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 Post subject: Poor diesel fuel economy
PostPosted: Mon May 05, 2014 6:11 pm 
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as back ground, i have a 1980 luv 4x4 with a 81 c223 and transmission in it. It have been running well, and starting no problem with the 12v glowplug system i have set up, other than a little goose on the gas pedal. However, after driving it for a couple weeks, i am starting to thing that i have an issue with poor fuel mileage. Unfortunately i dont know the age of the engine (older im sure) but could someone along its life have turned up a fuel adjustment? or perhaps the timing is off? The engine feels like it runs well, but i'm not sure because of the mileage. perhaps a head/compression leak? or old injection nozzles? any ideas would be greatly appreciated... oh and how difficult is it to change out the injection nozzles myself?
thanks guys!


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PostPosted: Mon May 05, 2014 9:14 pm 
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Your first step would be to actually measure your mileage.

Then let's troubleshoot. Injector nozzles would be WAY down my list.

Jack

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PostPosted: Mon May 05, 2014 10:38 pm 
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Ok i just topped it off, we 'll see what happens


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PostPosted: Thu May 08, 2014 9:17 pm 
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I just started a new job, so I'm not quite as active on the web as I have been. I may not see your post immediately, but I'll be checking.

Jack

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PostPosted: Mon May 12, 2014 12:55 pm 
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It may be another week or two before i can give a good mileage calculation, but ill keep it up to date. I have noticed a fair amount of smoke at idle. I honestly think a fuel adjustment has been turned up or something.


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PostPosted: Mon May 12, 2014 7:00 pm 
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I think i figured out the excess smoke! Its dumping from the crankcase vent tube, i guess i never really realized how much smoke that tube put off until i drove it on a 80 degree day. a bit of oil coming from it also (obviously). I guess that probably demotes my idea of a fuel adjustment being turned up.


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PostPosted: Mon May 12, 2014 7:26 pm 
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actually now i think i may be looking at excess blowby. I think a compression check is probably called for


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PostPosted: Mon May 12, 2014 7:45 pm 
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They all drip oil from that tube (it's called a "draft tube"). Some blowby is normal at this age. Turning up the fuel will generally produce more smoke, but not much more power.

Jack

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PostPosted: Tue May 13, 2014 7:52 pm 
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alright, i am suggesting that perhaps someone else turned up the fuel, and i may need to restore it to its original setting. I am not looking for extra power from fuel.


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PostPosted: Tue May 13, 2014 8:14 pm 
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jmilne123 wrote:
alright, i am suggesting that perhaps someone else turned up the fuel, and i may need to restore it to its original setting. I am not looking for extra power from fuel.

Ok, I misunderstood. I'd still leave it alone for now. That adjustment is pretty sensitive.

Being a 4x4 4-speed, you should be looking for around 30 mpg if it's running well and you're not too heavy on the skinny pedal.

Jack

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PostPosted: Wed May 14, 2014 5:12 pm 
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i drive it like an old man, i let it warm up in the mornings for a couple minutes and rarely does it see past half throttle. I have my fuel down to what my tank claims is "half". ill top it off next, see how many gallons are in it, then run it until "half" again with tracking mileage. that will give me a fair estimate i believe. my guess as of now is i go about 150 miles, maybe, on half a tank. so that would put me at (super roughly) 23 mpg.


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PostPosted: Wed May 14, 2014 9:56 pm 
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jmilne123 wrote:
i drive it like an old man, i let it warm up in the mornings for a couple minutes and rarely does it see past half throttle. I have my fuel down to what my tank claims is "half". ill top it off next, see how many gallons are in it, then run it until "half" again with tracking mileage. that will give me a fair estimate i believe. my guess as of now is i go about 150 miles, maybe, on half a tank. so that would put me at (super roughly) 23 mpg.
I'm not even going to venture an opinion about 23 mpg when it's estimated that way. When you've actually measured miles and gallons, let's take a look.

Jack

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PostPosted: Thu May 15, 2014 2:10 am 
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The proper way to measure mpg would be to top it off, keep track of your miles, top it off again at some point, and divide the miles you drove by the gallons used.

I'm sure you know that, but as Jack said, it's pretty hard to get a good estimate based on where the needle is.


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PostPosted: Thu May 15, 2014 2:10 pm 
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sounds good


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