Jump to content
SAU Community

Recommended Posts

Hello my tuning friends 

Just wanted to bounce some thoughts around here. What would you consider a normal time for fuel pressure to catch up to boost pressure?

Say your cruising at 4000 rpm at around 10% throttle, then you pin the throttle, how far behind the MAP pressure would you expect the fuel pressure to trail / how long would you expect it to take for the fuel pressure to catch up? Would you expect it to be linear, say the fuel pressure trails perfectly behind MAP by 2 psi and then when boost stabilises at the max setting, fuel pressure also stabilises?  

Reason I ask, very recently the fun police inside my ECU said no no to this happening (see attached picture) 

I've got the sad's looking at the data. Looks like my fuel pump isn't keeping up :(. Will have to think about long term solutions...

The silver lining is, the car drives fine. If you didn't look at any data you wouldn't know anything is wrong. 

FP lagging.jpg

I installed this pump just over a year ago -

https://aeroflowperformance.com/af49-1057-525lph-e85-hi-flow-fuel-pump

Do we think the pump is starting to fail, or should I be looking at anything else in the fuel system?

When it was originally installed, everything was fine. I checked the 98 and e85 tunes, all good. 

For quite a while now, maybe 8+ months I've been on 98 only and the pump has been keeping up. But now that I've put e85 in it (the tank is currently about 50% ethanol) the pump suddenly can't keep up. No idea what's changed in the past year to upset the pump. 

1 hour ago, Murray_Calavera said:

I installed this pump just over a year ago -

https://aeroflowperformance.com/af49-1057-525lph-e85-hi-flow-fuel-pump

Do we think the pump is starting to fail, or should I be looking at anything else in the fuel system?

When it was originally installed, everything was fine. I checked the 98 and e85 tunes, all good. 

For quite a while now, maybe 8+ months I've been on 98 only and the pump has been keeping up. But now that I've put e85 in it (the tank is currently about 50% ethanol) the pump suddenly can't keep up. No idea what's changed in the past year to upset the pump. 

I would not recommend using any of the aeroflow pumps. Very prone to failure.

*I use and recommend a lot of their products. Fuel pumps are still best to stay with the big player's TI, Bosch, Pierburg

  • Like 3
22 minutes ago, GTSBoy said:

It's less about the sock and more about what might have been shaken loose from the tank walls/floor maybe by E85 or summat.

Yep a thing for sure, in this case though I've been on e85 for many years. Maybe 6 or 7 years? Can't remember, but a long time now.

But yeah, looks like I'm going to have to swap out the pump for the 3rd time now, so we'll get to see what the sock looks like anyways. 

23 minutes ago, Dose Pipe Sutututu said:

lol they are sexy. 

My imaginary car would run a big boy electric fuel pump though. Maybe 2 of something like these in tank - 

https://fuelab.com/91901-1000hp-in-tank-power-module-fuel-pump/p327

But knowing my luck, I'd find out fuel lab can't make pumps and I'd be pulling them out again anyway lol. 

  • 1 month later...

I haven't logged any data yet, but I wanted to bounce this off everyone while I'm waiting to take the car out for a proper run. 

So the car was very hard to start this morning, finally fired and I took it to Supercheap to test the battery. Turns out the battery was low on voltage (can't remember the exact figure) and down about 250cca from where it should have been. Even though their simple battery tester said the battery was "fine, just needs a charge" they replaced it under warranty, pretty happy with that. 

Could a failing battery be the cause of the pump failing to keep up? The pump is pretty hungry, it pulls something like 20 amps from memory but I don't know how much this all matters when the car is actually up and running and the alternator is doing its thing. 

1 hour ago, Murray_Calavera said:

Could a failing battery be the cause of the pump failing to keep up?

Yeah, but maybe not. Maybe yeah. Maybe not. You know how it is. I mean, if the volts are low and the pump has reduced capacity, then it will maybe not be able to supply enough fuel to keep up with your peak demand, but it really shouldn't make it go lean as you're ramping up, then catch up again. The pump dynamics are (should be) a pretty instant trade off between flow rate and pressure, and even that shouldn't matter because it is actually the job of the fuel pressure regulator to take care of that dynamic, leaving the pump to see pretty much the same pressure and flow conditions any time the engine is running.

  • Like 1
1 hour ago, Murray_Calavera said:

Could a failing battery be the cause of the pump failing to keep up?

Maybe go log your voltage vs. RPM as you doodling around town. The issue could be your alternator is cactus which has been supplying fluctuating voltage to the rest of your car thus killing your pump early.

  • Like 1
15 minutes ago, Dose Pipe Sutututu said:

Maybe go log your voltage vs. RPM as you doodling around town. The issue could be your alternator is cactus which has been supplying fluctuating voltage to the rest of your car thus killing your pump early.

Should I be logging ecu voltage or battery?

Edited by Murray_Calavera

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

    • Seat of the pants assessment of the new intake: The car is way less "doughy" when hitting the loud pedal, especially off idle when stopped or in traffic, I did use a cheapo lazer thermal thingo to measure the temp around where the pod filter got its air, it was between 55 - 60°C, in saying this the car was shut off and not moving, so the OEM intake pipe was not supplying any fresh air to where the pod was when the car was at least moving A weird bonus was induction noise on the throttle in the cabin increased a bit,  I was worried that I was actually going to lose some of that induction noise I love so much, outside though, when I got the daughter to do a WOT drive by pass for me, the induction noise has increased alot when on the throttle, not quite ITB doort, but well up there I'm extremely happy with the results and have been exploring the country roads in the region  As for house mods: 1.New front fence is up and is awesome, it really upgraded how the joint looks from the street, and the added security is nice 2. Electricians have replace some interior lights, and with more lighting in the garage, a few new motion detecting lights out the front above the garage, front room, and at the front door, which I have already found heaps helpful coming and going, also now has fancy pants CCTV all round the house The only hold point for power though is the solar and batteries due to supply issues, although this will happen over the next few weeks 3. I have done a heap of landscaping out the front and I'm almost ready to do a new small retaining wall with some nice blocks to replace the brick and cemented in rocks around the raised garden beds cemented in river stone "was the fashion at the time" the house was built. I currently have a pallet of retaining wall blocks and 2 bulka bags of 20mm blue metal to replace the wood chip that is in the raised garden beds around the house 4. I now have 3 big raised garden beds for out the back to grow some vegetables, about 70cm high, 200cm long and 100cm wide 5. My 2 compost bins are already pretty full with brown, green and kitchen waste from the landscaping I'vedone so far, but they will probably take a few months to break down, so anything else that gets chopped, trimmed, and kitchen waste will just start filling the base of the raised garden beds to about 30cm before I start throwing 40cm of good compost, and stuff, for the vegetables to grow in, I'll need a few ton of compost and soil, but the local supplier can sent me bulka bags of the stuff Basically the logs, wood chips and a few strategically placed rocks for drainage, will give the beds some good organic materials down low to break down over time, and they will hold moisture during the warmer months to save the water in my big arse water tank if we don't get alot of rain So, all in all, the car and house mods are going well, and I'm really enjoying being retired, I sleep in too 0700 and slowly plod around inside until I feel like actually doing anything, and only work in the yard for as long as want, which has actually been alot over the last few weeks,  although when you look at it, it seems that not a huge amount of work has been done,  until I look at the before I started the work pics Happy days and good times indeed 
    • hahaha yeah. Plan is to get side skirts and probably just rear pods. But going to do them one-by-one. I've got a set that I really like from RHDJapen, but that one isn't shipped to AU. So need to find someone who can get it for me
    • Here's an idea, answer the questions I asked you as they are trying to work out WHY the LSD will be binding up in a straight line.
    • You haven't driven many modern cars then have you? Most of them have sfa steering feel with their stupid electric bullshit steering systems.
×
×
  • Create New...