It turns over good but wont crank?

SLEEZE

MEMBER
2001 GMC YUKON
V8
2WD
AUTOMATIC
200,000 MILES

01 yukon Will not start. It turns over good but wont crank. Every once in a while it will crank and the shut back off after a few seconds. Like it just uses the gas in the fuelpump/lines then shuts off. I was thinking it was a relay. But I have changed them.

1 Reply

WRENCHTECH

MECHANIC
20,761 POSTS

If your 2001 Yukon is not starting or only starting briefly before shutting off, there are a few potential causes to consider:

Fuel Delivery Issues: One possibility is that there may be a problem with the fuel delivery system. This could include a faulty fuel pump, clogged fuel filter, or a problem with the fuel pressure regulator. Insufficient fuel reaching the engine can cause it to start briefly and then shut off. Checking the fuel system components and ensuring proper fuel pressure is crucial.

Ignition System Issues: The ignition system could be another area to investigate. A faulty ignition coil, ignition control module, or crankshaft position sensor can cause intermittent starting issues. These components are responsible for generating the spark that ignites the fuel-air mixture in the engine. A malfunctioning ignition system can result in starting problems or engine shutdowns.

Security System Malfunction: Some vehicles are equipped with an immobilizer or security system that can cause starting issues if it malfunctions or is triggered. Check if the security light is flashing or staying on while attempting to start the vehicle. If so, it may indicate an issue with the security system that requires diagnosis and repair.

Electrical Connections and Grounds: Ensure that all electrical connections related to the ignition system and fuel system are secure and free from corrosion. Poor connections or faulty grounds can disrupt the proper functioning of these systems and cause starting issues.

Engine Control Module (ECM): The ECM controls various engine functions, including fuel delivery and ignition timing. If the ECM is malfunctioning or experiencing an intermittent issue, it can result in starting problems. Consider having the ECM checked by a qualified mechanic using diagnostic equipment.

Given the complexity of diagnosing starting issues, it may be best to have a qualified mechanic inspect your Yukon. They can use diagnostic tools to identify the specific cause of the problem and perform the necessary repairs.