[racerg35335]

Ok, so I was having lfp drops with and without ethanol (2A2D shadow codes) so Installed the Walbro 455 today... which by the way is not fun but could be worse.. The car started fine and I plugged the cobb in and lpfp was sitting at 72 (great). Did some driving and monitored it and all looked good. I stopped and got gas before doing logs and when I fired up the pressure was steady in the 60's. Came home and turned the car off again for 10 minutes and when I started up again it was in the 40's and 50's. This is exactly what it was doing with the stock pump. At first start pressure would be ok but when I turned the car off and restarted pressure would be lower. Has anyone ever experienced this?? I have attached a log to see if anyone has any idea what is going on. They look fine other than the lpfp. I was originally thinking the regulator but hpfp is fine even when lpfp dives. I am thinking lfp sensor. I'm running stg1+ agg right now and want to go back to my e30 map (or more now that I have the walbro). If it is just then sensor then I am fine with it just want to be safe. Let me know what you think. Thanks!

[Ænema]

The pressure definitely isn't where it should be. What's kind of odd is that the pressure was so constant, normally the LP will overshoot and fall slightly below target and repeat. I don't run an aftermarket pump so i can't really help you out or give you tips beyond that, sorry man.

[G.I.Joe]

I just put my Walbro 455 LPFP in yesterday, and did a few logs. Drove around for like 70-80 miles, and stopped and started again a few times. Even went up to ~E70 mix to see how the newLPFP would do. Now my old one wasn't too bad, but it just wouldn't hold the pressure at high rpm/load, which gave some nasty drops in performance just above 6k rpm.

Also I drove around with the COBB AP live monitoring the LPFP all the time between doing logs. A few times it dipped into the 60's in the midrange just after gunning it, but other than that it now holds 70-90 psi to redline.

I suspect maybe your problem lies with the LPFP sensor or the HPFP?

[Tony@vargasturbotech]

I would replace your LP sensor, if you are dipping to 40 PSI you would see your HPFP being effected too. So the sensor may not be reading properly.

[neilvosko]

Check ur Venturi lines

[robc1976]

Originally Posted by neilvosko

Check ur Venturi lines

This and fuel pressure regulator behind drivers seat.

[enrita]

Bad installation , as said venturi line probably off

[racerg35335]

Originally Posted by robc1976

This and fuel pressure regulator behind drivers seat.

Originally Posted by neilvosko

Check ur Venturi lines

Originally Posted by enrita

Bad installation , as said venturi line probably off

Thanks all but Install is fine. Pressure is reading exactly as it did with the stock pump. Fine at cold start up lower as restarts and time goes. Venturi is correct for sure. I'm at a loss other than the lfp sensor. Basically having the same issue as I did before the install. Has BBC anybody had regulator problems???

[racerg35335]

Originally Posted by Vargasturbotech

I would replace your LP sensor, if you are dipping to 40 PSI you would see your HPFP being effected too. So the sensor may not be reading properly.

Exactly what I was thinking. If lp is dipping that low it should be showing up in the hp? I will replace the sensor next. Either way.... at least I have a lpfp installed and ready for your turbos in the near future. Thanks for the response.

[racerg35335]

Originally Posted by Ænema

The pressure definitely isn't where it should be. What's kind of odd is that the pressure was so constant, normally the LP will overshoot and fall slightly below target and repeat. I don't run an aftermarket pump so i can't really help you out or give you tips beyond that, sorry man.

Yea man. Its got me a bit baffled. I'm gonna have to get a fuel pressure gauge and check it. Something weird is going on. I would def say sensor but I'm not getting the code associated with that.

[cleex024]

Originally Posted by racerg35335

Yea man. Its got me a bit baffled. I'm gonna have to get a fuel pressure gauge and check it. Something weird is going on. I would def say sensor but I'm not getting the code associated with that.

hey man...how did you do this? was the install straight forward? and are you running this in series, parrallel, alone?

thanks

[racerg35335]

Originally Posted by cleex024

hey man...how did you do this? was the install straight forward? and are you running this in series, parrallel, alone?

thanks

If you are referring to the fuel walbro (e85) fuel pump install, it replaces the factory lpfp. It is not a drop in and requires a good bit of modification to the factory fuel bucket in order to mount the walbro. Its a bit of a pain in the a $$ and I wouldn't advice it unless you are or plan on running high ethanol content and/or are having low pressure drops or yours trims are not in check. Their is a DIY on the bms forum.

[cleex024]

Originally Posted by racerg35335

If you are referring to the fuel walbro (e85) fuel pump install, it replaces the factory lpfp. It is not a drop in and requires a good bit of modification to the factory fuel bucket in order to mount the walbro. Its a bit of a pain in the a $$ and I wouldn't advice it unless you are or plan on running high ethanol content and/or are having low pressure drops or yours trims are not in check. Their is a DIY on the bms forum.

but this was the 455 lph right? the 355 one that terry installed said there wasnt much modification for it to fit right in and i imagine the 255 is probably just a drop in. my trims look pretty good but my lpfp drops in the upper rpm range...drops to about 50 psi at 6500 rpm.

[racerg35335]

Originally Posted by cleex024

but this was the 455 lph right? the 355 one that terry installed said there wasnt much modification for it to fit right in and i imagine the 255 is probably just a drop in. my trims look pretty good but my lpfp drops in the upper rpm range...drops to about 50 psi at 6500 rpm.

If I am correct the 455 and 355 terry was referring to are the same pump. I think he was referring to it being 355lph at 13.5 volts. Regardless the install is the same. As far as I know walbro does not make a direct drop in for our cars. Sounds like your lpfp is starting to run out of steam at higher rpms. You can also log your hpfp actual vs requested and make sure it is not being affected by the lp drop. Mine was dipping into the 20's before hpfp was being affected. But I am still having that problem... thinking my hpfp is going bad. Or you can just install the walbro and run more ethanol.

[cleex024]

Originally Posted by racerg35335

If I am correct the 455 and 355 terry was referring to are the same pump. I think he was referring to it being 355lph at 13.5 volts. Regardless the install is the same. As far as I know walbro does not make a direct drop in for our cars. Sounds like your lpfp is starting to run out of steam at higher rpms. You can also log your hpfp actual vs requested and make sure it is not being affected by the lp drop. Mine was dipping into the 20's before hpfp was being affected. But I am still having that problem... thinking my hpfp is going bad. Or you can just install the walbro and run more ethanol.

well mine dips into the high 40s but does not affect hpfp much if any...so if thats the case then i should be fine with what i have right?

[racerg35335]

Originally Posted by cleex024

well mine dips into the high 40s but does not affect hpfp much if any...so if thats the case then i should be fine with what i have right?

I still would be a bit uncomfortable with it going that low but in reality if your hpfp, trims, and afr are all on target you should be fine. You might wanna try running a lower ethanol content and seeing if you can get the lpfp up closer to target (72). Regardless keep a close eye on it. Thats how my problems started (dipping into the 40's) and I have replaced my entire lp fuel system trying to solve the problem. My problem seems to be on the hp side which is affecting the lpfp. My problem persisted even when running regular 93 though. If you hit target on 93 then there are no problems. Most likely your lpfp just can't keep up with the amount of ethanol content you are running.

[cleex024]

Okay thanks