P0507 High Idle Issue on 2001 Hyundai Santa Fe 2.7L V6: Diagnosis and EVAP System Fix
I'm experiencing a persistent P0507 (High RPM at idle) code on my 2001 Hyundai Santa Fe with the 2.7L V6 Delta engine. After replacing valve cover gaskets, PCV valve, and several dry/cracked vacuum hoses, the vehicle began exhibiting erratic idle behavior—racing between 1600 and 2400 RPM with intermittent whistling noises. I conducted multiple diagnostics: used carb cleaner to test for vacuum leaks (no results), tried propane gas with a hose (no change), performed engine smoking (no leaks found). I inspected the upper and lower manifolds, confirmed gasket seals were intact. The throttle body (TB) was thoroughly cleaned, and all components were reinstalled with new FelPro gaskets. Afterward, the idle continued to race but no longer searched—only whistling, which became more frequent but remained unlocatable. I replaced both upper and lower manifold gaskets from a junkyard source, cleaned them like new, and installed them. The car now idles around 1100 RPM with no searching, though the idle cannot be lowered further. I removed the Idle Air Control (IAC) motor to inspect it. During removal, I noticed plastic housing around the mounting bolts had split and detached—indicating possible stress or poor quality. I tested four IAC motors: original, junkyard replacement, a new OEM Hyundai part, and an aftermarket OEM unit. All original units showed spiral cracks from the electrical connector to near the TB air holes. The new Hyundai OEM was properly sealed but crooked in design—its reed flap opened unevenly. When installed, the cheaper aftermarket IAC reduced idle racing and brought it down to 822–895 RPM (still above the expected 700+ RPM), though now triggering the P0507 code. I suspect a defective or poorly designed IAC motor may have been the root cause—only becoming apparent after valve cover work. However, recent testing suggests an EVAP system issue is also at play. After further investigation, I discovered that when the fuel cap was opened and closed during operation, the idle would rise and fall noticeably. With the cap off, idle remained stable at ~900 RPM; with it on, idle spiked to 815–990 RPM. This behavior points strongly toward a vacuum-related EVAP system component. I replaced the vapor canister shutoff valve (located inside the drive shaft tunnel) and immediately saw the EVAP System Monitor go from 'Inconclusive' to 'OK'. The idle stabilized at 749 RPM, and no further P0507 codes have appeared after clearing the old code. I’ve now confirmed that this issue was not caused by a faulty IAC alone but likely involved a combination of poor IAC quality and an EVAP system leak or failure. This case highlights how vacuum leaks in the EVAP system—especially under specific conditions like fuel cap operation—can mimic high idle symptoms, even without visible leaks. It also underscores that P0507 on 2001 Hyundai Santa Fe 2.7L V6 engines may not always point to IAC or throttle issues but can be a symptom of underlying EVAP system faults. I’ve shared this experience in hopes it helps others troubleshooting similar symptoms, especially with older Hyundai models where parts quality and design flaws are common.
i DO NOT DO MANY HYUNDAI AS IT MOSTTLY FLEET VEHICLES i Tend to. that whisteling sound maybe is a clue- could be something only activated when engine running- ? SO did you look at EVAP purge valve if applicable? you replaced PCV - if you pinch off flow any change? Maybe eleminate the vacuum sources from engine to see if a change- ie ppower brakes, PCV, HVAC , whatever is vacuum operated.