Fuel Tank Crossover install
01-22-2012, 02:38 PM
#1
Pro
Thread Starter
Fuel Tank Crossover install
Any creative solutions for installing the crossover? I can't keep the siphon tubes straight:
I get the inner tubes all setup and lined up....get one side in, then when I bend the crossover tube, the inner tubes either twist so that they are not locked into their slots, or the whole plastic sleeve pops out of the metal tube!!! Get them all lined up again, and same issue.
The main issue seems to be the inner plastic tubes are ROCK hard....might as well be steel tubing and ANY bending of the steel main tube to get it in the second tank pops them out.
Was thinking of cutting the centers out of both tubes and putting some soft fuel line in there to allow bending the metal tube.
Any ideas/experience....or am I just doing it wrong!?!?
I get the inner tubes all setup and lined up....get one side in, then when I bend the crossover tube, the inner tubes either twist so that they are not locked into their slots, or the whole plastic sleeve pops out of the metal tube!!! Get them all lined up again, and same issue.
The main issue seems to be the inner plastic tubes are ROCK hard....might as well be steel tubing and ANY bending of the steel main tube to get it in the second tank pops them out.
Was thinking of cutting the centers out of both tubes and putting some soft fuel line in there to allow bending the metal tube.
Any ideas/experience....or am I just doing it wrong!?!?
01-22-2012, 03:32 PM
#2
I suspect if you closely inspect the ends you will find that a very small retention tab is broken, either on the lines or the steel sleeve. I fought this in the summer while installing an upgraded fuel pump.
Twisting the lines with the locking collar off is what breaks the tabs. Once the collar is off, you have to pull straight out, very slowly, not to break the tabs (very hard to do).
When we tried to put everything back together the ends would twist in, and feel like they locked, but would not stay when I bent the steel sleeve to make the connection. We tried everything, including flexable fuel hose, and nothing worked. Finally, after several failed attemps and a few choice words, we found the broken tabs (they are hard to see).
I bought a new crossover unit, slicked all of the male and female fittings (and o-rings) up with lithium grease, attached the driver's side and was very careful to bend the sleeve as little as possible. Everything worked.
This, and the slave cylinder assembly, are very poorly designed systems and if the engineers had to work on them they would be different.
BTW, make sure all of the o-rings are in place before you button everything up.
Good Luck
Twisting the lines with the locking collar off is what breaks the tabs. Once the collar is off, you have to pull straight out, very slowly, not to break the tabs (very hard to do).
When we tried to put everything back together the ends would twist in, and feel like they locked, but would not stay when I bent the steel sleeve to make the connection. We tried everything, including flexable fuel hose, and nothing worked. Finally, after several failed attemps and a few choice words, we found the broken tabs (they are hard to see).
I bought a new crossover unit, slicked all of the male and female fittings (and o-rings) up with lithium grease, attached the driver's side and was very careful to bend the sleeve as little as possible. Everything worked.
This, and the slave cylinder assembly, are very poorly designed systems and if the engineers had to work on them they would be different.
BTW, make sure all of the o-rings are in place before you button everything up.
Good Luck
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c6txvette (03-22-2023)
01-22-2012, 05:39 PM
#3
Pro
Thread Starter
I suspect if you closely inspect the ends you will find that a very small retention tab is broken, either on the lines or the steel sleeve. I fought this in the summer while installing an upgraded fuel pump.
Twisting the lines with the locking collar off is what breaks the tabs. Once the collar is off, you have to pull straight out, very slowly, not to break the tabs (very hard to do).
When we tried to put everything back together the ends would twist in, and feel like they locked, but would not stay when I bent the steel sleeve to make the connection. We tried everything, including flexable fuel hose, and nothing worked. Finally, after several failed attemps and a few choice words, we found the broken tabs (they are hard to see).
I bought a new crossover unit, slicked all of the male and female fittings (and o-rings) up with lithium grease, attached the driver's side and was very careful to bend the sleeve as little as possible. Everything worked.
This, and the slave cylinder assembly, are very poorly designed systems and if the engineers had to work on them they would be different.
BTW, make sure all of the o-rings are in place before you button everything up.
Good Luck
Twisting the lines with the locking collar off is what breaks the tabs. Once the collar is off, you have to pull straight out, very slowly, not to break the tabs (very hard to do).
When we tried to put everything back together the ends would twist in, and feel like they locked, but would not stay when I bent the steel sleeve to make the connection. We tried everything, including flexable fuel hose, and nothing worked. Finally, after several failed attemps and a few choice words, we found the broken tabs (they are hard to see).
I bought a new crossover unit, slicked all of the male and female fittings (and o-rings) up with lithium grease, attached the driver's side and was very careful to bend the sleeve as little as possible. Everything worked.
This, and the slave cylinder assembly, are very poorly designed systems and if the engineers had to work on them they would be different.
BTW, make sure all of the o-rings are in place before you button everything up.
Good Luck
01-23-2012, 09:48 AM
#6
Safety Car
The C5 tanks use a big rubber hose. The "new" C6 fuel system was put into late production 2003 C5s and 2004s. GM had a rash of cross-over pipe failures and had a TSB out on it. The cross-over coupler on the driver's side would most often crack. They suspect it was from the lack of any ability to bend.
Not sure if you can just get the rubber tube from the C5 for your application? I don't have any pictures of the actual tube, but it just slips over the blue parts fo the tanks and is secured whith hose clamps.
Not sure if you can just get the rubber tube from the C5 for your application? I don't have any pictures of the actual tube, but it just slips over the blue parts fo the tanks and is secured whith hose clamps.
01-23-2012, 11:54 AM
#7
The C5 tanks use a big rubber hose. The "new" C6 fuel system was put into late production 2003 C5s and 2004s. GM had a rash of cross-over pipe failures and had a TSB out on it. The cross-over coupler on the driver's side would most often crack. They suspect it was from the lack of any ability to bend.
Not sure if you can just get the rubber tube from the C5 for your application? I don't have any pictures of the actual tube, but it just slips over the blue parts fo the tanks and is secured whith hose clamps.
Not sure if you can just get the rubber tube from the C5 for your application? I don't have any pictures of the actual tube, but it just slips over the blue parts fo the tanks and is secured whith hose clamps.
01-23-2012, 12:09 PM
#8
Safety Car
I figured.... my 2003 vert was a late production with the new cross-over tube. It has a turn-lock setup on each end.
I wasn't sure if he could make it work somehow.
I wasn't sure if he could make it work somehow.
01-23-2012, 01:44 PM
#9
Pro
Thread Starter
So, you squeezed the metal tube in the center so you could connect the inner tubes by hand and then stretched the metal tube out and connected? That sounds feasible for my setup.....any pics or description of how you did that?
Thanks.
01-23-2012, 04:28 PM
#10
Was this on a C6? I would think if you compressed the tube, the two lines in it would stay rigid and break the plastic mounting points on one end.
01-23-2012, 07:26 PM
#11
Pro
Thread Starter
Well....I got it in!!!
After looking at it a lot and playing with it, it stayed in position while out of the car. Was thinking I would stick the end that twisted easily in first to set that, then worry about the end that popped out. Thinking I maybe could set the inner tubes in first, actually seeing them, then work the steel tube on. But, miraculously, it all stayed together and allowed me to do it.
Now I just have to lose sleep wondering if it is right, and wont know till it hits the track I suppose.....firing it up and running it won't test those inner tubes...
Hehe...
After looking at it a lot and playing with it, it stayed in position while out of the car. Was thinking I would stick the end that twisted easily in first to set that, then worry about the end that popped out. Thinking I maybe could set the inner tubes in first, actually seeing them, then work the steel tube on. But, miraculously, it all stayed together and allowed me to do it.
Now I just have to lose sleep wondering if it is right, and wont know till it hits the track I suppose.....firing it up and running it won't test those inner tubes...
Hehe...
01-23-2012, 07:53 PM
#12
Well....I got it in!!!
After looking at it a lot and playing with it, it stayed in position while out of the car. Was thinking I would stick the end that twisted easily in first to set that, then worry about the end that popped out. Thinking I maybe could set the inner tubes in first, actually seeing them, then work the steel tube on. But, miraculously, it all stayed together and allowed me to do it.
Now I just have to lose sleep wondering if it is right, and wont know till it hits the track I suppose.....firing it up and running it won't test those inner tubes...
Hehe...
After looking at it a lot and playing with it, it stayed in position while out of the car. Was thinking I would stick the end that twisted easily in first to set that, then worry about the end that popped out. Thinking I maybe could set the inner tubes in first, actually seeing them, then work the steel tube on. But, miraculously, it all stayed together and allowed me to do it.
Now I just have to lose sleep wondering if it is right, and wont know till it hits the track I suppose.....firing it up and running it won't test those inner tubes...
Hehe...
01-23-2012, 08:54 PM
#13
Pro
Thread Starter
The way to test it is to put fuel in it. We turned the pump on manually and checked fuel pressure at the test fitting of the injector plumbing. I would do this before you put everything together. We did this first and found out the tube inside the crossover came loose. We had 15 psi of fuel instead of 60 because of the difficulty of connecting the crossover tube on the c6. I will post up some pics of the tool we made. It is duel purpose. It compresses and expands the tube.
Was gonna do that anyway to test all my new AN lines and connections before putting it all under wraps. Thanks.
03-21-2012, 06:12 PM
#14
Pro
Thread Starter
Well....got the fuel system completed and pressurized today.
Went right up to 58 lbs as expected, which is good, but when you shut the pump off the pressure bleeds down almost instantaneously.
You can hear fuel moving around after the system is shut down for a few seconds....seems to be transferring fuel between tanks.
Is this normal? Am I safe since the pressure comes up alright? The "siphon system" is the cause of the loss of pressure upon turning off the system?
Thanks.
Went right up to 58 lbs as expected, which is good, but when you shut the pump off the pressure bleeds down almost instantaneously.
You can hear fuel moving around after the system is shut down for a few seconds....seems to be transferring fuel between tanks.
Is this normal? Am I safe since the pressure comes up alright? The "siphon system" is the cause of the loss of pressure upon turning off the system?
Thanks.
03-21-2012, 10:17 PM
#15
Instructor
Member Since: Aug 2008
Location: Columbus Ohio
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Here is a link that shows a diagram of the fuel system and shows the position of the check valve from the pump and the two pressure regulators.
http://www.c5help.com/fueltank.htm
Based on this diagram I would assume that if the fuel pressure is dropping that quick then you have a problem somewhere between the check valve and regulators. Most likely the fuel lines inside the crossover tube, specifically the line inside the crossover tube that flows from the driverside tank to the passenger side tank is not sealing properly. That is the sound you hear, the pressure bleeding off is the fuel leaking inside the crossover and draining into the tanks.
The leak is small/slow enough that the fuel pump can keep up and produce 58psi at the rail.
This is all theory, I am no expert and have no experience with this issue, but that is how I would trouble shoot the problem.
I recently reinstalled my fuel tanks and applied lots of lube on those crossover fuel line connections so I wouldn't damage or tear the o-rings.
I checked my fuel pressure after install and the pressure held after turning the pump off. I remember it dropping some, but only a little bit, and then it held at that pressure for hours.
Corvette fuel tanks are
http://www.c5help.com/fueltank.htm
Based on this diagram I would assume that if the fuel pressure is dropping that quick then you have a problem somewhere between the check valve and regulators. Most likely the fuel lines inside the crossover tube, specifically the line inside the crossover tube that flows from the driverside tank to the passenger side tank is not sealing properly. That is the sound you hear, the pressure bleeding off is the fuel leaking inside the crossover and draining into the tanks.
The leak is small/slow enough that the fuel pump can keep up and produce 58psi at the rail.
This is all theory, I am no expert and have no experience with this issue, but that is how I would trouble shoot the problem.
I recently reinstalled my fuel tanks and applied lots of lube on those crossover fuel line connections so I wouldn't damage or tear the o-rings.
I checked my fuel pressure after install and the pressure held after turning the pump off. I remember it dropping some, but only a little bit, and then it held at that pressure for hours.
Corvette fuel tanks are
