asbi

Anyone got a pdf or similar of this Tech Bulletin, it is to re-route the Mass Air Flow Meter wiring harness which can cause temp loss of power/misfire, it was dated 21-02-90.

If anyone can help my email address is kasbridge@ptc.com

I remember this being mentioned by someone on this forum a while ago, I have the text but not the illusatrations, and as they say - a picture is worth.....
Thanks,
Kevin.

KirkF

I looked but I don't see the TSB.

.
11/05 050728 Engine - Porsche Approved Oils
45/03 040123 Wheels/Tires - Approved Summer Wheels/Tires
41/03 031023 Tires - Winter Tire Supplement
0301 030523 Engine - Approved Engine Oils
1/03 030425 Body - Windshield Replacement Parts/Installation
1/00 001028 A/C Condenser Fan - Updated Ballast Resistor
1/00 001027 Oil Cooler Fan - Updated Ballast Resistor
99 01 991105 Vehicle - Year 2000 Hardware/Software Readiness
4636 990729 Front Brake Pads - Revised
9068 990113 Vehicle Security Codes - Requesting
2706 971211 Battery - Revised With 70 Ah Rating
8703 971001 A/C - Refrigerant 134a Use
77059 970101 Door Panel - Air Leak
66816 970101 Storage Box - Installation
19604 961107 Cylinder Head Studs - Installation Precautions
NHTSA96V147000 960801 Recall 96V147000: Steering Noise & Excessive Freeplay
29604 960711 Exhaust System - Sulfur Like Smell
19602 960625 Engine - Cleaning of Oil Circuits
49606 960611 Steering Gear - New Type Oil
89602 960606 A/C - Use of Correct Refrigerant
49602 960328 Rear Axle - Installing Distance Spacers
69603 960307 Roof Mounted Third Brake Light - Service Installation
49601 960130 Brake Fluid Reservoir - Revised Venting
89501 951219 A/C - Retrofitting R12 Systems to R134
WARR9512 950502 Warranty - Pre-Owned Program Changed
29501 950323 Ignition Distributor - Revision and Marking
9504 950323 Paint - Manual Supplements
TOOLS9502 950321 Tools - Quick Scope Plus
19501 950131 Engine Crankcase - Standard Replacement Parts
809501 950126 A/C Refrigerant - Identifier
X9402 941227 VIN Plate, Certification & Emission Label - Availability
19410 941215 V-Belt - Correct Tensioning Procedures and Tool
TOOLS9412 941108 Tools - Gear Puller for G50 and G64 Transmissions
19409 941108 Oil Drain Plug - Revised Torque Specification
89402 940505 Rear Blower Motor - Does Not Function
29402 940329 Battery - Discharged Unit Diagnosis
29403 940329 Ignition Distributor - Install Ventilation When Serviced
19406 940324 Cylinder Head - Correct Torque Specification
69403 940324 Windshield Cement - Mixing
29401 940310 Filler Pipe - Fuel Odor
89401 940301 A/C - Refrigerant Loss from Expansion Valve Connections
19404 940208 Cylinder Heads - Refacing Information
19403 940208 Camshaft Housing and Manifold - Revised Sealing
09401 940125 Vehicle - Approximate Oil/Fluid Capacities Chart
89302 931221 Campaign - Rear Heater Blower Resistor Replacement
49314 931221 Tires - Manufacturer Contact Information
NHTSA93V204000 931203 Recall 93V204000: Rear Heater Resister Defect
79301 931028 Seat Rail - Adjusting For More Leg Room
19306 931005 Engine Cooling Fan Hub - Available as Separate Part
39306 930928 Longitudinal & Differential Lock Friction Disc - Revised
49311 930928 Alignment - Revised Specifications
TOOLS9303 930921 Tools - Testers for Alarms, Central Warning, & Air Bag
19305 930921 Cooling Fan Motor - Correct Positioning
99308 930914 Radio - Discharged Battery/Alarm System Malfunction
49310 930805 Brake Vibration Damper - New Application Information
EQUIP9303 930729 Tools - Auto Scopemeter & Engine Analyzer
09301 930218 Tools - Special Wheel Balancing Adapter
29204 921012 Campaign - Replacement of Cruise Control Linkage Rod
NHTSA92V142000 921002 Recall 92V142000: Cruise Control Ball Sockets Revised
ATRATB078 911101 A/T - How To Use A Pressure Gauge
59101 910121 Recall - Hood Safety Latch Modification
NHTSA91V012000 910115 Recall 91V012000: Hood Safety Latch Improvement
ATRATB028 901001 A/T - Engine Vacuum Testing
ATRATB9002006 900201 A/T - Choosing the Right ATF
48910 891122 Tires (VR-Rated Summer ) - Do Not Mix With ZR Rated
X8905 891110 Towing - Instructions
48911 891020 Hand Brake Shoe Retaining System - Correct Installation
28906 891006 Ignition - Erratic Warning Light or Engine Performance
48906 891006 Brakes - Squeaks May Be Normal Performance
ATRATB8930 891001 A/T - Math Part II
X8904 890901 Parts Marking - Law/Policy
ATRATB8927 890901 A/T - Twenty Steps To Successful Repairs
88902 890901 A/C Refrigerant - General Recovery & Recycling Tips
ATRATB8923 890801 A/T - Math Formulas Part I
98903 890728 Radio - Alarm Contact Insulator When Replacing
08904 890616 Vehicle - Repair Times and Maintenance Schedules
18905 890505 Engine - Motor Oils That Minimize Carbon Build-Up
48903 890505 Tires/Wheels - Summer/Winter Tire and Wheel Rim Summary
68902 890217 Windshield Frame - Modification
ATRATB8754 870901 A/T - Front Bushing Wear
ATRATB8748 870801 A/T - Slipping or No-Shift/Metal Sealing Rings

If you see it in this list, I can get it for you, but according to alldata, this is all of them. Maybe that TSB didn't relate to my year of car (89)

Kirk

warmfuzzies

Adrian has mentioned it here before, I seem to recal something about a dot being placed on the meter housing or a blob of green? black? paint being used to ID those that had been repaired...

Kevin

JasonAndreas

Engine - Erratic Idle, Loss of Power, or Stalling

May 15, 1990
Subject: Engine, Inconsistent Performance
Model Group

911 C2/911 C4 2

Part Identifier Number

9750 9005
ATTENTION: Service Manager/Service Technician

This bulletin replaces Technical Bulletin Group 2, Number 9005, dated April 6, 1990.

Models Affected: 911 Carrera 2 and 911 Carrera 4, Model Years 1989 (K) and 1990 (L)

Concern: Inconsistent acceleration, erratic idle, loss of power or engine dies.




Possible Cause: The air flow meter wiring harness protective cover (Figure 1) contacts the engine ventilation hoses (Figure 2) causing current flow interruptions on the plug terminals.

Vehicle Information: The protective cover on the air flow meter wiring harness plug was discontinued from production date February 13, 1990.

VIN's 96 - LS 45 1659 Coupe 96 - LS 46 0409 Targa 96 - LS 47 1072 Cabriolet

Repair Information: 911 Carrera 2 model year 1990 and 911 Carrera 4 model years 1989 and 1990 prior to the above VIN's should be modified when the engine is removed or when working on the air flow meter, even if no engine performance problems are present.

Work Procedure: 1. Remove air filter housing cover and filter.



2. Push down locking spring on air flow meter wiring plug and disconnect plug (arrow in Figure 6).

3. To gain access to plug, pull wiring harness with plug between air flow meter and idle stabilizer towards rear of vehicle.



4. Pull back rubber boot and cut protective wire covering using side cutter or similar tool (arrow in Figure 3).



5. Heat protective wire covering with hot air blower to maximum 110~ C (230~ F). Pull off and discard protective wire covering (Figure 4).



6. Reinstall rubber boot on plug housing. Loop wiring harness along side of plug and tie wrap as shown in Figure 5.



7. Reconnect wiring plug. Make sure spring lock is engaged. Figure 6 shows wiring plug connected (engine removed).

Important: Do not use contact spray.



Work Procedure: 8. Check clearance between wiring harness and vent hoses. Distance should be at least 15 mm. If necessary, bend bracket on right shock absorber mounting slightly forward (arrow in Figure 7). Make sure vent hoses are properly installed on bracket at shock absorber mounting and on bracket in front of air flow meter. The small diameter hose must be routed below the large diameter hose, 9. Reinstall air filter and filter housing cover.



10. Mark air flow meter with a black paint dot as shown in Figure 8.
Parts Information: Tie wrap: PN 999 513 021 40

Labor Information:
Labor Operation: 97 50 19 OA
Damage Code: 97 50 40 000 1
Time Units: Engine installed - 80 Engine removed - 20

John Boggiano

You still having trouble then, Kevin?

asbi

All,
Thanks for the help, great response!

John,
Yes, one of those small but irritating problems. Engine is a little "jerky" when cold and when warmed up has a slight misfire on the overrun at around 2000-2500 revs on light throttle in 2nd and 3rd.

One of those things that could take an age to find, car is at 9m as we speak having the MAF unit checked, ISV, inlet manifold clean/replace, renewal of vacuum pipes between manifold and engine etc. Injectors will be cleaned also.

If this doesn't fix it I will probably just ignore it and see if it gets any worse, I already had new dizzy caps/rotors last year so this only leaves plugleads and coils or maybe something subtle like the problem described in the TSB above.

If I weren't such a fussy creature I probably wouldn't even have noticed it!!!
Cheers,
Kevin.

dfinnegan

Kevin,

Did you solve the "jerky" when cold problem?

Thanks,
Dave

Adrian

Kirk,
Your list from Alldata is for the 964 Carrera 4. To get the complete list of TSBs you also have to check the 964 Carrera 2 (which means you have to register another car). I have no idea why they did this when many of these TSBs apply to all models, but it has been this way from the beginning.
Ciao,
Adrian.

asbi

Dave,
In answer to your question - no.

After spending almost £2k doing various things I gave up, my problem is very slight and would probably not even be picked up unless you were very familiar with the car.

One of the things that made me feel better about it was the fact that an M5 I owned recently did exactly the same thing, M3s are also known for it apparently.

Sorry I could not be more help,
Regards,
Kevin.

Sal 965

Nearly every M5 does the kangarooing when cold - usually just give it a liitle more gas and try and keep in 1 gear less to keep the revs up. Propably not the correct answer but it works for me.

Wachuko

I

elbeee964

-- and that, students of Stuttgart, is one Grade-A, bulletin-conforming, stall-preventing, lightly dusted, beauty of a hail-Mary factory field fix...

Thanks, Jaime. (Was this a pre-emptive measure? I didn't see your 91 on the affected list.)

Huh. I also didn't notice this before at the bottom of the bulletin: you cut an hour off this repair's normal install time (of 80 minutes) by simply...

...removing the engine first.

Wachuko

I updated the wrong thread...

I noticed mine had the fix in place when I removed the airbox to get access to the rear shocks. Thought I would post a photo of what it looks like. Should have cleaned it first .

mshobe

oh JEEZ, do I wish I'd seen these photos a few months ago. That's the exact, simple fix and it's utterly amazing how completely it repairs what seems to be an otherwise failed ignition system.

Thorpedo

Bumping this old thread as the quick fix in the bulletin resolved my idle/hesitation problems. May be useful for others who have similar issues with early 964s. I had already cleaned ISV, MAF and replaced O2 sensor and this finally and quickly fixed the issue. I have to admit I felt pretty proud when I was able to cancel my backup appointment with the mechanic.