Skip the auto shop - Our mechanics make house calls

Q: Can't Start Engine after rebuild

asked by on

We had to replace the head gasket due to a compression leak in #5 to the cooling system. (Before this happened the car ran great with no problems). We disconnected the battery, stripped the engine down, had the head re-ground at an engine shop. Replaced the head bolts, gaskets, plugs etc. and put everything back together.
Then it wouldn't start. 1) We checked the fuel pump system and ECM relay drive. The fuel pumps runs during cranking. 2) We checked the fuel injectors with a test light. When cranking, they flashed 2 times in the first 2 seconds. 3) We tested the pick up sensor with a 1 volt meter. Manually turned the engine, the meter moved indicating a pulse. 4) Using an old time timing light tested the coil / spark output. While cranking, it flashed a couple of times in the first 2 seconds. 5) We check the MAP sensor and other sensors 5 / 12 volt power sources and ground. Our problem is when we crank the engine, the ECM will only fire for the first 2 seconds and then nothing

My car has 120000 miles.
My car has an automatic transmission.

Hi - congrats on being very thorough with your testing! If you spritz some starter fluid into the throttle body, will this start it for a second or two? That would confirm the total of your testing - that you have spark and fuel (temporarily) - resulting in combustion. If spraying gas into the throttle body allows the engine to run longer, you have isolated the problem to fuel supply. Coolant sensor failures (the sensor for engine management, not the gauge) are known for causing ECM problems with this engine, and it’s possible the ECM is bad period. I would recommend having a Car Is Not Starting Inspection completed by a mobile, professional mechanic, such as one from YourMechanic, to diagnose this problem if you are requiring of further assistance.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: The battery light is showing on the dashboard

This may be a sign of a weak battery, a failing voltage regulator or failing alternator. As you may know, the alternator is responsible for charging the battery while the engine runs by generating amperage and recharging the battery while...

Q: Engine swap

Hello - no, this swap will require custom engine mounts, transmission mounts, driveshaft, wiring changes, and many other not-so-little swaps or custom pieces. Better to buy or swap your Pontiac drivetrain for a Chevy package that is much more likely...

Q: Truck doesn't start

It is possible that your battery could have failed. I would recommend having a no start inspection performed by a qualifed professional to determine if the battery is performing as it should be. During this process I would also recommend...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.