Car cranks but won’t start?

May 2021 4 54 Report

Car cranks but won’t start?

I thought it was the fuel pump. So I replaced the help pump. I turn the key and can hear it. I checked the first plug. I attached a jumper to it and grounded it, cranked the car and there was spark. I checked compression by stuffing a paper towel into where the spark plug goes and cranked, and it flew out, I did that with all four cylinders. It cranks, but doesn’t turn over. It shudders a very small bit if I press the accelerator. I sprayed starting fluid into the air intake, and still nothing. I’m at a loss. 2007 Chevy Cobalt 2.2L

Cars & Transportation / Maintenance & Repairs

Anonymous

Replace all the plugs and check for spark on all the coils. Mqke sure the coils go in the correct cylinder. Rent or buy a compression gauge and check compression. Floor the gas pedal when checking compression. Good luck.

paul h

If you changed the fuel pump, you may still have air in the fuel lines which can prevent starting. Try this...turn ignition key to Run position without starting...you should hear the fuel pump run briefly and then shut off...turn key back off and repeat the on/off process a few times which will clear any air pockets in the fuel lines. Then try starting as usual.

If that does not help, you may have a bad/clogged IAC valve which controls airflow into the engine at idle/startup...a bad/clogged IAC can cause hard starts or no starts or stalling...try testing/cleaning the IAC if possible or try starting with gas pedal depressed a couple inches/ halfway to floor. If it starts that way and stays running as long as the gas pedal is depressed but dies when you let off , then that is a sign that the IAC is clogged/bad.

Tuneup been done ? may be due for some basic tuneup /filter changes...clean IAC, MAF and TB of soot buildup...check fuel pressure with gauge.....check for good spark with spark tester...check for good injector pulses with Noid light, check for good compression with a gauge...not just a piece of paper. etc.. You need proper spark, timing, fuel and air flow for the engine to run/start.