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

    • Welcome to my 2004 Toyota Mark ii IR-V Fortuna (series 2) With a 1JZ-GTE powerplant under the bonnet (hood) it'll give me plenty of scope for power upgrades. For those who aren't familiar with imports, the 1JZ-GTE is a 2.5L 6 cylinder VVTi engine with a single turbocharger. This has the factory R154 5 speed gearbox, along with a aftermarket 2 way LSD differential (brand unknown). Under the arches are a set of CST Zero 1 alloys, 18x9 +30 225/40 up front and 18x9.5 +15 265/35 on the rear. The car was quite low in Japan and there's evidence of the wheels catching the rolled arches/fenders. The tyre's aren't great so I'm in two minds whether to replace both or just the tyres and put up with the wider wheels on the rear. The car still uses stock brakes with the addition of some braided hoses. The exterior is stock with the exception of a BN Sports front bumper and a replacement Fortuna grill  Moving to the interior, the steering wheel has been replaced with a dished MOMO steering wheel (which will get swapped for my Momo Tuner for the time being) Defi Link Gauges are mounted above the climate controls and on the A pillar, the Oil Temp,Oil Pressure,Water Temp and Boost gauges should help with spirited and track driving  The stock seats have been replaced with some retrimmed Recaro bucket seats. Being a larger build these are a little snug, unfortunately the orange isn't for me so I'll look into replacing these down the line. Other modifications include a twin plate clutch, Blitz intercooler, Evolve alloy radiator, a stainless exhaust with decat, HKS EVC-S boost controller and coil overs
    • Apologies for the long read My R34 GTT was up for sale at the beginning of spring due to a few repairs creeping up. The strut tops needed replacing, roof and bonnet (hood) painting (yay for 3 stage pearl) and the underside stripped and treated. I sold the car which allowed me to be in a much better place financially. Leading up to the sale I was already thinking about the replacement. In an ideal world it needed to be a good all-rounder. Something I can mess around with, modify, do track days, do the school run, go on long drives etc.  Options included but not limited to... Laurel C35, Evo 8/9, Civic FD2, Impreza Hawkeye, Aristo and even an Audi S4 Avant (I've already got the Mazda 6 wagon). But there was always one car at the top of the list The Toyota Mark ii JZX110 I found an advert on a Facebook group for an example in Japan, from a seller called Jon at Rising Sun Exports. A few messages back and forth and Jon calls me from Yokohama one morning (or afternoon in his case). He briefly explained the import process, the costs involved and a repeat of the advert. After much deliberation, the price was agreed and the sale was locked in. I've never imported a vehicle so I jumped into the unknown head first. The money transfer was completed through wise.com (fees apply), very easy to use and the money was with him within a day or two.  The car suspension was raised for the vessel and the car dropped off at the port. It was 7 weeks later when the bill of lading was received and the freight invoice sent to me, followed by the export certificate a couple of days after (both digital copies) In the mean time the port had been in contact. I needed an agent to deal with the NOVA (notification of vehicle arrival) along with the tax/duty invoice, this was £75.00. The port also had a fee of £100, I'm guessing to cover the cost of the 10 day 'free storage' and for moving the car off the boat etc. They need a copy of the vehicle invoice, freight invoice and export certificate to allow the vehicle to pass through customs. The vessel arrived on Tuesday 5th August, the tax/duty invoice was generated and sent over. This is generally tax 20% and duty 10% of the vehicle value. Although the invoice came in at a higher amount than I had calculated. Once HMRC had received the payment the vehicle could be released from customs. I thought once the tax/duty was paid you could collect at any point, that's not the case. Your agent will need to book a collection slot, I requested Thursday 7th which was accepted, with a 9:00am slot allocated. It was a 5:00am start from Norfolk heading to Southampton. We eventually found the compound, upon presenting the bill of lading and some ID they released the car (they drove it out of the compound to the front ready for us to load up). The email from the port stated each slot had a 10 minute window, which seemed abit farfetched but the staff said it's not a strict rule. We were there for approx. 30-40 mins in total. A week prior to collecting I contacted my garage and explained the situation, I was able to get an inspection slot that afternoon. For the registration, DVLA require the car to be insured, for this I used a company called Adrian Flux who can insure the vehicle using the VIN number. 
    • Hey guys, looking for these side skirts if anyone can help me out. 
    • Wife and I are still looking for a new home. One condition was a large enough garage for a full-size lift in one bay. Now if only we could find something... We've been looking for almost a year now.
    • Thanks everyone for the ideas! Sadly, ramps are a no go for me. With young kids at home, I do most of my work late at night while they're sleeping. Starting the car multiple times wouldn't be a great idea.  I'll go see one of those new long reach low profile jacks and take a couple measurements to see if they will fit.   
×
×
  • Create New...