Boost Questions

[enormiss]

So I just installed some gauges, but have no idea what is "normal"
How much boost should there be unloaded while holding steady speed on level ground?
What would be the maximum you would ever see completly stock?

Here's what I'm seeing, now to find out what's wrong
The beginning of my trips see 2-4lbs cruising, with 8 easily seen while lightly accelerating from a stop.
Boost falls to zero after about 15min of driving...
If I introduce the pedal to the floor mat I can usually get boost to come on, but it goes straight to 15lbs.
Sometimes it only lasts seconds, then returns to 0
Other times it holds until I let off due to fear of loosing my license. ;)
EGT's run higher when I see 0 boost so I'm assuming it's not a boost gauge problem.

I'll pick up a fresh air cleaner today since I've seen posts about that causing funny behavior.

Thanks for any insight!

[Hubert]

To make boost you have to have heat. Heat takes fuel and load. You should see higher boost accelerating. Not much cruising 2-4 at highway speed level ground. 15 is a bit high for stock but quick load ups then it will fall off are ok. It will probably code if it holds more than 11 psi for sustained time (which would require your foot to be in it).

You should see good responsive boost between 1700-2200 rpm between 6-10 lbs depending on fuel pedal and load. Cruising again will be less and below or above rpms will be less. No boost idling or sitting still but maybe a little needle wiggle flooring it.

The stock program and boost control has some little nuiances that are well documented read up on the vacuum pump and waste gate vacuum solenoid.

A good secondary check is to look for black smoke.

[enormiss]

So much for the easy fix, fresh air cleaner didn't cure it.
Found some time today to trouble shoot
I tapped into the vaccum side of the solenoid and had steady 25 on the gauge.
Flipped over to the waste gate actuator side and had around 20 but would fall to 0 while driving around.
It never seemed to stay anywhere but 20 or 0.
Since my gauges are mounted on the doghouse I couldn't monitor boost.
Returned home to flip back to measure vaccum side of solenoid again and still had rock solid 25.
Drove around and I could see the actuator rod extended
Parked and moved rod easily by hand.
So guessing I need a new solenoid...
While searching I came across threads where map/boost sensor caused boost issues.
Any chance it could be that? Any idea where that's located on a van and how to test :)
Need the van for week long trip departing Monday
This is all new to me, so thoughts are appreciated.

[DmaxMaverick]

Sounds like your WG solenoid and vacuum pump are doing their jobs just fine. Your problem is going to be electrical/electronical. Start by looking for a connection/ground problem. Also, make sure your vacuum lines, especially those connecting the solenoid, are routed correct.

[enormiss]

Not sure if I'm using the proper part names
I ordered one of these since I'm crunched for time, it's not stocked, and it's reasonably priced.
http://info.rockauto.com/getimage/getimage.php?imagekey=87998&imageurl=http%3A//198.208.187.182/servlet/com.entigo.acdelcocatalog.servlet.ProcessImageServ let%3Flanguagecd%3DEN%26countrycd%3DUS%26user%3DIn ternetUser%26mfgname%3D%26prodlinecd%3D%26acpartnb r%3D214-637

I did test the part that's downstream with a hand pump and it would pull the wastegate and also held the vacuum.
Thanks for your thoughts, I'll look for loose electrical connections.
I like the simplicity of the WG being spring controlled, but there was another factory vaccum line T'd off the left side fitting on the above part
and I'm not sure what that controls.

[Robyn]

The plastic lines that connect the solenoid to the actuator can and do fail.

If the pump is working good and the actuator will hold vacuum then the solenoid is the likely culprit.

Good luck and keep us posted


Robyn

[enormiss]

That part cured it, runs good now.
I'm happy happy happy
THANKS :)