Base Fuel pressure with a Walbro 255?

tom04841 · 05-24-2005, 05:27 PM

Let me start off by saying i have a 90 nt that was converted to turbo.....stock turbo pistons, injectors, blah, blah, blah.

i got a really good deal on the 255, and realize i need an AFPR. I am just curious to what i should set the base pressue to once the AFPR and pump are installed?

I can provide any other info you may need.

Dred · 05-24-2005, 06:37 PM

39 psi for 1g 43psi for 2g (stock values).

Burnett03 · 05-24-2005, 06:59 PM

Quote:

Originally Posted by tom04841

Let me start off by saying i have a 90 nt that was converted to turbo.....stock turbo pistons, injectors, blah, blah, blah.

i got a really good deal on the 255, and realize i need an AFPR. I am just curious to what i should set the base pressue to once the AFPR and pump are installed?

I can provide any other info you may need.

38psi... Or you can bump it a bit to 43psi to get a bit more from whatever injectors you are running.

tom04841 · 05-24-2005, 07:37 PM

So would that 38-39 psi be with the vacuum line connected or disconnected?

Burnett03 · 05-24-2005, 08:07 PM

Quote:

Originally Posted by tom04841

So would that 38-39 psi be with the vacuum line connected or disconnected?

disconnected.. When setting base pressure its always with the vac line off.. When the line goes back on the pressure will drop (depending on how much vac.) the car is at.

Burnett03 · 05-24-2005, 08:08 PM

also i would bump the pressure to 43psi base just to be safe since you did a turbo swap? or did you swap the whole turbo engine?

DSM90AWD · 05-25-2005, 07:52 AM

Quote:

Originally Posted by Burnett03

also i would bump the pressure to 43psi base just to be safe since you did a turbo swap? or did you swap the whole turbo engine?

Just remember that without an AFC or eprom mod, running higher than stock fuel pressure will impact your fuel trims.

May want to update your vehicle profile with some of the other mods

tom04841 · 05-25-2005, 02:31 PM

Vehicle profile updated!!!

I basically converted my block to a turbo block, minus the squirters......1g stock turbo pistons and rods. Everything else was swapped over from a wrecked awd tsi. So i would imagine that the 38-39 psi would ork fine. If i was to set the base pressure at 43psi, wouldn't i be running rich?

Not to stray from my main question, but i can't seem to keep an O2 sensor from going bad in my car. I am on my third O2 in like 1000 miles. Got them from Autozone....Bosche O2. They will work for like a week or so, then die......its weird. Any Ideas?

JiggahMan · 05-25-2005, 02:57 PM

Quote:

Originally Posted by tom04841

Not to stray from my main question, but i can't seem to keep an O2 sensor from going bad in my car. I am on my third O2 in like 1000 miles. Got them from Autozone....Bosche O2. They will work for like a week or so, then die......its weird. Any Ideas?

Don't let the wires touch the exhaust mani, turbo, or downpipe.

DSM90AWD · 05-25-2005, 03:22 PM

Quote:

Originally Posted by tom04841

Vehicle profile updated!!!

Quote:

I basically converted my block to a turbo block, minus the squirters......1g stock turbo pistons and rods. Everything else was swapped over from a wrecked awd tsi. So i would imagine that the 38-39 psi would ork fine. If i was to set the base pressure at 43psi, wouldn't i be running rich?

Yes without an AFC or eprom mod you'd run rich and your fuel trims would likely pin at 80% (1990 ECU).

Quote:

Not to stray from my main question, but i can't seem to keep an O2 sensor from going bad in my car. I am on my third O2 in like 1000 miles. Got them from Autozone....Bosche O2. They will work for like a week or so, then die......its weird. Any Ideas?

BTW.. what ECU are you using? NT or Turbo? Are you sure you have the right O2 sensor for the right ECU?

Out of curiosity, how do you know the O2 is bad? CEL?

tom04841 · 05-25-2005, 04:45 PM

I have a 90 MT turbo ecu. I had autozone look it up, and there was nothing listed for a 90 turbo, so i got one for a 92 turbo. And yes, my CEL comes on throwing the O2 code

Talesin · 05-25-2005, 09:10 PM

I'd recommend running it at 36-38psi with the vac off... previous owner tossed one on with no AFPR, and it was running at 35psi with vac on. Hugemongously rich, really bad fuel stink, terrible mileage, and it ended up coring out the stock injectors.

Also, I'd recommend an Aeromotive AFPR. Mine's been pretty darn good, and Import Evolution sells an IE-AFPR kit with all the fittings and adaptor you need to bolt it up with a stock fuel rail. But be CAREFUL with the teflon tape. Put on a little too much, and it got into the aperture of mine... won't hold fuel pressure now when the car's off, takes it a bit to get press high enough to start. Oh, and the bolt-on B&M underhood fuel pressure gauge is a lifesaver. Cut down on adjustment headaches SO much.