CRITICAL ISSUES DETECTED — 3 critical violations found. Review immediately before driving.
MHD N54/N55
mhdn54.csv (Demo)
May 5, 2026 at 1:57 AM
Critical
3
Warnings
16

System Checks

LPFP Pressure
LPFP maintained >50 PSI throughout datalog
HPFP Rail Pressure
Rail pressure maintained >1400 PSI at high load
Timing Corrections
Issue detected: Timing Correction Excessive
9 violations
Short-Term Fuel Trim (Pinned)
STFT not pinned at limits (±30%)
Short-Term Fuel Trim (Idle)
STFT within ±3% at idle conditions
Boost Control
Issue detected: Boost Deviation
1 violation
Intake Air Temperature
IAT remained below 140°F warning threshold
Ignition Advance
Issue detected: Ignition Advance Drop
3 violations
Lambda Synchronization
Both banks spike to lean simultaneously - no leaking injectors
STFT Bank Differential
Issue detected: STFT Bank Differential
2 violations
Simultaneous Knock
Issue detected: Simultaneous Multi-Cylinder Knock
3 violations
Long-Term Fuel Trim
LTFT within ±10% range
Intercooler Performance
Intercooler efficiency within acceptable range
Turbo Spool Performance
Turbo spool time within normal range
Wastegate Duty Cycle
Issue detected: WGDC Maxed
1 violation
AFR Target Accuracy
AFR tracking targets appropriately for load conditions

Issues Found

Timing Correction Excessive

warning 9x

ECU pulling significant timing (>3°) due to knock or octane deficiency.

Use higher octane fuel (93+ octane recommended for Stage 2+)

Add ethanol content if fuel system supports it (E30-E50)

Replace spark plugs (max 15k miles on tuned N54/N55)

Replace ignition coils if over 60k miles

Consider less aggressive tune if octane/ignition components are good

ECU is protecting engine - sustained corrections reduce power and efficiency

Boost Deviation

warning 1x

Actual boost deviating >2 PSI from target in mid-RPM range - possible boost leak.

Inspect all vacuum lines for cracks or disconnects

Check intercooler couplers for looseness

Inspect charge pipe for leaks

Verify wastegate vacuum solenoids function properly

Check boost control solenoids

Inspect turbo wastegate actuators for proper movement

Perform boost leak test - common on N54/N55 with age

Ignition Advance Drop

warning 3x

Sharp timing drop >3° at high RPM - overly aggressive tune or knock detection.

Sharp timing drops indicate knock detection or overly aggressive tuning

Verify spark plugs are gapped correctly (0.024-0.026" for tuned N54)

Replace spark plugs if over 15k miles

Replace ignition coils if over 60k miles

Use higher octane fuel or add ethanol content

Consider re-flash with more conservative timing curve

Check for carbon buildup on valves (common on direct injection)

STFT Bank Differential

warning 2x

STFT banks diverge by >10% - vacuum leak or uneven injector performance.

Check for vacuum leaks on the bank showing higher STFT

Inspect intake manifold gaskets and vacuum lines

Clean MAF sensor thoroughly

Check for uneven injector performance (flow test)

Verify PCV system is functioning properly

Simultaneous Multi-Cylinder Knock

critical 3x

Multiple cylinders (≥3) pulling timing simultaneously - tune too aggressive.

CRITICAL - Tune too aggressive for current conditions

Reduce boost pressure immediately

Use higher octane fuel (93+ minimum)

Add ethanol content if fuel system supports it

Consider less aggressive tune file

Multiple simultaneous corrections indicate systemic issue, not isolated cylinder problem

WGDC Maxed

warning 1x

Wastegate duty cycle maxed at 100% - boost leak or weak actuators.

Perform boost leak test immediately

Check wastegate actuator preload/rod length

Inspect diverter valves for proper operation

Verify N75 wastegate solenoid is functioning

WGDC maxed means ECU cannot control boost properly

Notes

Violation Detail

Timing Correction Excessive (9)
Time Severity Message Details
205.36s warning Cylinder 1 timing pulled 3.7° (threshold: 3°) Cylinder 1 timing pulled 3.7° (threshold: 3°)
203.42s warning Cylinder 2 timing pulled 3.3° (threshold: 3°) Cylinder 2 timing pulled 3.3° (threshold: 3°)
205.50s warning Cylinder 2 timing pulled 4.3° (threshold: 3°) Cylinder 2 timing pulled 4.3° (threshold: 3°)
205.36s warning Cylinder 3 timing pulled 3.7° (threshold: 3°) Cylinder 3 timing pulled 3.7° (threshold: 3°)
205.36s warning Cylinder 4 timing pulled 3.7° (threshold: 3°) Cylinder 4 timing pulled 3.7° (threshold: 3°)
197.00s warning Cylinder 5 timing pulled 3.7° (threshold: 3°) Cylinder 5 timing pulled 3.7° (threshold: 3°)
203.06s warning Cylinder 5 timing pulled 3.3° (threshold: 3°) Cylinder 5 timing pulled 3.3° (threshold: 3°)
205.36s warning Cylinder 5 timing pulled 4.7° (threshold: 3°) Cylinder 5 timing pulled 4.7° (threshold: 3°)
204.87s warning Cylinder 6 timing pulled 3.3° (threshold: 3°) Cylinder 6 timing pulled 3.3° (threshold: 3°)
Boost Deviation (1)
Time Severity Message Details
205.95s warning Boost deviated 11.0 PSI from target at 4329 RPM Boost deviated 11.0 PSI from target at 4329 RPM
Ignition Advance Drop (3)
Time Severity Message Details
205.06s warning Timing dropped 27.7° at 5811 RPM (aggressive tune or knock) Timing dropped 27.7° at 5811 RPM (aggressive tune or knock)
205.95s warning Timing dropped 9.0° at 5336 RPM (aggressive tune or knock) Timing dropped 9.0° at 5336 RPM (aggressive tune or knock)
206.28s warning Timing dropped 7.4° at 5288 RPM (aggressive tune or knock) Timing dropped 7.4° at 5288 RPM (aggressive tune or knock)
STFT Bank Differential (2)
Time Severity Message Details
200.87s warning STFT banks diverged by 10.9% - vacuum leak or injector imbalance likely STFT banks diverged by 10.9% (Bank 1: -9.6%, Bank 2: 1.2%) - check for vacuum leak or uneven injector performance
201.72s warning STFT banks diverged by 11.5% - vacuum leak or injector imbalance likely STFT banks diverged by 11.5% (Bank 1: -16.1%, Bank 2: -4.6%) - check for vacuum leak or uneven injector performance
Simultaneous Multi-Cylinder Knock (3)
Time Severity Message Details
196.03s critical 3 cylinders knocking simultaneously - reduce boost or use higher octane 3 cylinders pulling timing simultaneously (worst: 3.0°) - tune too aggressive for current conditions
198.86s critical 3 cylinders knocking simultaneously - reduce boost or use higher octane 3 cylinders pulling timing simultaneously (worst: 2.7°) - tune too aggressive for current conditions
205.36s critical 6 cylinders knocking simultaneously - reduce boost or use higher octane 6 cylinders pulling timing simultaneously (worst: 4.7°) - tune too aggressive for current conditions
WGDC Maxed (1)
Time Severity Message Details
197.87s warning WGDC maxed at 97% - check boost system and wastegate actuators WGDC maxed at 97% - indicates boost leak or weak wastegate actuators

Diagnostic Graphs

Pull #1 - MHD N54/N55 Analysis

Comprehensive pull analysis with boost, fuel, timing, and IAT monitoring

LPFP Pressure - System Check

Low Pressure Fuel Pump maintained 56.4-86.8 PSI (threshold: 50 PSI minimum)

HPFP Rail Pressure - System Check

High Pressure Fuel Pump maintained 606-2740 PSI (threshold: 1400 PSI minimum at high load)

Timing Corrections - System Check

[WARNING] Issue detected: Timing Correction Excessive — 9 violation events detected

Short-Term Fuel Trim - System Check

AFR compensation monitored on both banks (safe range: ±30%, pinned at ±34% indicates issues)

Boost Control - System Check

[WARNING] Issue detected: Boost Deviation — 1 violation event detected

Intake Air Temperature - System Check

Intercooler efficiency monitored (max: 95°F vs 140°F threshold, avg: 89°F)

Ignition Advance - System Check

[WARNING] Issue detected: Ignition Advance Drop — 3 violation events detected

STFT Bank Differential - System Check

[WARNING] Issue detected: STFT Bank Differential — 2 violation events detected

Simultaneous Knock - System Check

[CRITICAL] Issue detected: Simultaneous Multi-Cylinder Knock — 3 violation events detected

Intercooler Performance - System Check

Intercooler heat rejection monitored (max rise: 11°F, graded: A)

Turbo Spool Performance - System Check

Turbo response monitored in mid-RPM range (2500-3500 RPM, analyzes boost vs target deficit)

Wastegate Duty Cycle - System Check

[WARNING] Issue detected: WGDC Maxed — 1 violation event detected

STFT at Idle - System Check

Idle fueling stability monitored (safe range: ±15%, separate from WOT pinned check)

Timing Correction Excessive Diagnostic

Detailed view of Timing Correction Excessive with violation markers (red dotted lines)

Boost Deviation Diagnostic

Detailed view of Boost Deviation with violation markers (red dotted lines)