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Car Service in Goolwa & Fleurieu Peninsula
D & D Mechanical & 4WD meet all your four wheel drive and car service or repair needs, wherever you are in the Fleurieu Peninsula...
Read moreV6 Engine Misfire Trouble and an Unwelcome Surprise Under the Bonnet
How D & D Mechanical & 4WD Diagnosed and Resolved a Mysterious Engine Issue
When a vehicle begins to underperform, it’s not just frustrating—it can also be a source of concern. At D & D Mechanical & 4WD in Goolwa, we pride ourselves on taking the guesswork out of car troubles and restoring our clients’ confidence in their vehicles. This case study outlines one such instance, where a misfiring engine and an unexpected discovery led to a challenging yet rewarding repair.
A local Goolwa resident reached out to D & D Mechanical & 4WD with complaints about their car - V6 Holden Commodore - misfiring at low revs, struggling under load while driving uphill, and experiencing cold start issues. With these symptoms, we booked the vehicle in for a comprehensive diagnostic and test service.
Diagnostic Process - Step 1
To kick things off, we connected our scan tool to the vehicle and retrieved the following fault codes:
- P0300: Random Multiple Cylinder Misfire
- P0301: Cylinder 1 Misfire
- P0303: Cylinder 3 Misfire
- P0856: Traction Control Input Signal
We road-tested the vehicle to replicate and confirm the symptoms, cleared the codes, and re-scanned the system back at the workshop. Once the fault codes reappeared, we knew it was time for a more in-depth investigation.
Diagnostic Process - Step 2
After removing the spark plugs, we found them fouled with fuel, particularly on the right leading bank of the V6 engine. From there, we suspected a potential injector fault, which prompted us to remove the intake manifold for further inspection.
What we uncovered under the bonnet was more than a simple injector fault—it was a bizarre and unexpected issue. Nestled under the injector rails were two deceased rats that had set up a makeshift nest. Unfortunately, during their time there, the rodents had chewed through wiring and fuel lines, causing significant damage.
We immediately contacted our client to share the findings and discuss repair costs. The discovery of the rats prompted curiosity, but neither the client nor our team could pinpoint a reason why the rats had chosen the engine bay as their home. However, the client did mention their dog had been growling and hanging around the car in recent weeks—a clue we all pieced together in hindsight.
Diagnostic Process - Step 3
At D & D Mechanical & 4WD, we don’t just fix problems; we ensure vehicles leave in better condition than when they arrived. First, we removed the fuel rail and cleaned out the nest and remains of the rodents. Then, we repaired the wiring and fuel lines that had been damaged by the chewing.
Once reassembled, we performed a thorough retest and found an additional issue—a fuel leak at a pressure return hose at the end of the fuel rail. We immediately ordered a replacement hose, installed it upon arrival, and conducted further testing. With all faults resolved, we cleared the codes, completed the reassembly, and carried out a final road test to ensure the car was running perfectly.
Engine Misfire Resolved
Thanks to the meticulous work of the team at D & D Mechanical & 4WD in Goolwa, the client’s car was returned to them in peak condition. The engine misfires were resolved, the fuel system was functioning optimally, and the vehicle’s overall performance was dramatically improved.
Our client was thrilled to have their car back on the road and running better than ever. While the discovery of the rats added an unusual twist to the repair process, it was a reminder of the importance of comprehensive diagnostics and thorough repair work.
For this repair, D & D Mechanical & 4WD in Goolwa ensured that every step of the process was carried out with precision. Beyond resolving the engine misfires, we advised the client to be vigilant about signs of rodents in and around their vehicle and home. It appears that this issue can affect those living in a suburban setting and not just in rural, farming locations as you would normally expect. Parking in rodent-prone areas or near possible food sources (like bins or pet food) can increase the risk of rodent activity under the bonnet. We also recommended periodically inspecting the engine bay for any signs of nests or damage.
With the vehicle’s issues resolved and proper maintenance advice given, the client could drive away with peace of mind. At D & D Mechanical & 4WD, we don’t just repair cars; we deliver results that our clients can rely on.
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