Ok, here's an update. The VE is getting starved. Starts and idles fine. If I run it up to, say, 2700 and hold it, it'll start to break up and lose RPM after a few seconds. Can this be anything other than the lift pump? I don't have the time or money to upgrade to the piston lift pump, so it'll have to be a stocker for now. I blew back through the supply line with 6psi and heard bubbling in the tank, so that's clear. Any thoughts before I buy a lift pump?

 

Greg

Sorry to hear about the troubles. Did you get that fuel pressure gauge on there yet like wannadiesel suggested? I'd suspect the LP since you just had the injector pump rebuilt right?

On a side note, i had a cutting out issue awhile ago, and it seemed jst to do it when i hammered down on the throttle. It turned out the problem was with the solenoid connection. It sure got me really scared, it would make connection then lose connection so it felt like a injection pump going dead.

I put on a few new fuel lines too awhile at the tank, and i got the wrong ones so i'll have to take the box off again someday But from what i'm told automatic tranny lines are good for diesel. So i think i'll be using them next.

PS. I still have this 6L IC sitting here

Jeff

 

Hey Jeff! I didn't have access to a FP gauge today. I'm wondering, can I use the bleeder screw on the banjo to tap in? If not, I'm not sure where to tap in without getting tapped banjos...Anyway, it's not cutting out like when the solenoid connector comes loose--I've had that happen too. It just gradually drops cylinders--even sitting in the driveway holding 2500+rpm with no load. It'll idle all day, and it got me down the road and back a couple miles. Funny, I leaned into it in 4th going down the road and she went like a scalded dog--more powerful that I remeber it ever being. A half mile up the road, it started to drop cylinders under load again...I've gotta think at this point it's starving itself. Yes, the IP is a recent BOSCH certified (whatever that means) reman.

Jeff, if you're still thinking about letting that i/c go, PM me

 

That banjo is really where you want to tap in -- you really have to have the gauge between the filter and the IP. Dave (wannadiesel) convinced me that the tapped banjo is the way to go -- it has A LOT more meat on the head for the pipe tap.

BTW -- did you check the feel of the manual lever on the LP? I hate to see you spending $40-50 on something that you will want to replace next summer with something different . . .

 

Greg

I found a great way to test the LP that seems to always work for me.

Open and hold the water drain on the fuel filter. If nothing comes out and the engine dies due to air being sucked in then you got a bad LP. If it pushes out fuel at a good rate, the LP is fine.


If the LP is bad when the water drain is open the VE tries to bring its own fuel on causing a vacum in the lines, so if the water drain is open it will suck up air and kill the engine.

Worth a try..........

Jeff

 

Jeff: I tried opening the water drain this afternoon while it was idling...it blew fuel out like a waterfall...

Alec: The manual lever will fill the fuel filter from empty in about 10-15 pumps.


Both of these scenerios point towards a good lift pump, but I have to wonder if it just can't provide the volume under load...heck, holding 2700 rpms in the driveway can't be that much fuel, now that I think about it. I'm confused. My buddy is bringing his fuel pressure test kit in the AM, so I'll know for sure one way or the other. Thanks for all the replies---if ya got any more bright ideas toss 'em on the table!
greg

 

It sure sounds as though the lift pump is good.

The brain isn't working too well today, so I may be way off, but:

The vane pump in the front of the VE is going to try to pull the same amount of fuel whether you are running full load or no load for a given rpm. Under lighter loads more fuel just flows back to the tank. So a restricted pick-up in the tank, etc., could cause the problem. So, too, could a restricted return line retard the timing, if the pressure starts to creep up on the dump side of the advance mechanism.

Try running the truck out of an open container -- both pick-up and return lines, and see what she does?? If you can, try running high rpms under load, and see if she actually runs better than high rpms at idle -- this might indicate a clogged return line.

You'll get it figured out, despite us trying to help

 

Well, the lift pump seems to have solved my troubles. Of course, the steel line that feeds the filter block twisted when I tried taking it off. Yes, it had been sitting in PB Blaster overnight...anyway, there was a compression fitting on the bottom of the factory line to seal things up---is this correct? Before I noticed it was a compression ferrule (sp?) on the end of the line, I took another piece of 5/16 steel line and put a bubble flare on the end of it. Then I was gonna splice a 2'' piece of diesel-rated hose between--will this work? I'd like to just get a replacement line from Cummins, but I haven't been able to get ahold of a source just yet. Haven't put the bubble flare piece in yet, I've got something farmhandy on there that leaks enough for a drip every 5 seconds...just enough for a test drive!!! Runs awesome, at least in the few miles I went. No stumbling and a lot more top end---shoulda checked on my LP a long time ago.

Alec: you got me thinking with the return line, so I took the time to blow that out and it seems like there was some blockage in there...I haven't driven it since, so I'll report back on that aspect of it tomorrow.

Thanks for all the help/suggestions etc fellas! For as simple as the fuel system is, it can be intimidating when it's 1 degree and your only vehicle is down...

 

So what fuel pressure did you have with the old LP, and now the new LP???? Get yourself a tapped and non tapped banjo from www.genosgarage.com!!!! This way you get more flow to the inj pump and can test fuel pressure later down the road!!! The stock bleeder is metric, so forget about plumbing a 1/8"npt fitting into it and checking fuel pressure with an old 30psi boost gauge, or oil pressure gauge. Pressure is pressure.

With a tapped banjo in place, all you need to check fuel pressure is like I said, old boost or oil pressure gauge, and boost tubing kit, of course along with tapped banjo. This doesn't have to be permanent, just plumb it up to troubleshoot etc.

I have a lift pump to filter head fuel line for you, but it will probly be til next weekend when I could get it in the mail to you. If someone else that went to the piston LP wants to chime in and give you their old fuel line.

 

I'm thinking about doing a lift pump soon. Mines prolly original. I got a few misses after a nice hard pull the other day. Power seems a bit lumpy at times. For some reason the plunger feels like it does nothing.

Do you guys use the parts house replacements or cummins parts?

 

Ok, here's the most recent update: Got my hands on a new line to go from the LP to the fliter block (thanks Dave ) but I can NOT get it to stop leaking at the LP! I even put a new compression piece on the steel line...not sure where to go from here, I thought the new brass piece would cure the leak. Maybe a silly question, but do I have to teflon tape a compression fitting? I thought the brass was supposed to make the seal...if not, I guess I made my first mistake again, haha. Thoughts/ideas appreciated fellas.
greg

 

wish I could help you I had my lift pump and lines off yesterday to mock up what I need for my piston lift pump and put her all back together and she was fine. is it posible that maybe some dirt got on the threads and causing it not to seal properly?

 

Teflon will not help, the sealing is accomplished at the flare, not on the threads. Take it apart and make sure everything is clean, and that nothing is scarred up from hard debris.

 

That's kinda what I thought. I'm going to pull the lift pump and have a closer look at the sealing surface in the morning---merry christmas to me To those that asked weather or not to go aftermarket for the LP---apparently I'm living proof that you might best spend the bucks on the real thing. I never thought I'd have to hand-lap a brand new sealing surface

 

Well, it looks as though the sealing surface in my new LP is bad...I tried to clean it up as best I could, but can't get the fitting to stop leaking. Maybe Fleet Pride will have the Cummins part in stock tomorrow...