One more Empty Fuel thread...40 min timer repeat
Thread Starter
Instructor
Joined: Sep 2007
Posts: 105
Likes: 0
From: Wichita KS
One more Empty Fuel thread...40 min timer repeat
I have looked at all the other threads and tried most of them, but had a few questions for the forum. I know there are options like top tier fule only, fuel additives to PCM upgrades to mechinal repair.
I have tried the techron and not sure if it is helping or not cause I only get the issue if I drive for a longer period of time. I took my 97 on the road for the first time in a long time and caught a pattern.
From the time I turned the key on until the guage went empty was almost 40 mins to the second. I turn the key off, removed it, and restart and started the timer in the car over. 40 mins later the same thing. I did this 3 times in a row before I got home. Today it is fine as well as long as I dont drive more than 40 minutes.
What is happening every 40 minutes? To timing issues points me to maybe the computer. Since my is 97 I was wondering the the PCM update to make the computer less senstive the the voltage issue is the way to go.
Any thoughts?
I have tried the techron and not sure if it is helping or not cause I only get the issue if I drive for a longer period of time. I took my 97 on the road for the first time in a long time and caught a pattern.
From the time I turned the key on until the guage went empty was almost 40 mins to the second. I turn the key off, removed it, and restart and started the timer in the car over. 40 mins later the same thing. I did this 3 times in a row before I got home. Today it is fine as well as long as I dont drive more than 40 minutes.
What is happening every 40 minutes? To timing issues points me to maybe the computer. Since my is 97 I was wondering the the PCM update to make the computer less senstive the the voltage issue is the way to go.
Any thoughts?
Drifting
Joined: May 2008
Posts: 1,490
Likes: 17
From: Oakville, Ontario
that timing issue at 40 minutes is interesting, love to hear some comments on that. I've got a 1998 and Techron works mighty fine for me as well. I bought a case (six) on sale in Niagara Falls last week, so should last me for a couple of years.
Pro
Joined: Feb 2004
Posts: 718
Likes: 1
From: barrie ontario
I have looked at all the other threads and tried most of them, but had a few questions for the forum. I know there are options like top tier fule only, fuel additives to PCM upgrades to mechinal repair.
I have tried the techron and not sure if it is helping or not cause I only get the issue if I drive for a longer period of time. I took my 97 on the road for the first time in a long time and caught a pattern.
From the time I turned the key on until the guage went empty was almost 40 mins to the second. I turn the key off, removed it, and restart and started the timer in the car over. 40 mins later the same thing. I did this 3 times in a row before I got home. Today it is fine as well as long as I dont drive more than 40 minutes.
What is happening every 40 minutes? To timing issues points me to maybe the computer. Since my is 97 I was wondering the the PCM update to make the computer less senstive the the voltage issue is the way to go.
Any thoughts?
I have tried the techron and not sure if it is helping or not cause I only get the issue if I drive for a longer period of time. I took my 97 on the road for the first time in a long time and caught a pattern.
From the time I turned the key on until the guage went empty was almost 40 mins to the second. I turn the key off, removed it, and restart and started the timer in the car over. 40 mins later the same thing. I did this 3 times in a row before I got home. Today it is fine as well as long as I dont drive more than 40 minutes.
What is happening every 40 minutes? To timing issues points me to maybe the computer. Since my is 97 I was wondering the the PCM update to make the computer less senstive the the voltage issue is the way to go.
Any thoughts?
If I restart the car it will last for another 40 mins.
Tried techron and it not work.
Does anyone now what the PCM upgrade is and what changes are made?
I have HPtuners and there are a few tables relating to the sender and gauge that could be modified.
Melting Slicks
Joined: Feb 2007
Posts: 3,266
Likes: 8
From: Indian Rocks Beach FL
St. Jude Donor '08-'09-'10
I have the same problem and posted about it some time back.
http://forums.corvetteforum.com/c5-t...e-problem.html
I haven't tried the firmware fix yet.
http://forums.corvetteforum.com/c5-t...e-problem.html
I haven't tried the firmware fix yet.
Instructor
Joined: Jun 2008
Posts: 103
Likes: 0
From: Vero Beach Fl
Same Problem
I have looked at all the other threads and tried most of them, but had a few questions for the forum. I know there are options like top tier fule only, fuel additives to PCM upgrades to mechinal repair.
I have tried the techron and not sure if it is helping or not cause I only get the issue if I drive for a longer period of time. I took my 97 on the road for the first time in a long time and caught a pattern.
From the time I turned the key on until the guage went empty was almost 40 mins to the second. I turn the key off, removed it, and restart and started the timer in the car over. 40 mins later the same thing. I did this 3 times in a row before I got home. Today it is fine as well as long as I dont drive more than 40 minutes.
What is happening every 40 minutes? To timing issues points me to maybe the computer. Since my is 97 I was wondering the the PCM update to make the computer less senstive the the voltage issue is the way to go.
Any thoughts?
I have tried the techron and not sure if it is helping or not cause I only get the issue if I drive for a longer period of time. I took my 97 on the road for the first time in a long time and caught a pattern.
From the time I turned the key on until the guage went empty was almost 40 mins to the second. I turn the key off, removed it, and restart and started the timer in the car over. 40 mins later the same thing. I did this 3 times in a row before I got home. Today it is fine as well as long as I dont drive more than 40 minutes.
What is happening every 40 minutes? To timing issues points me to maybe the computer. Since my is 97 I was wondering the the PCM update to make the computer less senstive the the voltage issue is the way to go.
Any thoughts?
Very interesting. I have the exact same problem on my 98. I have tried bottles of Techron off and on, maybe 5 times. I can still set my clock by it at 40 - 45 minutes. It doesn't matter whether it is highway driving or around town, it's all about the time. It will be great if someone comes up with the fix this time!
Thread Starter
Instructor
Joined: Sep 2007
Posts: 105
Likes: 0
From: Wichita KS
I agree with you....I can set the clock by it. I have and will continue to try techron but there is something to the 40 min thing. I am a computer programmer by trade and try to look at the logic of things. I can see sulfur could cause some issues by it sounds like a system/computer issue because of the 40 min clock.
What does the computer do every 40 minutes?
What does the computer do every 40 minutes?
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Tech Contributor
Joined: Dec 2003
Posts: 19,384
Likes: 87
From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
Interesting. Thats the first time I've heard of that one and it's got to be significant that its 97/98s that are affected.
Again Techron fixed my 02 but it only ever happened once so I caught it early. It seems like you don't have the regular sulfur issue.
Again Techron fixed my 02 but it only ever happened once so I caught it early. It seems like you don't have the regular sulfur issue.
Advanced
Joined: Oct 2008
Posts: 74
Likes: 0
From: Canton Michigan
I just started having fuel gauge problems as well. I have been doing the Techron thing for about a week to see if it works but it seems to be a little different then the normal issues. I drove the car around a bit and my gauge was at 1/2 and then all the sudden it went dead. I stopped at a gas station an filled up and the car took 16 gallons to fill and im pretty sure thats way more then half a tank. When i started my car the gas gauge stayed at empty till i put about 40 miles on it then it shot to full and stayed full another 40 miles(it should NOT say full after driving 80miles) then slowly started decreasing. It all seemed normal until it hit 1/2 tank again and it went totally dead again. I fill it up when it goes dead and it takes almost exactly 40 miles for it to flip to full again. Its not exactly the same as your problem but its so confusing that is seems to do the same thing at the exact same time
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
sound like a module has a "clock" battery that is dead and the computer or bcm is referencing a "refresh" action every 40 minutes. Without test power, the gauge goes dead?
Last edited by coupeguy2001; Jun 4, 2009 at 10:24 AM.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
I remember reading in the manuals about a time function where the car draws fuel from the left tank or something and after a specific minute time, it then commands the right tank to transfer fuel. I no longer have the manuals as I gave the car and manuals to my son. This happened to me as well. It stopped after I got the firmware updated via the dealer.
Safety Car
Joined: Jan 2001
Posts: 4,385
Likes: 689
From: Boise ID
I remember reading in the manuals about a time function where the car draws fuel from the left tank or something and after a specific minute time, it then commands the right tank to transfer fuel. I no longer have the manuals as I gave the car and manuals to my son. This happened to me as well. It stopped after I got the firmware updated via the dealer.
Note: The 1997 through 2002 and early built 2003 Corvettes (Starting on November 25, 2002 with vehicle identification number 35111542, all Corvettes and all 2004 XLR use the FFS fuel system) without the FFS system did not have a secondary regulator which prevents the siphoning of fuel (LH to RH) after the vehicle is turned off. The siphoning could balance the fuel such that, at start-up, the sender voltages could be similar. That is why there is a 40 minute timer on the P1431 DTC on these vehicles to allow the fuel to transfer to the LH tank after start-up.
Advanced
Joined: Apr 2003
Posts: 57
Likes: 0
From: Greenville SC
This thread is interesting. I also have been having fuel empty problems on my 98 for the last 4 years. I have been using texron and it seemed to work untill this last week. Now I have a new problem. When I fill the car up it only reads about 7/8 full. I drive for about 40 min. and gurge goes to empty. I stoped about 2 hours later and restarted the car and the gauge worked, I think, not sure the level showen was right. I am now thinking of removing the senders. How bad a job is it. Special tools needed? Repace parts or just clean senders? I am getting tired on refueling using the trip meter.
Intermediate
Joined: Oct 2005
Posts: 41
Likes: 2
From: Bedford NH
I have the same exact problem with my 97. When the tank is filled the gauge only goes to about 7/8 of a tank. The gauge will work fine for about 4- 45 minutes and then it's dead. I have to stop and restart the car and then the gauge usually, but not always, starts working again. I've tried Techron but that hasn't helped.
Burning Brakes
Joined: Aug 2008
Posts: 1,058
Likes: 90
From: Indiana
I have the exact same problem and several doses of techron has not helped. But now the problem is that the last time I drove 40 minutes and the gauge died, It hasnt started working right again. When I start the car now the gauge works for about 10 seconds and the gauge dies. Is this a transfer problem? The last time I filled up the pump kept clicking off on me. There must be a way to fix this without breaking the bank.
Thread Starter
Instructor
Joined: Sep 2007
Posts: 105
Likes: 0
From: Wichita KS
I have some some other "empty fuel check engine" threads that talk about it and it is way to complex for me but there are some decent information available. I think I remember reading that it is about a 800 repair from dealer but most folks believe that it will still happen even after a repair.
I also read somewhere that the fix from the dealer for the firmware was the make the computer less sensitive to the voltage changes in the tank. It may or may not work, but if you have not had any updates done you make get the fuel cutoff fix which sucks as well.
Since mine is one of the 40 mins then empty...it does sound like some sort of timer or something. Any other ideas appreciated? Oh, and for mine. I can immediatley pull over, turn car off, pull key, start and I am back to normal reading.
I also read somewhere that the fix from the dealer for the firmware was the make the computer less sensitive to the voltage changes in the tank. It may or may not work, but if you have not had any updates done you make get the fuel cutoff fix which sucks as well.
Since mine is one of the 40 mins then empty...it does sound like some sort of timer or something. Any other ideas appreciated? Oh, and for mine. I can immediatley pull over, turn car off, pull key, start and I am back to normal reading.
