1g FPR and W 255

[nuclearr]

What makes it that some 1gs do not have an issue running a 255 on the stock FPR?

Is it just a better stock FPR?

I had a 90 tsi fwd with a 255 and had no issues with it running rich.

 

[Black95TSIawd]

For the most part, it has nothing to do with the FPR. 2g's have a problem due to the siphon in the fuel tank that is used to bring fuel to the fuel pump from the other side of the saddle. That siphon is very small and once a high pressure fuel pump is included into the mix, the system backs up.

 

[Imback]

Correct. I have a 255 and am still using my stock FPR with no issue.

 

[MindBlowin03]

Its not that you would have issues but its certainly not the best way to do things. When you install a 255 pump your low and mid fuel trims are way out of whack weather you know it or not.

 

[Imback]

The low and mid fuel trims are easy to get back in spec if you know what your doing. And my low and mid did not change much after installing the 255.

 

[olddsmer]

Normally the 255 will overrun the 1g fpr. The diaphram usually weakens and
you start to run rich. Most reputable shops will tell you to put in an AFPR.


Regards
Greg

 

[nuclearr]

I know that I am running rich in my 2g with the 255. I was asking because I do have the stock fuel rail off my 90 gsx which I scraped about a year ago.

I know I need a AFPR I am just trying to get the car running to test drive the AWD swap which is nearly complete.

 

[MindBlowin03]

The low and mid fuel trims are easy to get back in spec if you know what your doing.

Agreed. You can usually tune that out if you have just a little bit knowledge.

I know that I am running rich in my 2g with the 255. I was asking because I do have the stock fuel rail off my 90 gsx which I scraped about a year ago.

I know I need a AFPR I am just trying to get the car running to test drive the AWD swap which is nearly complete.

Have you drilled the syphon hole bigger yet? If not it is very easy and literally only takes about 30-45 minutes total to do. I would definitely do that.

 

[1badpurple]

I was running the stock fpr with my wally pump. The diaphragm would eventually bust and I would just throw another stocker on.

 

[diambo4life]

No idea why you guys are having so much trouble with your stock FPRs. Here's what I have in my car:

• Bosch 044 Motorsports fuel pump (setup in the tank)
• Stock feedline to fuel filter.
• Stock fuel filter w/-6AN fitting on top.
• Walbro 255 inline pump (aka 392) [located bwtween stock fuel filter and fuel rail]
• 3/8" fuel line between fuel filter and fuel rail which has -6AN fitting only on the entry side.
• Four 1,600cc/m injectors.
• Stock FPR.
• Stock fuel return line.

Both pumps rewired (14.0-14.5VDC @ idle)

No problems. Car's run primarily on E85 although I run pump gas in it during winter months. No issues. Been doing so for 3 years now and I regularly run 35psi+ boost.

 

[Bricktop]

No idea why you guys are having so much trouble with your stock FPRs. Here's what I have in my car:

• Bosch 044 Motorsports fuel pump (setup in the tank)
• Stock feedline to fuel filter.
• Stock fuel filter w/-6AN fitting on top.
• Walbro 255 inline pump (aka 392) [located bwtween stock fuel filter and fuel rail]
• 3/8" fuel line between fuel filter and fuel rail which has -6AN fitting only on the entry side.
• Four 1,600cc/m injectors.
• Stock FPR.
• Stock fuel return line.

Both pumps rewired (14.0-14.5VDC @ idle)

No problems. Car's run primarily on E85 although I run pump gas in it during winter months. No issues. Been doing so for 3 years now and I regularly run 35psi+ boost.

Ditto. I'm only running a rewired Supra TT pump and a Stock fpr,return. still working great after 1.5 years.

 

[nuclearr]

Have you drilled the syphon hole bigger yet? If not it is very easy and literally only takes about 30-45 minutes total to do. I would definitely do that.

I am not familiar with that mod. Do you happen to have a link?

But what does the siphon have to do with running rich on a stock FPR?

I was running the stock fpr with my wally pump. The diaphragm would eventually bust and I would just throw another stocker on.

I have heard that before thanks. Brian

I see you sold your car what did you replace it with?

 

[92AWDHX40]

When i got my wally i had to get the afpr, i was running rich problem solved.

 

[magik95]

Today I had drilled out the siphon hole to 1/8 because I was running seriously rich because the return was backed up.

I originaly thought my afpr was crap so I took it off put the stock fpr back on same problem. Now that I dilled out the siphon it is a 100% better. Also the afpr would not adjust before I drilled the siphon now
it does.

 

[nuclearr]

Thanks I did not know about this I already have my rear seat out and the inspection plate off so it will be easy to drill the siphon pick up.

I know I need a AFPR, but I do not have a stock fuel pump right now I had to get new pump and fuel senders as the ones in the tank went bad from siting. The pump I got came with a 255 on it.

 

[1badpurple]

Yea I did sell the car. Its ok though, I replaced it with a 91 gsx!