: Fuel Leak! Fuel Pump Melting & Smoking!!



CTSV_510
06-02-10, 08:43 PM
I have had a slight starting issue for a while now...the fuel pressure at start-up wasn't holding so I have had to run the fuel pump twice before starting. Turning the key to the on position runs the pump for 2 seconds, then a switch to off and then to start and it would start fine. Since I NEVER had any fuel leaks, I suspected a faulty check valve in the fuel pump assembly (after consulting the service manual.) Well I kind of learned to live with the issue since dropping the fuel tank @ 10 or whatever hours of labor would be awfully expensive to fix something that was little more than a nuisance.

On Sunday I was running around town doing errands, then I stopped at the gas station on the way home and filled up the tank. When I got home and got out of the car, there was a pretty strong smell of gasoline. I looked under the car and found this:

http://i305.photobucket.com/albums/nn240/ctsv510/Fuel%20Pump%20Leak/fuelleak3.jpg
.
http://i305.photobucket.com/albums/nn240/ctsv510/Fuel%20Pump%20Leak/fuelleak4.jpg

Holy crap that was the first time I'd seen anything like that. I threw a catch pan under it and then jacked up the passenger side of the car until the flow stopped. I inspected for damage but saw none. The leak was obviously coming from the top of the tank, which is absolutely impossible to see or even reach with your fingers. I lowered the car back down and the fuel started spilling out again. 30 minutes later and a full gallon had drained out. I ended up jacking up the drivers side next to try to get as much drained out as I could and got about another gallon.

I searched and found just one single forum member that had the same issue. I contacted him and found out that he ended up cutting a hole underneath the passenger side rear seat right above where the leak seemed to be coming from. Much easier than dropping the exhaust, driveshaft, and rear subframe to lower the tank. His issue was a loose locking ring that holds in the fuel pump assembly. He was able to simply tighten it back up, button up the hole and move on.

I wish my issue was that simple. After cutting a small hole and looking around, it wasn't obvious where the leak was coming from because the locking ring was definitely fully locked. I reconnected the battery and turned the ignition to on while me and my buddy watched for a leak. Immediately, smoke started flowing out of the hole so I shut the ignition off and disconnected the battery. We opened up the hole more, here is a shot looking from the passenger side into the car at the top of the fuel pump assembly:

http://i305.photobucket.com/albums/nn240/ctsv510/Fuel%20Pump%20Leak/goodside.jpg

Looks OK from here. Now from the other side....

http://i305.photobucket.com/albums/nn240/ctsv510/Fuel%20Pump%20Leak/burntside2.jpg
.
http://i305.photobucket.com/albums/nn240/ctsv510/Fuel%20Pump%20Leak/burntside1.jpg
.
http://i305.photobucket.com/albums/nn240/ctsv510/Fuel%20Pump%20Leak/burntside5.jpg
.
http://i305.photobucket.com/albums/nn240/ctsv510/Fuel%20Pump%20Leak/burntside4.jpg

:eek:

YES, that is a hole burnt right through the electrical connector piece that comes out of the top of the fuel pump assembly.

I believe I am pretty lucky to have not blown up in the car at some point in the past year or so. Now, WHAT THE HECK CAUSED THIS????

I have a maggie with a magnavolt (Magnuson brand fuel pump voltage booster) that I have been running for 18000+ miles. My buddy and I went back over the entire installation of the magnavolt system and how it ties into the fuel pump curcuit. Everything is exactly as specified in the manual, with the addition of the extra ground connections to prevent the magnavolt from burning up, which was a very common problem. The original fuel pump fuse gets changed from a 20A to a 30A when installing the magnavolt.

Now I KNOW I have never read about anyone having this issue anywhere on this forum or ls1tech. It doesn't seem that the magnavolt is to blame because there are people out there that have run them for a whole lot longer than I have with no issues like this.

My buddy works at a corvette shop and has a line into GM so he is ordering me a new pump tomorrow. I still need to figure out WHY this happened so I can make sure it doesn't happen again.

Maybe the starting issue I've had (mind you this is the only odd symptom I've had, the car runs flawlessly otherwise) was actually my fuel pump going bad? Could a dying pump cause this piece to burn up somehow? I bought the car used with about 36k miles on it 2 and half years ago so who knows what happened to it before then. As long as I've owned it I never ran out of fuel, which I hear can cause damage and shorten the life of a fuel pump.

Any help or ideas is appreciated!

Tom

darkman
06-02-10, 08:57 PM
Why does the original pump get a 30A fuse instead of a 20A ?

CTSV_510
06-02-10, 09:04 PM
Why does the original pump get a 30A fuse instead of a 20A ?

That's what the instructions call for...literally on the first page. I plan on asking Magnuson that though tomorrow when I call them...but again it's the same instructions for everyone and I haven't heard of this happening before.

bneal1022
06-02-10, 09:09 PM
Thanks.. getting dark on the east coast... Now I will have nightmares. Dude, sorry... no really holy crap, sorry.

darkman
06-02-10, 09:11 PM
That's what the instructions call for...literally on the first page. I plan on asking Magnuson that though tomorrow when I call them...but again it's the same instructions for everyone and I haven't heard of this happening before.

Well I am no expert on electrics, but the idea that a circuit can be "upgraded" to handle additional load with simple fuse change strikes me as risky, although going from 20-30A may be no big deal. In any event, the 30A fuse apparently did not protect you from whatever went wrong, which is what a fused circuit is supposed to do.

heavymetals
06-02-10, 09:11 PM
It would take an inspection of the terminals to see what part of the connection failed.

Could be a bad crimp, or it finally failed from stress.

The cause is the amount of current (the fuel pump) was drawing.

The Magna volt bumps the voltage so a connection going bad is gonna be exasperated.

Glad you didn't arc over and go poof. :eek:

(I have fire extinguisher brackets by the way)

darkman
06-02-10, 09:17 PM
(I have fire extinguisher brackets by the way)

And mine is coming back out of the trunk tomorrow morning.

CTSV_510
06-02-10, 09:30 PM
I will be doing more inspection tomorrow when I have a better metal snipping tool to make this hole bigger and cleaner. I will pull and check the electrical connection closely.

deedubb
06-02-10, 10:37 PM
Woah man, that's scary! I'm more scared of the hole you cut with a hand axe! Atleast you'll have a trap door now, but the event that this will ever occur again after you've fixed it this time is probably null.

CTSV_510
06-02-10, 10:45 PM
I'm still pondering whether this is likely to happen again if I go with a new stock pump and keep the magnavolt. I'm concerned with reliability of going to non-GM parts, but this situation doesn't exactly make me feel great about just replacing everything with the same parts.

CTSV_510
06-02-10, 10:48 PM
Looking at the magnacharger install intructions for other vehicles, it seems that the CTS-V is the only one that uses a magnavolt that they have you change the fuel pump fuse out to a larger one. :hmm:

darkman
06-02-10, 10:50 PM
I'm still pondering whether this is likely to happen again if I go with a new stock pump and keep the magnavolt. I'm concerned with reliability of going to non-GM parts, but this situation doesn't exactly make me feel great about just replacing everything with the same parts.

Since you will have an access hole there, you could add an in-line 20A fuse for just the stock pump.

heavymetals
06-02-10, 10:55 PM
Get a better pump, if one will fit (Walbro).


http://www.walbro.com/

CTSV_510
06-02-10, 10:57 PM
Since you will have an access hole there, you could add an in-line 20A fuse for just the stock pump.

How would that be different from changing the 30A back to a 20A in the normal fuse location?

benelliwang
06-02-10, 11:12 PM
CTSV_510, I am glad that my instruction helped you with getting access to the tank. The magnavolt sounds like it works like a boost a pump, and I am not a big fan of such stuff. It increases voltage to over drive a fuel pump to keep the fuel pressure up, which taxes the oem pump and wires. Sometimes, when the dark stars align, it will cause issues like your vehicle. When I was doing the twin turbo set up on the corvette, I did the follwoing:
1. Run a thick gauge wire from alternator to the fuel pump. The oem wire becomes the switch for the relay. Additional fuse is added.
2. I run a higher capacity fuel pump and tuned the car for it.

Unfortunately I ran out of fuel as the injectors are at 96% at 17psi, I will have to upgrade to dual pumps if I want to up the boost.

Good luck and let me know if I can help.

CTSV_510
06-04-10, 05:01 PM
I actually can't believe my fuel pump was still working :

http://i305.photobucket.com/albums/nn240/ctsv510/d6b36326.jpg

The fuel pump lock ring is a pain in the ass to get off without the special GM tool.

CTSV_510
06-07-10, 10:14 AM
In case anyone is interested....here is some info for cutting a hole for access to the fuel pump/

To start the hole, use a regular drill with a drill stop on it so that it can only go down about and 1/8" just to get through the sheet metal. You don't want to go too far because you could damage the electrical wiring, sending unit or the tank itself. This picture is looking in from the passenger rear door at the area below the rear passenger seat:

http://i305.photobucket.com/albums/nn240/ctsv510/Fuel%20Pump%20Leak/Undersseat.jpg

I cut the hole out with tin snips - the metal is very thin and very soft so it was very easy. The lock ring that holds the fuel pump assembly in is a pain to get off. I cut the hole a little bigger at the top of the picture to get a 10" piece of copper pipe at a good angle on the ring to break it loose. Use a big hammer for this - I used a mini sledge and you have to whack it really really hard or you're wasting your time. You will see that I cut the plastic fuel line connection because I was replacing the whole assembly. If you're re-using these parts, you may have to cut the hole bigger in a different spot to get a good angle on the lock ring.

http://i305.photobucket.com/albums/nn240/ctsv510/Fuel%20Pump%20Leak/Lockring.jpg

CTSV_510
06-07-10, 10:24 AM
For an update...

I replaced the fuel pump assembly (pump, level sensor & sending unit) and soldered in a new connection for this piece of the electrical harness. I took out the 30A fuel pump fuse that Magnuson tells you to use and replaced it with the stock 20A fuse. I read through the instructions for all the other Magnuson kits and the CTS-V instructions are the only ones that tell you to upgrade the fuse. This fuse upgrade is suspect to me to so I am starting out this time with the stock 20A to see how it holds up. After 2 days of driving (and getting on it pretty hard) the fuse hasn't blown. I will feel much safer using the 20A fuse for a circuit that was designed for it.

We tested the voltage with the car running to make sure the Magnavolt wasn't malfunctioning and boosting 17 volts all the time, and everything appears to be working correctly. The pump is getting the correct amount of power under normal conditions, and the ground for the circuit tested out perfect so that is not an issue.

I will be monitoring this connection for some time to make sure there are no signs of a repeat issue. I will provide some updates on how the 20A fuse is holding up. If it works fine, then I would have to recommend that anyone with a maggie and magnavolt go back to the stock 20A fuse for protection against something like this.

PISNUOFF
06-07-10, 10:40 AM
So where was the fuel leaking from? Was there a hole melted in the pump housing, tank itself, a line or something?

ctsv154
06-07-10, 11:03 AM
He said it was coming out of the hole. Replaced the pump and connector and problems all gone.

CTSV_510
06-07-10, 11:18 AM
So where was the fuel leaking from? Was there a hole melted in the pump housing, tank itself, a line or something?

The fuel was leaking through that hole that was melted in the housing. You can see it in the pictures in the first post of this thread. Here is a video of the original leak. :eek:

bCTlpq30Ri4

Twitch
06-07-10, 01:51 PM
In case anyone is interested....here is some info for cutting a hole for access to the fuel pump/

To start the hole, use a regular drill with a drill stop on it so that it can only go down about and 1/8" just to get through the sheet metal. You don't want to go too far because you could damage the electrical wiring, sending unit or the tank itself. This picture is looking in from the passenger rear door at the area below the rear passenger seat:

http://i305.photobucket.com/albums/nn240/ctsv510/Fuel%20Pump%20Leak/Undersseat.jpg

I cut the hole out with tin snips - the metal is very thin and very soft so it was very easy. The lock ring that holds the fuel pump assembly in is a pain to get off. I cut the hole a little bigger at the top of the picture to get a 10" piece of copper pipe at a good angle on the ring to break it loose. Use a big hammer for this - I used a mini sledge and you have to whack it really really hard or you're wasting your time. You will see that I cut the plastic fuel line connection because I was replacing the whole assembly. If you're re-using these parts, you may have to cut the hole bigger in a different spot to get a good angle on the lock ring.

http://i305.photobucket.com/albums/nn240/ctsv510/Fuel%20Pump%20Leak/Lockring.jpg
If it's not already there, the mods should put this in the FAQ thread. Guys looking to go big might find this helpful.

The Tony Show
06-07-10, 02:01 PM
Indeed they will. Thanks for posting this up, 510.

CTSV_510
06-07-10, 02:06 PM
:highfive:

nmaier2201
06-07-10, 02:39 PM
Thanks for the measurements on where to chop up the back seat... If my pump ever dies I will MUCH rather cut that up replace it and then tack in some other metal plate as a band aid.

and now thanks to you I'll know exactly where to cut.

CTSV_510
09-06-11, 03:03 PM
Another forum member just had the same issue last week with a stock fuel system (no magnavolt, no supercharger).

Hopefully it doesn't become more common as these cars age.

Albertan
09-07-11, 03:33 PM
Melting the electrical connection at the fuel pump is a common fault with some GM vehicles. This is the first I've heard
for a Cadillac. Fellow I work with spent a long time with fuel pump problems before finding it was the melted plug. (His was a minivan)

CancerJCC
11-27-11, 02:06 PM
Well I added a Walbro 255 along with the Racetronix hot wire kit yesterday/today and thought I'd add my pics to this thread.

All in all this wasn't terrible to do but did end up taking longer than I thought it would (what mod doesn't though). A few things to consider:

Be extra careful hammering with the copper pipe. I was wacking the business out of mine and didn't realize it had split and started cutting into the tank. A few more millimeters and I'd have been through the top of the tank! :helpless:

If you plan to reuse the sheet metal like a door then cut BIG the first time. I had to cut another strip and then a small piece in the corner. It still closed up decently but I'd like to have had ONE nice rectangle to fold in/out.

I would definitely do it this way vice dropping the tank. The "door" seals up nicely (see pic) and without thinking about what it is it matches up to the other aluminum tape spots under the seat.

First "nice" cut.
http://i349.photobucket.com/albums/q365/CancerJCC/Internet%20Uploads/2011-11-26_10-15-35_306.jpg

http://i349.photobucket.com/albums/q365/CancerJCC/Internet%20Uploads/2011-11-26_10-15-46_185.jpg

Reference to fuse box pic.
http://i349.photobucket.com/albums/q365/CancerJCC/Internet%20Uploads/2011-11-26_10-16-00_295.jpg

Everything zip tied up out of the way.
http://i349.photobucket.com/albums/q365/CancerJCC/Internet%20Uploads/2011-11-26_10-41-47_716.jpg

http://i349.photobucket.com/albums/q365/CancerJCC/Internet%20Uploads/2011-11-26_10-41-56_500.jpg

The angle I had luck with.

http://i349.photobucket.com/albums/q365/CancerJCC/Internet%20Uploads/2011-11-26_13-51-04_400.jpg

Some randoms of the fuel assembly for the guys in the fuel pickup thread.

http://i349.photobucket.com/albums/q365/CancerJCC/Internet%20Uploads/2011-11-26_11-36-32_900.jpg

http://i349.photobucket.com/albums/q365/CancerJCC/Internet%20Uploads/2011-11-26_11-36-39_34.jpg

http://i349.photobucket.com/albums/q365/CancerJCC/Internet%20Uploads/2011-11-26_11-36-51_763.jpg

http://i349.photobucket.com/albums/q365/CancerJCC/Internet%20Uploads/2011-11-26_11-49-47_383.jpg

http://i349.photobucket.com/albums/q365/CancerJCC/Internet%20Uploads/2011-11-26_11-49-55_810.jpg

All buttoned up!

http://i349.photobucket.com/albums/q365/CancerJCC/Internet%20Uploads/2011-11-27_11-03-58_533.jpg

8's on a drag radial
11-28-11, 11:55 AM
I just experienced the same problem. Filled my tank up, got home and it was leaking. Once it burned a gallon or two it stopped leaking, but starting stalling a bunch while driving. I cut the inspection hole and it had the burned plug.

I'm not sure where the fuel leak is coming from, but I ordered the pump and pigtail from Lindsay Cadillac and will replace.

Thanks for the info...this thread was very useful.

verywhitedevil
04-03-12, 10:08 AM
Another forum member just had the same issue last week with a stock fuel system (no magnavolt, no supercharger).

Hopefully it doesn't become more common as these cars age.

looks like it is starting to happen. mine did this over the weekend. stock fuel system w 42lb green tops.

so purchased the entire fuel pump assembly, just in case.

I thought I was only doing a fuel pump upgrade/install until I looked under the car and saw fuel pouring out.

CTSV_510
04-03-12, 11:00 AM
looks like it is starting to happen. mine did this over the weekend. stock fuel system w 42lb green tops.

so purchased the entire fuel pump assembly, just in case.

I thought I was only doing a fuel pump upgrade/install until I looked under the car and saw fuel pouring out.

Geez....not good news at all. I need to open mine up and take a look this weekend and check all the connections, I haven't looked in a while. It's a shame, the fuel pump assembly was about $400 if I remember correctly.