Initial test report

Given that I get lots of questions from readers about my ‘chugging’ issues in regards to checking this and that, so here is the report that Ferrari provided me initially when I brough the car to them a few months back. I’ll post more from the time line soon.

These are the findings on the F355, thus far.

1. Checked function of both Check Engine Lights and both Slow Down lights – ok (Ref – DashLights).
2. Carried out load test of battery – passed (Ref – Battery Load Test). Note, when gaining access to the battery found an oversized screw had been used in the wheel arch trim. This had damaged the plastic nut behind causing it to spin around with the screw which then couldn’t be removed. It was necessary to cut the screw head off in order to remove the trim and a replacement screw and plastic insert nut are required to re-assemble.
3. Checked charging system and confirmed alternator operating correctly with engine running. Output voltage approx. 14.0-14.2v (Ref – Charging Voltage). Noticed engine not running smoothly, slightly rough idle.
4. Carried out fuel pressure measurements at both rails. 3.8bar at Bank 1 and 3.7 bar at Bank 2. Values are acceptable and just slightly over the 3.4+/1 0.2 spec (Ref Fuel Pressure…).
5. Measured temperature of exhaust system during warm up and once operating temperature reached. No major discrepancies between individual cylinders of the same bank (Ref – Thermal_Bank…). Found on first test Bank 2 headers slightly cooler than Bank 1 however during later testing found Bank 1 at approx. 400degC and Bank 2 at approx. 450degC. Measured temps of inlet and outlet (Ref Thermal_Cat…) and found Bank 2 cat slightly cooler during warm up than Bank 1 and outlet temps were consistent.
6. Switched off engine after reaching operating temperature and observed over 30 minute period and found the values are out of spec for allowable pressure loss over 1 hour 2.7 +/- 0.3bar (Note: Non return valve spec is 1.5bar)

1. After half hour period started engine and confirmed an extended crank period.
2. Removed vacuum lines from fuel pressure regulators at the rails. No fuel evident at vacuum lines. Used vacuum generator on the diaphragm and then monitored for vacuum loss. No evidence of loss.
3. Carried out cold start and confirmed engine easy to start. Switched back off and carried out fuel pressure loss check over half hour period with a cold engine – Bank 1 dropped to 1.9bar and Bank 2 dropped to 1.7 bar.
4. Brought engine to operating temperature and then took readings of exhaust gas with analyser from all four tail pipes. HC and O2 values higher than expected indicating potential misfires (Ref – Exhaust Gas…).
5. Switched off hot engine and then restarted after 30 seconds without the chance for heat soak etc. Engine start consistent with the ease of a cold start.
6. Installed ignition indicators in line between leads and spark plugs and confirmed ignition indication at all 8 cylinders.
7. Removed spark plugs and visually inspected (Ref – Spark Plugs…). Found the electrode insulator of cylinder 7 darker than all other spark plugs indicating the cylinder that may be running richer. There was also a minor tracking mark on the insulator. Tested spark plug function in bench tester and it is still functioning correctly (Ref – SparkPlug_Test).
8. Measured spark plug gaps and found they are all within the 0.6-0.7mm spec.
9. Using a borescope through the spark plug well, inspected and found no major visual discrepancies between individual cylinders (Ref – Borescope…).
10. Carried out compression testing of all cylinders. Repeated test for cylinder 4 which had the lowest reading and cylinder 6 which had the highest reading (Ref – Compression Test…) and found similar readings in second tests. Values are fairly consistent and unlikely to be the cause of the reported fault symptoms.
11. Carried out cylinder leakage test of cylinder 4 and observed approx. 12-15% leakage which is in the allowable range.
12. Carried out leak testing of the intake system using a smoke machine. Observed smoke emerging around the inlet pipe collars for cylinder 2 and 7, with the more pronounced leak at cylinder 7 (Ref – AirLeak…)
13. Lined up timing paint mark of Bank 1 exhaust cam with timing case cover inspection window. With this mark lined up the Bank 2 intake cam is also lined up. Noticed mark for Bank 1 intake cam sits slightly out of window in the direction away from the exhaust cam. Bank 2 exhaust cam sits slightly out of window in the direction towards the intake cam.
14. Used thermal camera on the hot film air flow meters and observed similar readings between both sensors of approx. 50degC. (Ref – Thermal HFM)
15. Connected diagnostic tool to each Motronic and read out errors (Ref – 103862_Errors). Note: Revolution sensor error active is normal when errors read with engine stationery.
16. Ran parameter report with engine at idle and compared Bank 1 and Bank 2 readings (Ref – 103862_Idle_Parameters). The engine temperature values displayed are not plausible (Bank 1 showed 514degC and Bank 2 showed 360degC). Additive fuel trim at 0.54 for Bank 1 and 0.44 for Bank 2 and Multiplicative at 0.28 for Bank 1 and 0.43 for Bank 2. Confirmed function mode changed from Open Loop to Closed loop once engine at operating temperature.
17. Ran data acquisition and cross-checked catalytic converter temperatures with thermal camera and they are plausible. Checked function of air flow and confirmed trace indicates increased air flow with increased engine RPM. Ran engine at approx. 3,000RPM and monitored readings for both sensors. Bank 1 approx. 525m3/hr and Bank 1 approx. 475m3/hr. Oxygen sensors both fluctuate correctly between lean and rich however the pattern has some anomalies.
18. Deleted errors from both Motronics. Removed all test equipment and re-assembled engine bay for road testing.
19. Roadtested, no engine related warning lights came on however suspension warning light came on after approx. 15 minutes of driving (Ref – SuspensionWarning). Slightly rough idle evident throughout road test, no loss of power and was able to accelerate up hills in high hear. Found if coasting with no accelerator pedal input and then applying a very small amount of input there is a brief and minor hesitation.
20. After roadtest used thermal camera to inspect exhaust system. No discrepancies between individual cylinders. (Ref – PostRoadtest_Thermal) Found Bank 1 headers at approx. 380degC and Bank 2 headers at approx. 420degC. Bank 1 cat inlet hotter though at 440degC compared to 390degC for bank 2. The outlet temperature of both cats was even at 420degC.
21. Repeated exhaust gas analysis testing post roadtest. CO and CO2 readings have reduced however HC has significantly increased, O2 is fairly consistent.
22. Checked both Motronic ECUs for errors post road test – no errors stored (Ref – 103862_Post_Roadtest_Errors)
23. Read parameter report at idle post road test and compared. Checked the effect the road test and hot idle period had on fuel trims. (Ref – 103862_Post_Roadtest_Parameters)

1. Repeated data acquisition of oxygen sensors post road test and found a more stabilised reading than what was originally observed. (Ref – PostRoadtest_SDX_O2…)
2. Switched off engine and left for 45 minutes. Started and found engine still able to be started however there was a slightly extended crank period (Ref – Extended Crank)
3. Road tested again after the extended crank. Slightly rough idle however no lack of power.