1998 Volkwagen Beetle Emissions Trouble Codes
Hello, My friend has a 1998 Volkswagen Beetle and im helping fix it, its throwing three codes (i forget the exact phrase) but the engine is running rich in open loop operation(bank 1 (obviously because theres only one bank) and lean in closed loop operation (bank 1). we dont have the money to just start replacing parts and hoping it works so i took it to my friend and we tested the catalytic converters and oxygen sensors. one oxygen sensor flucuated its reading from 10-0volts, the other fluctuated from 7-0 volts. what is the voltage at the oxygen sensors supposed to be? also the computer said the Catalytic converter was running at 560 degrees, but when we measured the temperature with a infra red heat gun, it said the exaust was 300 F before the catalytic and 200 F after, i might be wrong but isnt the exaust supposed to be hotter after the cat? and insigt into the VW specs would be a huge help...
Cars & Trucks - Volkswagen - Beetle - 1998 Volkswagen Beetle
Answers & Comments
Need to know the codes before we can do anything else.
I'll have to get back to you on the voltage at O2 sensors but they could be ok. Cat's perfect output gotta be 100 degrees lower than input. Get codes and I'll help you out.
Try our manuals section to get spec's.
Thanks for the codes now I'll tell you what they mean. You basically have to replace your Mass Air Flow Sensor. BUT before you condem that check all of the wires on its connector. THEY ARE ALWAYS LOOSE SPLITTING FULL OF CORROSION ETC.
This is one of the worst sensors VW had ever put out.
Whats happening is that the air flow is insufficient, and the o2 sensor is getting a constant rich reading and the ecu is correcting it by making the long range fuel trim lean. So replace or ( if you luck out ) repair the wiring as I described. Keep me posted
I could answer this question for you However, I think you can answer it your self with the shop manual and the inspection of the exhaust system you described to me. If the guy your using is not ASE certified you may be wasting your time and money.