Walbro 255

**Adam_94_T/A** · 08-20-2011, 12:12 PM

So back in march i purchased a new Walbro 255 fuel pump. since i have had it in the car i have had bad fuel pressure and by bad i mean 22 psi and it bleeds off. knowing that this is low and knowing that 43.5 psi is optimal i changed the fuel pressure regulator, injectors and fuel filter. I am dreading taking the tank out again due to the pain it is................. does anyone have any other ideas before i jump head first into taking tank out again?

**pajeff02** · 08-20-2011, 06:15 PM

The only thing I recall reading about is that a hose on the pump assembly in the tank may be sliced or split open. Pretty sure that was on an LS1 equipped car and I am uncertain if the pump style is the same. I know we run 58 psi versus the LT1's lower fuel pressure. Curious as to what you find.

**35th-ANV-SS** · 08-20-2011, 06:21 PM

Subscribed. I know some people frown on the idea, but you could do the trap door so you can easily access the fuel pump for future repairs/replacement.

**Ain't Right** · 08-22-2011, 11:47 AM

Recently did the trap door because tye pump died witha FULL $60 tank of gas. Worth every effort to do the trap door!

**Adam_94_T/A** · 08-23-2011, 03:09 AM

Talked to a tech last night and he says one of two things is happening. He said either the check ball is jacked or one of the lines in the tank is cut or loose. Will see what it is this weekend hopefully if the hurricane passes by fast.

**5.0THIS** · 08-24-2011, 10:37 AM

I would not recommend cutting a huge hole in your rear floor to access the pump. Do it the right way. Lots of potential safety issues with putting a hole there.

**mike171562** · 08-24-2011, 01:03 PM

Check the hose on the pump, mine popped off on me, I did the trapdoor when I installed it and it only took a few minutes to get it out.

**Black beauty** · 08-17-2012, 12:00 PM

Yes I have done that and that's better then dropping everything

**Firebirdjones** · 08-18-2012, 11:12 AM

cracks me up when this subject appears. Everyone wants to take the easy route and start hacking on the car.

It's not all that bad to drop the tank, just about every new vehicle out there is like this today. Even most of your classic cars retrofitted with fuel injection are converted to an in tank pump. Doing that as we speak on my blazer, so when that pump dies I'll be pulling a rather larger 37 gallon tank,,,try that on for size

**5.0THIS** · 08-18-2012, 11:22 AM

Originally Posted by Firebirdjones

cracks me up when this subject appears. Everyone wants to take the easy route and start hacking on the car.

It's not all that bad to drop the tank, just about every new vehicle out there is like this today. Even most of your classic cars retrofitted with fuel injection are converted to an in tank pump. Doing that as we speak on my blazer, so when that pump dies I'll be pulling a rather larger 37 gallon tank,,,try that on for size

You mean it's not a good idea to give your fuel tank a big potential hole to explode right into the interior of the car in a crash?? It's almost as if the factory didnt do it for a reason. Because dropping the fuel tank is suuuuuch a hard job.

**Firebirdjones** · 08-18-2012, 12:13 PM

Originally Posted by 5.0THIS

You mean it's not a good idea to give your fuel tank a big potential hole to explode right into the interior of the car in a crash?? It's almost as if the factory didnt do it for a reason. Because dropping the fuel tank is suuuuuch a hard job.

I know what you mean.

**Adam_94_T/A** · 08-20-2012, 02:18 AM

Well sorry i didn't post back up its been some time since ive been on here. I ended up pulling the pump out and putting new hose clamps on every line going to the pump as well as replaced the hoses. i did not use a sealing epoxy or rtv on the housing of the pump itself after talking to the tech he said it didnt matter. I didn't do the trap door cause i do not want to hack my car to pieces. Pulling the tank is pretty easy just have to drop the rear end down. It was out and back together in about 8 hours hardest part for my was trying to get the filler neck to clear. If i could change anything i would make the neck removable. Sorry for not posting anything sooner i have been deployed so have other things on my mind.

**Black beauty** · 09-28-2012, 10:41 AM

Hell yea best bet trap door

**Black beauty** · 04-19-2013, 05:06 PM

How much pressure does the stock fuel pump have on 1995 t/a

**5.0THIS** · 04-20-2013, 12:11 AM

Should be 43-44psi at idle with the vacuum line to the regulator disconnected.

**RONS98TA** · 04-20-2013, 07:15 AM

Originally Posted by Firebirdjones

I know what you mean.

I did the trap door thing and replaced the stock sheet metal with a piece of stainless sheet metal. All you need to do is add a rubber seal around the hole and a piece of metal the same thickness or thicker, then screw it down. I probably used 20 screws to hold it in place. So if in the future you need to change or modify the pump, it's a 2 minute process. There is no safety issue if you replace the metal with something as good or better than what was there. I didn't "hack" my car at all. Just my 2 cents.

**5.0THIS** · 04-20-2013, 01:11 PM

Originally Posted by RONS98TA

I did the trap door thing and replaced the stock sheet metal with a piece of stainless sheet metal. All you need to do is add a rubber seal around the hole and a piece of metal the same thickness or thicker, then screw it down. I probably used 20 screws to hold it in place. So if in the future you need to change or modify the pump, it's a 2 minute process. There is no safety issue if you replace the metal with something as good or better than what was there. I didn't "hack" my car at all. Just my 2 cents.

There absolutely is a safety issue, no question. I dont care if you hold the piece of metal down with 100 screws (or bolts). The metal's thickness is also of little relevance in this case. In the event of a rear end crash, the metal will always buckle and fail at its weakest point. By cutting a hole in the metal structure there, you've easily created the weakest point in the crash structure, and the metal would almost certainly fail there if hit hard enough. A jointed section (i.e screws or other bonding) is always going to be a point of failure. A solid piece of (uncut) metal there will crumple but isnt likely to be punctured or ruptured. For some people, I guess the risk to reward ratio is acceptable though.

**Firebirdjones** · 04-21-2013, 07:03 AM

Correct, if it met crash safety standards, GM would have incorporated the door in the car during assembly. There's a reason these cars don't have interior access to the gas tank.

Even the NHRA has similar rules for fuel cells.

It becomes even more critical with these 4th gens since they don't have a real trunk seperating the passenger compartment (unless you have a convertable).

I'd even tend to believe that it could become a liability if you ever sold the car, and the new owner happened to be rearended and an issue developed. 2 4th gens we've had were rearended and totaled, so I'd say that's a big chance to take.
Every used 4th gen we've bought I've pulled the rear carpet just to make sure the floor hasn't been hacked, I simply won't buy one that has. I've dropped the tank in all of them for fuel pumps, it's really not that bad to do.

**5.0THIS** · 04-21-2013, 07:41 PM

Originally Posted by Firebirdjones

I'd even tend to believe that it could become a liability if you ever sold the car, and the new owner happened to be rearended and an issue developed. 2 4th gens we've had were rearended and totaled, so I'd say that's a big chance to take.
Every used 4th gen we've bought I've pulled the rear carpet just to make sure the floor hasn't been hacked, I simply won't buy one that has. I've dropped the tank in all of them for fuel pumps, it's really not that bad to do.

That's a good point; I'd never considered that. It would make me wonder: if they cut corners putting in a fuel pump, what else did they cut corners on. Just my opinion.

**Firebirdjones** · 04-22-2013, 04:49 AM

Originally Posted by 5.0THIS

That's a good point; I'd never considered that. It would make me wonder: if they cut corners putting in a fuel pump, what else did they cut corners on. Just my opinion. :shrug:

You and I think alike. I've always thought that when shopping used cars. When they tell you "well it just needs this $20 part and it will be fine" or it's missing some other minor details that don't cost much to fix. It's always made me wonder how that car has been treated if they can't throw a $20 part at it, then it's likely they didn't want to spend money on oil changes either, or who knows what else. That stuff really kills the sale for me.