2005 Chevy express 3500 w/ 6lt.V8- 50,000 miles

Tiny
NICKELLBAGS
  • MEMBER
  • 2005 CHEVROLET TRUCK
The vans voltage gauge in dash is constantly changing. The van sputters like its not getting fuel, and dies in high alltitude or under load. Check engine light comes on, and as soon as the veichle gets back to a lower elevation, the problem corrects itself. The dealership said the fuel pump, so I had that done, did not fix it. I had it hooked up to the computer, and it said low voltage to the map sensor, and misfire? What should I do? Replace the map sensor, voltage regulater, altenator? Please help for it is a commercial rig, and I need it for my job! The elevation ranges from 4,000 ft to about 8,500 ft.
Wednesday, February 14th, 2007 AT 5:46 PM

4 Replies

Tiny
SERVICE WRITER
  • MECHANIC
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It sounds like the barometric readings are off and can be caused by a bad maf. You you clear the KAM (keep alive memory) by removing the battery cable and touching the two cables together. If you do this, and then drive it with better results, then I would expect the MAF is bad.
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Wednesday, February 14th, 2007 AT 8:21 PM
Tiny
NICKELLBAGS
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In your reply, you said to remove the battery cable, and touch the two together. Woud that be taking off the neg. And touching it to the pos. With the pos. Still conneected to the battery post? Thankyou much for the reply! Would you be able to tell if the mass air flow sensor is bad by looking at it?
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Wednesday, February 14th, 2007 AT 9:30 PM
Tiny
CLEAVAGE4U
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NO! BOTH cables need to be removed from battery! Or you'll damage the pcm! But skip this at this point.

Cancel that thought and Service Writer's that was a different sensor we were working on. :Oops:

Can you find out what the code number is. I'm guessing it is po106. It may require a quality scanner to diagnose, The dealer doesn't seem to be helping you much. IF there is an independent that is current on technology, may want to take that route.

There may be a vacuum leak causing the problem as the manifold air pressure will be dropped. A vacuum hose disconnected, the seal for the map sensor, a restriction in the vacuum source to the map. Check the connector at the map as well for tightness, corrosion, damage.

A little carb or throttle cleaner spray or propane torch unlit but opened valve can help uncover a vacuum leak. But going around the intake or vacuums to the map or map may uncover it as the idle will changed when it sucks in the combustable.

The sensor chould give.8-2 volts to be in spec. There is refernce to a possible throttle body issue that can trigger this codes. The Throttle plate may be activated electronically and you don't want it to shut while you have anything in the throttle bore. Might be worth taking the air snorkel off an taking a look at the throttle body for damage.
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Thursday, February 15th, 2007 AT 5:01 AM
Tiny
SERVICE WRITER
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Sorry, my brain fell out.


https://www.2carpros.com/forum/automotive_pictures/30961_super_stupid_1.jpg



If the code is po107, The diagnostic chart points out the map sensor, the pcm or the wiring between them is the problem.
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Thursday, February 15th, 2007 AT 11:51 AM

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