on my initial repairs last week.
Last edited by DG'sVette; May 23, 2006 at 10:50 AM.
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
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
I think I would take care of the O2 sensor before continuing. My 95 left front O2 sensor went bad a few years ago. I don't remember hard starting but rough idle and an intermittant miss while driving. When I gave it throttle it would show black smoke out the left muffler. You can switch O2 sensors, should show if the sensor is a problem, if the same then it would be in the circuit to PCM. The hard starting when cold, if the case, could be another problem. Closed loop (O2 sensor sending signal) would be after coolant temp 140 or so... exhaust temp 600* unless heated sensor, it would be sooner.
Thread Starter
Pro
Joined: Jan 2005
Posts: 579
Likes: 0
From: Denton Texas
OK, I replaced (2) O2 sensors. The ones before the cats. Still no luck same conditons.
I took it down to Corvettes of Dallas this morning. I just heard back from them. The fuel pressure regulator is bad according to them so I'm going to pick up the car tomorrow & replace it later this week. They said I need to start there before I can go any futher.
My new question is:
What type of regulator should I buy? Adjustable or OEM?
Who has the best prices for the different options?
I took it down to Corvettes of Dallas this morning. I just heard back from them. The fuel pressure regulator is bad according to them so I'm going to pick up the car tomorrow & replace it later this week. They said I need to start there before I can go any futher.
My new question is:
What type of regulator should I buy? Adjustable or OEM?
Who has the best prices for the different options?