Sorry guys, posting after a long time. Was too busy sorting out life!
Drove to Jaipur last week, my OHC returned 12.5kmpl with 100% AC and out of the 650kms I drove, about 20% was city driving. I've got much better FE in the city! Could reach a 100-110 kmph easily but she was grunting after that so decided it is time to set things right!
I went to Pandit & Co yesterday morning. After a TD and discussing the symptoms, we did a compression test. Saw that it had gone down to 150.
CULPRIT: The Abro motor flush was too strong for her and that engine flushing is NOT recommended for older engines especially who have not been flushed regularly.
There was an expensive treatment available and so decided to test on just one cylinder first.
It was a small tube holding 9ml of chemical that was put into cylinder 1 with a squirt or 2 of machine oil. The plug + wire were put back on but the switch wire (which powers the electricals) was taken off. The engine was cranked for 2-3 seconds a few times and then the switch was put back on and the engine was fired and idled for 10-15 minutes, with light revs in the end, exhaust smoking!
RESULT: After this, the plug was removed and the compression was tested in the cylinder. Ok, in the beginning, we were expecting the compression to rise to about 170 (+/- 5) but it went up to a 180, which was unbelievable. (185 is a new engine)
I was asked to drive and see if I saw a difference but it would take time for the treatment to take full effect in any case. I drove around for about 45 minutes and could see a difference for sure (or maybe it was psychological).
Anyway, I went back there and decided to get the remaining 3 cylinders treated as well. Same procedure, but we let her idle for an hour. The best part was, in about 20-30 minutes, the engine sound VANISHED, it sounded dead silent and like a fresh engine that was so full of life.
We didn't do any more compression tests after this but I am in the process of making the best of the treatment right now.
CONCLUSION: Have to drive her under 50-60 and very gently, no red lining and be very gentle, have to do this until 500kms (this will cause regular heat expansion and contraction and seal the internals for compression to remain intact), and return for the final compression test and to get the plugs and injector cleaning done. Was warned that if I don't be gentle then I'd just blow up the $$ spent, out of the exhaust ;-)
Did about 140 kms yesterday with speeds under 60 and low revs (FOOT ACHED!) Managed to get FANTASTIC FE until now, haha, I think she is
coming back to life!