How to adjust fuel pressure with adj reg?

[BRAD_PADGETT]

I am confused and probably out to lunch. I am trying to increase fuel pressure by making the adj screw longer on the fuel pressure reg longer. Now I am throwing code 44-lean. Am I going the wrong way? Should I shorten the screw on the fuel pressure reg? My mechanic told me to lenghten the screw but I think he may be wrong. Thank- Brad- I do have a fuel pressure gauge but have not checked pressure.

 

[Gary Wells]

I think that he is wrong, too, and none of my business, but if you have a gauge, why are you not using it?

 

[BRAD_PADGETT]

I simply haven't had the time since I got home at 5 today to hook up the fuel pressure gauge. I am looking for which way the screw should go-up or down-increase fuel pressure or decrease. I think that lenghening the screw reduces fuel pressure which is why I am throwing a code 44. Any advice is appreciated. Brad

 

[ChrisCairns]

I am confused and probably out to lunch. I am trying to increase fuel pressure by making the adj screw longer on the fuel pressure reg longer. Now I am throwing code 44-lean. Am I going the wrong way? Should I shorten the screw on the fuel pressure reg? My mechanic told me to lenghten the screw but I think he may be wrong. Thank- Brad- I do have a fuel pressure gauge but have not checked pressure.

Clockwise = increase fuel pressure.
Counter clockwise = decrease pressure.

Attach the gauge .... without it you're just guessing.

 

[fitz3820]

Attach the gauge .... without it you're just guessing.

Your motor will thank you for it...monitor knock too.

 

[BRAD_PADGETT]

Chris and Fitz- Thanks for your solution.I was trying to raise fuel pressure in order to get my BLM to around 128 at idle. Scanmaster shows 150 blm. I was told to go counterclockwise in order in increase fuel pressure. Wrong- I really leaned it out. I go slow and ask alot of ?. I also have a knock gauge and live by it. Alky inj really works. I just need to get IAC to 20-25 and BLM to 118-138 at idle. Once acheived-I can turn up the turbo boost until no knock. I will then need new rubber. Thanks- Brad

 

[ChrisCairns]

Chris and Fitz- Thanks for your solution.I was trying to raise fuel pressure in order to get my BLM to around 128 at idle. Scanmaster shows 150 blm. I was told to go counterclockwise in order in increase fuel pressure. Wrong- I really leaned it out. I go slow and ask alot of ?. I also have a knock gauge and live by it. Alky inj really works. I just need to get IAC to 20-25 and BLM to 118-138 at idle. Once acheived-I can turn up the turbo boost until no knock. I will then need new rubber. Thanks- Brad

You're welcome. And we've all been there so continue asking away.

If your IAC counts are higher than 20-25 turn the adjusting screw on the TB clockwise. If they're lower, turn the screw counter clockwise.

BLM's "should" be controlled by the chip at idle if it's a newer chip. The older one's didn't do that. The biggest problem I've seen with high BLM's is a leak pre O2 sensor, post exhaust port. In other words, an exhaust manifold leak. At idle or cruise, not under boost, the leak will suck air into the manifold via the Venturi principle (kinda like sticking your head out the window while the car is at speed)....just as it sucks your breath out, the manifold sucks air in. So your O2 sensor reads more oxygen in the exhaust stream than actually comes out of the engine's cylinders. The ECM then increases fuel, thinking it's lean. You can check by looking at your spark plugs. Black and sooty = rich. Crappy gas mileage is also a symptom.

Keep us posted as you get faster.

 

[Ormand]

(kinda like sticking your head out the window while the car is at speed)....

I thought just dogs did that?

 

[BRAD_PADGETT]

My IAC is 16 at idle which is two low. Where is the agjusting screw on the 85 throttle body? Thanks- Brad

 

[ChrisCairns]

Ooooh. I used to have an 84 but since I sold it I can't go look.

Sorry, I have no idea. Perhaps it looks like the 86/87....look for something on the side of the throttle body that when the throttle is closed the end of the throttle plate shaft will rest against it. An idle control. It's not really an idle control, idle is controlled by the chip, but a minumum air adjustment screw.

 

[HvyMtlV6]

My IAC is 16 at idle which is two low. Where is the agjusting screw on the 85 throttle body? Thanks- Brad

Brad,
Its behind the throttle-body, between the firewall and throttle, where the bracket is for the throttle cable is attach to, it might have a cap on it, mines had one on it, its a star-bit type of screw, hope thats helps you

 

[BRAD_PADGETT]

Thanks alot for the info. I thought this was the correct screw but the shop manual didn't say. Brad