SureTrack Real Fix: No Start Hot

Real Fixes from ShopKey’s SureTrack® expert information resource are documented issues from actual shop repair orders 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 currently available free with the purchase of a current Snap-on® diagnostic software version or in our ShopKey Pro product.


Heat can cause a lot of problems. Sometimes your car won’t start when it’s hot and it can be really inconvenient since you’re probably away from home at the time. Follow this Real Fix to see how a no start condition when hot was diagnosed and repaired on this Acura Legend.

Vehicle
1990 Acura Legend 2.7L

Title
Engine Does Not Start When Hot, Replaced Fuel Injection Relay

Complaint
The customer states the engine does not start when hot.

Cause
Confirmed the customer’s complaint and found the engine did not start when hot. Connected a spark tester at the spark plug wire and found there was a strong, steady spark. Connected a fuel pressure gauge to the fuel rail, tested fuel pressure with the key on and engine off, and found there was no fuel pressure. Visually inspected the fuel tank wiring harness and found no obvious signs of damage. Used a multi-meter to check for the presence of voltage at the fuel pump and found voltage was not present. Used a set of fused jumper wires to apply voltage and ground to the fuel pump, and found the pump was responsive and fuel pressure was within specifications. Used the multi-meter to check for the presence of voltage at the input terminal of the fuel injection relay and found voltage was present. Used the fused jumper wire to bypass the fuel injection relay and found the fuel pump was responsive. Used the multi-meter to check for continuity across the input terminal and output terminal of the fuel injection relay. Used the set of fused jumper wires to apply external power and ground to the relay control winding and found there was no continuity across the input terminal and output terminal of the fuel injection relay. These test results verified the fuel injection relay was faulty.

Correction
Replaced the fuel injection relay, performed a road test and verified the vehicle operated properly. The customer’s complaint did not return.


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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.