Hey everyone I am still fairly new to these IDI’s and can’t seem to figure out how to get more fuel outta my factory turbo’d 94?

I have adjusted the main fuel screw underneath the triangle plate, backed the torque screw all the way out till it’s literally hanging on by 2-3 threads and have even screwed the “minimax” screw all the way in too ! Nothing is helping me make more fuel. The truck doesn’t smoke when I floor it or anything thing unless I am revving it up while parked. My objective here isn’t to roll coal but it feels super lazy at higher rpm’s and I want more fuel for more power but at 15 psi I am at my limit. Any info can help me cause it’s driving me nuts. Really don’t wanna spend $2k on a performance pump if I am not at my max. Truck just has a wicked wheel 2 and that’s it !

 

Check your fuel pressure by removing the schrader valve from the fuel filter and running a line inside the cab to a 0-15 psi gauge. What happens to your fuel pressure when your driving up a grade at full power? You should have 3-5 psi. If not, than your mechanical lift pump is getting weak.

 

Do you have a pyrometer? I've read that you want to adjust the fuel delivery screw a maximum of two or three flats (60-180*). If you adjust it too much you'll roll coal constantly and suffer from high exhaust temps.

Be aware that the mechanical lift pumps are known to leak diesel into the crankcase. I'm going to change the 3rd one on my 6.9l IDI this weekend when I get a Facet Duralift pump I ordered.

 

I have an electric lift pump already, deleted the mechanical pump and is running 5-7 psi perfectly fine under any load including carrying 2k pounds of water and car wash equipment. Did filters and other things and have ruled out everything.

i have an egt gauge too and I have maxed out my Injection pump too and I still don’t smoke like you are mentioning. I believe I bottomed out the screw but it’s so tight I don’t wanna risk breaking it by tightening it if it is bottomed out. Full throttle carrying all that water and flooring it up a grade I barely see 1000ish degrees on my gauge.

does anybody have a pic of the screw bottomed
out ?

 

Here's a good thread.

https://www.ford-trucks.com/forums/8...ctor-pump.html

Do you have a way to set the timing on your IDI? Apparently there's a second screw you can adjust that effects the IP timing.
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I have no way to check timing sadly !

 

So I brought the boost down at 8 psi and I can get it to smoke a tiny bit but only when I lug it. It still acts like it’s outta fuel above 2000ish rpm especially after 2500rpm. The truck use to leave little clouds of smoke when I use to floor it and now it doesn’t? Something is weird here !

 

How did you bring the boost down? Do you have a boost gauge?

 

you descriptions of what you adjusted sounds like you did something seriously wrong. the fuel screw on the side of the pump under the cover should not be turned more than about 3-4 flats on the allen wrench( about 1/4 turn)
i have no idea what you are talking about with the torque or minimax screws.

 

Nothing got done wrong as I haven’t messed with the fuel screw since this issue began. Been almost 6 months since I last touched it. This issue happened over time where the truck started smoke less and less. Torque screw controls fuel top end and the minimax screw supposedly controls top end. No offense but if you didn’t know what I am talking about why comment ? I am looking for people with experience sorry !

 

i do know what i am talking about, i had 7 IDI powered trucks. 2 88's, 2 89,s a 90, a 91, and a 92 that i only had for 3 months. it was a pile and the dealer bought it back and the injector pumps on all of them only had one fuel adjustment screw that was under the plate

 

The thread I linked mentions a second screw on the IP that can be adjusted. The problem is that unless you have a pyrometer, piezoelectric spark adapter and timing light you're just shooting in the dark doing any adjustments to the IP.