Hi guys, a friend has a problem with his 99 Chevy 1 ton, and while I didn't have the answer, I knew that someone here would. His truck is throwing black smoke, turbo is spooling, but no power. He said that he had this problem before and it was some sort of a switch or sensor down in the valley under the intake manifold. He has found one designed for off road use, and for a heck of a lot cheaper than what the stealership wants. My question is: Is this a doable project within a reasonable amount of time by 2 or 3 guys that can turn a wrench? Or is this something that requires special tools available to those at a stealership? He said it was something called a "pump program box/turbo pressure sensor switch/pump pack" I've not checked for codes or anything. He is a OTR trucker and I thought I would try and find out what information I could for him. Thanks in advance for any help. You guys rock!

 

check air filter , leaky exhaust , check cross over pipe and clog cat will make black smoke low boost lost of power PMD going south could do it also

Also do vacuum test

Also check the LP make sure it working if it took a dump IP does all the sucking so have lost power and black smoke

Reference Material: Vacuum system
Why Does the 6.5 have a Vacuum Pump?
Diesels do not create vacuum inside of the intake like gasoline engines. Gasoline engines rely on vacuum for numerous things, such as: brake boost and HVAC controls. The Diesels rely on hydroboost systems for brake boost and electrical motors for HVAC operations. GM put the vacuum pump to control a couple of devices on the truck, read on for more info.

So, where's the vacuum pump?
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Please note, you may not have the piece of tubing in the way unless you have an intercooler.

What components does the vacuum pump provide for? The list includes: EGR (if equipped) and the turbo waste gate system.

On vans the vacuum system also controls the HVAC system.
EGR's are normally found on "S" Vin engines. Another way to tell is if the truck is a 6 or 5 lug, it will have an EGR (unless its been removed).

Where are these EGR and Wastegate solenoids?

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So how do I know if my vacuum pump is working correctly?
You will need a vacuum gauge to properly test the pump itself. You will want to hook the gauge up as close to the pump as possible. You want to see at least 20”+ Hg of vacuum at Idle.

Do I have to hook directly up to the vacuum pump?
It is best if you do, however, you can test farther out on the on the vacuum system. You can check the vacuum at the soleniods, EGR, wastegate. This will help you determine if it is a bad device or a bad vacuum line if the vacuum pump tests good.
*Note: Testing after the solenoids may give a skewed reading as they regulate the amount of vacuum given to the devices.

My vacuum level is not very good?
If you are directly attached the gauge to the pump, and you have low or no vacuum, then your pump is bad. If testing further out on the system, you will need to connect directly to the pump to insure that you have no leaks in the lines between the gauge and the pump.

Are leaks common?
Very common. Leaks come from chaffing, hardened plastic lines cracking, etc... Sometimes the vacuum level may be okay, but if the engine rocks one side to another, it may open up a crack in the line and you will lose vacuum.

I don’t have a gauge, but I suspect I don’t have good vacuum. What do I do?
A real quick check of your vacuum system, which can be done at any time, is checking your waste gate actuator.

With the engine at idle, locate the turbo, and the can on the side that has the arm in it, should be drawn up inside. Pull on it, to see if you can pull it out. If you can, you don’t have sufficient vacuum. That is not to say that the pump is bad, but just an indicator that you vacuum level to the turbo portion is not enough. You will need to do further troubleshooting to determine what’s wrong. If it doesn't move then you most likely have enough vacuum at the wastegate.

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My waste gate actuator failed the test, now what?
You will need to determine if the waste gate solenoid is bad, have a leak, or bad vacuum pump.

How do I determine if my waste gate solenoid is bad?
Check to see if you have vacuum BEFORE the solenoid. These solenoids will go bad after some time. The little ball inside of them will rust that actually opens and closes the vacuum to the actuator. It will get stuck not properly regulate the vacuum. It may get stuck “off” which means no vacuum gets to the actuator, it may get stuck “on” where it has full vacuum all the time. The last condition would create a DTC (computer code for over-boost).

How do I check to see if I have computer codes?

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Depends upon if you have an OBD-I or OBD-II computer. 1996 and after are OBD-II and require a code reader, pre 96 you can check with a paperclip. Check the FAQ’s.

I have a code for my turbo, and EGR.
Coupled together these two codes indicate a vacuum problem. Both systems rely upon the vacuum system to work properly.

I have a heavy duty vehicle that does not have an EGR. My vacuum system is not working, what are my options?
If you have a 2500HD or 3500 truck, not equipped with an EGR system, you may opt to abandon your vacuum system, and use strictly a spring tension waste gate operator. Instead of using a vacuum system to hold the waste gate closed, you use spring tension. Once boost is built to it’s maximum allowable level, the waste gate blows open. The spring tension provides the proper pressure to maintain a safe boost level.

Can I get more boost out of my turbo with a spring type waste gate actuator?
Yes, but remember, there is a limitation here for the engine. You don’t want to be driving more than 12 psi of boost pressure into the engine with stock tuning, or more then 15 psi with an aftermarket tune.

Where can I get one of these spring type waste gate operators?
There are over the counter ones available from vendors, or you can opt to build you own (Check the FAQ’s). Other members have done so, and you can search to see what they have built. Search the term "Turbo Master."

*NOTE: If you install a Turbo Master, your computer will no longer be able to control boost levels.
I have an EGR system, can I fully abandon my vacuum system?
No, you will still need vacuum for your EGR to work properly.

You must still leave all your solenoids hooked up to the electrical system, because the computer is looking for feedback and a circuit to them. Without them connected, the computer will generate a DTC code. You can only remove the solenoids and EGR if you have an F code computer or an aftermarket tune that has EGR Delete on it.

What would keep me from abandoning the vacuum system?
If you have an EGR or your HVAC controls are vacuum operated.

If I abandon the vacuum system, can I remove my vacuum pump?
Yes, you can, this means that you will require a shorter serpentine belt. Members have reported that it needs to be 1 inch shorter than your original, you may want to do some further investigating to make sure on your own.

Normal Vacuum Pump Delete sizes are:

* 94-95 :: 101.5"
* 96+ :: 99.5"

 

Thanks, I will print this off and use it when I actually get to see the truck and can troubleshoot before jumping in. Thanks again!

 

Hi imnew to this diesel bombers website, I have a few vacuum pump questions. I have a 98 halftone 6.5 diesel. Its an s vin motor with an egr. Should I be able to spin it around freely. Or is it supposed to be spring like loaded and not be able to turn it all the way around?

 

well to solve your problem, take all that vaccum stuff off your turbo and throw it in the trash.

put a turbo master on it or make your own, as there are some threads on here to make one homemade, but make sure you have a boost gauge.

PM civola2005 he has a good one

 

thanks ebarresi!!!

 

 

Hi everone today am here to ask that We have a 1999 Chevy 3/4 ton silverado with a 5 speed transmission.
Trying to figure out what the hours are in the flat rate book to change this out.

 

Change what out.
The vacuum pump.

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First and foremost check the codes-they can go a long way to diagnose the problem.

Secondly the only sensor under the intake is the oil pressure sensor,while important it is only a secondary power supply for the fuel lift pump.Replace with AC Delco ONLY!

The LP primary power source is the ECM controlled LP relay which activates for a prime cycle when the wait to start light is on and then once the engine is running is activated by the ECM when it recognizes a running engine from CPS(crankshaft position sensor) and OS (optical sensor)signals.

Verify that the LP works by opening the water in fuel drain Tee valve located near the thermostat housing while the engine idles and note what happens.
If the engine stalls the LP is not working and further diagnosis is required-if it turns out that the LP is dead replace with a LP from a 93 model year AC Delco part.Aftermarket options do exist but are pricey like walbro LP's,any stock style aftermarket LP is poor quality.

Black smoke indicates unburnt fuel and causes very high EGT's and can melt down an engine in short order if not repaired.

A boost gauge and EGT gauge should be high on his list of needed accessories with these engines.

To check wastegate operation have him try to force the wastegate open at idle,at rest the wastegate lever should be down and away from the actuator and at idle it should pull up firmly so that it requires some decent force to overcome the vacuum canister.

Vacuum readings at the wastegate actuator should be 18+" and if you trace the vac line back to the wastegate solenoid,the other vac line from the vac pump should have a reading of 24+" from the pump.

Now as mentioned above the exhaust,air filter and sometimes the PMD can all affect this,often though it is a bad wastegate solenoid,cracked or leaking vacuum lines or a bad vacuum pump.
A bad diaphram at the actuator has also been know to cause the problem.

Mentioned above,a turbomaster from Heath Diesel can be used to eliminate the entire vacuum system except for the wastegate solenoid-an electrical connection is needed there to prevent the service engine light and trouble codes.