AboutRon Wolff Expertise I am proficient in the following areas of VW Air Cooled Models from 1968-1979:
Vehicles: Super Beetle, Beetle, Thing, Karmann Ghia, Bus, Westfalia/Bus
Areas of expertise years 1968-1979
Engine Rebuild advice for all air cooled engines
VW Brake system replacement
Automatic Stickshift transmission
VW KOOL and DPD air conditioning systems (ex. thing)
Westfalia Electrical system dual battery
Westy Refridge Repair
Westy Cabinet Repair
Westy
AFC Fuel Injection system (1975 bugs) (1975 bus/Westys)
Soundproofing
General type 4 engine rebuild/technical data (i.e. 1.7 ltr, 1.8., 2.0) for buses
VW Air Cooled Beetle and Bus Paint codes
VW Distributor Compatibility Information
Westy component repair
Emission Systems
Exhaust Systems
General Electric System
Door rebuild (windows, seals, vent windows)
Body Panel Removal and general repair (non-welded)
Charging System
Convertible top Installation: Beetle
CV joints
Engine Troubleshooting
Valve Train
Non areas of expertise:
High Performance Modifications
Front end related components
Rear suspension (spring plate adjustment)
Bodywork / painting
Experience
Past/Present clients I often contribute to the westfalia users group technical boards. I have been a member for about 4 years. My usermame is 76Heatwagen
I restore vintage Volkswagens and currently own 4 of them.
Expert: Ron Wolff Date: 3/9/2007 Subject: fuel injection, '78 bus
Question Mr. Wolff,
I have read through your past answers and am thankful you donate your time. Though I came close a few times, I have not been able to search past strings on this site, or type2.com, for an answer to my problem. I have a '78 bus, all original, except for the electronic ignition which is a recent addition (which has not had an effect on the problem). By necessity I have become fairly proficient at diagnosing the troubles with my van, but am currently stumped. For the most part, I use the Bently manual. Some time ago the gas mileage started to decrease. I had built the motor only 30,000 miles prior. I cc'd the heads to achieve the proper combustion ratio, and drove it very "cool" with the help of my head temp gauge. It ran great! I also use a CB performance air/fuel ratio gauge that assures me, my current problem is in the mixture. Where I used to get 15mpg city, it's now 10. highway was 20, but now closer to 14. The ground connectors on the fuel injection are on tight to the best of my knowledge (I checked them), and the AFM checks out to the book's specs (I even tried a rebuilt spare I've been carrying around--no change). The head temp sensor is new. I am going mad. I pulled the motor suspecting bad heads/rings, but there were no problems: they were tight as new. And clean, too. The man who honed the cylinders said that it looked like the rings were getting washed. Indeed, I think so. But wherein lies my problem? Do you have any thoughts? I don't have a spare ECU, but that'd be my next guess (though I've never actually heard of one of them failing this way). Sorry to be so winded. Holler if you have an idea for me. Thanks! -- Geoffrey
Answer Hi Geoffrey,
Did you do a test on the injector output? If so, here are some additional checks:
1) Run engine until oil temp is above 176 degrees
pull the wire off the temp sensor
connect ohmmeter, specified resistance: less than 300 OHM
2) Cold Start Valve Leaking
3) Intake air preheating control bad: check that with the engine warm or ambient air temperature about 68 degrees warm air supply is closed.
4) An injector may be open continuously:
Remove injectors but leave them attached to ring main
pull wire off ignition coil terminal 1
operate starter briefly and check if more than two drops leak from each injector per minute.
5) Full throttle contact on throttle valve sticking.
Pull one wire off full throttle contact - see if speed drops.
