smoke clears on stock turbo

2

.204

New member
I have a 94 with a nv4500. No fuel plate and afc mods 5x16 injectors 20 degree timing 4k gsk and 60lbs valve springs. It smokes hard on the bottom but when the turbo lites it will clear it up. Should a stock turbo be able to do that?? It will make 40lbs of boost and fuel pressure is set at 45psi
 
.204 said:
I have a 94 with a nv4500. No fuel plate and afc mods 5x16 injectors 20 degree timing 4k gsk and 60lbs valve springs. It smokes hard on the bottom but when the turbo lites it will clear it up. Should a stock turbo be able to do that?? It will make 40lbs of boost and fuel pressure is set at 45psi
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that doesn't sound right at all, my twin setup doesn't even completly clean up my 5x.014's

where you reading fuel pressure? hows the fuel filter?....who's injectors?
 
.204 said:
I have a 94 with a nv4500. No fuel plate and afc mods 5x16 injectors 20 degree timing 4k gsk and 60lbs valve springs. It smokes hard on the bottom but when the turbo lites it will clear it up. Should a stock turbo be able to do that?? It will make 40lbs of boost and fuel pressure is set at 45psi
Click to expand...

Sounds like lift pump fuel pressure is dropping quickly as RPM rises. I'd install a gauge and watch lift pump pressure as you run wide open up through 3000 rpm.
 
i am reading fuel pressure just befor the pump. The filter is new im not sure on the injectors i got them used form a buddy of mine, and yea the egt needle moves real fast!
 
I would check to make sure there aren't any leaks in the boost line to the AFC housing, and also check fuel pressure under load.
 
Rite. I have plans for twins just wanted to get the fuel done first. I still have the stock dvs could they cause this
 
You shouldn't be able to totally clear the smoke with stock DV's and stock injectors after working over the plate and AFC for full fueling.

You need to check pressure after the the lift pump and fuel filter, I assume you're checking pressure right at the injection pump inlet, that's a great location.

Checking pressure at idle or 2500 with no load is useless when it comes to hot setups with bigger injectors, you need to check lift pump pressure when the truck is WOT and at full load.
 
I was in it to day and watched the fuel pressure rite now it shows 60lbs at idle and at WOT it shows 40 i can not get it to go less than that. my last upgrade was the 4k gsk i tought that was my prob. but it still does not smoke much more on the top end
 
i run stock DV's and still dont clean up with the twins. has it always been able to clean up the smoke or did this just start happening?
 
.204 said:
I was in it to day and watched the fuel pressure rite now it shows 60lbs at idle and at WOT it shows 40 i can not get it to go less than that. my last upgrade was the 4k gsk i tought that was my prob. but it still does not smoke much more on the top end
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60 lbs at idle does not sound right... i believe these are the cummins specs for the stock lift pump.
-17-22 psi at idle, 25-35 at 2500 rpm no load


Where is your fuel pressure reading from?
 
ya those are cummins numbers, however there is absolutely nothing wrong with runnin around 50psi to the pump. The afc is what Id be checkin first, make sure that foot is gettin outta the way.
 
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