how do you check the lift pump in a 95/auto? my mileage has been getting worse and worse and its time to do something! Anything would help.

 

Drill and tap the banjo bolt for the fuel inlet on the pump, attach a needle valve , and then a line and a pressure gauge, crank her up and check the pressure. Infidel would have more details on drilling the stock banjo.

 

can we get a part list for this and what pressure it should be at?

 

I beleive dodgeram.org has some info on checking fuel pressure on their site somewhere. FWIW , i would change out the overflow valve before i would suspect a bad LP , i have never heard of one failed yet.

 

Theres a writeup on the site someplace from earlier posts on this one. You use a needle valve with a 1/8 NPT male connector and a compression fitting and run a grease gun hose (or hoses with a female-female adapter in the middle) to the sender.
You need to drill and tap the banjo bolt where the fuel enters the injection pump to 1/8 NPT and screw in the needle valve. I had to use metal epoxy here since no matter what I did it leaked.
You should see 25psi-ish at idle and 30-35psi at 2k RPM no load I believe.
Be careful to clean the metal filings from all the fittings, this is all north of the fuel filter.
I also have a 95 with abysmal fuel mileage. Ive got an appointment to upgrade to a DTT transmission so the convertor will help economy Im sure. But on the highway I dont get much better mileage so Im convinced its either the injection pump or injectors. There seems to be a rash of 95 autos with awful mileage. I wonder if this is pump calibration? Or maybe with less power on the motor, the injectors get sooted up?
Sounds like a great time to upgrade to a 215 pump and 370 injectors.

 

Most often low fuel pressure on a 12 valve is due to the overflow valve, not the lift pump. For most folks just replacing it is easier than measuring fuel pressure.
You won't find a better OF valve price than here:
Precision Diesel Injection and Turbo Inc.
Marty Tompkins
888-734-7349
$35 + $7 shipping and handling.



To check fuel pressure on 12 valve:

I drill and tap the top of the injection pump banjo bolt to 1/8'' pipe
thread, then install a male x female 1/8'' needle valve with 1/8'' tubing
compression fitting in it. Boost gauge or oil pressure tubing pushed
though some 1/4'' tubing to protect against cuts and kinks to the gauge.
For a gauge you can use a fuel, boost, oil or water pressure gauge, for a 12
valve it must be at least 40 psi, 60 psi is best.

Use no Teflon tape, it doesn't work
with diesel. Instead use anti-seize or Permatex #2. Remember you are
working on the clean side of the filter, keep everything spotless.
Compression fittings with a ferrule that slips over the tubing will leak
if overtightened, finger tight with one half turn of a wrench is plenty.
The ferrule should be replaced if the fitting is ever removed.

If you can tap your manifold for a pyro tapping the banjo bolt is a piece
of cake. Just drill from the inside to keep the hole straight and tap from
the outside. You can also connect to the bleed screw on top of your fuel
filter with the appropriate adapter to tubing if you don't want to tap.
The adaptor is available from TST for $25 they say it is only for temporary use though http://www.tstproducts.com/index.asp...PROD&ProdID=62 .

After the install start your
engine with the needle valve closed then open it slowly till someone in
the cab signals you that it's just reading pressure. If you tighten down
the packing nut under the valve handle the setting can't move. The valve
will control pulsation and buzzing and can also be shut down in the
unlikely event that you have a leak. Without a valve to restrict the flow
the gauge will pulsate so badly that you won't be able to read it in the
short time before it self destructs.

Parts list; 1/8'' needle valve - $2.50 from the hardware store, plastic
oil pressure tubing kit that comes with the compression fittings - under $10
from any auto parts store. 1/4'' tubing for protective sleeve - less than $2.
Gauge is your choice and may come with tubing. The pressure gauges I
use cost around $10 from here http://www.surpluscenter.com/sort.as...s&keyword=NFGA , bringing the total cost to less than $20 and a
couple hours of your time.

Here's how to do it with Cummins "special tool" which is nothing more than a tapped banjo bolt http://dodgeram.info/tsb/1996/14-07-96.htm

 

What is considerd bad mpg and what is good. I'm getting about 15 running it on the matt about 75-80

 

I get 8 mpg

 

-whistle-
you got me beat mine is getting 10mpg =(
If I ever track this down you guys will hear about it first.

 

[QUOTE=infidel]You won't find a better OF valve price than here:
Precision Diesel Injection and Turbo Inc.
Marty Tompkins
888-734-7349
$35 + $7 shipping and handling.



Agreed. Although the price has gone up to $42 +shipping. Still MUCH better than the $78 I was quoted here at the diesel shop. Of course, the big box auto parts places acted like I was crazy to even ask. Thanks for the info.

 

I was getting lower than average mileage with my 12 valve. So I change my over flow valve (Thanks Marty) and installed a BHAF and outerware. I went on a short 3 day trip covering 2500+ miles hauling horses one way and hauling bulls(15,000# of bullls) back home and got 12.5 MPG loaded going 70-75 mph. Im sure the filter and valve both helped with this. Better throttle response. I'd try the OFV its cheap.

 

15MPG is about what a stock 4x4 with 4:10 axles and an auto will average. Get a good intake, like Scotty II, get your overflow valve replaced, get your valves adjusted and get your timing bumped to 16*. Also might help to go synthetic axle and Xfer case lubes and be sure to add some power kleen (I use a qt) and pint or qt of cheap 2 cycle TCW oil. Both these additives pay for themselves.

 

The basics of performance checks:
-check fuel pressure at idle, at 2k rpm, and then pinch off the return hose.
-check for boost leaks, pressurize the system and spray soap on everything.
-conditions of all your filters.
-if timing has never been set, then it will need it.
-adjust your valves

The most common problem we see for poor mileage is leaks in the boost/system. The rubber boots are getting worse every year, gaskets in the manifold leak alot.