2500

me too.. problems didn't start until I replaced the lift pump. to ad insult to injury... the lift pump was not bad... the secondary filter screen was totally plugged. after I changed the fuel filter... flat forgot about cleaning screen.

will be changing return lines soon...

GAmes

Since you said that the truck "runs like a champ once started" it is pretty obvious the lift pump is good. These pumps are nearly bullet proof but the best way to check them is to install a pressure gauge. If it starts ticking the internal return spring is getting weak, then it is time to replace it. I'm guessing the rubber fuel lines need to be replaced at a minimum. If that doesn't do it check the hard lines for corrosion and/or replace the grommet I listed.

2500

yup.. a pressure gauge is the only way to check... check infidel's posts for technical details on how.

went to local fuel injection pump rebuilder and scored an extra fuel inlet banjo bolt. tapped for 1/4 NPT, then found a 1/4in pin valve to fit. hooked up a snapon oil pressure gauge. without pin valve, gauge will destroy itself in a hurry.

there's a pressure relief valve on fuel return side of P pump that regulated pressure to pump. my new pressure relief valve purchased from cummins (no warranty) failed only 6 month old. stretched spring to increase pressures.

manually prime system until you hear relief valve let off pressure to know when valve is kicking in. then read pressure on gauge. best to be within 35-45 psi with engine revved up.

infidel

The mechanic is pulling your leg if he didn't put a gauge to it, which isn't a slam bam thing to do on a 12 valve.
Once a gauge is hooked up there are a few simple tests you can perform that will isolate the cause of low fuel pressure.
How to measure fuel pressure here> https://www.dieseltruckresource.com/...41&postcount=9

1fatxl

I know I saw a website somewhere that sold a kit to install a underhood guage right onto one of the banjo bolts. Does anyone know where that was? AI thought it was Geno's but can't find it there.
thanks

Dartmouth 12V

For those of you who are finding problems after changing the lift pump, it isn't terribly surprising. While changing the pump, it is pretty easy to disrupt the other lines in the area. It is relatively common to create an air leak in the line between the preheater and the lift pump or the hard line to the fuel filter when changing the lift pump.

infidel

Probably saw it here
http://www.fostertruck.com/gauges.htm
Only problems with this set up is the gauge is only 30 psi, most trucks can hit 35 or more.
Other problem is it's under the hood, you can't see it while under load while driving. Guess you could use some longer hose and clip the gauge under a wiper to see it going down the road.

You can make your own set up cheaper and better by just buying the adaptor here http://www.tstproducts.com/fuelpressureadapter.aspx, a $10 - 60psi gauge from the hardware store and a grease gun hose to hook the two together.

caburnside

GAmes, thanks for telling me not to have them over night the 5 dollar part if it was not in stock. Gave them the part # and they told me today that they did not have it in stock today and asked if I wanted it overnighted to them to pick up the next day. I thought back to the $5 turning into $60 and 7 days and laughed and said no thanks, and walked out with just my new head gasket.

GAmes

In my case, the fuel to Ft.Worth and back would have cost that much, but it still pisses me off. You did order one anyway, right?

caburnside

I'll call the Arlington and Dallas ones first, is their a Cummins house in Ft. Worth? If so I will call them as well. If none of them have one then I will have one ordered. Right now my truck is at my techs house and he is going to be digging into the head tomorrow and take a look at the fuel lines as well. I will see what his diagnosis is.

Fueling around

You have plenty of time to order the part and pay standard freight. It will probably take your tech friend a week to get the head done. It needs to be planed flat. If you're lucky the shop can machine the head to accept the captive style valve stem seals. Also check the valve guides. Exhaust valves tend get very sloppy.

Fueling around

There is a list of symptoms.
Poor starting
Poor performance
Fuel in engine oil
Very hard to prime system after a filter change
A click that follows engine rpm
External fuel leak around the primer button. (Can repair, but pumps are cheap so I would replace it.)


As infidel pointed out, the best is to test the fuel pressure. The trick is to find a way to read the pressure while you load the engine. The first shop I visited had a hill close by to do a dynamic check on fuel pressure.
The easiest is if the shop has a chassis dyno and will check the pressure under load.

My fuel pressure checked OK, but I had the "click" when temps dropped to -30°. Wasn't a bother until it started the click at -20° and finally -10°.
Replaced the pump and no more click.

1fatxl

Hard start again this A.M.
Had to lift fuel shutoff solenoid, how hard should that be to do?, was really stiff

infidel

It shouldn't be all that hard. You need to remove the solenoid and give it a good cleaning. Replace the boot if it's torn.

1fatxl

That is on tap when i get off work tonite. Is the blue fuseable link available at Napa or someplace or do we need to order from someone like Fosters?
If so anyone got the part # for napa so I can stop and get one, might just as well replace that while I am in there.
thanks