Can a Walbro 255 damage the stock fpr?

[idt512]

Bought a 2g with a Walbro 255hp fuel pump without an AFPR, had a stock pump laying around so I put that in place temporarily until I get my 190lph pump. Anyway the problem Im having is the car runs lean at WOT (only .79-.85V on the logger), it runs perfect at part throttle and has no driveability issues, o2 sensor cycles properly. I add about 5% fuel on the SAFC and seems to have no change on the o2 voltage, Im wondering if its possible to have an o2 sensor that cycles properly but does not quite get up in voltage even thougth the AFR is correct, or do I have a faulty stock FPR?

Turbo is a T28 @ 7psi (until problem gets solved), injectors are Evo 560cc, my SAFC hi throttle setting is at -8%, I should have plenty of fuel with those settings

 

[TheBigPhantom]

I would also like to know the answer to this question

 

[SpeedAddict62]

One key thing to remember is a narrowband O2 sensor is very inaccurate at anything other than stoich (14.7). If you ever see a graph of AFR vs. voltage output for a narrowband, you'll see that it is very much non-linear and changes in AFR around stoich result in a large change in voltage while changes in AFR far from stoich result in little to no change in voltage. As long as your O2 voltage stays within that range at WOT, and you aren't getting any knock, I would say it isn't something to worry about. To be totally sure, you would need to install a wideband O2 sensor to get an accurate reading of AFR.

I've driven around with a 255 HP and stock regulator for probably close to a year and just recently installed 1000cc injectors. Although I'm definitely overrunning the FPR, (my base pressure with the vacuum line on is around 44 psi!) it still holds pressure just fine.

Why don't you consider buying an AFPR instead of taking out the 255 HP? You'll have more than enough fuel flow with consistent fuel pressure, and they can be had for around $210-230 with a full install kit. MAPerformance seems to have the best prices.

 

[Raptoreborn]

Great topic!

I had the same problem when I purchased my car. It had the 255, which over ran horribly so I decided to purchase the 190 pump versus spending over $200 for a fpr. Which would all depend on your goals.

 

[pj91gsx]

I dont think it damages it but it does over power the stock regulator, making the car run rich at idle. Maybe when driving too idk. It washed my cylinders down in less then 20 miles also didnt have an oil cooler and lots of gas in the oil. I know better now.

 

[crimsondragon]

You have a higher chance of blowing out the injectors than damaging your FPR.

 

[pj91gsx]

You have a higher chance of blowing out the injectors than damaging your FPR.

Theres an even higher chance of you rings wearing out. My friends rings wore out after the 255 was on for 1 year.

 

[1LE]

I dont think it damages it but it does over power the stock regulator, making the car run rich at idle. Maybe when driving too idk. It washed my cylinders down in less then 20 miles also didnt have an oil cooler and lots of gas in the oil. I know better now.

I can say that a 290lph pump damaged my stock FPR, so I'd imagine it's possible that a 255lph might as well. Seemed to work fine at first, but after a few years it started noticeably overrunning while on boost, then a couple years after that, the FPR just up and died. Engine would flood instantly when I tried to start it. Buy an AFPR now and avoid the rush later on.

 

[240sxpooter]

if you tune your car in properly then the the walbro 255 shouldn't cause any problems

 

[AWDTSIer]

Not trying to hi-jack the thread but what is a 190 LPH capable of?

 

[240sxpooter]

Not trying to hi-jack the thread but what is a 190 LPH capable of?

RRE Instructions

 

[idt512]

Wow havent on here in a while, I thought nobody ever answered this thread... Anyway, my problem has been solved, it turned out to be the Oring on the fuel pump assembly was on the wrong side of the spacer, when I installed my stock fuel pump I copied the exact same mistake, but when my Walbro 190 arrived in the mail, I went over the instructions and saw the correct way it was supposed to be installed, plenty of fuel now

 

[No_Skillz]

if you tune your car in properly then the the walbro 255 shouldn't cause any problems

Yes it will. Without an AFPR you cannot raise fuel pressure 1:1 with intake pressure. You can compensate during idle, but the tune will be a mess at higher RPMs.