DB2 injection pump fuel metering screw.

[56pan]

Was wondering if anyone knew how far you could screw in the fuel metering screw on a DB2 inj. pump and save me looking it up? My pass. side valve cover gasket is leaking and I'm about due anyhow for a rebuilt pump and injectors so thought I'd do that too. It's a mil. surplus engine, AM General block and I've got all the cooling upgrades and dual stats. Also a Peninsular intercooler and A-Team turbo. I believe it can handle more than the ~11 psi I'm getting now. Max. EGT now never goes past ~650 degrees. Any specs. on the fuel screw adjustment would be appreciated. Thanks.

__________________
'93 C2500 280,000 m.
40k on new AMG mil. surplus engine
A-Team turbo.
Straight pipe exh. (but it ain't that loud).
Peninsular intercooler
Boost, EGT, Glowshift intercooler in/out temp. 3 guage pod.
Rebuilt complete susp. with polyurethane bushings. (Bad idea).
20k on GM 4L80E rebuilt trans.
Dual thermostat/Duramax fan/high flow water pump.

[Robyn]

650 F EGT ???
Measured where, down pipe or at the port outlets ???

You can safely go to 1000 F at the exhaust port outlets under a hard pull.

If you're tail pipe flow is clean under hard pull then you can definitely handle more fuel.

Give the fuel screw another 1/4 to 1/2 turn and see what she does.

Has the pump been adjusted prior ??

You don't want to see rolling coal under boost.

if you have an after cooler you can sneak up to 15 psi and be Fine.

The 6.5 is just not heavy enough (head bolts and gaskets) to manage more boost, at least not and live long and prosper.

One exception is IF you have 18:1 pistons then a bit more can be squeezed in.

Ideal exhaust under hard pull with full boost is very little smoke, possibly a light haze of gray, NO COAL and EGT at no more than 1000 F pre turbo (Ports)

You should see a puff of gray/black when mashing the throttle until the turbo spools and then it should clear out.

[56pan]

Thanks for the input. After I put on the A team turbo I'd never exceed about 850 F. on EGT with my foot in it. It would go quite a bit higher than that with the stock GM turbo. After I put on the intercooler with that new turbo, it woudn't go much past 650-680 so I know I can stand more boost, but I_totally_agree with you on the 15 psi. limit on these engines. The EGT probe is right at the inlet to the turbine in a hole I tapped in the casting. I'm pretty sure this new mil. surplus engine was an NA, so I'm assuming my comp. ratio is 21.3 to 1. The inj. pump will be for a turboed engine and hopefully will have the standard fuel metering set up accordingly. No rolling coal now at all. Barely perceptible smoke when my foot's in it. Usually can't see it.
And who do you folks recommend for inj. pumps and injectors?

[Robyn]

You can use a touch more fuel.

12-15 psi is a good spot for these engines, and they can live there.

The GM X TURBOS all had drive pressure issues that caused far too much EGT

Also with the charge cooling you are getting rid of some Intake air temp that really helps things too.

Good luck

[phantom309]

Too much fuel delivery can also be metered by less application of the throttle,.
turn the pump up to stun,. then drive it by your gauges,.;)

My old 94 has enough fuel to make over 25psi,. but it only gets 10-30 second squirts,. pulling a constant load you have to concentrate on right foot weight,.