Jump to content
SAU Community

Recommended Posts

Hey guys,

Just having a bit of a high fuel pressure problem after installing my new Walbro 460lph fuel pump, was hoping someone might be able to think of something I have done wrong here.

So to give you all the information, I have just replaced my old Walbro GSS-342 with a brand new genuine Walbro F90000262. Straight swap over really, just removed the old pump and installed the new one, had to modify the cradle a tiny bit to fit obviously, but nothing drastic, very simple stuff. The only thing I did differently was instead of using the stock wiring harness, I ran wires from the pump directly through the lid using Superben's idea:

post-107339-0-16369000-1373095582_thumb.

Then from there to the relay and earth point, all as per normal. I otherwise haven't touched anything, didn't touch the fuel pressure regulator or anything in the engine bay from when the car was last running. I am using a Sard FPR as well.

After finishing everything off, I primed the pump to check it was working and it seemed to be, got this:

998031_10151473575522541_1255224751_n.jp

Seemed all good, so I primed it a couple more times for good measure, checked the pressure was still at 43psi, and then started the engine. Everything sounded fine, didn't suspect any issues until I looked at the gauge:

1014438_10151473575397541_77391480_n.jpg

This is just at idle, no throttle being applied. I checked everything over again, but for the life of me I can't figure out what I may have done to cause the fuel pressure to go out? Only thing I can think of is maybe having the lid/hoses off for a couple of days may have let air/something else in to upset the regulator? OR, perhaps there was an issue with my old fuel pump? I wouldn't have suspected so, it never surged or gave any trouble. Tuners never mentioned the car starving of fuel at all.

Any ideas? I would simply adjust the regulator again, but I'd like to know why the pressure has jumped up in the first place...

Link to comment
https://www.sau.com.au/forums/topic/428855-fuel-pressure-too-high/
Share on other sites

  • Replies 51
  • Created
  • Last Reply

Top Posters In This Topic

There are the higher rated sard Type-R fuel regs but I couldn't see that being a problem at idle. The FPR doesn't actually feed any fuel back to the return it only really comes in play under boost as far as I understand. Really got me stumped trying to work out whats going on. When you prime the car does the pressure go to the correct 43 psi again now or does it jump the higher pressure?

Return line probably isnt big enough

Yeh? Standard return line... Surely not everyone using this pump has upgraded fuel lines?

There are the higher rated sard Type-R fuel regs but I couldn't see that being a problem at idle. The FPR doesn't actually feed any fuel back to the return it only really comes in play under boost as far as I understand. Really got me stumped trying to work out whats going on. When you prime the car does the pressure go to the correct 43 psi again now or does it jump the higher pressure?

Nah when priming it always goes to 43psi. It's only when the engine is running that it goes to 60psi.

Ah disregard my post I just read a little more to get a better understanding (haven't mucked around with aftermarket fuel regs yet) I'd have to agree that increasing the fuel return is likely cause couldn't be much else at idle coming into play

Do you have some spare fuel line lying around that you can run from the FPR outlet to a large container/bucket, then start the car and see if theres a different in fuel pressure. It's not the safest way to do it but will give you an answer as to wether it is the FPR or return line that is causing the issue.

Obviously be careful if you decide to do this because of fuel vapours and stuff, probably best to do it outside :)

But yeah if you use the largest size fuel line that will fit on the Reg then you should have no restriction there. I can't say I've ever heard the return line being a problem, but thats not to say it isnt the problem.

The return bypass hole in the reg is probably only 2mm in size so I don't think the return line size will matter much. Are you sure the reg is genuine? I assume all was well with it before the pump change?

Can you perhaps try fitting another reg? I run the relatively cheap SX reg with twin Walbros on e85, no issues here.

Unfortunately I don't have another reg I can try, or any fuel hose :/

I am pretty sure the reg is genuine, I bought it from a seller on here... Hmm, this is a bit trickier than I thought it would be :(

What voltage is present at the pump now, as apposed to before? Is the FPR adjustable?

Was 14v, haven't actually checked this time. I'll have to borrow a multimeter. The FPR is adjustable yeh. I was going to try to adjust the pressure, I just don't want to cover up any problems by doing so. It was all working fine with the old pump, so just want to be sure everything is ok.

I get around 62psi pressure before it reaches the fuel reg so it sounds like maybe the reg isnt doing its job and is just running full pressure straight as it comes out of the pump.

what does that mean? The reg creates pressure in the system before it, all the way back to the pump.

what injectors? i would not be too concerned unless its bouncing, its not uncommon to to run 60-80 base pressures depending on target boost and pump capabilities. ID recommend a base of 60-100psi depending on application. I generally run 60psi on bigger injectors ie 1000 and 2000cc.

Basically keep TOTAL pressure under the injectors limits.

ID725 - 8.5 bar, 123.5 psi.
ID850 - 7.0 bar, 101.5 psi.
ID1000 - 7.0 bar, 101.5 psi.
ID2000 - 9.0 bar, 130.5 psi.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Hello!  i just finished manual swaping my r34 skyline with a r33 rb20de box(RB71C)box  When the car is running it squeaks crazy loud and it was smoking from the gearbox area. The gearbox is fine it was tested. The clutch slave cylinder seems like it doesn't fully releases the clutch. I want to ask if this noise is from the throw out bearing or could it be the clutch assembly or disk att.xFliq87Gzw6kImKBVqDebXkj0fBqymk0JaYeP3_3SlM.mp4
    • A few small updates since the previous post and lessons. I decided to do a little interior light upgrade on the 110. I quite like the iilumo items, even if they're a bit of a premium over other brands. You'll also note the Stedi Fogs, that will go into the S15 fog lights as I needed to match the bulbs since I got the new ones earlier. I hope they fit as the body is quite a bit longer than your normal bulb.  Annoyingly, I managed to trip the fuse, which normally wouldn't be an issue until I located the fuse. I can't say I've ever come across this. I had lucked out that someone nearby had a spare, but oddly enough Toyota dealerships seem to keep this in stock. I ordered some to keep in my stash and as luck would have it, someone else nearby tripped the same fuse so I passed on the favour.  I also did a little service on the 110 ahead of some additional work coming up. It's been annoying that Goleby's stopped carrying this particular HKS filter for the 110, so now I need to keep them on order from Japan. I also took the opportunity to install a bash plate and number plate riser. The plate riser is such a cheap but nice fix to help really tidy up the car. I'm tempted to now also replace my headlights, on this car. Both items were from Project Aero.    I also needed to replace the rear tyres on the 110, and after trying to get it aligned learnt that I need to replace some bushes in the front end, so that's next.  Closing out this update with a nicer picture as always! 
    • Yeah mate, never miss it.
    • Any going to watch World Time Attack at SMSP this year?
    • Appreciate the correction on the "ground", that will make a huge difference to looking at this. That makes complete sense about AF70/AF71 which is what I had come down to being the issue, one of these. I'll have another look in the ignition wiring when I get a chance next week. I'll also make up a jumper wire for running that AF73 test.  ECU is fine, relay itself is fine, pump harness is fine and the pump itself is fine. I am going to upgrade the Walbro 255 anyway with a DW300 I have since I need to replace the fuel sender and I'm going to upgrade the FPR with my chasebays kit ready for new plenum/injectors/dbw, but I'll get this working first. That's why this is so frustrating. 
×
×
  • Create New...