New Fuel Pump and car is rich

[jgio213]

Hey Guys...
Here we go... about 3 weeks ago I installed a fuel-lab AFPR in my car to prepare for a new wally 255. At the time I had a 195 pump in there and set my regulator to 43PSI and had zero issues, car ran great, regulator did its job perfectly. Today I threw in the new 255 pump and I'm a bit stumped. The AFPR is only reading 20PSI no matter how it's adjusted, the car is running rich, and It will not build boost at all when I test drove to see what else is going on. Also when shutting the car off the pressure on the gauge immediately drops to zero. On the test drive AFR's were all over the place and the car ran like shit whenever i got on the gas. I'm not sure what's changed beside the pump obviously, but is an air pocket or something like that feasible? The pump has been rewired for years, and I run FIC 750's, and car was tuned to 20lbs of boost and ran like a top before putting the 255 in. I haven't found any fuel leaks or anything like that and I'm really stumped and looking for guidance before I take the 255 out and put the 195 back in to see if it goes back to normal. All adjustments were attempted with the vac line off regulator and clamped, and car was at running temp. Thanks in advance for any help, hope we can sort this out.

John

 

[91talonts1]

How are you reading fuel pressure? If it's one of the little regulator mounted ones that come with the afpr they can be hit or miss. If actual fuel pressure was 20psi I doubt the car would run, let alone run rich.
Nice 2gb talon btw!

 

[steve]

Today I threw in the new 255 pump and I'm a bit stumped. The AFPR is only reading 20PSI no matter how it's adjusted

That sounds a lot like it's leaking inside the tank. Did you make sure that there is a check valve on the pump? How is the pump coupled to the feed tube, O-rings or what?

 

[AWD-Tony]

Bad pump or not assembled correctly would be my guess. Also recheck the wiring to make sure you're getting property voltage out of the relay.

 

[jed344]

Sounds like a leak at the pump.

 

[jgio213]

How are you reading fuel pressure? If it's one of the little regulator mounted ones that come with the afpr they can be hit or miss. If actual fuel pressure was 20psi I doubt the car would run, let alone run rich.
Nice 2gb talon btw!

Thanks for the like, I dig yours as well. Its the fuel lab guage that came with it. I originally thought bad gauge as well, but it was reading perfectly prior to putting the 255 in So i think like others have mention it is leaking in the tank.

 

[jgio213]

That sounds a lot like it's leaking inside the tank. Did you make sure that there is a check valve on the pump? How is the pump coupled to the feed tube, O-rings or what?

Hi steve,
The pump has the orings on it, as far as a check valve I did not notice one or put one on it but I do have some kicking around. Are you referring to a check valve on the feed tube? And if it is leaking in the tank has it just not seated properly, or bad oring? either way Im going to pull the assembly back out and start over.

 

[jgio213]

Bad pump or not assembled correctly would be my guess. Also recheck the wiring to make sure you're getting property voltage out of the relay.

Voltage was good I did check that. So im guessing like you said and others I assembled the pump incorrectly. I'm going to pull the assembly back out which is awesome, and go back through the vfaq and see where it went wrong hopefully.

 

[jed344]

Most times it’s the black O rings that fit over the pump. I never had a issue with them sealing even with a walbro 450. Just ran out of pump is with my new walbro 525 I am switching to the STM bulkhead fitting so it will for sure seal.

 

[jgio213]

Spot on guys thanks for the suggestions. When I removed the pump again the black o-ring didn't seat properly and I forgot to add this spacer in there so naturally it was my own error and nothing wrong with the pump or regulator. Regulators set and shes running like a champ now, so I appreciate the help.

 

[steve]

Good job! Glad you solved it.