leaning out above 7 lbs of boost

[michaelg]

My car leans out past 18:1 whenever i get above 7lbs of boost. I am currently running a maf-t and a Safc. in attempting to fix this problem i have upgraded to a walbro255 and rewired it with an stm rewire kit. I am also running evo 8 560cc injectors. i have in the last month also changed the plugs, wires, and the fuel filter. im completely lost as for what to do next.

 

[Dsmkauai]

Have you done a boost leak test yet? Is your gm maf working? Are you running a afpr with the w255 or stock fpr?

 

[T-Flexx]

I would check for an exhaust leak at the manifold or close by.

 

[xiteamxi]

My first thought was the afpr assuming you have one not rising 1:1 with boost as it should.

 

[michaelg]

I would check for an exhaust leak at the manifold or close by.

did that[DOUBLEPOST=1416285650][/DOUBLEPOST]

My first thought was the afpr assuming you have one not rising 1:1 with boost as it should.

that makes sense... is there any particular aftermarket one youd recommend?[DOUBLEPOST=1416285932][/DOUBLEPOST]

Have you done a boost leak test yet? Is your gm maf working? Are you running a afpr with the w255 or stock fpr?

I've done both a boost and exhaust leak test and found nothing. also im only trying to eventually make 300 hp so i was told an afpr wouldn't be necessary...

 

[Dsmkauai]

The reason a afpr is needed is you risk over running the stock regulator with the w255. This could be your leaning out. You have any way to check base fuel pressure?

 

[michaelg]

The reason a afpr is needed is you risk over running the stock regulator with the w255. This could be your leaning out. You have any way to check base fuel pressure?

how would i do that? thereason i just upgraded my fuel pump a week ago is because i was having this issue with the stock fule pump.

 

[Dsmkauai]

Well a afpr usually has a gauge and you just use that. If you don't have one yet you can tap a fuel pressure gauge into the fuel line. Or If you have a friend with a shop that has a fuel pressure tester kit maybe they can help you check. If the stock fpr isn't keeping up with your fuel demands, your def lean. Not saying it's 100% your problem but worth checking out.

 

[michaelg]

Well a afpr usually has a gauge and you just use that. If you don't have one yet you can tap a fuel pressure gauge into the fuel line. Or If you have a friend with a shop that has a fuel pressure tester kit maybe they can help you check. If the stock fpr isn't keeping up with your fuel demands, your def lean. Not saying it's 100% your problem but worth checking out.

that would be odd... im running a 13b at 10 lbs of boost

 

[Dsmkauai]

That has nothing to do with it. The stock fpr isn't meant to handle a w255 rewired. Just saying its all over this site if you search. I know you can run them and get away with it, I did it with my gvr4 for awhile with no real issues. I've added a fuel lab afpr to take out any risk. Especially since I'm turning the boost up! What else could it be? Your tune, vacuum leak at a line. Are you sure the line is on the fpr and has no tears? Maybe your maf is no good or a O2 sensor? Or you need to dial in your translater and safc? Could be many things.

 

[xiteamxi]

did that[DOUBLEPOST=1416285650][/DOUBLEPOST]
that makes sense... is there any particular aftermarket one youd recommend?[DOUBLEPOST=1416285932][/DOUBLEPOST]
I've done both a boost and exhaust leak test and found nothing. also im only trying to eventually make 300 hp so i was told an afpr wouldn't be necessary...

I'd recommend the fuel lab afpr , there smaller and which makes mounting easier though aeromotive has nice stuff. As for not needing one that's more due to the fuel pump not the 300hp your shooting for. If your trying to save some cash I'm sure you can find a used one. Bottom line if you upgrade the fuel pump you should get an adjustible regulator. Black Friday deals maybe?