2003 Suburban - leak around in-tank fuel pump gasket?

calsdad · August 26, 2015

Vehicle is a 2003 Chevy Suburban 4x4 2500 series with the 6.0L engine.

I'm wondering if anybody has ever seen this before - and if there's anything "special" I should do to make sure it's fixed.

I've posted here before that I was seeing Autoenginuity throw a code related to "fuel flow insufficient" - well apparently that was because the fuel pump was dying. Over the last month or so the truck just started dying on me while I was driving. Mostly when driving on the highway - but as the problem got worse - it would die on side roads too. So I figured that the fuel pump was going bad.

Another problem I was seeing - for years now actually - was that if I filled the tank to Full - it would leak constantly until the level got down to about 1/2 full. I avoided this issue by just not filling the tank past 1/2 or so unless I was going on a long trip.

When the pump started dying - I figured it's a good time to fix both problems. So I finally got the tank out tonite (no thanks to GM assembly line workers who saw fit to put the hose clams holding the two hoses in the rear on with the screw on THE TOP - making it a real beeatch to get off ).

It still had about 5 gallons of gas in it - so I started moving it around so that the gas was around the fuel pump area - and lo and behold - gas starts peeing out from what looks like right around the gasket where the pump goes into the plastic ring welded to the tank. At least now I know where the gas was coming from.

Tomorrow I'm picking up the new pump from the dealer. What I'm wondering is - is there anything "special" I should be looking at here to make sure that this new pump seals up nicely to the tank and I don't continue to get gas leaking out from around that gasket?

I took a look at the old pump and didn't see anything obvious about the gasket which would indicate why it would be leaking.

txab · August 26, 2015

You're derailing your own thread

calsdad · August 27, 2015

Kind of confused why you haven't been getting a Evap Leak Code. You mentioned that you have been driving it for years with a leak. I don't understand how it could pull a vacuum test on the system when it has a leak. Anyway i am not sure if the suburban tanks are like the pickups where the Fuel Module sits down in a small well like area. And All the sand and salt accumulate on top of the Fuel Module. So they have a tendency to have a severe rust problem usually causing a leak. A quick smoke test can verify the problem. As far as the clamps I undo the hose at the filler neck and drop the hoses with the tank. No big deal. Also how is the condition of you locking ring. I usually put a new one on if it looks compromised from the rust. Also make sure everything is perfectly clean. Also I put a little lubricant on the o-rings. Don't over do it.

One last comment. All the complaining and bitching in the world Is not going to make the job any easier or any harder. You approach the job the best way you know how and get the job done. As far as 10 minute jobs there is no such thing.

Remember Murphy's Law

I wondered about that myself (the no evap code thing). I just figured the leak was small enough to leak - but not cause enough change in the vacuum to trigger a code.

I picked up the new fuel pump yesterday - and got it installed in the tank. Before installing the fuel pump and the ring - I cleaned them up and carefully applied a coat of paint to them . I figure that ought to at least help ward off rust for a little while. The old fuel pump and the retaining ring were heavily rusted. I lightly greased up the gasket around the fuel pump and installed the pump into the tank - and then poured 5 gallons or so of gas back into the tank and started moving it around so the gas would accumulate in the pump area.

I didn't see any leaks after doing this for about 5 minutes. So I'm hoping that means the new fuel pump (and gasket) - has fixed the leaking problem. On the old pump - the gas peed out immediately when I put the tank on it's side so the gas was accumulated down near the pump.

After putting the pump into the tank - I carefully sprayed Fluid Film all around the tope of the fuel pump (avoiding the line connections and the electrical connector) . Hopefully this also helps ward off the rust for a while. Not sure I'll have the truck long enough to see if this helps - but it's a once chance thing so I figured might as well do it.

Hope to get the tank in tonite and see if this fixes the problem of the truck dying.

calsdad · August 28, 2015

I got the tank installed back into the truck last night and first filled it up to 3/4 full - and so far anyway - no leaks. So that's one problem fixed. Then I took it out for a drive with some around town and then up a couple of exits on the highway - and it didn't die. But it was still not running right. I had to make a run to HD - and the wife wanted to do some shopping - so I took another trip with up the highway - on a route that previously the truck would stall on one or two times (it's the same route I take to work).

Well the problem - or at least part of the problem - is still there. The thing was idling lousy - and then stumbled a few times accelerating onto the highway. Then it died again. It starts right up - accelerates like crazy - will run at 85 mph and seemingly not have a problem - but there's still something wrong with it.

So I get it home - put the Autoenginuity on it and pull the codes. This time - for the first time since I started seeing the code - the "fuel supply insufficient" code is gone. So it seems as if there really was a fuel pump problem (besides the leaking) . But now I've still got the following:

P0300 Random/Multiple cylinder misfire detected

P0342 Camshaft position sensor A Circuit Low input ( Bank 1 or single sensor)

P0343 Camshaft position sensor A Circuit High Input (Bank 1 or single sensor )

I did a little research - and found a bunch of accounts of people having the same issue with their Chevy and GMC trucks - and seeing the same symptoms as I am seeing: bad idle, stumbling - and occasional engine dying.

So hopefully the dealer has a camshaft position sensor in stock - and then I've got to pull the intake manifold off and replace that.

Duelin · August 26, 2015

Kind of confused why you haven't been getting a Evap Leak Code. You mentioned that you have been driving it for years with a leak. I don't understand how it could pull a vacuum test on the system when it has a leak. Anyway i am not sure if the suburban tanks are like the pickups where the Fuel Module sits down in a small well like area. And All the sand and salt accumulate on top of the Fuel Module. So they have a tendency to have a severe rust problem usually causing a leak. A quick smoke test can verify the problem. As far as the clamps I undo the hose at the filler neck and drop the hoses with the tank. No big deal. Also how is the condition of you locking ring. I usually put a new one on if it looks compromised from the rust. Also make sure everything is perfectly clean. Also I put a little lubricant on the o-rings. Don't over do it.

One last comment. All the complaining and bitching in the world Is not going to make the job any easier or any harder. You approach the job the best way you know how and get the job done. As far as 10 minute jobs there is no such thing.

Remember Murphy's Law

calsdad · September 13, 2015

Just a follow up on the fuel pump issue.

I replaced the fuel pump with an AC/Delco a couple of weeks ago. Since then I've been chasing the running issue so the truck has not been driven a huge amount (other than on test runs). But - the tank was filled to F (it's down to about 1/2 full now) - and during that time there has been no evidence of any leaks.

The "fuel supply insufficient" code that had been producing reliably - is now definitively gone. Since I replaced the pump and cleared the code - it has not come back - this is over probably 14 - 15 different times I've driven the truck - and multiple times of clearing the codes and/or pulling power off the battery to reset the computer.

Trying to diagnose the missing / quitting problem the truck has been having - I've also run the fuel pressure test and the pressure also seems to be fine.

It appears the fuel pump was definitely bad - and the problem (that problem at least) - has been fixed.

Doug_Scott · August 26, 2015

Take a good look at where the ring attaches to the tank. Perhaps it is not the gasket leaking, but the actual ring itself. I have not seen a fuel tank sending unit/fuel pump mount since late 90's vehicles, do they still use that lock ring type of attachment? If so, the gasket is a simple o ring. Almost impossible to get it wrong. But, the mount it connects to on plastic tanks is also sealed to the tank. That seal may be leaking in your case.

I know how frustrating it is when you come across something that looks like it was done just to piss off the person that has to fix it years down the road, but, remember that the fuel tank is likely put in and plumbed with the bed of the truck not in place, and all work is done from the top side of the frame. That is why the hose clamps are that way. To have them serviceable from the bottom, the guy in assembly would have to lay on the floor to tighten them, and he already has enough to do in the 38 seconds per job he is allowed. The proper solution is to provide an access panel in the bed of the truck that can be opened to allow anyone to service the sending unit/pump assembly. Especially on the vehicles that now have the fuel filter inside the tank, as though that will somehow reduce the need to change the filter. The dirt that plugs the filter up is not coming from outside the tank.

calsdad · September 1, 2015

Followup:

Replaced the fuel pump and installed the tank back in the truck. Replacing the fuel pump appears to have fixed the leaking problem - I have filled up the tank to Full for the first time in probably 2-3 years - and there's no signs of leaks. At least that's one problem fixed.

As described earlier - the running lousy/ stalling problem was still there though. So I replaced the camshaft position sensor. That seemed to make it run just a tad bit better - but it's still missing, running lousy at idle - and acting like it wants to die when driving on the highway.

Saturday (after replacing the camshaft position sensor on Friday) I took the truck up to Home Depot because I desperately needed to pick up a load of concrete to finish off a job I was in the middle of when the truck started acting up and I stopped driving it.

Coming back with a 3000 pound or so load (truck and trailer) - the thing felt to be running rough on the highway and every now and then it would seriously buck and surge and miss - but the engine never quit. So it appears the new fuel pump and camshaft sensor made at least some difference in the driveability.

When I got home - I put the laptop on it again and pulled the codes. This time - it's showing a crankshaft position sensor code. Which I've seen mentioned numerous times as one of the most prevalent causes of missing and poor idle.

So today - I picked up a crankshaft sensor at lunch - and got the thing installed tonite after I got home (that's a story in itself).

Now the truck barely runs. When I went to start it - the engine is acting like it's running on one or maybe two cylinders. It will barely rev up - and then it quits.

I'm getting near my wits end with this thing. It's really starting to piss me off. Tomorrow night - I'm going to try putting the old crankshaft sensor back in - on the idea that maybe the new sensor was just bad right out of the bag.

But I'm starting to wonder if there isn't some sort of electrical problem with this truck that is the root cause of all these problems. It's starting to seem like I'm chasing my tail here. I replace parts - the codes go away - only to be replaced by something else.

calsdad · August 26, 2015

The tank is a black plastic - there's a grey plastic ring that is somehow welded or bonded to the tank body - and the fuel pump is held down to that grey plastic ring with a locking ring that engages metal tabs that are bonded into that grey plastic ring. There appears to be an O-ring in the grey plastic - and then there's a black rubber gasket/ring that seals the fuel pump assembly into that grey plastic ring.

When I get the new pump I was going to install it - and then put some gas in the tank and turn it sideways again to see if the leak was really coming from the pump or it's seal - or if maybe it was coming out from around where the ring bonds to the tank.

Sorry - I feel absolutely no sympathy for some guy on an assembly line who saves himself 5 seconds by doing a crappy job - and causes me an hour and a half of extra work plus a bunch of cursing and swearing in the meantime.

The week before I worked on this truck - I spent a number of days doing work on my Acura TL. I have to say - and I have owned a number of Honda cars as well as this one - that it's PLAINLY OBVIOUS that Honda engineers it's cars to be maintainable. I had to change out the front calipers - as a for instance of what I'm talking about - the bleeder screw on the back of the calipers is a 10mm - and so are the bolts that hold the little brake hose retaining bracket. So I need one wrench to take both of those pieces off. If it was a Chevy - I would probably need three different sizes - the bolts would be rusted to hell and frozen in - and there would probably be a mix of inch and metric to boot.

The underside of my Acura - even though it has 120k miles - and gets driven all the time during the winter - and almost never washed - is pretty much rust free.

The truck has 70k miles - only gets driven in the winter when I need to get thru deep snow - and is rusted all to hell. I kept picking rust flakes out of my ears as it dropped down into my face while I was removing the gas tank.

I'm sorry - but my experience going back 30 years is that American car quality seriously leaves something to be desired. I like the Suburban - but GM wasn't exactly putting their best efforts out when they put that thing together.

txab · September 1, 2015

I think you need to have a crank relearn performed after replacing the sensor

Doug_Scott · August 26, 2015

The tank is a black plastic - there's a grey plastic ring that is somehow welded or bonded to the tank body - and the fuel pump is held down to that grey plastic ring with a locking ring that engages metal tabs that are bonded into that grey plastic ring. There appears to be an O-ring in the grey plastic - and then there's a black rubber gasket/ring that seals the fuel pump assembly into that grey plastic ring.

When I get the new pump I was going to install it - and then put some gas in the tank and turn it sideways again to see if the leak was really coming from the pump or it's seal - or if maybe it was coming out from around where the ring bonds to the tank.

Sorry - I feel absolutely no sympathy for some guy on an assembly line who saves himself 5 seconds by doing a crappy job - and causes me an hour and a half of extra work plus a bunch of cursing and swearing in the meantime.

The week before I worked on this truck - I spent a number of days doing work on my Acura TL. I have to say - and I have owned a number of Honda cars as well as this one - that it's PLAINLY OBVIOUS that Honda engineers it's cars to be maintainable. I had to change out the front calipers - as a for instance of what I'm talking about - the bleeder screw on the back of the calipers is a 10mm - and so are the bolts that hold the little brake hose retaining bracket. So I need one wrench to take both of those pieces off. If it was a Chevy - I would probably need three different sizes - the bolts would be rusted to hell and frozen in - and there would probably be a mix of inch and metric to boot.

The underside of my Acura - even though it has 120k miles - and gets driven all the time during the winter - and almost never washed - is pretty much rust free.

The truck has 70k miles - only gets driven in the winter when I need to get thru deep snow - and is rusted all to hell. I kept picking rust flakes out of my ears as it dropped down into my face while I was removing the gas tank.

I'm sorry - but my experience going back 30 years is that American car quality seriously leaves something to be desired. I like the Suburban - but GM wasn't exactly putting their best efforts out when they put that thing together.

You are missing the point here. The guy on the assembly line has a defined job to do in a defined amount of time, is given the tools to do it, and is shown how to perform that task. That task is also laid out in the ISO standard that they are building to. I doubt there is even room under that chassis on the assembly line in order for him/her to even be able to assemble it that way. It is not their call, and not their fault it is designed to be assembled that way. Blame the people responsible, not the messenger.

As for how your Acura is assembled, my guess would be you have never worked on the sister car line of the Acura, the Honda. Having to pull a timing belt and motor mount out just to be able to get to the water pump is not something that was engineered for repairing. Every manufacturer has their "stupid, not planned or thought out" part that is replaced as part of maintenance. And every manufacturer has at least one item that is dead simple to change or access. It is all part of the process. Like you, my experience also goes back 30 years, actually I am mistaken, it is 40 years now. Cars today compared quality wise to those cars of the 70s and 80s is apples and oranges. Cars today are far better quality wise compared to those 25-40 years ago. Any new car I bought up until about 95 or 96 went back to dealers with a minimum of 25 defects that needed to be addressed before the 12 month warranty was up. Back then you used to wait until the last month of warranty, then take the big list in and drop the car off for a week or so. My last 6 or 7 new vehicles have each had maybe 2 warranty claims each. The current 2010 GMC was the first GM vehicle that did not warp rotors under warranty, and they still are not warped.

calsdad · August 26, 2015

I don't think I'm missing any points here.

First off - the fuel pump crapped out at 70k miles.

The fuel pump in my Acura is still going at 108k - and the two Hondas I had before that went 180k plus on each of them - and were still going when I stopped driving them.

The guy on the assembly line may have a defined job to do - but I think you're the one missing the point: He saved himself 5 seconds - and cost me an hour and a half - for something that if he spent 5 seconds would have saved me about and hour and 20 minutes. Furthermore , Chevrolet lets the factory workers get away with it instead of paying attention to the little things that cost people money and time down the road.

It's the typical "screw you customer" attitude that I see every time I turn a wrench on an American built automobile.

As far as the timing belt thing goes : I have changed them. Like I said: I had two Hondas before I had this current Acura - and did the timing belt on both of them.

I also worked on the wife's Pontiac Gran Prix a few years back. That thing was FAR harder to work on than either the Honda CRX or the Civic I owned.

I do quality and customer useability for a living - American cars have gotten better in the last 30 years, but in my experience they still have a long way to go.