Author Topic: New engine- poor mileage (Read 3500 times)

Rabbit TD · « **on:** April 22, 2009, 05:50:59 pm »

I've been driving my Rabbit with it's new 1.6 T/D engine to work for about a month now that I built last winter. The problem is that it gets about 20% less mileage than the N/A it replaced. I got 50-52 out of it and I"m only getting 41-42 out of this one. The engine has 500 or better compression, starts right up, has good power and has absolutely no visible smoke I can see while driving..
I did have to take the T/D pump off at about 200 mi. to re-seal it and put new shaft bushings in and have been using the N/A pump from the other engine, I will be putting the T/D back on this weekend. I have the N/A pump timed at 1.10 with rebuilt Giles injectors {155's}. This engine doesn't make much boost, 5-6 at most on a long pull but for the N/A pump it feels pretty good. The engine did have a lot more power with the T/D pump on it though and I never touched the fuel screws on either pump. I just can't understand how it can use this much more fuel and have no smoke at all and the other engine smoked pretty bad but got great mileage, 20% better actualy. I guess this engine would be a 1.6 version of the eco-diesel with this pump but there sure ain't no eco {economy} to it :cry: Any ideas why it uses more fuel under the same conditions as the other one?

maxfax · « **Reply #1 on:** April 22, 2009, 06:16:37 pm »

Have you been using that extra power alot??

Did you do new bearings and all that on the engine?? It may just need some more break in time..

Vincent Waldon · « **Reply #2 on:** April 22, 2009, 06:20:40 pm »

When you rebuilt it did you do rings, bearings, etc ?

Been using conventional oil or synthetic ?

About how many miles have you put on it ?

My general feeling would be that after only a month your engine is a long way from being broken in and your best mileage is yet to come.

I've been tracking my new engine since the day I built it and it took approximately 20K miles before the fuel economy smartened up... bearings and rings are tight in a new engine and it takes a while for them to find their groove.

You also have to be a little careful when comparing mileage on summer fuel vs. mileage on winter fuel... dunno if that's a factor in the numbers you're experiencing.

EDIT: maxfax beat me to the punch. :wink:

Rabbit TD · « **Reply #3 on:** April 22, 2009, 07:55:02 pm »

Yes the motor was completely rebuilt, bored .020, crank polished and all new bearings and a new head and a rebuilt turbo. I know I don't have a lot of miles on it yet and I am using the same Shell Rotella 15-40 that I used in the other motor. It gets run pretty hard on the highway but identicly to the way the other engine was used though , But wouldn't you expect it to be at least making some smoke to be using that much more fuel, especialy pulling mountains full throttle? The other engine would put out a hell of a lot of smoke doing that and got 10 mpg better and on the same pump on top of it. I guess it is a break in issue but it's had over 500 lbs. compression since it's first 400 miles, about 2,000 now and I've never seen the EGT over 1200 on the mountain with this pump yet.
I just hope with the T/D pump it doesn't go down to 30 mpg :lol: . I had the T/D pump originaly set at 1.0 and that's where I'm gonna start from this weekend when I put it back on. We'll see what happens then, it did have a lot more power with it originaly, just leaked bad.

maxfax · « **Reply #4 on:** April 22, 2009, 07:55:27 pm »

Oooh didn't think about winter fuel.. I wouldn;t think that would make that huge of a difference, but on a new engine it would make it seem worse..

Fuel quality in general may even be contributing.... Gas and diesel both have not been quite up to par lately due to the surplus....

Rabbit TD · « **Reply #5 on:** April 22, 2009, 08:00:19 pm »

Quote from: "maxfax"

Oooh didn't think about winter fuel.. I wouldn;t think that would make that huge of a difference, but on a new engine it would make it seem worse..

Fuel quality in general may even be contributing.... Gas and diesel both have not been quite up to par lately due to the surplus....

The fuel quality is something I didn't consider, that could be a factor too, thanks for the answers.

maxfax · « **Reply #6 on:** April 22, 2009, 08:06:05 pm »

Give it some more running.. Bearings gotta wear in, even with the compression where it is the rings are probably not properly worn in and causing some drag.. Like Vince said it could take up to 20K miles for it to hit it's prime..

Vincent Waldon · « **Reply #7 on:** April 22, 2009, 08:18:08 pm »

In terms of smoke...think of the motor being tight... lots of friction... so not as easy to turn. Not gonna make more smoke... it's not using more fuel than it needs... but it needs more fuel to overcome the friction.

Rabbit TD · « **Reply #8 on:** April 22, 2009, 08:23:59 pm »

Quote from: "maxfax"

Give it some more running.. Bearings gotta wear in, even with the compression where it is the rings are probably not properly worn in and causing some drag.. Like Vince said it could take up to 20K miles for it to hit it's prime..

The only problem for me with that is by 20,000 more miles the way I am I''ll probably want to build a 1.9 for it if the body is still strong enough :lol: I can't let things alone : :roll:

maxfax · « **Reply #9 on:** April 22, 2009, 08:25:54 pm »

I know where you are coming from, and I feel your pain!!!

Smokey Eddy · « **Reply #10 on:** April 23, 2009, 01:26:07 am »

I think 40+ is okay for a 1.6td isn't it?

I'm getting 40 roughly (double what i was getting pre new aaz head). and i drive like a moron sometimes.

a TD will never ever get the mileage like a N/A will.

Duster 5.9 · « **Reply #11 on:** April 24, 2009, 10:32:46 pm »

Quote from: "Smokey Eddy"

a TD will never ever get the mileage like a N/A will.

Why is that. this seems to be right on target for an answer too. I would figure that a turbo engine would have to work less and get better milage, but doesn't seem to be the case.

maxfax · « **Reply #12 on:** April 24, 2009, 11:11:32 pm »

[quote="Duster 5.9]Why is that. this seems to be right on target for an answer too. I would figure that a turbo engine would have to work less and get better milage, but doesn't seem to be the case.[/quote]

I would think the same thing myself.. Oddly enough I've always heard heard that with the Benz diesels.. The Turbos DO get better milage.. :?

vanbcguy · « **Reply #13 on:** April 26, 2009, 05:28:56 pm »

Disconnect the hose to your LDA and you probably will get better mileage... A few PSI of boost to burn the "leftover" diesel but no extra fuel and your mileage will probably go up.

Rabbit TD · « **Reply #14 on:** April 26, 2009, 05:55:16 pm »

Quote from: "vanbcguy"

Disconnect the hose to your LDA and you probably will get better mileage... A few PSI of boost to burn the "leftover" diesel but no extra fuel and your mileage will probably go up.

That's the problem, I don't even have the T/D pump on it because it leaked so bad I had to put my N/A one on till I got it fixed. That is the pump that was on the 52 mpg engine before and that engine smoked pretty'bad. This engine doesn't smoke even a little. I thought with this setup it would be sort of a Eco-Diesel in a 1.6 version which supposedly got better mileage than the one with the LDA, right now I'm getting 10 less than the other one without a turbo got.