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Hello. Hope anyone can help me with this one. As in the topic I have this car (it's equivalent of VW Golf mk IV) over a year. Few months ago, I've noticed low power (dyno showed at 1st test 98hp and 2nd 89hp so it's not consistent but much less anyway), increased, about half fuel consumption and bit rough start. I have VCDS scan tool and there's no other DTC except HVAC flap motor and Central Locking. Before I bought it, previous owner changed CAT and EGR. I think his mechanic tried to fix it just by seeing the code(s) and changed these parts. I Have done these tests with EGR which Paul has taught in his book: I've backprobed signal and ground wire (signal to DVOM and ground to battery (-) to fully open the valve (it's ground controlled). It clicked and signal showed 3.74V. At closed possition is 0.98V. I've disconnected the connector and signal V jumped to 4.75V so wire integrity is good. Passages are clean because on running engine, fully open valve completly stalled it immediately. And now the most interesting part. Although it looked good on DVOM, on the scan tool not so much. The voltages looked the same but potentiometer wasn't reacting. When I grounded it only Duty Cycle was going 100% for a second and it went off (still grounding it - valve open). Like it was loosing signal or something. The opening valve % stayed at 0% and only Duty Cycle somethimes showed 100% (maybe 1/5 times) for a second and then 0%. I know that valve is good because when i drive (monitoring data) at steady speed: signal voltage, potentiometer and duty cycle showing good parameters and working as it should. BUT when i press gas pedal (not WOT) it looses signal and everything is at 0% (signal V is 0.98V). I let go gas to it's previous position, it's back to normal again. Situaton repeats everythime.
If anybody would have any suggestions, I'd appreciate it.
Forgot to mention that right now LTFT is 7% and LTFT oscillates +/-5%. It depends on random acting out of the system. It can go up to 18% and it can go down to 0.6%. No vacuum leaks. MAF is clean. Don't know if I forgot to add any other variables.
Last edit: 4 years 8 months ago by Didymos. Reason: Forgot to add other variables.
