Jump to content
SAU Community

Recommended Posts

Hi,

My stock fuel pump was making a hell of a noise so I got a Walbro GCA3386-2 (255LPH)

The mounting is different from stock. With this the strainer attaches directly to the pump while the stock pump sits about half way down the mounting bracket with a pipe to the strainer at the bottom. So with this the pump has to be mounted at the bottom of the bracket. 

Not sure what is the cause but on boost the car is running very lean. AFR is showing 18:1

On normal driving its fine.

The car has a Haltech fitted. Am I supposed to get it remapped after fitting the pump?

Do i need to change the FPR from the stock one?

Link to comment
https://www.sau.com.au/forums/topic/481207-leaning-out-after-new-fuel-pump/
Share on other sites

Was it a stock pump that was removed? if you have gone to a smaller pump that will cause the lean issue.
The walbro also require a wiring & relay upgrade as they draw a lot more current than the standard pump.

No need for retune after a pump swap but if its going lean check vac line to fuel reg, pump part numbers and that the filter on the pump isn't blocked.
 

Thanks Rob. I didnt know it requires a wiring and relay upgrade. Is it to do with the "relay mod" that some other threads mention?

Can you give any more detail on the wiring upgrade?

The vacuum line from the intake mani to the FPR  is fine. 

The new pump came with its own strainer. So that is new. I forgot to change the fuel filter in the engine bay. Will change that too.

 

10 hours ago, Die$eL said:

Can you give any more detail on the wiring upgrade?

It's just a case of giving the pump a decently thick power feed (and decently thick earth to go with it!) that is no longer passing through the original fuel pump controller. The relay allows you to switch the power to the pump however you like/need (ie, possibly still with the fuel pump controller) but the relay makes the power path direct from a main 12V +ve to the pump. Fatter wires to carry the current without burning up or causing voltage drop problems.

15 hours ago, Die$eL said:

 

Can you give any more detail on the wiring upgrade?

 

Generally I use a 50 amp relay, 40amp fuse with 5mm wire for positive and 3mm for negative. Either use an uninsulated crimp and pot the factory cap connection or use a new bulk head

https://www.efihardware.com/image/4937/Submersible-Pump-bulk-head-terminal

 

Most big pumps like the walbro 460l will draw 22-27amps at full load so I like to make sure it's up to the task. Even the old 255l will draw 14amp at idle and 22amps at full load. 

Did you change the fuel filter at the same time @Die$eL? Because if you didn't, there's a fair chance that is your problem. The filter will be full off contamination, including brass from the failed pump.

Thanks for the detailed info. This really helps.

I will upgrade the wiring, relay and change fuel filter then report back. 

Edited by Die$eL
  • Like 1
  • 4 weeks later...

A Big thank you for all of the advice. 

I've upgrade the wiring and this has resolved the leaning out issue. 

I've done a video detailing what I did and bits used etc. Hopefully it can help others who experience the same issue.

 

  • Like 1
On 9/26/2020 at 11:42 AM, White GTS-T said:

Did you change the fuel filter at the same time @Die$eL? Because if you didn't, there's a fair chance that is your problem. The filter will be full off contamination, including brass from the failed pump.

I've decided to run the car for a little before changing the filter just incase there was any contamination which got in while i was working in there. 

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

    • ok so if i wanted to go 18's i would go for 8's  in front 30+ or 32+ off set at front and the back 9 would be ok? what offset should i aim for.. then can i do some  hunting for wheel rim choices..    If i get this - will this fit all around: Size: 18 x 8.5 +37 - n what tyres size tyre should i get for front n back?  
    • Absolute f*cking nightmare. I had to take breaks constantly, and I was always pissed off when I got home. The line split in Italy on day 2 (we drove from the Netherlands), lol. Driving any narrow European town was... well, sh*t.   Appreciate it man. Here, I'll just drop a favourite from the load I took on Saturday.   I'll update here when things happen with the car, the thing is, with stock power and almost everything chassis-wise taken care of, there really are no problems. 268,000kms now and counting.  
    • Ah! I actually managed to snag a lightly used set.... that aren't so suitable for me right now. They don't work on a GTT without some cutting or creative heat moulding. I thought about reselling them myself cause I didn't want to murder them, but it looks like I'm probably going to attempt to murder them/melt them because I may as well. @GTSBoy @PranK can somebody close this thread?
    • Hey mate,  I have a set, one is slightly damaged but wont be noticable once installed.  Shoot me a message if your still after them 
    • I couldn't wait But, the black constant tension hose clamps were too thick and there wasn't enough clearance at the T/B and I couldn't get it to seat properly, so I had use a silver one there I also added some 3" silicone over the alloy bit that goes through to hole on the radiator support as it looked like it was sitting on the edge of the hole in the radiator support, I never noticed a rattle or anything, but there was a witness mark It is basicly done, and I can live with the silver hose clamp at the T/B, I will get a black clamp for the head vent though where it is attached to the bulkhead fitting  It never stops...LOL, only issue now with the shock tower brace is it slightly touches the under bonnet liner now, if I leave it it will either wear some paint off the brace where it touches, or damage the liner, so I removed the liner to see what I have to work with, with the liner removed I have about 20mm of clearance, but sadly the middle part of the underside of the bonnet is only dusted with paint and looks crap, so I cannot have that, but.... as I have a roll of Carbuilders premium under bonnet insulation in the garage laying around that is only 5.5mm thick (we were going to use it on the boys Patrol, but he crashed the front of it a few months and it was written off, hence why he now drives my old Honda Accord Euro), I'll use the OEM liner as a template and get the Carbuilders stuff fitted up to cover that dusted paint up
×
×
  • Create New...