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Car starts then rpm gauge drops immediately

Jason97GrandprixGT

Jason97GrandprixGT

New member
I need help I replaced both 02 sensors, map, maf and iac sensor, also the fuel pump and filter. Now car won't stay on what did I do wrong

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Do you still have pressure in the fuel rail after the car shuts down? Almost sounds like it's not feeding it fuel after the initial prime when you turn the key on.
 
Any Security light on? Have you tried holding the throttle and seeing if it will stay running if you give it gas?
 


^this^ The aftermarket MAF's for these cars can suck. I'd rather go to a JY and get a MAF than hassle with trying to get a new one to work out of the box from what I've seen. Or get a genuine Delco MAF as FFDP said.
 
why won't it run? Air, fuel, spark
diagnose instead of throwing parts at it.

fuel: you've replaced the filter and pump. Was it an OEM pump or aftermarket?
Get under the car, disconnect the line from the pump into the filter. Put a container under the end of the hose.
Key on without starting, listen for the pump to run and shut off. Did any fuel come out? if not your new pump is f*cked. I had two new airtex pumps crap out in one week because the check valve stuck closed and the system would not prime.

OK so if fuel came out leave the line disconnected. Unscrew the filter. Go the the front of the engine and use an air line through the to purge the fuel lines from front to back. reconnect the filter and fuel line from the tank.

Reprime a couple times, press the fuel needle valve and make sure gas comes out. Better yet use a pressure gage to check. You should have at least 50 psi at the rail and the pressure should not drop after prime.

Find the diagram for bypassing the fuel pump resistor by bending the relay tab and do that.

Next remove a spark plug then reconnect the wire from the coil. Crank the engine. If you have spark then your ICM and crank position sensor are good. If no spark you need to investigate further.
 


mguzzo said:
why won't it run? Air, fuel, spark
diagnose instead of throwing parts at it.

fuel: you've replaced the filter and pump. Was it an OEM pump or aftermarket?
Get under the car, disconnect the line from the pump into the filter. Put a container under the end of the hose.
Key on without starting, listen for the pump to run and shut off. Did any fuel come out? if not your new pump is f*cked. I had two new airtex pumps crap out in one week because the check valve stuck closed and the system would not prime.

OK so if fuel came out leave the line disconnected. Unscrew the filter. Go the the front of the engine and use an air line through the to purge the fuel lines from front to back. reconnect the filter and fuel line from the tank.

Reprime a couple times, press the fuel needle valve and make sure gas comes out. Better yet use a pressure gage to check. You should have at least 50 psi at the rail and the pressure should not drop after prime.

Find the diagram for bypassing the fuel pump resistor by bending the relay tab and do that.

Next remove a spark plug then reconnect the wire from the coil. Crank the engine. If you have spark then your ICM and crank position sensor are good. If no spark you need to investigate further.
Click to expand...
It started running after I unplugged the maf connector so what could be the problem

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in that case id be checking the fuel pressure and the harness to the crank.

all them parts you just changed mean nothing. with these obd2 cars you need a code to follow, or your guessing.

a crank sensor will not throw a code most of the time, and neither will a bad fuel pump.
 
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