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Anyone regret doing a Cummins swap?

Had a similar problem (long time ago, but seems like it was worse). Problem was a faulty lift pump. It was a new lift pump as well.

Buddy of mine sold me a case (very similar pump) lift pump and thats what I ran on it for years.
 
SHARPMACHINE said:
Had a similar problem (long time ago, but seems like it was worse). Problem was a faulty lift pump. It was a new lift pump as well.

Buddy of mine sold me a case (very similar pump) lift pump and thats what I ran on it for years.
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With the shit qc these days, the thought crossed my mind. :laughing:

A bad lift pump is what was causing similar issues on my buddies bobcat. I was able to diagnose it with clear hose thanks to someone's suggestion on here.



So my alternator showed up last Monday, opened the box and immediately noticed the pulley was a 6 rib :homer: What's funny is almost every other alternator for this engine listed as a 6 rib except this one specifically said 8 rib. Was ablento swap it out at a vatozone in Spokane on our way out of town. Same exact p# but had the 8 rib pulley.

Did a Cummins ever come with 6 rib accessories? Or only gas engines?
 
Holy fuck, I just realized retardo had the lines at the lift pump backwards and was back feeding the p pump :mad3:

Switched it back and still have air out of the loft pump, probably fucked it up trying to fight the injection pump. What an idiot.
 
YotaAtieToo said:
Holy fuck, I just realized retardo had the lines at the lift pump backwards and was back feeding the p pump :mad3:

Switched it back and still have air out of the loft pump, probably fucked it up trying to fight the injection pump. What an idiot.
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bro
p pump just has a gallery in it that feeds the elements
doesn't matter which end is fed pressure, just gotta have the restrictor fitting on the return line (and well, I guess it helps if the return is on the higher side of the pump, but...)
 
[486] said:
bro
p pump just has a gallery in it that feeds the elements
doesn't matter which end is fed pressure, just gotta have the restrictor fitting on the return line (and well, I guess it helps if the return is on the higher side of the pump, but...)
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Bro

The ‘restrictor’ fitting is a check valve, controlling pressure in the injection pump. A ball and spring.
 
TrailTamer said:
Good point.

Although I’d want it to be fed as how it was from the factory so the flow through fuel filter is correct and to not back feed fuel through fuel injectors’ return line.
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the "return" from the injectors is just to provide a 'low pressure' area behind the injector pintle
whether it is 1 psi or 40 doesn't really matter for function, it'll increase your injector nozzle opening pressure by the same amount (which is entirely pedantic when you've got ~300 bar opening pressure and peak significantly higher than that)

I'm kinda confused now what we're talking about, lemmie give a re-read

ETA: oh right the lift pump was plumbed backwards, I read it as the injection pump feed/return was plumbed backwards
either way I was giving him shit for saying that the injection pump would be capable of "fighting the lift pump"
then got a li'l side tracked
 
@[468]

The way his guy plumbed it….

Feed:
Tank > lift pump > injection pump return line (no filtrating!)

Return:
Injection pump supply > filter > tank

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yeah those ones do have the injector returns on the pressure side

remember the center of the filter is the clean side
looks like lift pump was just pooping against the check valve in the return fitting, NBD

there an electric lift pump in the tank or something? an inline injection pump will make a slight vacuum but you'd have had to crank the absolute fuck outta that guy to have gotten it to suck from the tank
 
[486] said:
yeah those ones do have the injector returns on the pressure side

remember the center of the filter is the clean side
looks like lift pump was just pooping against the check valve in the return fitting, NBD

there an electric lift pump in the tank or something? an inline injection pump will make a slight vacuum but you'd have had to crank the absolute fuck outta that guy to have gotten it to suck from the tank
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That was part of my issue, I wouldn't start with out either unless it was 30 seconds after I just ran it.


Can anyone verify what amount of air is normal coming out of the lift pump? At idle it appears to be zero, but under throttle, there is some slight aeration happening.

Maybe I'm off saying it was fighting the injection pump, but could going against the check valve cause an issue?
 
I would hook it up correctly and see how it goes. All the b series engines I have will start within a turn or two, even if they’ve been sitting for months as long as it’s not below freezing.

Tank-> lift pump-> filter-> injection pump-> tank

I wouldn’t think slight aeration would be a big issue seeing as how you’re generally returning the majority of the fuel to the tank.
 
Just had a 12 valve lift pump fail after 15000 miles.

I’d hook it up properly first as well.

Any time having to prime and purge air from a 12 valve it’s been almost instantaneous. Not like some other engines.

Be interested to see if there’s any aeration on acceleration with a proper setup.
 
YotaAtieToo said:
That was part of my issue, I wouldn't start with out either unless it was 30 seconds after I just ran it.


Can anyone verify what amount of air is normal coming out of the lift pump? At idle it appears to be zero, but under throttle, there is some slight aeration happening.

Maybe I'm off saying it was fighting the injection pump, but could going against the check valve cause an issue?
Click to expand...
li'l bit of air is fine, that's why it has the return, to send the air back to the tank

it pumping against the check valve is exactly the same as any other mechanical fuel pump sitting against a closed needle and seat or whatever.
The discharge is the fitting closer to the block, right?
That meanss the pushrod is lifting the piston against spring pressure, the piston return spring pressure sets the maximum fuel pressure. When there is no flow the piston just sits fully compressed and the push rod rattles around riding the cam lobe doing nothing.

As an aside, the air is likely from the o-rings on the bundy fittings at the tank switching valve and tank sending units, if all your rubber lines are good.
 
[486] said:
li'l bit of air is fine, that's why it has the return, to send the air back to the tank
Click to expand...

Maybe I'll take a video

[486] said:
it pumping against the check valve is exactly the same as any other mechanical fuel pump sitting against a closed needle and seat or whatever.
The discharge is the fitting closer to the block, right?
That meanss the pushrod is lifting the piston against spring pressure, the piston return spring pressure sets the maximum fuel pressure. When there is no flow the piston just sits fully compressed and the push rod rattles around riding the cam lobe doing nothing.
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every carb mechanical pump ive been around had a return, so im not sure i get the comparison.

[486] said:
As an aside, the air is likely from the o-rings on the bundy fittings at the tank switching valve and tank sending units, if all your rubber lines are good.
Click to expand...

I have a clear hose before the lift pump also, there is no air going into it.
 
Pocahontas said:
I would hook it up correctly and see how it goes. All the b series engines I have will start within a turn or two, even if they’ve been sitting for months as long as it’s not below freezing.

Tank-> lift pump-> filter-> injection pump-> tank

I wouldn’t think slight aeration would be a big issue seeing as how you’re generally returning the majority of the fuel to the tank.
Click to expand...

Three said:
Just had a 12 valve lift pump fail after 15000 miles.

I’d hook it up properly first as well.

Any time having to prime and purge air from a 12 valve it’s been almost instantaneous. Not like some other engines.

Be interested to see if there’s any aeration on acceleration with a proper setup.
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It's hooked up properly already

It fired up instantly after sitting for 6 or so hours.

I think I'm going to just leave the lift pump alone for now and just see how it drives. If the air intrusion is bad enough, it should be very obvious.
 
Fired it up this morning. Typical mechanical diesel where you touch the key and it fires. Went to take a video of the air in the line out of the lift pump and there wasn't any :confused: :laughing:

With how the lines are ran currently, temporary and extra long, the line pulses and vibrates like crazy, so it's hard to see, but there is no air now, so just going to run it.
 
Threw the internal regulator kit in the alternator.

Every says to just run the wires under the cover, but I bent it and filed it slightly as it just seemed to tight. Otherwise pretty straightforward.

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I really think this truck is rejecting it's transplant :homer:

Hooked up key on power to the orange wire per the instructions and everything on Google. No charge.

Alternator body is grounded

Orange terminal (green wire from truck) has around 9v when it's connected, but same voltage as battery when unconnected and key on (12.2)

Tried revving

Even tried hooking up yellow (constant 12v)

Nothing

Wtf

Bad alternator out of the box?
 
So I'm pretty sure I fried the internal regulators, instructions said to hook key on power to the terminal with the orange wire. I assumed that with 2 wires on the truck side and 2 terminals on the alternator, the other wire would go to the other terminal. We'll if you do that, even though both have positive power, it will pop and fry something :homer:

I tried 1st regulator and loner alternator, nothing, new alternator and 2nd regulator with just key on power, nothing, but if I touched constant power to it, it would charge. For some reason I felt I should touch it to the green thermal, pop, now it won't charge.....

So glad I listened to you assholes

"JvSt uSe the dOdgE oNe, iTs so eZ" :flipoff2:

Either way, it's not charging when hooked up correctly. Whtf is the truck only putting out 9v to the key on power?
 
no idea, I got a ford regulator on mine so it wouldn't pulse like the dodge regulators tend to do.
 
yeah I have one of those regulators for the other k30 I'm building but haven't used it yet.
 
Im so curious where the issue lies now. For my swap I bought a one wire Hagemeister and have had nothing but good times with it. I did buy the same little converter doo-dad that you have when I was doing my cross country trip for the "just in case" scenario that the Hagemeister failed. Havent used it so no help on my end! Initially my plan was to use the stock 6BT alternator and ford voltage regulator...then I realized I hated electronics and was willing to swipe the credit card and hope that it didn't fail and leave me stranded LOL. Curious to what your solution ends up being, as Ill keep it in mind if I ever have to use the "doo-dad"
 
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