Engine - Misfires, Runs Rough, and Poor Starting
Boxster7/97 2425
Binder - 2, Fuel & Exhaust
Date: 10-22-98
Water in Air Cleaner Housing
Vehicle Type:
Boxster
Model Year:
As of 1997 (V)
Concern:
Water entering the left-hand air guide and air cleaner housing.
Situation:
Engine misfires during driving, rough running, poor starting.
Information:
Water can enter the air cleaner housing via the air guide when the vehicle is driven in unfavorable weather conditions, e.g. during rainstorms. This can cause engine misfires and rough running.
These problems do not necessarily have to occur during these weather conditions; they could show up later on. Please ask the customer whether the vehicle was driven in these weather conditions.
Modification:
1. A gasket between the outer left air guide and the body seals out water (Figure 2, dot-dash line).
2. A deflector (Figure 1, item 1) is fitted on the air cleaner intake opening, and a water separator bowl (Item 5) is fitted on the air cleaner housing.
3. The formerly used water shield support in the flow duct has been omitted.
Introduction:
Seal on the air guide, deflector and omission of shield support. As of August 25, 1997 production, from the following Vehicle Identification Numbers (VIN):
98 OWS 620 150
98 6WU 62 0075
Water separator howl on air cleaner:
Beginning on the 28th of October 1997, from the following Vehicle Identification Numbers (VIN):
98 9WS 621 166
98 6WU 62 0533
Fault Codes:
One or several of the fault codes below may be stored in the fault memory of the engine control module (DME) after occurrence of the complaint:
Troubleshooting:
If one of the items below is applicable, replace the air flow sensor (MAF) and carry out the modifications on the air cleaner and air guide.
Fault code P0101 (DTC 115) is displayed alone or with several of the aforementioned codes in the fault memory.
If fault code P0101 (DTC 115) is not displayed, start diagnosis with the engine at operating temperature. (air conditioner off, no loads switched on) Read out the values for mass air flow and adaptation in the DME "Actual values" menus and compare them with the adaption limit values below.
Adaption limit values at idle speed:
- Mass air flow set point: 1%24 kg/h
- Adaptation value, range 1 (TRA/TRA2): Adaptation limit, rich limit: + 0.37
- Adaptation value, range 1 (TRA/TRA2): Adaptation limit, lean limit: - 0.37
Adaption limit values at no-load engine speed of 2500 rpm:
- Mass air flow set point: 30-60 kg/h
- Adaptation value, range 2 (FRA/FRA2): Adaptation limit, rich limit: 1.25
- Adaptation value, range 2 (FRA/FRA2): Adaptation limit, lean limit: 0.75
Assessment criteria for implementation of the modification:
Air Mass:
- If value is at limit or outside of range, (signal not plausible).
- TRA/TRA2 and FRA/FRA2: If both values are approximately the same; or have reached either the lean or rich limit stop. The fault occurs symmetrically, meaning both TRA/TRA2 and/or at FRA/FRA2
To determine, pull off the MAF electrical plug. The engine now switches to the emergency program mode, and any previous rough running of the engine should be eliminated.
Parts Information:
The following parts are required to perform the retrofit:
Part Number Description
986 504 565 00 Gasket, outer air guide (I = 630 mm)
996 110 905 01 Water separator bowl (bowl, fleece and gasket)
996 110 907 00 Holder for water separator bowl
900 910 010 09 Hexagon nut M6 (2 ea. required)
996 110 903 00 Deflector
999 512 541 00 Retaining clamp (stainless steel)
996 606 123 00 Air flow sensor
Required Tools:
Phillips screwdriver (small) Electric drill
38 mm Hole Saw 2 mm & 6.5 mm drill bits
1/4" ratchet extension 6 mm & 10 mm wrench
Dremel with grinding bits Torque wrench 10-60 Nm (7.5-44 ft lb.)
Sheet metal cutters Jig Saw
Shop Supplies:
Acetone Vacuum cleaner
Grease Plastic body wedge
Sealant Shop light
Torch
Work Procedure:
1. Lift the vehicle.
2. Remove rear cover, part number, 986 504 129 00 of the underside panel.
3. Cut out a template (use copy of template pattern).
4. Place the template (Figure 1, Item 7) against the air cleaner housing from below according to the housing contours. Note: In order to facilitate handling, coat the rear side of the template with grease, Vaseline or similar to temporarily bond" it to the air cleaner housing. Insert the two hatched areas into the corresponding rib gaps up to the corner edge of the first seam of the air cleaner housing.
5. Make pilot holes for the three bores using the 2mm drill bit. Then drill all bores with 6.5 mm drill bit.
6. Enlarge the center bore to 38 mm +/- 1 mm using a center bit.
7. Remove all drilling chips from the air cleaner housing (use a vacuum cleaner with small flexible suction nozzle if necessary). Remove the drilling template. Remove grease residues from the air cleaner housing.
8. Insert the holder (Item 3) through the 38 mm bore and fit it in the air cleaner housing.
9. Fit the water separator bowl (Item 5) and the gasket (Item 4) on the holder in the air cleaner housing using the two M6 nuts (Item 6). Tightening torque: 10 Nm (7.5 ft lb.)
10. Reinstall the rear cover of the underside panel.
11. Remove the left-hand air guide (refer to References: Boxster Technical Manual, Volume 6, Repair, 66 56 19 - Removing and installing the engine compartment vent).
12. The further procedure depends on the VIN:
As of 98 3VS 62 0061: Go to Step 14.
13. Remove the shield support, part number, 986 575 569 00 previously installed in the flow duct (no longer required). The riveted shield support is fastened on the flow duct with three rivets. The front support wall must be cut off with a saw blade so that the rivets can be removed. Grind off the rivet heads with a straight grinder. After removing the shield support, leave the rivet stumps in the flow duct and cover them with body sealant to protect against water leakage. Go to Step 16.
14. Remove the shield support, part number, 986 575 569 00 previously installed in the flow duct (no longer required). To do this, unscrew the upper fastening screw and disengage the shield support.
15. On the flow duct, remove the formerly used left-hand fastening hook of the shield support using a saw blade.
16. Fit deflector (Figure 1, item 1) with retaining clamp (Figure 2, item 2) on the air cleaner intake opening. The deflector is fixed on the air cleaner intake opening by means of a locking lug. Ensure the restraining clamp is fitted within the guide ribs. The deflector must be fitted horizontally; the open side must face up.
17. Tighten the restraining strap so that the deflector no longer can be rotated. The deflector must not touch the body after installation.
18. Clean rear side of the air guide and degrease using acetone or similar (Figure 2, dot-dash line A-B).
19. Starting from point A, stick on the gasket under slight tension up to point B on the air guide (dot-dash line). Note: Distance of the gasket from the outer edge: 1.5 mm (Figure 2, detail Z). At start point A and end point B, stick on the gasket so that there is no space with respect to the locking rib (= hatched area) of the air guide (View Y). Cut off any part of the gasket that sticks out.
20. Before fitting the air inlet grill, place the air guide in the body aperture and check whether the gasket is visible from the outside. Correct position of the gasket if necessary.
21. Join air inlet grille and air guide. Reinstall engine compartment vent (refer to References: Boxster Technical Manual, Volume 6, Repair, 66 56 19 - Removing and installing the engine compartment vent).
22. Lower the vehicle.
Warranty Info:
Labor Operation Time Units Description
24 25 31 OD 130 TU Includes: Fitting deflector and water separator bowl on
the air cleaner, removing shield support, removing and
installing air guide, fitting gasket for air guide.
Damage Code
2425 10 0002
Literature:
Boxster Technical Manual, Group 6: - Repair: 66 56 19 - Removing and installing the engine
compartment vent Boxster Technical Manual, Group 0: - DME diagnosis On-Board Diagnostic (OBD II) manual
Make copies of template as necessary.