can a stock fuel ecu run a 400lph pump okay

Well i think my pump is giving up the ghost as my car seems to becoming leaner and leaner over the couple of months but when i put more fuel in it has very little to no affect,i was told when mapped it was on the limit of the fuel pump so well needs must now to keep the engine safe,

so what i have brought is the 400lph walbro nice little unit but was wondering is it just a straight swop or am i needing to modify and bypass the stock fuel ecu to run it?

anyone?

saying that will i need a check valve

I would think so. If you are BPU you won't be running much above 4 bar fuel pressure which is about a 15 amp draw on a GST400.

I wouldn't try running a GST450 on stock wiring though.

I have to say these new Walbro GST pumps have some impressive flow figures. The GST450 is still making 300lph @ 6 bar

Lyndon.

well i just fitted it and the car starts then cuts out straight away gutted, lak of preasure not good with suprapod round the corner

You can fire the intank pump up by shorting the diagnostics ports with a paperclip. I'm sure you'll find the info on here for which pins.

If you get it to run constantly without the engine on you'll know if it's working...from the sound. The step back from that is to give it 12v from another source outside of the tank. This will prove if the pump works or not.

another member is running this pump on stock wiring and fuel pump ecu, so that answers that question,

with my problem it seems to have the 9v prime power but once i connect it to the pump it losses the voltage when i startbthe car i see 6v to get it started then it drops to 0v and soon cuts out.

i will double check my wiring this after noon( well rip it out and start again as maybe i put in a drity crimp from the bottom of my tools you never know ) but before i do i will check resistance through the connections to the actual pump so i will be able to pinpoint it to the pump or my posiblely bad conector.

i have just seen another thread where a member had to bypass his fuel ecu even with a 255lp, im thinking my ecu was on its way out as i was getting less and less fuel over the last couple of months i thought it was the pump but looks like it might be the ecu, great just before suprapod

well just check all wiring and it was all 0.2 ohms the pump its self was 0.4 which i thought was abit high but when i give it a feed straight from the battery by sorting b+ , fp it was flowing as normal

just fitted the relay mod and all is good boosting to 1.3 at 11.2 afr

my wiring diagram for mod http://www.mkivsupra.net/vbb/attachment.php?attachmentid=154220&d=1341391583

Well done for geting your car back up and running especially in time for Saturday, but maybe I am missing something here.

If you are running it as per your diagram then the pump only ever sees 12 volts, and never the 9 as previous, so why leave a known failed ECU in place? Now I am guessing the pump ecu is a pretty simple bit of circuitry and controls the pump from a series regulator transistor or IC and if its starting to fail to the degree it coudnt provide enough current for the uprated pump. If thats the case then there is every chance that whatever inside is starting to go down and whether thats a zener diode, electrolytic capacitor, resistor or other semiconductor, this will get worse and in time may not even provide the current you need to fire the relay you have added. Personally I would see this as a short term fix and would be looking at using the feed from your main ecu to trigger a relay with a very low coil current requirement, or relacing the fuel pump ecu and then using your mod. Just my opinion by the way.

shane totally agree, this is a short term mod and will change the ecu im unsure if this is down to the j spec ecu vs higher flow pump