SureTrack Community Fix: It’s All in the Fuel

Real Fixes from the SureTrack® expert information resource are documented issues from actual shop repair records and community discussions. Read on to see how SureTrack can help you correct issues that are not easily diagnosed using OEM information alone. SureTrack is available at no additional cost in our ProDemand product.

When a customer brings you their car but leaves out a critical detail, either on purpose or not, it can wreak havoc on your diagnosis. SureTrack community member DYERDAD had a Pontiac Bonneville in their shop that was running poorly and they checked everything that could have been the obvious cause. What they didn’t know from the customer could have saved a lot of time and frustration. They posed the question to the community, and with the help of fellow community member DAG1365 and others, they were able to resolve the issue quickly.

The following Community Fix summarizes the interaction between members of the community that led to the solution.

2005 Pontiac Bonneville GXP 4.6L

Vehicle running rich, wrong fuel.

Customer states that vehicle isn’t running right.

Diagnostic Steps Performed/Parts Replaced
Confirmed customer’s complaint. Runs super rich at start up. 5:1 on PCM. Fouls plugs in one start and can’t clear flood to start warm. Can get to run but says it’s adding 20 percent on trims. Still rich but startup won’t happen or is hard to start. Smokes horribly when it is running. Checked EVAP system, fuel pressure, MAF, PCM, grounds and engine coolant temperature. Fuel pressure is good. Unplug 02 to reset fuel trim and still does it on cold startup. What am I missing.

Decided to drain fuel tank and found last couple of gallons to be diesel. Not enough to make it smell like diesel in the gas when running. Customer didn’t mention accidently putting diesel in tank.

Drained bad fuel and replaced with fresh. After running vehicle for a while it is back to normal.

SureTrack® adds to the power of ProDemand® with an exclusive combination of real-world knowledge and powerful diagnostic tools, all wrapped in an interactive community of professional technicians. Designed to help automotive shops increase accuracy and efficiency from diagnosis to completed repair, the industry’s most comprehensive repair information resource is just a few clicks away.

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About the Author

Nick Taylor

Nick Taylor is the SureTrack Community Administrator and a Senior Applications Specialist at Mitchell 1 with over 25 years of experience with electronic repair data systems. Nick previously worked in the automotive dismantling and engine rebuilding industries.