FI-TECH needed help PLEASE DESPERATE
Thread Starter
Racer
Joined: Jul 2017
Posts: 399
Likes: 115
From: chico ca
FI-TECH needed help PLEASE DESPERATE
I have 68 327 stock motor. Decided to get fi-tech, probably the worst decision of my life. Here is what I have and my problem. There has to be somebody out there who has gone through this and knows what my problem is. It sure runs great until it doesn't start. LOL Why did I make a change from carburator? the carb was bad thought it seemed like a great idea.
Voltage is perfect never goes below 11.4 when cranking. New HEI distributor and coil seems to be working fine. Spark is happening during cranking.
ECU seems to be fine because they sent me a new unit and the exact same problem continues to happen....no change at all with new unit.
Fuel gauge on the "ittle dashboard" says it is 99% when running (monitor)
All other setting are on default settings.
No fault codes except the fan 1 because I forgot to turn it off. I have no electric fans.
Any help would be greatly appreciated. I really want this to work. I have to much time and money invested.
- Starts perfect when cold. Can drive anywhere for any amount of time and the car runs great.
- Once I turn the car off I can start it easily 50 times if I don't let car sit.
- PROBLEM: If I wait 5 min. or more the car will not start until the car cools all the way back down. (I have had a timer numerous times and 5 min seems to be the consistant failure time)
- How to solve problem....Carry around a can of starting fluid and spray a ton down unit, push gas pedal to floor and its starts up and will run great.
Voltage is perfect never goes below 11.4 when cranking. New HEI distributor and coil seems to be working fine. Spark is happening during cranking.
ECU seems to be fine because they sent me a new unit and the exact same problem continues to happen....no change at all with new unit.
Fuel gauge on the "ittle dashboard" says it is 99% when running (monitor)
All other setting are on default settings.
No fault codes except the fan 1 because I forgot to turn it off. I have no electric fans.
Any help would be greatly appreciated. I really want this to work. I have to much time and money invested.
Le Mans Master
Joined: May 2003
Posts: 8,877
Likes: 3,556
From: Fernandina Beach FL
2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
I'm wondering what kind of fuel system upgrade- vapor lock sounds like the issue. If it starts with starter fluid- it's not getting fuel...
Have a fuel pressure gauge on the line anywhere?
External pump? Surge Tank?
Have a fuel pressure gauge on the line anywhere?
External pump? Surge Tank?
Thread Starter
Racer
Joined: Jul 2017
Posts: 399
Likes: 115
From: chico ca
FI tech
I have the external pump and filters that come with system. There is no fuel pressure gauge except that when it gets started it reads the pump is working on the control module screen. I was thinking fuel pump issues but fI-tech says if it was bad it would always run bad. The fact that it runs so good ( when running) I guess I believe them?? I am hoping someone out there has had a similar problem and it is just an adjument.
Le Mans Master
Joined: May 2003
Posts: 8,877
Likes: 3,556
From: Fernandina Beach FL
2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
But when it's not running/starting- maybe the pump is NOT working.
Modern fuel injection systems -
when you turn the key to ignition- the fuel pump kicks on for a couple seconds to prime the pump and squirt fuel from the injectors- just like you are having to do with starter fluid.
To me- and I'm not at all familiar with FI tech and how they initialize starting- but sounds like you turn off the car- the fuel is hot and the pressure bleeds down (could be a bad injector-bad fuel pump) and evaporates after a few minutes.
I'm just telling you it's an obvious fuel issue- first thing I would do is put a fuel pressure meter on it-
Richard
Last edited by Richard454; Aug 31, 2019 at 11:08 PM.
Le Mans Master
Joined: May 2003
Posts: 8,877
Likes: 3,556
From: Fernandina Beach FL
2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
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
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
do you pause breifly wiht the key on before you crank it (building fuel pressure)?
That would be a bummer to find EFI doesnt solve the hot restart issue that carbs can have with ethanol gas.
That would be a bummer to find EFI doesnt solve the hot restart issue that carbs can have with ethanol gas.
Race Director
Joined: Jul 2015
Posts: 13,082
Likes: 3,399
From: SW Florida.
Run a 12 volt wire directly to the fuel pump. Add a switch. When car does not start, flip switch. Starts up? Now we gotta figure out the things that fire the pump. It could be that whatever fires it when cold is shut off cuz it is warm, and the oil pressure switch that keeps it on hasn't kicked in yet. So there has to be a starter or starter circuit relay that also fires the pump that is not doing it's job.
Drifting
Joined: Aug 2015
Posts: 1,939
Likes: 477
From: NSW, Australia
C3 of Year Finalist (track prepared) 2019
When you turn the key to "on" for a hot start (before turning to start), look down the barrels of the throttle body. You should hear the pump prime, and see fuel squirt into the barrels. If fuel does squirt in, make certain that you have good spark during cranking. You either don't have fuel, or you don't have good spark, or possibly it is actually flooding, but that seems unlikely given it will hot start fine until 5 minutes has passed. Shouldn't be too difficult to work out which. I assume that your handheld controller continues to work/respond/show values correctly while the car won't start?
Melting Slicks
Joined: Oct 2012
Posts: 2,156
Likes: 273
From: Dunedin NZ.
Just throwing this out there, what if it is just a lack of oxygen in the intake manifold caused by the fuel in the intake manifold evaporating? You need air, fuel and spark to make the engine run, if the oxygen in the manifold has been driven out by the evaporating fuel this mixture won't ignite. Seems you have spark and fuel. When next it is sitting in this condition take off the air cleaner hold open the throttle and blow some air into the intake as a test.Kinda mouth to mouth resuscitation for engines:-)
Thread Starter
Racer
Joined: Jul 2017
Posts: 399
Likes: 115
From: chico ca
Vented locking cap. I just had someone turn key, heard pump and saw fuel squirt in. Starts fine. Let it idle for 10 min and shut it down. Will wait five min and go see if the squirt of fuel is the same or maybe none at all? To be continued! Thanks for all the advice. I am trying one thing at a time.
Melting Slicks
Joined: Sep 2010
Posts: 3,306
Likes: 697
Not familiar with FI Tech but have a number of LS swaps under my belt.
Not any kind of a expert but here's my .02.
So get the car warmed up completely but sitting in you driveway or garage. Trying to duplicate the non-start conditions. If you don't have the fitting suggested above just disconnect the fuel line dumping it to a safe container to see if you have fuel pressure when you try to restart. If no fuel it's the fuel pump (I agree with above most electric fuel pumps either work or they fail completely) or the signal to the fuel pump 12 volt is not getting there. On LS engines the ECM looks for crank rotation to keep the fuel pump relay energized. How does the FI Tech determine to turn on the fuel pump on or not? I'm just suggesting the ECM might be not be getting the "turn on fuel pump" signal when somewhat warm.
Could it be a electric issue instead of strictly fuel?
Not any kind of a expert but here's my .02.
So get the car warmed up completely but sitting in you driveway or garage. Trying to duplicate the non-start conditions. If you don't have the fitting suggested above just disconnect the fuel line dumping it to a safe container to see if you have fuel pressure when you try to restart. If no fuel it's the fuel pump (I agree with above most electric fuel pumps either work or they fail completely) or the signal to the fuel pump 12 volt is not getting there. On LS engines the ECM looks for crank rotation to keep the fuel pump relay energized. How does the FI Tech determine to turn on the fuel pump on or not? I'm just suggesting the ECM might be not be getting the "turn on fuel pump" signal when somewhat warm.
Could it be a electric issue instead of strictly fuel?
Le Mans Master
Joined: May 2003
Posts: 8,877
Likes: 3,556
From: Fernandina Beach FL
2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
It sounds like you have covered a lot of the bases...
If the injectors are leaking down- and not spraying correctly- that could be an issue.
On one of the fuel injection conversion I did-
I had a bad o ring in the regulator- injectors were just sort of dribbling as there was not enough pressure- causing a no start. I changed the pulse time of the injectors - back and forth -up and down. Then I misted the intake with gas and it fired up....
I'd definitely get a pressure meter there and see what's going on. Then you can see what happens after 5 minutes- if the pressure drops all the way down- then you'll know what to chase. Plus you'll be able to see the pressure at a cold start.
Like I said the injector can be turning on- pump on- but not at the right pressure- you can get a raw gas puddling in the intake- not good on a hot engine.
Randomly guessing- good luck!
Richard
If the injectors are leaking down- and not spraying correctly- that could be an issue.
On one of the fuel injection conversion I did-
I had a bad o ring in the regulator- injectors were just sort of dribbling as there was not enough pressure- causing a no start. I changed the pulse time of the injectors - back and forth -up and down. Then I misted the intake with gas and it fired up....
I'd definitely get a pressure meter there and see what's going on. Then you can see what happens after 5 minutes- if the pressure drops all the way down- then you'll know what to chase. Plus you'll be able to see the pressure at a cold start.
Like I said the injector can be turning on- pump on- but not at the right pressure- you can get a raw gas puddling in the intake- not good on a hot engine.
Randomly guessing- good luck!
Richard
Thread Starter
Racer
Joined: Jul 2017
Posts: 399
Likes: 115
From: chico ca
Just did a test today when hot. Car always kicks over like it is going to start than dies. When I turn on key I hear pump but no gas at all. I think the first little kick is what might have been left over. I have turned the key numerous times activating the fuel pump with no gas in the throttle body.
1. Ecu bad and not allowing gas to come in. Doubt this because this is my second system that did exact same thing.
2. Fuel pump making noise but not pressure?
3. Adjust cranking 170 degrees numbers through hand held to dump more fuel on hot start.
4. Heat soak or vapor lock.
I guess first step step to get gauge and see what fuel pressure is then go from there.
1. Ecu bad and not allowing gas to come in. Doubt this because this is my second system that did exact same thing.
2. Fuel pump making noise but not pressure?
3. Adjust cranking 170 degrees numbers through hand held to dump more fuel on hot start.
4. Heat soak or vapor lock.
I guess first step step to get gauge and see what fuel pressure is then go from there.