LS1GTO.com Forums banner

1 - 20 of 30 Posts

·
Registered
2004, Pontiac GTO
Joined
·
26 Posts
Discussion Starter #1
Hey gang so as I've said in another post I just recently bought a 2004 GTO. Heads/Cam and procharger. 60lb injectors. I bought the car, did a couple of pulls, didn't notice any issue but they weren't long pulls. Just quick roll ons. About a week ago I was getting onto the toll road and got into it for a few seconds. And the car started breaking up. So I immediately stopped at an oriellys on my way home and got a fuel pressure gauge. Car was losing pressure under load very quickly. Which is the first video named "Needs more pump". I replaced the factory fuel pump with a Deatschwerks DW300C. Should be plenty of pump right? The second video shows I'm still losing pressure very quickly. The pressure gauge is hooked up at the rail. Let me know what you guys think. I want this car at 100%.


 

·
Registered
2004, Pontiac GTO
Joined
·
26 Posts
Discussion Starter #3
Pull the pump and check youre oring work. Prolly messed up. Assuming the wires aren't burnt up now.
I was losing pressure the same way before I installed this pump so I would assume the issue is not with the pumps installation. But something else. And I've check the wiring in and around the tank. It's all good.
 

·
Registered
Joined
·
639 Posts
I was losing pressure the same way before I installed this pump so I would assume the issue is not with the pumps installation. But something else. And I've check the wiring in and around the tank. It's all good.
Could be a bad regulator. Clogged filter. If you were losing pressure like that before and now after the pump it’s quite clear where the issue is. Could also check the two soft lines for a blockage.
 

·
Worthless reject member
Joined
·
39,242 Posts
If you bought the car already modded it probably had a higher volume pump in it already.

Depending on your setup and how much fuel you need, you might just be out of pump. I also agree with checking the regulator and filter, although from what i understand the regulator does not typically go bad. I think going with a new bucket and a drop in pump is better than putting a drop in pump in an old bucket, and a custom setup is better than that for higher fuel consumption needs.

There is also the known issue with the stock bucket and higher flow pumps that cause the bucket to get sucked dry when the fuel level is low.

Are you running the factory hard lines? How much boost are you running? What blower head unit do you have?
 

·
Worthless reject member
Joined
·
39,242 Posts
Could also check the two soft lines for a blockage.
You know, this made me think of the russel fuel lines a lot of owners have on their cars. I wonder how they hold up after years, or for that matter up to ethanol.

Wouldn't be a bad idea to replace both hoses anyway, by the engine and by the tank. The tank supply plastic line is still available from GM.

I wouldn't imagine it is possible for an easy replacement for the in-tank hose from the bucket. I'll have to look into that one.
 

·
Registered
2004, Pontiac GTO
Joined
·
26 Posts
Discussion Starter #7
Could be a bad regulator. Clogged filter. If you were losing pressure like that before and now after the pump it’s quite clear where the issue is. Could also check the two soft lines for a blockage.
There's another filter? I thought the only one was the one in the tank. I read that GTOs don't have in line filters.
 

·
Registered
2004, Pontiac GTO
Joined
·
26 Posts
Discussion Starter #8
If you bought the car already modded it probably had a higher volume pump in it already.

Depending on your setup and how much fuel you need, you might just be out of pump. I also agree with checking the regulator and filter, although from what i understand the regulator does not typically go bad. I think going with a new bucket and a drop in pump is better than putting a drop in pump in an old bucket, and a custom setup is better than that for higher fuel consumption needs.

There is also the known issue with the stock bucket and higher flow pumps that cause the bucket to get sucked dry when the fuel level is low.

Are you running the factory hard lines? How much boost are you running? What blower head unit do you have?
I said it had the factory pump in it. I replaced the factory pump with the DW300C. The fuel system had not been modified by the previous owner except for the 60lb injectors.

Factory lines, supposed to be close to 10lbs with the pulley setup, and P1SC.
 

·
Registered
Joined
·
639 Posts
There's another filter? I thought the only one was the one in the tank. I read that GTOs don't have in line filters.
They don’t have in line technically. Just the filter built into the bucket. Then the sock as some people refer to it as a filter as well.
 

·
Registered
Joined
·
639 Posts
Eite
I said it had the factory pump in it. I replaced the factory pump with the DW300C. The fuel system had not been modified by the previous owner except for the 60lb injectors.

Factory lines, supposed to be close to 10lbs with the pulley setup, and P1SC.
Either way it’s not a good idea to run without reference. Maybe one of those fancy controllers would help.
 

·
Registered
2004, Pontiac GTO
Joined
·
26 Posts
Discussion Starter #11
They don’t have in line technically. Just the filter built into the bucket. Then the sock as some people refer to it as a filter as well.
Where is this filter in the bucket? I had the bucket apart and only saw the one on the pump.
 

·
Premium Member
Joined
·
113 Posts
Could be the regulator (Built into the bucket) or as said above, the filter which is white like the bucket and snaps apart to remove it.
 

·
Registered
2004, Pontiac GTO
Joined
·
26 Posts
Discussion Starter #14
Could be the regulator (Built into the bucket) or as said above, the filter which is white like the bucket and snaps apart to remove it.
Thanks for the suggestions everyone. And I got a new filter for that one you mentioned. So many threads said the only filter was the sock on the pump. Then I finally found one explaining the one you're referring too. How can I test the regulator there?
 

·
Premium Member
Joined
·
113 Posts
Thanks for the suggestions everyone. And I got a new filter for that one you mentioned. So many threads said the only filter was the sock on the pump. Then I finally found one explaining the one you're referring too. How can I test the regulator there?
Only way is to test everything else and eliminate any other cause... Make sure the fuel line isn't pinched under the tank, no leaks etc, and if it still drops like that, I'd say regulator. When you turn off the key does it drop the pressure right down? if so, then I'd have to suspect the regulator as well. It should hold pressure when the key is turned off.
Another thing since you will be replacing the filter, is make sure the spacer under the O-Ring on the top of the pump is in place. it keeps the o-ring up in the line to seal it.
 

·
Registered
2004, Pontiac GTO
Joined
·
26 Posts
Discussion Starter #16
Only way is to test everything else and eliminate any other cause... Make sure the fuel line isn't pinched under the tank, no leaks etc, and if it still drops like that, I'd say regulator. When you turn off the key does it drop the pressure right down? if so, then I'd have to suspect the regulator as well. It should hold pressure when the key is turned off.
Another thing since you will be replacing the filter, is make sure the spacer under the O-Ring on the top of the pump is in place. it keeps the o-ring up in the line to seal it.
I checked the lines, no pinches. I checked for leaks, no leaks. I pressurized it with key on but not running several times. The pressure didn't drop with the key on but yes it did drop when I turned the key off. And yes I took the spacer off of the factory pump and put it on the DW300C.
 

·
Registered
2004, Pontiac GTO
Joined
·
26 Posts
Discussion Starter #18
Did you double up on the oring?
No, is that something I was supposed to do? If so which ones? Factory pump didn't have any doubled orings. Also is there a different technical term for the regulator on the bucket? I can't seem to find it for sale anywhere under the name fuel pressure regulator.
 

·
Worthless reject member
Joined
·
39,242 Posts
No, is that something I was supposed to do? If so which ones? Factory pump didn't have any doubled orings. Also is there a different technical term for the regulator on the bucket? I can't seem to find it for sale anywhere under the name fuel pressure regulator.
DW says to use 2 orings for the pump. Usually one is fine, it is just precautionary.

But if you are losing pressure, it is something to check.
 
1 - 20 of 30 Posts
Top