63 FI idle problem
Thread Starter
Instructor
Joined: Jun 2007
Posts: 248
Likes: 0
63 FI idle problem
Hi..... I need more help with my 63 FI unit.
I now have it installed and running. With help from this forum.......... my previous problem was resolved by replacing my cranking valve because it was running too rich.
Now after engine warms up (180 degrees) and fast idle screw disengaged, it seems to run well over 1500 RPM but it does not idle below 900/1000 RPM without dying after a few seconds (acts like its not getting fuel). I was able to adjust idle fuel screw all the way in (car running) without any affect..... which does not seem right to me. Idle speed screw now adjusted to idle at about 1200 RPM.
Would sure appreciate some tips on where to begin isolating this problem.
Thanks walt
I now have it installed and running. With help from this forum.......... my previous problem was resolved by replacing my cranking valve because it was running too rich.
Now after engine warms up (180 degrees) and fast idle screw disengaged, it seems to run well over 1500 RPM but it does not idle below 900/1000 RPM without dying after a few seconds (acts like its not getting fuel). I was able to adjust idle fuel screw all the way in (car running) without any affect..... which does not seem right to me. Idle speed screw now adjusted to idle at about 1200 RPM.
Would sure appreciate some tips on where to begin isolating this problem.
Thanks walt
Last edited by zuke6562; Nov 22, 2008 at 10:38 PM.
Le Mans Master
Joined: Feb 1999
Posts: 5,841
Likes: 376
From: Mobile AL
I would be very surprised if only one problem was keeping your engine from idling at 800 rpm. Before even looking at the FI unit for problems, I would ensure that the engine had an appropriate cam grind for fuel injection, all eight cylinders were making good compression, and that the valve lash was set correctly.
I would then check the things listed below after convincing myself that the FI unit contained only stock, matched (7375 series) components.
1. ignition spark timing.
2. unit calibration settings.
3. spider hub condition.
4. axle link balance.
5. condition of 8 nozzles.
6. gear pump condition.
7. type / condition of gasoline in tank.
8. crankcase vent system condition.
I would then check the things listed below after convincing myself that the FI unit contained only stock, matched (7375 series) components.
1. ignition spark timing.
2. unit calibration settings.
3. spider hub condition.
4. axle link balance.
5. condition of 8 nozzles.
6. gear pump condition.
7. type / condition of gasoline in tank.
8. crankcase vent system condition.
Thread Starter
Instructor
Joined: Jun 2007
Posts: 248
Likes: 0
Hi..... I need more help with my 63 FI unit.
I now have it installed and running. With help from this forum.......... my previous problem was resolved by replacing my cranking valve because it was running too rich.
Now after engine warms up (180 degrees) and fast idle screw disengaged, it seems to run well over 1500 RPM but it does not idle below 900/1000 RPM without dying after a few seconds (acts like its not getting fuel). I was able to adjust idle fuel screw all the way in (car running) without any affect..... which does not seem right to me. Idle speed screw now adjusted to idle at about 1200 RPM.
Would sure appreciate some tips on where to begin isolating this problem.
Thanks walt
I now have it installed and running. With help from this forum.......... my previous problem was resolved by replacing my cranking valve because it was running too rich.
Now after engine warms up (180 degrees) and fast idle screw disengaged, it seems to run well over 1500 RPM but it does not idle below 900/1000 RPM without dying after a few seconds (acts like its not getting fuel). I was able to adjust idle fuel screw all the way in (car running) without any affect..... which does not seem right to me. Idle speed screw now adjusted to idle at about 1200 RPM.
Would sure appreciate some tips on where to begin isolating this problem.
Thanks walt
Before I put this FI unit on I had a holly carb on it for several years. To try and install the FI unit in increments..... I installed the FI dist and ran it to make sure it was running ok. So I feel ok about the dist and its settings. Only after I was satisfied did I begin to install the FI unit.
Will keep u guys informed as I progress on my check list. Thanks again........
Last edited by zuke6562; Nov 23, 2008 at 02:18 PM. Reason: add color
Pro
Joined: Feb 2005
Posts: 564
Likes: 1
From: Saint George Utah
It took me 10 years of frustration to get my 63 FI to idle right. Tried all the obvious stuff like vacuum leaks, another new vacuum diaphram, etc. My solution was to enrichen the idle stop (not the idle screw) and to time the engine by ear rather than paying too much attention to the timing marks. Then you can adjust the idle misture and idle speed screws accordingly. (I assume you've already confirmed your choke is releasing all the way.)
Thread Starter
Instructor
Joined: Jun 2007
Posts: 248
Likes: 0
It took me 10 years of frustration to get my 63 FI to idle right. Tried all the obvious stuff like vacuum leaks, another new vacuum diaphram, etc. My solution was to enrichen the idle stop (not the idle screw) and to time the engine by ear rather than paying too much attention to the timing marks. Then you can adjust the idle misture and idle speed screws accordingly. (I assume you've already confirmed your choke is releasing all the way.)
Race Director
Joined: Feb 2007
Posts: 15,468
Likes: 8,948
From: northern california
C2 of Year Finalist (track prepared) 2019
Hi Troy...... what do u mean by enrichen the idle stop ??? The choke stays about 3/4 closed even at 190 degrees. It was opening all the way but because it acted like it was not getting enough gas..... I adjusted the choke to be richer..... but made sure the idle stop was not engaged.. Thanks for the info Aloha Walt
Let's start with first principles:
1. At idle, such as it is, how much manifold vacuum does your engine produce?
2. Your choke is adjusted too rich. And your enrichening of it is the wrong approach to solving an idle fuel problem, if that's what's going on. I'd reset it so the text on the cover is right side up and approximately level and then resume troubleshooting the real problem.
3. Do not adjust the set screws on the Fuel Meter as a means of fixing an idle problem. That's not what they are for. However, just for grins, can you make and post a photograph of how they are presently adjusted?
Jim
Le Mans Master
Joined: Feb 1999
Posts: 5,841
Likes: 376
From: Mobile AL
You are a bold man, Lockwood. I admit that I can't understand the tech info in this thread. I'm still trying to identify the idle stop on a 7375 unit.
After I learn how to adjust the idle stop, I'm going to look into engine timing "by ear". For years I've been setting timing with a light "by eye"! I've never even tried to use my other God-given senses.
After I learn how to adjust the idle stop, I'm going to look into engine timing "by ear". For years I've been setting timing with a light "by eye"! I've never even tried to use my other God-given senses.
Race Director
Joined: Feb 2007
Posts: 15,468
Likes: 8,948
From: northern california
C2 of Year Finalist (track prepared) 2019
You are a bold man, Lockwood. I admit that I can't understand the tech info in this thread. I'm still trying to identify the idle stop on a 7375 unit.
After I learn how to adjust the idle stop, I'm going to look into engine timing "by ear". For years I've been setting timing with a light "by eye"! I've never even tried to use my other God-given senses.
After I learn how to adjust the idle stop, I'm going to look into engine timing "by ear". For years I've been setting timing with a light "by eye"! I've never even tried to use my other God-given senses.
Bravery, certainly in my case, has nothing to do with it.
Jim
Last edited by jim lockwood; Nov 26, 2008 at 08:20 PM.
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
Pro
Joined: Feb 2005
Posts: 564
Likes: 1
From: Saint George Utah
Hi Troy...... what do u mean by enrichen the idle stop ??? The choke stays about 3/4 closed even at 190 degrees. It was opening all the way but because it acted like it was not getting enough gas..... I adjusted the choke to be richer..... but made sure the idle stop was not engaged.. Thanks for the info Aloha Walt
Thread Starter
Instructor
Joined: Jun 2007
Posts: 248
Likes: 0
Walt,
Let's start with first principles:
1. At idle, such as it is, how much manifold vacuum does your engine produce?
2. Your choke is adjusted too rich. And your enrichening of it is the wrong approach to solving an idle fuel problem, if that's what's going on. I'd reset it so the text on the cover is right side up and approximately level and then resume troubleshooting the real problem.
3. Do not adjust the set screws on the Fuel Meter as a means of fixing an idle problem. That's not what they are for. However, just for grins, can you make and post a photograph of how they are presently adjusted?
Jim
Let's start with first principles:
1. At idle, such as it is, how much manifold vacuum does your engine produce?
2. Your choke is adjusted too rich. And your enrichening of it is the wrong approach to solving an idle fuel problem, if that's what's going on. I'd reset it so the text on the cover is right side up and approximately level and then resume troubleshooting the real problem.
3. Do not adjust the set screws on the Fuel Meter as a means of fixing an idle problem. That's not what they are for. However, just for grins, can you make and post a photograph of how they are presently adjusted?
Jim
I am thinking that I should take the FI unit off the car and set it up on a jig to see if all the nozzles work as they should before I go any further. What confuses me is that, when I first started the car up..... it worked well idling at between 800-850. The next day it stated blowing black smoke (fuel). I changed the cranking valve and although it ran ...it never worked as it did the first day. Seem like it getting worst every time I try to work it..... to a point where I have to pump the accelerator to keep it going.....
Anyway.... thanks for your help...... Aloha walt
PS.... if I decide to have it redone again (it was done by Jack Podell approximately 10 years ago... but never installed) what is the turnaround time and cost I can expect today??
Thread Starter
Instructor
Joined: Jun 2007
Posts: 248
Likes: 0
Walt,
Let's start with first principles:
1. At idle, such as it is, how much manifold vacuum does your engine produce?
2. Your choke is adjusted too rich. And your enrichening of it is the wrong approach to solving an idle fuel problem, if that's what's going on. I'd reset it so the text on the cover is right side up and approximately level and then resume troubleshooting the real problem.
3. Do not adjust the set screws on the Fuel Meter as a means of fixing an idle problem. That's not what they are for. However, just for grins, can you make and post a photograph of how they are presently adjusted?
Jim
Let's start with first principles:
1. At idle, such as it is, how much manifold vacuum does your engine produce?
2. Your choke is adjusted too rich. And your enrichening of it is the wrong approach to solving an idle fuel problem, if that's what's going on. I'd reset it so the text on the cover is right side up and approximately level and then resume troubleshooting the real problem.
3. Do not adjust the set screws on the Fuel Meter as a means of fixing an idle problem. That's not what they are for. However, just for grins, can you make and post a photograph of how they are presently adjusted?
Jim