Boost Vacuum Lines

[96K3500]

I have a quick question that someone may be able to answer, I have almost finished installing the Optimizer in my 94 K3500.While installing the lines from the vacuum pump and wastegate diaphragm to the controller,i noticed that the rubber connector the lines slide into on the controller end came off. I slid the lines back into the connector but upon closer inspection found that the controller appears to have a metered (orificed)port and an larger port.which component connects to the orificed port? or maybe a simpler question would be white line left or right? J.R.

[JohnC]

It's been a while, but if I recall correctly, the vacuum pump attaches to the port with the small orifice (so when the valve is in "vent" mode it doesn't drain all the vacuum.)

I'm sure someone else will pipe up if I'm wrong.

[96K3500]

Thank you sir,I'll hook it up that way and put someone in the seat and load the engine up and see if the actuator moves.

[JohnC]

You might not see it move, unless you get to an overboost condition. Hard to do (and hard on the trans) sitting still. Do you have a boost gauge? That's the best indication it's working correctly.

The solenoid is prone to failure, especially when it gets hot.

[Robyn]

My recommendation would be to spend a couple $$$$, get a ECM from either John Kennedy or Bill Heath and install a Turbo master.

Set the boost maximum to 12 psi and keep your EGT at or slightly under 1000F PRE TURBO.


My Dahooooley is set up with a Heath Chip and a Turbo master and works sweet.

I never liked the vacuum setup, not even.

It was fine for the "house car" application so that the average villager did not fry the thing, but the vacuum is just too much of a PITA.

With a buttload of miles running 6.5's the track record is hard to beat with a mechanical waste gate control.


Just sayin.

[Aftermath]

Do what Robyn said, then you can toss the hp robbing vacuum pump, but will need to get a smaller sepentine belt . Heath did my chip and its awesome.

[Low_Bridge]

My 6.5 came with an absent vacuum line to the turbo & tied back. Somewhere I believe I remember seeing a turbo was changed or upgraded.

As I understand because the vacuum line went south the turbo had to be tied back(?)

Pictures attached ~ Question? What will be the best course of action on this repair & be most dependable.

Thanks ~

583758385839

[Yukon6.2]

It looks like the PO disconnected the stock waste gate system.
Myself i would make an adjustable boost control with a spring and bolts.
There may be a reason to return to stock if the computer is upset with the existing configuration.Right now the wastegate will not open,which could cause engine damage without gauges.

[Low_Bridge]

1. Add a boost gauge

2. Go w/ manual that eliminates vacuum actuation

I'm on the right track?

I think I need 6.5 turbos for dummies. Watched a video or 2 on making a manual........still some loose ends in my head.

thanks

[DmaxMaverick]

3. Add pyro (most important, actually)

If the vacuum pump works, and the rest of the plumbing is good, or can be made good, just fix what you have. When things start breaking and get deeper into your pocket, then consider a manual WG control. Manual isn't better than OEM (the opposite, in reality), but has its use. Is the SES lamp on, or come on under heavy load/acceleration? If so, what codes?

[Low_Bridge]

Thanks guys..... is the "boost bolt" acceptable to run a line to for the gauge?

[DmaxMaverick]

Thanks guys..... is the "boost bolt" acceptable to run a line to for the gauge?

A simple, innovative, effective, and non-invasive solution. I have drill and taps on hand, and probably wouldn't, but I see no reason to not use it if you prefer.

[Low_Bridge]

doesn't the top need to be popped off to vacuum / clean out the shavings from tapping & drilling? or are there other options?

[DmaxMaverick]

doesn't the top need to be popped off to vacuum / clean out the shavings from tapping & drilling? or are there other options?

Yes and no. You can, but I drill and tap them while under air pressure unless I have another reason to remove inlet. Shavings are blown outward. Wear eye protection. Otherwise, it's just a few bolts and a gasket. No biggie, either way.

[Low_Bridge]

so just pipe some air pressure into the intake when drilling & tapping ~ (?)

The SES stays on ~

She starts fine & we went from coast to coast in Florida with it last weekend.

I thought she could of braked a little firmer. The Front pads are fine & the rear shoes are do to be changed out..... (test the vacuum pump also?)

Codes ...... time to buy a reader,,,,, point me in a direction on a recommendation ......

[DmaxMaverick]

Yes. Remove the air inlet pipe (between turbo and intake inlet), and attach a shop air hose to the inlet (use your imagination, function is simple). No more than 5-10 PSI is needed. The key is to maintain positive air pressure in the intake while drilling/tapping to blow out the shavings. You could use a shop vac (blower connection) and some duct tape if you have no other option. That's a lot of air volume, but the pressure should be sufficient to gitterdone.

If the SES lamp is on, you really need to hear what the computer has to say. The vacuum system is closely monitored, and the key means of protecting the engine. Without that control, you rely on a properly adjusted mechanical WG (yours is not), or the computer's ability to defuel (which is probably happening).

OBDII code readers are simple and cheap these days, especially if you have an Android phone or tablet. Get your hands on an ELM327 Bluetooth adapter (Amazon/eBay) and install the Torque app from the Google store. The free version (Torque Lite) is all you'll need. Most all of the cheapest adapters are at least minimally functional for reading and clearing codes.

Brakes are completely separate from the rest of this discussion, but none of it is unique to your truck, except for the brake assist system. Unlike most gassers, your truck doesn't use vacuum for brake assist. It has a Hydroboost system, which is hydraulic, powered by the power steering pump, and in series with the power steering system. From master cylinder to the wheels, it's essentially the same as every other truck on the road (to include ABS systems, if applicable). The brake components at the wheels, that's old school. Nothing new there. Good service and parts are as important as with any vehicle.

[Low_Bridge]

Upon completion of the above & adding new vacuum line & say I get no Codes .......When do I disconnect the tie back on the gate?

Thanks for getting me on track!

[JohnC]

If you hook up the vacuum, you need to disconnect the tie back so it can work as intended. Until you do, it'll continue to set codes.

[DmaxMaverick]

Upon completion of the above & adding new vacuum line & say I get no Codes .......When do I disconnect the tie back on the gate?

Thanks for getting me on track!

As soon as you have vacuum at the actuator or some other WG control solution. If you have a vacuum pump, apply about 15" Hg to the actuator nipple. Verify the actuator is able to hold the vacuum with minimal leakage, and you can't move the WG linkage by hand, and that end will be functional. If you have at least 20" Hg vacuum from the vacuum pump, no significant leaks, a working WG solenoid, and sound electrical to the PCM, it should good to go. At the same time, you may find out just why someone wired the WG shut. Depending on what you find, you may decide that ditching the vacuum system may be the better option, but wiring the WG shut is never the option, outside a temporary situation or diagnostic purpose.