24v Cummins Smoking - bad injection timing? but brand new pump

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

CovenStine

Junior Member
Joined
Dec 9, 2015
Posts
20
Reaction score
6
Ram Year
1999
Engine
Cummins
Hello, all
I have a rather unique problem, and was hoping I could get some insight from you.

I bought a ’99 Cummins about 18 months ago, and started having issues, and after a ton of time & parts, she’s still not running right.

The short version? I have a new head, a new injection pump, removed the tuner, and tried a computer swap, and the truck still sounds –and smokes –like injection is happening in the #6 cylinder after the valve opens. I believe this to be electronic in nature, and I’m trying to figure out what electrical or computer issue could be causing it.

The long version?
The lift pump died on me in September, but was caught quickly thanks to the pressure gauge the previous owner added after he killed an injection pump. Might be related, might not.
Over thanksgiving break, I noticed some throttle lag & surging, and sort of figured that it was an APPS, but once I wasn’t hauling anything anymore, the issue went away, and I thought nothing more about it.
Come mid-December, the truck started running rough and smoking badly- no catastrophic sounds or anything, as far as I heard/can tell.
I took it to the shop, where they found an “Injector Pump” code in the primitive computer, so- since she passed a compression test- they replaced the injector Pump.
Upon startup, she still was running just as rough, and smoked just as badly. Upon further testing, the truck failed a Leak-Down test, apparently leaking out the exhaust valve of the #4 cylinder. The head was found to be leaking & damaged from an old overheating problem & an over-rev, resulting in some old valve contact- again, in #4. The bent pushrods were replaced, the head was replaced (and rebuilt by the local Cummins specialist machine shop, as the ‘new’ head was assembled poorly) and everything was buttoned back up.
This time, upon startup, she was still running just as rough, and smoking just as badly- subsequently they found a VERY minor leak in the Leak Down Test in the #6 cylinder, but nothing else is obvious mechanically. Upon further trial and error, they found that if the #6 cylinder is starved for fuel, the smoke problem goes away (but obviously, it’s still running very rough).

The mechanic seems to think it’s a problem in the bottom end of the motor, and is of the opinion that it’s time to just rebuild the motor and be done with it.
I disagree for 3 reasons:
  1. For about the first half-second of running after startup, the truck sounds FINE; I think that there is no way anything is heating up fast enough that the problem is coming from thermal expansion
  2. The “bad” cylinder (according to the Leak Down Test) has moved from #4, with known valve contact, bent pushrods, and a bent valve, to #6. All 6 cylinders have throw/travel within spec, all 12 rods have throw/travel within spec, and the only way a valve could open earlier than it’s supposed to, would be if the lobe MOVED on the cam, but all 11 other lobes stayed put- which I think is impossible.
  3. I’m SURE I have not over-revved or overheated this motor, and I’m 99% sure that the previous owner didn’t either. That means it’s been running with a cracked head, bent valve, and a bent pushrod for 100k miles+, so this teensy leak in #6 shouldn’t even be noticeable.
To my way of thinking, that leaves 2 possibilities: the brand-new Industrial Injection pump isn’t doing its job right, or something is wrong electronically- be it a sensor or wiring or whatever.

So now I have a truck that isn’t running right, with a brand new radiator, injection pump, and head, sitting in my driveway for me to ATTEMPT to fix.
AAAAAnd I'm wishing I'd just bought a 12-valve and been done with it...
Any thoughts, suggestions or even judgements would be most appreciated. Thanks!!
 

dudeman2009

Senior Member
Joined
Feb 9, 2016
Posts
1,562
Reaction score
208
Location
Arizona
Ram Year
2001 1500 Sport with enough electrical modifications to make my brain hurt
Engine
Magnum 360
Lots of guys talk up the 24v like its some godsend, but really its just a 12v with more parts to break.

Its very possible for a diesel engine, especially a cummins in the pickup world to run for 100K miles after having a piston crash with the valvetrain. I've seen longhaul trucks drive from new york to cali and back to michigan with valve adjustment screw completely missing and the pushrod slamming into the rocker the whole time.

First off, what shop are you taking it to? Do they specialize in diesel, or are they an auto shop with a guy who says he knows diesel? I'll tell you right now, any diesel tech can work on automotive without much trouble. I'd never trust an auto tech to work on a diesel without the proper classroom and hands on training that a technical school or apprenticeship program can provide.

I have some questions of my own, what color is the smoke? When the injection pump was last replaced, did they read the numbers off it and make sure they replaced it with the same pump number? The injection pump appears the same as a standard VP44 injection pump but it is not, if a standard VP44 pump is used, problems will result. The key on the injection pump shaft must be matched to the old one, and they properly stamped key must be used.
 
OP
OP
C

CovenStine

Junior Member
Joined
Dec 9, 2015
Posts
20
Reaction score
6
Ram Year
1999
Engine
Cummins
Yeah, I'm learning about the 24v's failings, one part at a time.
It's a diesel specific shop, but their specialty is PowerStroke's. They do have a certified Cummins tech on-staff, and we have a Cummins brand shop here that this guy knows some mechanics at.
It's my understanding that several other wrenches were consulted.
The smoke itself is 100% black rich diesel fuel. I have a good nose, and am quite sure that no lubricating oil is being burned.
Unfortunately, I can't say one way or another on the pump- the original has been returned for a core charge, and all I have is the new one. Where would I find this number, and can d correlate it to a VIN or a block number?
thanks for your help, again!
 

dudeman2009

Senior Member
Joined
Feb 9, 2016
Posts
1,562
Reaction score
208
Location
Arizona
Ram Year
2001 1500 Sport with enough electrical modifications to make my brain hurt
Engine
Magnum 360
They screwed the pooch if they sent the old pump back without recording the information on the injection pump data plate. There are 21 differently 'timed' keys, unless you can confirm that the new pump has the same 3 digit code as the old one, there really is no guarantee that anything you do will fix it, short of taking to an authorised cummins dealer to have it re-timed.

Black smoke, can be caused by a bunch of things, but only a couple apply to this situation. Namely, a bad injector, static timing not correct, fuel injection pump malfunction.

Supposedly if cyl.6 is starved of fuel the problem stops, it should run much better, not perfect but better. If it does run better, i'd start to suspect the injector (you can swap it with another cyl to see if the problem follows. If it doesn't run better, then the pump is likely out of time and that just happens to be the cyl that's being injected at the right time to produce tons of smoke.

I'd contact the previous owner who you said also had to replace the injection pump, its possible they would know what the number way, if not they could contact the shop they took it to who should have the pump number in their purchase documentation.
 
OP
OP
C

CovenStine

Junior Member
Joined
Dec 9, 2015
Posts
20
Reaction score
6
Ram Year
1999
Engine
Cummins
I realized when I posted this on the Cummins forum that I failed to mention that they put a new injector on #6, already. It's my understanding that the new injector is still there.

I called the local Cummins branded repair shop, and then Dodge to try to find the Stock timing code to no avail (long shot, I know.
They put the Cummins tech at the Dodge dealer on the line with me, and he said that as long as the timing key matches the pump body, the pump/key combo's are interchangeable; i.e., if I swap an 032 pump and its key out with an 029 pump and key, it shouldn't matter.

Is that false?

I suppose it's entirely possible that they effed the key up on assembly, as it's aluminum, so it could be out of time because of that, too...

I feel like I've been leaning on you very heavily, DudeMan, but I really appreciate your help!

Just as a verification, on the VP44 Diagnostic page over at BlueChip ( https://www.bluechipdiesel.com/vp44_diagnostics.html ) mentions that "TO MAKE THE ENGINE START AND IDLE ONLY, YOU DON’T NEED ANY SENSORS OR COMPUTERS OR ELECTRIC LIFT PUMP. YOU ONLY NEED 12 VOLT POWER, GROUND, AND FUEL TO THE VP44."
If that is true, and since this 'smoking' problem presents at idle after about .5 seconds, than this MUST be either a faulty VP44, or a timing issue of the VP44 itself, correct? The injectors were tested, the tubing is good, the head is new, the push-rods' movements are in spec, the cylinder movements are in spec, the sensors are irrelevant; there's nothing left...

TIA, friends!
 

dudeman2009

Senior Member
Joined
Feb 9, 2016
Posts
1,562
Reaction score
208
Location
Arizona
Ram Year
2001 1500 Sport with enough electrical modifications to make my brain hurt
Engine
Magnum 360
Hmm, it might be that the Cummins tech is right, I never did any pump work on the Cummins in the semis where the original pump didn't go back in. I just called up a buddy of mine from school who works for Cummins. While he hasn't worked on or learned the intricate details of the old engines like this one, he said he's pretty sure that the keyway is matched to the pump only. As far as he's aware, its due to the assembly process of the pumps, its just easier to build them and modify the keyway instead of trying to get them all to line up within a few hundredths of an inch or so.

What I got from that, as long as the new pump number and key number match you're good. He also said that its common for the key to become damaged if the gear was put on incorrectly or if they key wasn't seated properly. The keys can mash and will cause problems similar to what you're describing. Its also possible that whoever did the install, put the key in backwards, the arrow should point towards the pump.

Its not listed in any general or factory service manuals (Cummins own manuals excluded) to remove the pump gear after its installed and torqued down to ensure the keyway isn't damaged.

I told him about the black smoke a bit but I didn't know a new injector was in that cyl at the time. Since its new, there is no need to talk about testing that injector. You should ensure everything is torqued to spec on the high pressure fuel line though. He did mention that if cyl 6 was a problem and the rest were fine, the engine would run pretty smooth, not rough really at all, especially above idle. But if it runs crappy its likely that its all injectors that are injecting at the wrong time, and that cyl 6 just so happens to be doing so at a point to cause lots of smoke.

From what I know of the pump, it has its own pump computer and can run the engine based on its input if it cannot get anything from the crank sensor, but will only do so if there is no input from the crank sensor. If the computer in the pump were bad, it wouldn't just be cyl 6 producing that much smoke.


Unfortunately, based on what my buddy said, and what you have said. I think the only thing you can really do is have the gear for the injection pump pulled. This time when they put it on, they need to do so with the keyway at the 12o'clock position, get it in (it will be a slight press fit) and gently slide the gear on (lithium assembly grease can be used if applied and wiped off with a finger) and torque it down. Then remove the lock nut and washer and check the keyway again.
 
OP
OP
C

CovenStine

Junior Member
Joined
Dec 9, 2015
Posts
20
Reaction score
6
Ram Year
1999
Engine
Cummins
I've been really busy, and haven't had the chance to tear the front cover or the valve cover off to check the timing and the rocker action.
However, I did make a video because I'm not sure I'm describing things correctly.
In the video are two startups of the engine. one is a dead-cold start with a "hot wire test" setup on the injection pump (removing the computer / sensors / APPS from the equation entirely) and the second was the third in a sequence of start/stops, so you can see the level of smoke without the solar glare making it look white.
To my ears, the first start sounds beautiful until about revolution 3, whereas the second start doesn't last that long.
I want to get the truck inside (so I'm not fighting with blow-sand to keep the motor clean) and pull the valve cover & film it in high speed, so I can match the rocker timing of cylinder #6 vs the others.
Before I do that, I have to get a 6-point 17/16" socket, and check the keyway alignment.

I have a question out to Industrial Injection about their testing prior to shipment, but I'm hoping really hard that the pump's good.

Anyway, let me know if you have any thoughts, I'll keep tinkering.
Thanks for your help!
 

dudeman2009

Senior Member
Joined
Feb 9, 2016
Posts
1,562
Reaction score
208
Location
Arizona
Ram Year
2001 1500 Sport with enough electrical modifications to make my brain hurt
Engine
Magnum 360
A picture is worth a thousand words, a video is worth so much more. I do see some white smoke, but I also see black smoke with the popping. That popping matches with a single cylinder going through its pace. Right off the bat it sounds like a stuck open or sticking injector. Since the black smoke follows the pop, i'd say its flooding one of the cylinders and still burning while the exhaust valve is opening.

There is a couple other possibilities. You mentioned it had a tune? Are you certain that you took it back to the factory tune? Do you have a non-contact infrared thermometer? If you do, check the temperature at each exhaust port after you get it running for a few minutes. They should all be about the same temp, if one is quite a bit hotter or colder, thats your problem cylinder.

Otherwise, i'd say the injection pump is operating perfectly, the rest of the time its running it sounds great. Its just the one cylinder thats popping.
 
OP
OP
C

CovenStine

Junior Member
Joined
Dec 9, 2015
Posts
20
Reaction score
6
Ram Year
1999
Engine
Cummins
I seem to remember there being a teensy bit of white smoke on startup months ago, so I guess in this setting I didn't think anything of it.

With regards for the tuner, yes, I'm sure it's disconnected. I contacted the manufacturer and unplugged what they told me to unplug (the tuner itself and the MAP sensor intercept harness). I DID notice, before removing the tuner, that my cooldown timer (which was set to idle until I got an EGT of 350 degrees) took substantially longer to idle to cold and shut itself off than it did before the truck started running like crap.

Okay, I let her run for briefly, and checked the temp of all 6 cylinders.
Cylinder 1 ran at 87, 2 at 95, 3 at 98, 4 at 130, 5 at 108, 6 at 82.
I have to hope that, if they did a bunch of compression tests and removed the head twice, that the injector tubes were inspected.
I'm assuming, based off of that info, that I need to do injectors, and I doubt the 40HP ones will need bigger pencil tubes.
Incidentally, it appears that the injection pump keyway is aligned, and I can't imagine it skipped a tooth and still sounds THIS acceptable.
5o5WmsB6Wt7lxMsmop2kPjiVDrP0aVLB-YbamyTjh1Bvh7ekruzEBI7EkdV0ix7yU1PgFJ5T5urWlq-4xy56owKoynqe6YXf9fFrqxXEHZIdjkK2P3DaaUCnESVbIPdSP33SFhHElzErVOIPM7ycP77qDT6FgAYjrv1FmRqwWaP2qIWaik8NY4W2y8__Ty_7W_WgjAMQQWPcIrJuUxB64VCjE_XaXzj-K-WESKri92BGfA6y8H6Iv7XwMPyRimJcJmmud__f8oezqGcQ1IZ8yTXbrKyCplaYeQ6BR82YcvzYVULsfnXQPjUjbDcE8JR48va6o_6962QxRZkSU7ecnis56Q9_jozP_69GLuMlhhSIVcyaukVvmRtfQGOB_PwCOvmdaYEtqykwPb-jlr4Png8dlINn5vLJGA8-TYbk0yk_tgNOpy--UerjI8Yr7o9WOnPm87m2z6kUEZ3eS-yrWCzqg5AqOQUxEk2o42kpbltMJwsZJrlOLH3kDql0C0dYvFRDTgNxTS4XkDjs3NPkKfRtMn4tON7udInyIV9ajsSv-7XKgMvvIlyhEwUZ3_r-DIXAqS4oXJ8VuVomOT5USzRHWItk9zpyf7HZZolAtyWsen3e9IE=w719-h1275-no

As always, thanks very much for your help!!
 

dudeman2009

Senior Member
Joined
Feb 9, 2016
Posts
1,562
Reaction score
208
Location
Arizona
Ram Year
2001 1500 Sport with enough electrical modifications to make my brain hurt
Engine
Magnum 360
The injection pump gear won't skip, it's not possible without coming apart, violently.

As for the temps, they are pretty close and to be expected. The middle of the block is going to be hotter than the ends, a badly stuck injector would be much hotter than that, but one that's sticking or weak wouldn't cause that much of a difference. I'm unsure how the exhaust is setup but if it exits from the middle of the header thats where most of the heat will be.

It might not hurt to check the injector spray pattern if they didn't. A couple pieces of cardboard and and injector tester is all that's needed.
 
OP
OP
C

CovenStine

Junior Member
Joined
Dec 9, 2015
Posts
20
Reaction score
6
Ram Year
1999
Engine
Cummins
It's a stock exhaust, so it does exit the middle of the header, but I only let it run for a minute or so, and checked the temp very close to the head. I couldn't recall the exact numbers, but the disparity was much more significant early after startup.
I'll ask 'em about checking the injectors today. Thanks!
 
OP
OP
C

CovenStine

Junior Member
Joined
Dec 9, 2015
Posts
20
Reaction score
6
Ram Year
1999
Engine
Cummins
I'll ask 'em about checking the injectors today. Thanks!

I asked, and they said they did not do an injector test (pop/close/pattern- anything), they starved cyl #6 and the popping decreased dramatically, and cyl #6 is the one with the slight pressure leak into the exhaust manifold, so that was the "problem cylinder" in their minds. They swapped out THAT injector, with no results.
 

dudeman2009

Senior Member
Joined
Feb 9, 2016
Posts
1,562
Reaction score
208
Location
Arizona
Ram Year
2001 1500 Sport with enough electrical modifications to make my brain hurt
Engine
Magnum 360
I asked, and they said they did not do an injector test (pop/close/pattern- anything), they starved cyl #6 and the popping decreased dramatically, and cyl #6 is the one with the slight pressure leak into the exhaust manifold, so that was the "problem cylinder" in their minds. They swapped out THAT injector, with no results.

They did all that work and didn't test the injectors? Thats ********, either they don't know what their doing, or someone is trying to take you for a ride. Anytime a diesel is experiencing problems that relate to the fuel system, before anything is replaced (unless it's obviously broken or throwing a code) the injectors should be tested. If they are removed for any reason, even if they aren't part of the repair, they should be tested.

In diesel, there are really only two things that affect how it runs. intake air and the associated valve train, and fuel injection.

I'd go back and try to get them to test the injectors and not charge you for some of the labor, since they should've done it in the first place. Not that everyone does it that way, but at Sears we refund your money if we suggest a solution based on what we found and that didn't fix the problem. We recently did that on an alternator on an oldsmobile silhouette, and you have to pull half the engine mounts and rock the whole damn engine forward to get to the alternator. It didn't fix the problem, so we didn't charge him for in install or removal.
 
OP
OP
C

CovenStine

Junior Member
Joined
Dec 9, 2015
Posts
20
Reaction score
6
Ram Year
1999
Engine
Cummins
Smart injectors, perhaps?

I like to think that they're used to Fords knowing when an injector is bad- their specialty is 99+ fords, and people come for a good ways to get their expertise- me living a block away, was just happy to have a Diesel Mechanic nearby. Ah well, live and learn.

I'll try to double check with the wrench himself on Monday, as I was only able to catch the owner yesterday, so he may or may not have known everything.

I can't, in good conscience, ask them to comp me much of anything, other than perhaps a few minutes to do the actual injector testing- after I pull 'em; they've already comped me 80 hours or more, plus all the parts. Asking for more feels unfair in the extreme.
 

dudeman2009

Senior Member
Joined
Feb 9, 2016
Posts
1,562
Reaction score
208
Location
Arizona
Ram Year
2001 1500 Sport with enough electrical modifications to make my brain hurt
Engine
Magnum 360
I like to think that they're used to Fords knowing when an injector is bad- their specialty is 99+ fords, and people come for a good ways to get their expertise- me living a block away, was just happy to have a Diesel Mechanic nearby. Ah well, live and learn.

I'll try to double check with the wrench himself on Monday, as I was only able to catch the owner yesterday, so he may or may not have known everything.

I can't, in good conscience, ask them to comp me much of anything, other than perhaps a few minutes to do the actual injector testing- after I pull 'em; they've already comped me 80 hours or more, plus all the parts. Asking for more feels unfair in the extreme.

Fair enough, testing them isn't too hard or time consuming. It shouldn't be more than an hour or two to test all six properly. Pulling them yourself would save a lot of time. Make sure you mark them as you take them out. white tire crayon will mark them just fine and not cause any damage (I use tick marks instead of numbers as its kind of hard to write on a small round thing) Sharpie is also a good way to mark them, just wipe them off with a clean cloth or the sharpie won't stick. To get it off, just hit it with a bit of gasoline and a rag or parts cleaner (do not use brake clean).
 
OP
OP
C

CovenStine

Junior Member
Joined
Dec 9, 2015
Posts
20
Reaction score
6
Ram Year
1999
Engine
Cummins
Hello,
I FINALLY found the time to put in the injectors. Took me long enough- partly due to parts delays, partly due to me being nervous and trying to line up a friend’s help (anything can be daunting when you’re down one hand). In the end I found it to be easier than expected, except getting the #6 fuel line back threaded. I was rather surprised how restrictive the Injector Tubes seemed to be (although, my lungs are not calibrated, but they seemed more restrictive than the ~.075” holes would warrant).
Is it possible that when my injector pump **** the bed that it clogged up all six tubes?
I also found it odd how long it took to prime the injector pump. After two quick-taps on the starter, I hotwired the lift pump and it ran for almost five minutes at 0.5 PSI before it ‘caught’ and I got 15PSI at the injection pump.
Unfortunately, she didn’t start. She was still smoking like a maniac, which I suppose is expected, but it only ever seemed to catch on 2 cylinders. Not sure if I ought to pull the lines and flush them, and swap the tubes, but I’d imagine that one tube would be obviously worse than the rest.
It did seem odd that the #6 cylinder had a different # injector in it: the Bosch number (…193630) was the same, but 5 injectors were stamped ‘939 870’ whereas the last one was stamped ‘908 203’ (where the first triplet was circled).
i'm a bit leery of just cranking away at it waiting for it to catch even if i've got pressure at the injector pump... it just FEELS wrong. Maybe that's my small gasser
In case it would help, before I ordered the injectors I shot a high-framerate video of the valvetrain, to make sure that the ‘bad’ exhaust port (#6) was not being opened. I cannot see a blip, it looks perfectly timed to me. What do you think?
As always, thanks for your help!
~C
 

dudeman2009

Senior Member
Joined
Feb 9, 2016
Posts
1,562
Reaction score
208
Location
Arizona
Ram Year
2001 1500 Sport with enough electrical modifications to make my brain hurt
Engine
Magnum 360
The video looks fine to me. I'd take pipe cleaners to those tubes, see how much gunk comes out.

That hole is 3/40ths, or aprox 1/13th of an inch. For size approximations, those coffee stirring straws are about 1/10th of an inch outside diameter, inside is going to be close to 1/16th of an inch. You also have take into account, the human mouth can only generate a couple PSI, you're running around 4500PSI from that injection pump.

As for it not priming. Did you follow proper bleeding procedure?
 
OP
OP
C

CovenStine

Junior Member
Joined
Dec 9, 2015
Posts
20
Reaction score
6
Ram Year
1999
Engine
Cummins
Apparently I can't follow simple instructions, but once I followed the injector-by-injector bleeding procedure, it started right up.
Turns out it was a multi-part problem.
As I had done a hot-wire VP44 test, and it still ran like crap, I knew it wasn't the computer. Turns out it wasn't ONLY the computer. My Adrenaline tuner caused it to start running like crap again, when I reconnected it.
So in the end, I'm thinking it was a combined failure, a tired VP44, ancient injectors, and a bad tuner. The garage dealt with the VP44, but I guess didn't isolate the injectors and the tuner explicitly, as you suggested, and chased their tail for a while.
I was a bit confused myself, because it started great the first time, idled clean- then I plugged in the tuner and turned the truck around to unload it, and got really worried as it was smoking like crazy again- so I disconnected the tuner and took her for a test drive.
If you want a laugh, I did scare myself witless. I drove it down the end of my block, and then watched my tailpipe in the mirror as I was accelerating, and promptly blew off an intake boot, so the light smoke just STOPPED, and the truck lurched like it dropped out of gear. For about a minute and a half I was convinced I'd killed it. That's what I get for approaching this with only Naturally Aspirated Gasoline experience.
I think my next step is to get my tuner working again, as my EGT's went through the roof with the lack of a tuner and the 50HP injectors. I'd thought it would be able to handle it fine, as it has a 4"+ turbo-back exhaust, and a much larger than stock air filter, but if a replacement tuner doesn't get the EGT back into range, I'll have to do something else. But that's a different discussion entirely.

Regardless, thank you SO MUCH Dudeman et. al., you saved my bacon. Still rather flabbergasted that they wanted to do a full rebuild, so spending 500$ instead of 8,000$ is fan-freaking-tastic.

~C
 
Top