MAP voltage to high?
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Teching In
Joined: Dec 2010
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MAP voltage to high? 95 Camaro Z28. What should the MAP voltage be key on engine off? I'm getting 4.58 volts. Seems a little high don't it? It's not setting a code. Car won't start because it's flooding out.
Check the connector. They are known to get brittle and break....
Here's a t/s schedule.
1. Inspect the rubber nipple (fitting) from the MAP sensor to the throttle body. Repair as necessary. CAUTION: When testing the MAP sensor, be sure that the harness wires are not damaged by the test meter probes.
2. Test the MAP sensor output voltage at the MAP sensor connector terminal B. With the ignition switch ON, and the engine OFF. Output voltage should be 4 to 5 volts.
3. Test the MAP sensor output voltage at the MAP sensor connector terminal B at a hot, neutral idle speed condition. The voltage should drop to 1.5 to 2.1 volts.
4. Test MAP sensor supply voltage at sensor connector terminal C with the ignition ON. The voltage should be approximately 5 volts (�O.5 V).
Also, check the fuel pressure regulator vac hose. It should be dry. If there's fuel in it, the diapram is ruptured, and is flooding the engine w/ fuel.
W/out a code set, the map volts are not out of range. [either hi or low].
Another source for flooding could be the eng temp sensor..Shows -40*, and floods the engine w/ fuel.
Here's a t/s schedule.
1. Inspect the rubber nipple (fitting) from the MAP sensor to the throttle body. Repair as necessary. CAUTION: When testing the MAP sensor, be sure that the harness wires are not damaged by the test meter probes.
2. Test the MAP sensor output voltage at the MAP sensor connector terminal B. With the ignition switch ON, and the engine OFF. Output voltage should be 4 to 5 volts.
3. Test the MAP sensor output voltage at the MAP sensor connector terminal B at a hot, neutral idle speed condition. The voltage should drop to 1.5 to 2.1 volts.
4. Test MAP sensor supply voltage at sensor connector terminal C with the ignition ON. The voltage should be approximately 5 volts (�O.5 V).
Also, check the fuel pressure regulator vac hose. It should be dry. If there's fuel in it, the diapram is ruptured, and is flooding the engine w/ fuel.
W/out a code set, the map volts are not out of range. [either hi or low].
Another source for flooding could be the eng temp sensor..Shows -40*, and floods the engine w/ fuel.
Last edited by Old Geezer; Mar 18, 2011 at 08:47 AM.
Thread Starter
Teching In
Joined: Dec 2010
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Temp sensor checked out good. MAP is reading 4.5 volts key on engine off. The came is much larger than stock and I wonder how much vacuum it's actually pulling. I'm going to try pulling vacuum with a hand pump to lower the voltage at the MAP and then see if that helps. And I will definately be checking the regulator.
Thread Starter
Teching In
Joined: Dec 2010
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Yea. I did a lot of diagnosing this weekend. Changed plugs saturday morning and it runs now but it's still flooding on the #2 cylinder. I've checked the plug wires again and swapped plugs and it looks like I need to test the injector. May be stuck open. I'm trying to find an injector shop in Southern Indiana.
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The MAP should read a pressure if about 85 KPa.
Find the part number of the MAP, then download datasheet. It has a formula to know exactly how much volts it should read for a given barometric pressure.
Find the part number of the MAP, then download datasheet. It has a formula to know exactly how much volts it should read for a given barometric pressure.
Launching!
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