j_stickers

Hi guys,
I have been lurking for a while. Guages are installed (pyro pre turbo) The instructions were great! I've changed the the tranny oil to Mobile 1 synthetic with an extra quart or so. It shifts better now.
So now to my question. I turned the power adjustment screw in one turn last night. The idle went up to 1000rpm. Adjusted it back down to 750rpm. It took about a quarter inch of adjustment to get it there. I dont have very much adjustment left. the boost is better now at WOT was eight now twelve. EGTs are less than nine fifty. When should I stop turning up the pump? I don"t want to overdo it.
Thanks John

Monty

When a pump adjustment screw has been turned in too much. Your truck will take alot longer to come back down to idle after running it at high RPM or between shifts with a 5 speed. This is right at the point of almost a full fuel runaway.

Your boost numbers seem low.

There are a couple more adjustments that you should take into consideration. Those being the AFC cone and the star wheel. I wont even throw in the smoke screw which only puts a preload on the spring. Most guys just run it flush with the housing.

Dont forget to fill in your signature so we can see what year model of truck and modifications you have done. It will help us in the future to anwser your questions.

j_stickers

I have checked the intercooler connections and everything seems fine. I have not pressure checked the IC. I'll play with the AFC cone and star wheel next. How big of adjustments should I make to the power adjustment screw at this point, 1/4 turn at a time?
I don't want to experience a runaway.

Monty

1/4" increments are fine. Be sure and keep a log of performance gains you get by each turn. Boost psi, egt, RPM etc.

jiMMyCTD

well i finalyl WOT on mine tongiht, and i only hit 12-13 as well. the gentle man i bought it from said he turned the pump up some but nothing else. so i gues sill have to read the article on how to adjust the other items listed on teh pump.

jiMMy

dodgeman01

I have read about the runaway thing and on my 93 pump i can't see this happening. I rurned the screw in as far as I can go. whats stopping me is the idle goes up and the adjustment screw is not even touching the plate with the spring on it. is mu pump different or something? I mean the truck does not run as good as I think it should with max boost being 15psi. I even ran with the cone out of the truck and did not gain anymore HP just smoke at take off. tried backing the throttle linkage off until it fell out of the plastic ends. I could get a lot more boost but the truck idles at 1k rpms I hit 25 pounds of boost with the idle set there but the truck is hard to stop because it iddles so fast. I can do 35 MPH at idle DM01

Redleg

Are you sure you have full travel at the pedal? And, tighten the cable to get all the slop out. You might be hitting the floor with room to spare at the throttle. This is a common problem. Raising the idle a bit from stock is better for the engine too. It keeps the fluids pumping better and the pressures up a bit, especially if you "need" to idle for extended periods.

Monty

Have you taken the power screw out and removed the washer and the lock ring or tamper proof ring? On my pump, I have found that about 1 turn out from where it starts hitting the tack weld marks or where it starts to get hard to turn, is where you are at the mark of runaway or full throttle fueling. NeedMoPwr has experienced this and it is common. No urban legend.

DO NOT run without the cone, this will let the fuel pin that rides on the cone come too far out. Resulting in fuel pin seal leakage.

If your idle screw is not even touching the throttle linkage plate, the only way that I can see to bring back down the idle is to re-index the throttle plate. This consists of removing the allen head nut, taking the plate off, and re splining it to the throttle shaft.

Alec

Dodgeman & j stickers et al,

Have you guys checked to make sure that your fuel pins aren't sticking in the AFC?

There is a little pin that pops out of the front of the bore in the AFC and rides on the eccentric. This can get stuck pushed in, greatly reducing fuel delivered by the pump. Might explain low boost, etc.

Running with the cone out normally results in this pin falling out, or at least leaking like crazy -- so if that didn't happen, I'd be suspicious dodgeman . . .

If you cycle the "throttle" to wide open with the engine off and the AFC eccentric out, it should pop out fully half way into the bore. If it doesn't come out that far, put some WD 40, or fuel additive on it to lube it up, and work it in and out (cycling the throttel, and pushing it in with a small screwdriver or something).

That pin is more imprtant to the amount of fuel delivered by the pump than the full fuel screw. You want it to come out as far as it can (without leaking) -- that is what Mike's PowerPin does.

j_stickers

I adjusted the linkage about a week ago. It wasn't going full open. That helped alot, I thought the truck could only go 75.
I removed the collar from the fuel screw before I started. It wasn't welded only a band clamped around the screw. I haven't checked the AFC fuel pin. Sounds like that should be next before any more adjustment.

Bushy

Ahhhh... Monty..... normally you just tweak the throttle rod to bring your idle plate back into contact with the idle screw. Altering the index mark isn't the best way to do this and can result in some other problems.... did I miss read the situation here....?????
This adjustment is part and parcel of the "breakover" spring adjustment.
Sorry if I'm in left field here.....

pb.

Monty

Nope, your right Bushy. My short term memory is not the best these days. Sorry for putting the cart before the horse.

furious70

here's a related Q-- is there any rough guide to what TQ increase you get from each turn of the full fuel screw? Just curious if anyone had ever tested that

j_stickers

Well guys. Months later I finally took off the AFC cover. Marked the diaphram and star wheel. Checked for the fuel pin to stick out at open throttle (truck not running) Nope it’s stuck. Sprayed some penetrating oil in. Still nothing. Any ideas besides opening it up daily and spraying it?
There was some sticky grease on the eccentric what should be used in there?

mopar2ya

Ill probably catch hell for saying this, but I cut the crimp off the fuel screw ran it all the way in. Pulled the cover off the aneraid, removed the plastic washer, turned the star wheel down, assymbled the aneroid (be sure to be the pin positioned right), then cranked the allenhead screw down until flush (under tin cap on top of pump). With this I ran 25 psi and 1100-1150 EGTs with stock exhaust.

To adjust the idle I popped the cap off the idle screw broke the jam nut loose and used needle nose pliers to turn it back till around 900 (i used to idle alot)

Its been like this for years and a ton of miles. Its getting a bit weak as its only running about 18 psi now.

Be sure to check the cast elbow comming off the turbo, mine had a buhr and it didnt seat correctly and limited me to 14 psi.