HELP! Need more miles, not more power.

Armed Partisan

Registered User
Joined
Aug 21, 2013
Posts
16
Reaction score
0
Location
Cocoa, FL, United States
Oh, it starts up lickity-split. I live in FL, and it's Springtime, it starts on perhaps the second or third cylinder; much faster than my Marauder did. When I first got it, in AR, I had to use the glowplugs, which were burnt out. I replaced three of them, and no problems after that, but here in FL, especially since I replaced the Lift Pump and nailed down some of the electrical demons, it starts without plugs, even when cold, even after a week or so of sitting.

I find the stories about people being screwed by Pensacola Diesel to be distrubing, but if they cheated me, they did a very convincing job. If these Delphis are some other brand remarked, they did it with very good consistency. They came in factory boxes, they're all BB marked. I guess they could be defective, but they're cetainly in better shape than the ones I had in there, which were likely the originals that came from the factory (all dated 86), one of which had extreme carbon build up around the nozzle, which indicated to me that it was leaking.

After turning the injection pump fuel screw down about half a turn (I want to see if I can choke this b-word) and seeing no difference in sound, smoke or performance, I'm gonna do a road test to work this week (either tomorrow or Wednesday) which should be a 75.6mi round trip. That oughta give me a pretty good indication as to fuel consumption AND some clue as to if my injection pump is simply putting too much fuel in there. Will report back when I find something out.
 

FordGuy100

Registered User
Joined
Apr 1, 2006
Posts
8,749
Reaction score
282
Location
Silverton, OR
Turning the fuel only increases/decreases max fuel flow amount. If you go wide open with a turned down pump, you will use less fuel in an instantaneous time period, but your acceleration to speed will take longer (could potentially make it use slightly less fuel).

The reason I asked about starting was compression. Low compression due to whatever reason can have an impact on FE. But it would also manifest itself with harder starts, cylinders not catching right away, or cold smoke (which can also indicate bad timing or fuel injectors.

I doubt the injectors are bad. But, that does not mean they are tip top either. If you dont have a shaky idle, or cold smoke that smells like diesel, they probably arent that bad off. If injectors alone were costing you several MPG's, you would have rough cold idles, and cold idle/driving smoke among others.

Really what I'm thinking is this is a culmination of at least a couple smaller thing, impacting your fuel econonmy. And there are a metric (s)hit ton of things that effect MPG's.

Jack up the wheels and see if they all turn like they should. Next move onto tire inflation. Make sure alignment is ok, and not to far off. You now have a right that will role down the road decently. Make sure brakes dont stick, I guess this could be caused by debris in the line to each individual side. Rule that out and we can check it off the list. Does the truck have anything that is creating a bunch of wind resistance? I'm not talking towing mirrors, but like old campers (its an example), this could also effect it (the bigger the deflection, the bigger hit in MPG's). I doubt you have to worry about that, but now we can move one.

After that you have a truck that should drive down the road with the least resistance possible. You said you drive like a grandma, so we can take that out of the equation. What is your top speed? Anything over 55 will hit you hard, as wind resistance is porportional to the square of velocity (Buggati Veyron only requires 300hp to push it 150mph, but 1000hp to push it 240mph, or something like that). Next is engine, trans, and axle. Is this 2 or 4 wheel drive (I forget), if 4 make sure that the hubs are unlocked. How you test a rear end to make sure its good I have no idea. I would assume if you jacked the rear end up, and rotated the wheels by hand if you heard or felt any odd resistance perhaps its bearings or something in the axle. I doubt this is the case.

Now its on to engine/trans. Does the trans seem to shift at the right points? I ask because it has an adjustment on the top of the IP that can effect this. Shifting to early will lug the engine, shifting late will rev it out. I would think revving it out would consume more fuel, in fact I would wager on it considering your driving style. I'm sure there are a ton of other trans tests you could self test, but I cant think of any right now.

And then you have the engine. Like I said earlier, I dont think its just one thing, its probably a culmination of things, and the same goes with the engine. Have you been around enough IDI's to know what they should sound like? I ask because your timing by ear (I can only imagine how frustrating it is to have bought the timing meter to have it not work), you can compare your engines sound to the others to get it as close as you can. It could be a bad IP, worn out enough it not doing the right timing advancing/retarding that it should (these are not fixed timing pumps). After that it starts getting trickier. Anything on the belt drive worn out and causing some resistance?

One thing I just thought was your water temps. 220* could cause the fan clutch to engage more than it ought to, sucking power. I have my sender in the top of the water pump, and see 190* basically. A fully locked fan will suck a few mpg's, but you would constantly hear it spinning (like an airplane under the hood). But the high temps could cause the fan to have a higher rpm than normal, sucking some hp and mpg's.

I'm out of idea's LOL
 

Armed Partisan

Registered User
Joined
Aug 21, 2013
Posts
16
Reaction score
0
Location
Cocoa, FL, United States
Well, I've never had an alignment done, and it's probably not had one for many years. I might take it to a shop for that this week (planning on doing an alignment and installing a headgasket on a Toyota Paseo on Friday). I should probably take a closer look at the brakes. Sure, I did the hardware kit on the back, and I've never made a mistake. :rolleyes: Couldn't hurt to check 'em again.

Also, the transmission was shifting very hard when I first got it. I got used to doing a "double pump" on the throttle when it was near a shift point, which smoothed it out considerably. I adjusted the VRV to make it shift a bit smoother, but now there is the occasional hesitation on shifting when I first start out. I imagined that the vacuum had to build up, vacuum pump might be going out/leaking, because after a few minutes of driving, it doesn't hesitate anymore.

I do drive at 55mph (at least since I got back from AR) and I don't have anything on or in the bed. No mudflaps, nothin'.
 

cpdenton

Truck needs paint.
Supporting Member
Joined
Aug 20, 2012
Posts
1,810
Reaction score
75
Location
Conway AR
I know on my truck....I have a new moose junior pump. I don't drive like a grandma though!

I have a timing meter and have messed with timing quite a bit. At first I set it to 8.5 btdc. Mileage was about 11 to 12. I reset the timing to 7....way less haze from the tailpipe and an increase to about 14 to 15 mpg. Turbo spools better as well which has increased seat of the pants power.


So, I believe you could adjust the timing and gain some mileage back.just my personal experience.
 

Black dawg

Registered User
Joined
Jan 9, 2006
Posts
3,991
Reaction score
697
Location
sw mt
Did you actually check the accuracy of the odo, or just speedo? The relationship between these can vary.

Do you always get fuel at the same place? I would almost always get fuel at this particular station, until one day I was able to put almost 26 gallons in my front tank. Normally didnt run the tank that low, so all the other times, I had no idea that the pump was showing I put in more fuel than actual. All the years of getting fuel at this station, my mpg was 13.5, and as low as 10 at some times. The last time I checked the mpg (with diesel from a different station) was right at 16mpg.
 

Clayton

Full Access Member
Joined
Dec 30, 2009
Posts
531
Reaction score
0
Location
Ky
Before I swapped the c6 I could easily do 18 cruising at 55. Could be a bad injector but doubtful, I bought several sets of new BB's from pensacola. They seemed to always pop between 1825 and 1875 give or take a little, Not optimal but they will run fine. A new delphi BB is a new delphi bb no matter where it came from. I have heard of the occasional dud but never seen one myself. If you've got no leaks and the timing is set properly it may be time for a pump.
 

Forum statistics

Threads
91,198
Posts
1,128,136
Members
24,024
Latest member
Bugoo

Members online

No members online now.
Top