My 1985 VW Van is giving me troubles - when it runs cold it is fine, but after 10 minutes or so it starts backfiring like crazy and then I lose all power after about 20 minutes - we?ve checked all the obvious things - air filter, gas pump, gas filter - we think it may be the injectors or the oxygen sensor - my neighbor thought it might be the piston rings, but it?s not blowing smoke - anyone ever heard of this or any suggestions??
Sounds like it's running rich all the time. That's fine when cold but not when warm. I would suspect the oxygen sensor as one possible cause since it tells the ECU if it's running too rich or too lean. I don't know much about the injection systems on the older VW vans but it's possible that if there's a fuel pressure regulator that it's bad and it's allowing too much fuel into the engine. Also, the coolant temperature sensor could be faulty and failing to tell the ECU that the engine is warm.
If there's a vac. line going to the ecu then check it. Also watch the tail pipe for smoke. Black clouds indicate a rich mixture. You can also try it with the o2 sensor unplugged.
SFC
"koonster" schreef in bericht news:1_603267 snipped-for-privacy@autoforumz.com...
On my 84 the problem of running rich all the time was the wire from the 2 sensor to the ecm. It's not a single standard wire like it looks! It's a coax wire and the insulation is hardning and cracking shorting the center signal to outter grounded shield. I had to replace the wire from the ecm connector to where it connects to the o2 sensor. Microphone wire from radio shack works fine. the part of the wire attatched to the o2 sensor is also the same type of wire. There should be a low positive voltage on the wire when it's connected up of around 1 volt and when warmed up the voltage should rise and fall as the ecm reacts to the changes. Don't jump into the vanagon's injection blindly or your spend a lot of time and money with no results!
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