Time to consult the masses......... Finally took the crew on a road trip and the fuel mileage was horrible. Lucky if I was getting 8 miles to the gallon. 1993 stock motor with no mods; motor has 210k on it with an automatic tranny. The exhaust also emitting some very noxious eye burning fumes, no black smoke but does have a light blue haze when cold. Doesn't not use any oil, at least not on this trip.

When I fired her up after finishing the conversion, she sputtered terribly so I changed the fuel filter, which helped a lot. When I start her up in the cold weather, she sputters and finally picks up the revs, but will move with great difficulty if I try to take off without letting her warm up. I've dumped in some injector cleaner with each fill.

No gauges, so do not know what the boost numbers are. Some local advice I've received to date is to change the fuel pump; could be the injectors not atomizing the fuel properly. It's getting air throw a BHAF.

Hope this is enough info to garner addtional advice and opinions.

Thanks,

 

I had a similar issue this past summer,only I had excessive egt's as well. The solution was new injectors,3 of the 6 old ones had cracked tips causing over fueling resulting in poor mileage. I would also check into a tighter torque converter because at 210k its provably pretty sloppy.

 

The converter is my first thought also. Does it seem like it slips a lot?

 

Bill, I did notice "some slippage" or it was searching in between speeds of 40-50 mph. But once up to speed it quit searching. I am getting a new tranny with all DTT componenets soon but I didn't think it could be all related to the TC!!

Thought maybe someone else had gone through this. The exhaust fumes are horribly eye burning, which leads me to think its fuel ralated but honestly, I'm grasping at straws here.

 

probably needs some timing.

 

TIming and injectors....

 

Yea it sounds like the timing needs to be advanced.

 

Would timing help blue smoke?

 

Gentlemen, thanks for the responses. Brandon, I'm assuming if I follow your process on Youtube I should be good to go. As for injectors all I have laying around are a set of PODS. These will have to do for now!!!!

What is the latest greatest injector for these beasts nowadays???? I'm sure there are numerous threads on this!!

 

Burning oil, (the blue haze you referred to) is normal when it's cold. And being in Manitoba, it's pretty darned cold! Heck, I burn oil when it's 'cold' down here in South Florida!
I'm thinking it's a fuel issue too. I don't think a sloppy TC would make your mpg's that low, but I could well be wrong. Are you using the tank from the crew, or from the donor truck? Fuel lines and injectors? And how long were they sitting around for?
Reason I'm asking about the lines and tank is the nasty smell of the exhaust. I'm just wondering what you're burning. And the injectors because of poor mpg's. I don't think the mpg's are fuel supply related, but fuel delivery into the pistons/combustion chambers will make a huge difference. As will air supply. If you haven't already, check the turbo for axial and lateral runout, (up-and-down and side-to-side play,) and all connections in the air system.
I wonder also, (I know, there's so many things to check, ) about valve adjustment. Have you checked them? Have a look at that too. Spec's are in the sticky.

Good luck!

 

first, under normal circumstances, winter driving in town I can get as low as 10mpg so it's not that out of the ordinary

second, that injector cleaner is killing your mileage I'll just about guarantee it. I used some injector cleaner and I lost 3-5mpg. The stuff can't be good for the truck to be used on a regular basis... I stopped using it and I immediately was getting like 200kms per tank more.

City driving in the winter with our trucks is BRUTAL. the constant stop and go plus it's usually not running long enough to even get up to temps. That doesn't help either.

I'd recommend letting the truck warm in neutral if possible too. personally I normally don't let it warm up much before driving it. I start it, let it high idle for 30second to a minute in neutral and then just drive it real easy for the first few minutes. Seems to work fairly well. Unless it's like -20 outside then I'll let it idle in reverse sometimes before driving it.

oh and don't forget running the 2 stroke oil in each tank! it makes a bigger difference in the winter for mileage than it does in the summer.

 

lots of good stuff mentioned above, i,ve also found a smaller exhaust housing helps economy.

 

Yes indeed, lots of good advice. My dually which is essentially the same drive train with no mods knocks down 20-22 mpg and it has 247k on it.

I guess it is going to be a process of elimination.

 

With the eye watering haze I'd look at timing and /or an air leak on the suction side of the fuel system. My $.02.

 

Not to get off subject, but 2 stroke oil?????

What does this do (other than smell good)