[Rx7man]

I've turned my pump on my 93 up to the edge of runaway, still feel like I'm not getting enough fuel, truck burns clean, still have stock turbo, has a little shaft play, makes 18 PSI.., Has DennyT fuel pin, I just installed 3800 governor springs which sure got the pedal sensitivity up but it's still a total dog.. Now I know I'm not going to get P pump power out of it, but I figured a little more than this was possible... My butt dyno says it's 200 hp.. a bit over stock but nothing to write home about.

 

[9297oldram]

What are you doing about the intake and exhaust?

 

[NIsaacs]

I've turned my pump on my 93 up to the edge of runaway,

How do you know? How much have you turned it? When you turn it up it is natural for the idle to increase, doesn't mean a runaway, but you will need to turn the idle back down. The best way to increase power is a set of injectors but you should be able to get about 250hp without.


My '91 D-250 dyno's 263/708 with 50hp Bully Dog injectors and about 1.5 turns on the power screw. Factory intake and exhaust, and #16 turbine housing. Factory gov spring and fuel pin maxed.

 

[9297oldram]

How do you know? How much have you turned it? When you turn it up it is natural for the idle to increase, doesn't mean a runaway, but you will need to turn the idle back down. The best way to increase power is a set of injectors but you should be able to get about 250hp without.


My '91 D-250 dyno's 263/708 with 50hp Bully Dog injectors and about 1.5 turns on the power screw. Factory intake and exhaust, and #16 turbine housing. Factory gov spring and fuel pin maxed.

When your close to runaway your RPM's will want to hang and not drop fast like normal. It's normal for when you turn in the Power Screw the idle to increase, most will give it a timing bump to lower the idle and help with performance.

If you have the factory intake you'll gain some by drilling some holes into the front side of the factory air box. Also removing the restrictive factory muffler will gain some.

 

[Rx7man]

Yup. I adjusted the idle.. It did run away a couple times... I had a board ready in case the key didn't work.
Filter housing has some extra holes and a k&n.. Exhaust is stock but straight piped

 

[9297oldram]

A smaller turbo housing will help out, when it seems to run out of power are you looking at your fuel pressure to make sure that isn't your problem? Might be time to upgrade to a THD HVLP.

 

[Rx7man]

I haven't got a fuel pressure gauge installed yet.. it's on the list

Yeha, this turbo is tired, it'll get 60mm HX35 very soon, I have a spare one.. I don't think it'll do much for peak power but should bring it in sooner at least

 

[Blackduck59]

Have you backed off the smoke screw and AFC spring?

 

[Remps]

Should be able to hit at least 25-30 psi with stock injectors/turbo, regardless of lift pump condition, unless a dirty fuel filter is becoming a restriction. Is the AFC working properly? Is it leaving a mark on pretty much the full travel of your Denny t pin? Did you re-index the throttle, or shorten the 3800 spring?

 

[Rx7man]

Should be able to hit at least 25-30 psi with stock injectors/turbo, regardless of lift pump condition, unless a dirty fuel filter is becoming a restriction. Is the AFC working properly? Is it leaving a mark on pretty much the full travel of your Denny t pin? Did you re-index the throttle, or shorten the 3800 spring?

Reindexed.. AFC spring backed off.. Marks all the way on the pin, smoke screw turned in a bit

 

[Rx7man]

Why would you back off the smoke screw.. That's less pre boost fuel

 

[N1NJ4ON3R]

Smoke screw should be flush with afc top. Star wheel is for fine tuning pre boost smoke. I agree with Remps on boost. If you're close to runaway, boost #'s should be 28-30+psi(h1c). My pump @ tamper collar with h1c(18cm2) made 28psi. More afc tuning.

 

[9297oldram]

Why would you back off the smoke screw.. That's less pre boost fuel

The smoke screw is at the top of the fuel pin so if it's screwed down it's giving the pump more fuel off from idle. You want the pin all the way to the top that's why people mod the inside the top of the AFC to make sure the fuel pin goes all the way up as far as it can.

 

[1972RedNeck]

The smoke screw is at the top of the fuel pin so if it's screwed down it's giving the pump more fuel at idle.

No. The smoke screw gives more fuel pre-boost under acceleration when turned in. Nothing to do with idle.

 

[myother4x4isaCJ7]

I have a feeling it is not getting full throttle travel due to the re-indexed throttle.

 

[Rx7man]

Smoke screw in is more pre boost fuel.. Backing it out sure ain't going to help me

Its making power way higher into the rpm range than it used to.. Its just never fueling as hard as I think it should

 

[N1NJ4ON3R]

You may need help tuning your ve.

 

[Rx7man]

I'm far more familiar with p pumps for sure

 

[Blackduck59]

Agreed in is more fuel but with an aftermarket pin plus winding back the AFC spring in my case it is just to smoky down low.
Have a THD pin and the AFC ground so the slide pin just sits on the thickest part of the fuel pin. Even there with the spring wound back it can be smoky down low, but it does get up and go well.

Will see what happens when I can get my reset injectors in.

I can get better than 18 psi with the H1c, even with a tight AFC spring

 

[Remps]

As someone mentioned, you are probably getting less throttle now after re-indexing. Try turning the high idle screw flush so the throttle opens more. If you can't get enough travel try putting the throttle rod to the inside hole on the throttle linkage to get more movement of the linkage per inch of foot feed. Hope that makes sense lol. One can also cut the high idle stop off the throttle linkage where it hits the high idle screw to get the throttle to open further.