Fuel tank leaking after new pump

[gmcman]

I just reinstalled the fuel tank, new Bosch pump, new tank pressure sensor, new fuel filter, and new vent valve.

I went to fill it up, upon leaving I pulled away to set up the Torque Pro screens and I could smell fuel.

Looked underneath and saw this.




Hard to see but it's draining down near where the strap is and the front third of the tank bottom is wet, but not the front of the tank.

Curious.if anyone has been through this, I'm assuming it's the pump seal but could be a hose.

Frustrating.

 

[Reprise]

My money is on a hose. You're not going to see drainage that quick out of the pump seal unless it was, say, filled to overflowing, or it was pressurized at high psi for some reason, etc.

The quick disconnects on the hose use plastic latches (thin, but work OK if not broken). One of them may be compromised. Or you could have a pinhole leak from one of the hoses.

Unfortunately, it sounds like you're going to have to at least partially drop the tank to see. And you'll most likely have to release both hanger straps; releasing only one won't let that side hang down very much, if the other is left in place.

When I lowered my tank (for the rear brake crossover line replacement), I used two floor jacks, and lowered the front rear one a little bit more, as needed. That might work for you, instead of dropping the entire tank all the way down (and it's a lot heavier now, if you filled up).

PS: I have the XL / LWB, and the bigger gas tank, so things might be a little different for you. But they're probably pretty similar.

 

[mrrsm]

NOT THIS FUEL PUMP....

Fuel Gas Pump & Sending Unit Module for Trailblazer Envoy SSR Bravada Ascender

Fuel Gas Pump & Sending Unit Module for Trailblazer Envoy SSR Bravada Ascender Condition: New Brand: AM Autoparts Product code: 681344**371680

www.ecrater.com

But... YES... to THIS Old Style Trailblazer Black Silicone Rubber Fuel Tank Sealant-Gasket...at that Off Brand Fuel Pump Link... with it's "Deep Collar" Design... IF... you can FIND One anymore.

ACDelco used to have THIS style of gasket available over on Amazon.And unless the entire Retainer Locking Ring Mount has is Rusted & Rotted OFF of the Top of the Plastic Fuel Tank.... THIS Style of Fuel Tank Gasket NEVER LEAKS:

Also Brother... If the underlying problem is because the Locking Ring is TOAST... Try THIS Repair Kit to install a Sealed Replacement Ring:

GM PLASTIC GAS TANK LOCK RING REPAIR TR7

THIS REPLACEMENT LOCK RING WILL FIX THE RUSTED OUT TABS THAT HOLD IN THE FUEL PUMP ON MOST FULL SIZE GM CARS & TRUCKS WITH A PLASTIC TANK.

gastankrenu.net

This is THEIR GM Kit Step By Step R&R Video and if it comes down to cases and you've GOT to do something like this... You will WANT to get the Best OEM Pump and hopefully experience what THIS Kit can really do for you:

Here is an Actual "Worst Case Scenario" Rescue Installation:

 

[Mooseman]

Could also be the o-ring seals inside the hose connectors. One could have been nicked during the install. There are two per connector.

The thing that will really suck is that in any case, you will have to lower a full tank unless you have a way to pump it out.

 

[gmcman]

Thanks for the replies.

I can drive it this week and get the gas out that way. The fuel isn't pouring out and I had no drips after I got home....my guess was the sloshing....but just a guess.


I used a new lock ring and the tabs were still in good shape.


@mrrsm , I used the gasket from the Bosch pump....but I also have a new AC gasket.

 

[JerryIrons]

For my EXT, I have in the past done a partial lowering of the tank, keeping connectors connected and putting key in on position to get fuel up to pressure to check for leaks. Used floor jack to lower it on to boards if I remember correctly. Maybe you can lower it a little to get a mirror up there and inspect. If I remember correctly, you'll need to keep an eye on lowering it, there isn't a whole lot of slack in some of those electrical connectors.

 

[mrrsm]

Yes... and typically...this is about as low as it should get before being 'disconnected'. This exemplar vehicle is a Tahoe that presented with a Remote Start Problem and was throwing a ****P0442 Code along with a Heavy Fuel Odor... very similar to what @littleblazer had to deal with a few years back:



The Fuel Pump R&R begins at around 7:00 into this (WWW) Watch Wes Work Repair Video:

...and re: Post #4 Above... to *Echo* what @Mooseman mentioned in this Linked Thread... Here is some interesting information about "Leaking Fuel Lines"...

Fuel Lines leak! Help.

2008 GMC Envoy. Got a fuel leak just over the transfer case. There are flexible lines that come from the tank and connect to the two steel hard lines in this location. I don’t think it’s the connection. I believe my lines (which start here and extend forward and up to the fuel rail) have rusted...

gmtnation.com

**** P0442

Freaking p0442

I've been doing battle with the escalade on this for about 2 years now. Inspection is coming up in April so I would like to figure it out. That being said, here's where I'm at so far... Vent solenoid. Command system seal. Wouldn't respond. Replaced. Still throws code. Purge solenoid. Same...

gmtnation.com

 

[gmcman]

Brief update, after the 1st night, I didn't see any more leaks....

Drove it to work the next day, dry. Drove home....dry.

So I topped it off this AM, went a little past the first click of the pump....dry. Drove around the parking lot, quick turns, quick stop.... nothing.

Maybe the pump seal needed to seat? Not sure, but it looked good when installed.

I'll keep updating.

 

[gmcman]

I filled up again to check the evap and as before, acted like it was flooded and I got the P0440 code.

I meant to add when I replaced my fuel filler neck with the Dorman, my OE fuel cap would not seat. There is a tiny vertical line, slightly raised above the surface, almost like a seam...that blocked the locking tabs from turning. I thought it was a depth issue so I shaved the top of the tab, (bad idea) then had to shave the side of the tab on the gas cap.

When I shaved the top part of the tab, that now kept the cap from fully sealing.....

Either way, the only part that hasn't been replaced was the purge solenoid. I removed that and put 12V to it....nothing. New solenoid, has a "click" with 12V. My thought is the vapors are filling the intake causing a rich mixture, if I remove the line at the TB it will start after a fill up.

So new gas cap, waiting readiness test.

 

[Paintbrush]

'05 Trailblazer with 4.2L...Replaced the fuel pump about six months ago. Two weeks ago while filling the gas tank I noticed gas dripping from the middle of the tank. I dropped the tank when I got home ( getting good at this ) and found the the high pressure fuel line was not seated all the way onto the pump. After inspecting the connector I found that either an o-ring or plastic spacer was missing causing the connection to leak due to the hose not seating all the way. I ordered another hose since you can't just order the rings or spacer. It arrived with the missing spacer; about a 1/4" wide. My question is about the other side connection: how many o-rings is that supposed to have????? I can't find any parts diagram that breaks down that far or any photos.

 

[NJTB]

I filled up again to check the evap and as before, acted like it was flooded and I got the P0440 code.

I meant to add when I replaced my fuel filler neck with the Dorman, my OE fuel cap would not seat. There is a tiny vertical line, slightly raised above the surface, almost like a seam...that blocked the locking tabs from turning. I thought it was a depth issue so I shaved the top of the tab, (bad idea) then had to shave the side of the tab on the gas cap.

When I shaved the top part of the tab, that now kept the cap from fully sealing.....

Either way, the only part that hasn't been replaced was the purge solenoid. I removed that and put 12V to it....nothing. New solenoid, has a "click" with 12V. My thought is the vapors are filling the intake causing a rich mixture, if I remove the line at the TB it will start after a fill up.

So new gas cap, waiting readiness test.

I don't know why, since the fuel filler neck is for the year TB, that damn fuel cap won't fit.
I checked it in the store (Autozone) when I bought it, and realized it wasn't going to fit. Tried a few, found one from a different year, and it did fit.

 

[Mooseman]

I don't know why, since the fuel filler neck is for the year TB, that damn fuel cap won't fit.
I checked it in the store (Autozone) when I bought it, and realized it wasn't going to fit. Tried a few, found one from a different year, and it did fit.

That's been a common complaint about the original cap not fitting the replacement fillers. Do you have the part number of the one that did fit?

'05 Trailblazer with 4.2L...Replaced the fuel pump about six months ago. Two weeks ago while filling the gas tank I noticed gas dripping from the middle of the tank. I dropped the tank when I got home ( getting good at this ) and found the the high pressure fuel line was not seated all the way onto the pump. After inspecting the connector I found that either an o-ring or plastic spacer was missing causing the connection to leak due to the hose not seating all the way. I ordered another hose since you can't just order the rings or spacer. It arrived with the missing spacer; about a 1/4" wide. My question is about the other side connection: how many o-rings is that supposed to have????? I can't find any parts diagram that breaks down that far or any photos.

I believe the return line has 2 o-rings as well.

 

[NJTB]

That's been a common complaint about the original cap not fitting the replacement fillers. Do you have the part number of the one that did fit?



I believe the return line has 2 o-rings as well.

No, just tried gas caps from other year TB's. If I remember correctly, the one that fit was from 2002.

 

[Paintbrush]

That's been a common complaint about the original cap not fitting the replacement fillers. Do you have the part number of the one that did fit?



I believe the return line has 2 o-rings as well.

Yes, it has two. They are so close together that it looks like one. Thanxs!!!!