Turbo boost gauge

Two Jayhawks wrote:

ScottG wrote:
The turbo is always called for, that is it's always working making boost even under very light throttle because the exhaust is always going through it and spinning it. Even at idle it may make enough boost to make the needle sit just above zero. If it doesn't read anything unless you stomp on it then something is wrong.

Scott I'll respectfully take your word for this as I'm not a diesel tech. I have had my current unit for 9 years now and my gauge rests at zero absolutely at idle as well as highway cruise. I watch all my gauges so I'm quite sure of this. It will jump only under a hard acceleration. I mostly baby it so I rarely see it move.

Hi,

You might have a problem with the turbo bearings. The turbo might be spinning much slower than it should, due to bad bearings, probably caused by not running it for a long time, or to long between oil changes. Or you might have a bad gauge. A mechanic can hook up a gauge, and then tell you by just running it up to say 1500 RPM in park. If the gauge moves, your turbo is working (can't dertermine if 100% or just 50%) if it does not move much, then the turbo bearings might be bad. It is not that rare to have a bad turbo at that age.

I would not be calling Cummins for a replacement turbo, but rather call a place like Banks that sells aftermarket turbo kits for your engine, and larger intake manifolds.

If you have any black smoke while going up mountains, this indicates to much fuel for the amount of air, (thus bad turbo is suspected). A good turbo will improve the fuel mileage, and reduce the smog a LOT.

http://www.bankspower.com/ You might be able to get some used turbo's from them, as they normally upgrade stock motors with larger ones, and probably do something with the old stock ones. (not just through them in the scrap metal bin).

My guess?

You probably have a 50% chance that either the turbo is bad, and the gauge is right, you only spin the turbo really fast at wide open throttle, and are getting poor mileage as a result.

50% chance is you are getting 9+ MPG and the turbo gauge is not correct. You are not making a lot of smoke on the freeway, and when climbing the mountains.

Still my guess is bad turbo at your engine age. It is possible that one of the prior owners did not change the oil for over 2 years, or over 15,000 miles and let a lot of soot form in the oil, and that can destroy the bearings.

With a properly working turbo (especially a Banks upgraded turbo and air intake system) you will increase your MPG, and probably not need to "Floor it" to go up the mountains.

Good luck!

Fred.