7mgte having to add too much fuel maft pro

[1987mkiii]

I just installed my rebuilt 7mgte 60-1 trim ct-26 with 550cc injectors and maftpro running in speed density, the issue is that when the mainscale is set at -25 like it should be for 550cc injectors it runs lean, I had to set it for over +20 to make it run good. It runs good at that setting except for hitting boost cut at like 4psi (due to adding +23 on mainscale)

Any ideas why, I have the stock fpr and that is the only thing I could think of that may cause this, when the fpr fails will is fail like this and not provide enough pressure?

Any other reasons why I would have to ADD fuel with 550's?

Thanks in advance

 

[topekamk3]

Stock fuel pump?

 

[1987mkiii]

Yes stock pump for now, I have a walbro to go in it but I didn't think that would cause this considering it has the issue at idle as well so the pump should be sufficient

 

[topekamk3]

It could be getting pretty weak, but first thing I would check is fuel filter/sock on the fuel pump. I just had an issue with losing fuel pressure in boost and it was just a plugged up filter.

 

[1987mkiii]

Would you suspect the pump before the fpr?

Is the aeromotive kit worth it for my application?

 

[topekamk3]

I'd think pump/filter before fpr. However if you have a walbro 255 you are putting in, I'd get an adjustable fuel pressure regulator.

 

[IndigoMKII]

You asking the old worn out fuel pump to supply MORE fuel than it was intended to do AND question why it's not working properly?

Do this, walbro 255 or comparable and the AFPR kit. The j-tube is a massive restriction in the fuel system not to mention all the banjo bolts.

 

[1987mkiii]

So to sum it up I should do both as they are both going to be necessary for this build. As far as I can tell there are no other components in the system that would create the need to add fuel with larger injectors.

 

[topekamk3]

Yes and do a fuel filter as well, then unless you have a pinched line you should have no issues.

 

[jonahs_supra]

Do you have correct wideband selected?
What do you have boost enrich. set at?
Mine was doing the same thing but im running stock injectors
Purchased A1000 afpr and set base pressure to 42psi...ran good til walbro began to die after 6 months lol
Also i increased boost enrich to IIRC 1.4 or 1.6