Author Topic: Mileage going wrong way (Read 4336 times)

Trimster · « **on:** March 28, 2008, 07:03:46 pm »

Just did rings, head, valves,... and the fuel mileage is going the wrong direction. With blown head gasket, over heating and oil consumption out the wazooo, I was getting 45mpg. Fresh rebuild, runs like a top. No ... and I mean NO smoke, no oil consumption, engine temp right on the mark... we got 36mpg for the first 5K miles as the engine breaks in. Now it's down to 32. We're running reg. Diesel. The engine runs like a top. More pep than before the rebuild... runs smoother, everything seems normal... accept the mileage. No fuel leaks either. Glow plugs good, injectors seem good. Any ideas where to look? What to tinker with?

TIA

jtanguay · « **Reply #1 on:** March 28, 2008, 08:08:03 pm »

driving habits the same?

Trimster · « **Reply #2 on:** March 28, 2008, 09:57:52 pm »

Driving the same. Mostly freeway. 80 + miles per day.

burnt_servo · « **Reply #3 on:** March 28, 2008, 10:22:59 pm »

i remember a friend of mine buying a early 90's jetta diesel brand new , and being told by the dealer that it would take at least 60,000km for the engine to break in and the fuel consumption to go down ........

it might still be "breaking in " ......

if it was mine , i'd be playing with the injection timing .

jtanguay · « **Reply #4 on:** March 29, 2008, 01:52:02 am »

if this is just a re-ring with a light hone, it shouldn't take as long to break in. it should be loose enough unless new pistons were installed with the 2mm gap.

Trimster · « **Reply #5 on:** March 29, 2008, 07:17:30 am »

..it was a mondo hone. I tend to make sure it's way! cross hatched. Specs were good to the wide side for the ring & piston fitting...Ok but to the large end of the spec. Mmmm, so I need to figure out fuel pump timing....

jtanguay · « **Reply #6 on:** March 29, 2008, 02:05:43 pm »

what did you time the engine to?

Trimster · « **Reply #7 on:** March 29, 2008, 02:15:38 pm »

I did not do the final cam-pump timing. We have a stellar old-school VW shop here. In fact, this truck use to be his. He did the timing.