New here, been following for a year or so. Need some advice if possible, Have a 2001 Chevy Blazer, 4dr. 4WD. Just changed a fuel pump (just learning how to do this stuff), but now am confused on how the lines are supposed to re-connect to the pump. There are three connections, but one is larger than the other 2. I believe they are 5/16 and 3/8 respectively, with only one being 3/8. By cutting off the previous snap connections, I am confused exactly which line goes into the respective fuel pump outlet line.

There are 2 lines on the wall that connect to the pump at the wall, the other goes up past the tank and connects further down the line. The two lines did state "fuel", is the other line the return fuel line? Is it the larger of the 3 connections? I have looked for a display of connections on the box that I got the fuel pump with. It just says right, left.

I know this is a dumb question and I should have gotten a diagram of the re-assembly before I started cutting. But this vehicle drives me nuts at times and am at my wits end with the things I have had to have done to it in the last year. Now, I can't FIND a diagram of the re-assembly......

HEEELLPP!

 

OK, not an expert by any means, but have been under there working on fuel pumps a fair amount recently.
The larger one, at least on my two, was on the right as you look at them where they come over the rear axle, (it's also the easy one to match to the fuel pump.
The middle one on the fuel pump should have an R on it, that's the small one from the front of the truck, and that makes the one on the left, (again, looking at them while laying where the fuel tank is normally mounted), the vent, which should run to that box thing.

That's what both my trucks happened to be, and hopefully it's standard, but I can't promise anything.

 

Thanks for your response, much appreciated, let me make sure I got this right before I go down in the garage and attempt to connect these lines.

The two lines, starting from middle to left are the R for return, and V for vent, respectively. These lines are the two smaller 5/16ths, connections on the pump, and are connected to the fuel pump from the two 5/16th connections that are protruding out from the left rear wall. Correct?

The larger line is the 3/8ths, its the last line connection on the fuel pump on the right side, looking from the rear of the vehicle. This line connects to the line that is directly below the two connections on the left rear wall. I am assuming this is the actual fuel feed line. It sure shoots out gas fast as I have been trying to get these lines together. I hope that I read what you responded correctly. Your fuel pump sounds EXACTLY like the one I installed.

I can over-analyze things, and have not ever worked on a vehicle before other than changing a tire or a windshield wiper. My old lady thinks I am nuts to even try this, but I am tired of paying these guys to do work on this vehicle.

 

If I am reading your response correctly, then yes, that's the way mine were both set up.
Do you still have the hard lines coming over the rear differential? That's where mine changed to the quick connect lines.
Either way, R and the big one go to the front, and V goes to the evap canister below the fill port.

 

Once again thanks for your help and time. ..

Yes, I guess that is the rear differential where there is "2" lines for quick snap of nylon lines coming from the pump. So you are saying one is the "R" or return, which is the middle connection on the fuel pump, and the other is the fuel feed line, which is the large 3/8ths on the fuel pump?

It kind looks like this:

O Both of these lines are 5/16ths. These are where
O The acutal feed line and R line plug into? Which one
is which?

There is one more line below that, that has a quick snap connection to it also, feeds all the way up the line rail to the front of the vehicle. This is the Vent line you are saying? Its a 5/16ths hose also.

Now, one more question if this is correct. I, like a dummy, just cut the connections off of the old pump. If the fuel feed line is 3/8ths inch, and the connection is only 5/16th., how do I get that to adapt to fit? I have a 3/8ths connection on the fuel pump feed line, but on the rail the two quick connections are 5/16ths. How do I make that fit?

...... I am going start work on this now, I am off today and would like to get this taken care of. Its been sitting for awhile and I am tired of being REAL_Still when it comes to this vehicle. Really appreciate your help and information! Thanks!

 

I worked on it this morning for awhile and am confused on one thing. On the fuel pump itself, the R and V line have 5/16th connections. The fuel line from the fuel pump is a 3/8ths connection. All of the connections that come to the fuel pump are 5/16's..........How do I make a connection from the fuel pump that is 3/8's, connect into a 5/16's?

All I see for sale are 3/8th inch connections with a 3/8th inch nylon hose connected to it. Is there a 3/8th inch connector to the fuel pump that has a 5/16ths connection on the other end? I went to 3 stores today and they looked at me like I was crazy or something. Why would they make the line 1/16ths of an inch larger? This is driving me crazy.

I tried to adapt it to a 5/16ths connection with a 5/16ths adapter installed in the 3/8ths inch hose. It would not fit tight, so I used a clip and some wire. When I tested it, the compression coming from the pump literally blew that gas right through the connection. It is getting tremendous compression, and that line just would not hold. I tried 3 different things, gas blew through all 3 of them. I did not know a fuel pump would have that much compression!

It is just a simple matter of getting connections that will fit. I am lost...any advice would be appreciated. I wanted to be driving this vehicle this week-end. The tags expire today, and I have to get it to an inspection station before I can get new tags.

 

On mine, the main line, going over the rear diff, was also 3/8's, no adapters needed.
As far as locating the right lines, I would suggest either researching what the quick connect lines cost at either a parts store or dealer, or going ahead and hitting a scrap yard for them.
You can buy new plastic inserts for them at any auto parts store, by the way.

And my fuel pump had a larger sized output, it's the one furthest forward as you are looking at the pump installed in the tank.

 

So you are saying that I should have a 3/8ths connection from the fuel rail to the fuel pump as yours does? That makes sense...why is mine 5/16ths? If you put a 3/8ths connection on there it kind of slips around and is not tight as it should be.

I will be going to a GM parts outlet today.

When I get this thing together, I will be hollering like I won the lottery! Thanks again for your help and patience!

 

Okay, heres what happened. Its fixed, yes. Someway, somehow, there was a 5/16's clip on the 3/8ths line thats on the fuel rail. The line below was the 5/16ths. that was the return line. Its just like you said, a 3/8ths to a 3/8th connections. Went to a GM parts shop today, and the clerk pulled up a diagram of the lines. He told me that I THINK (meaning ME!) its a 5/16ths, he said its not and to look at it real good. He said it is a 3/8's as it connects to the 3/8's line from the pump. Guy told me that I was just moving a little too fast and was not paying attention......I took the crotch kick like a champ..lol

Man, I did like you said and made quick connections from AutoZone. The clerk there told me to BOIL the nylon lines before putting the adapter on. He said to literally BOIL them to get a total connection from one line to another. I did, *wow, worked! They turned without crimping also! It did not take over 35 minutes to do the 2 lines correctly.

That GM parts place wanted $130.00 for the 3/8ths line, and $112.00 for the 5/16's. I knew I had to learn how to do it then....thats a lot of money for some simple little nylon lines.

Thanks pal, it started right up. Now lets see how long she will run! I definitely will be back if something goes wrong! I feel comfortable enough to do it without any hassle now. Just have to have a little more patience!

 

Great to hear you got it working, and nothing feels as good as getting it fixed yourself.