Hi Folks, I’m looking for a little help. I have an old Bobcat with a Perkins 4.154 CAV pump. Machine came to me not running. I just replaced injector nozzles, set em to 2200, checked compressions, leak downs, pump timing, and replaced all fluids and filters. My problem is the engine is running rough. A little smoke; when it runs for awhile, I have to open the doors or I’ll get fogged out. Not what I would call too much smoke. Oh compressions are all around 380 +\- 20-30 psi. I checked my pump timing, and the cover had been removed and the timing circlip had tool marks on it, but the timing seemed correct at 18BTDC. With a laser thermometer checking each exhaust flange, I get about 100 degree swing across all 4 cylinders, so they’re all firing (at least sort of). Fuel has also been drained and replaced. I’m really scratching my head here. That engine should be running fairly smooth, and it’s just not nearly as smooth as I think it should be. Any thoughts would be appreciated. Thanks!
Did you try loosening individual injector lines to see if it isolated to one or more cylinders or they all act the same way with the line loosened?
I just considered that this evening! No, I haven’t tried that yet. Certainly going to tomorrow am. Good idea
Did u happen to get the DES# off the injectors.?? 2200 psi seems a smidge low.. If u can get the DES, I’ll look it up. It’s also possible the cam ring inside the pump has smashed lobes.?? How does it start.?? What color is the smoke.?? Have U moved the timing any.??
I don’t know what DES number is? The pressure for the injectors, per the manual is 1800 - 2200. When they came to me, none of them was opening over 1500. I did move the pump a bit, advanced it from where it was, because according to the book, it was set to fire at TDC, not 18 degrees before, so I tried to get it a little closer. But the pump had been in that position for years, so tomorrow I’m planning on putting it back, and seeing how it does. The guy also told me it was always hard to start. Now that I’ve changed the nozzles, and advanced the pump a bit, it fires right up, but I’m not sure the pump timing is 100% accurate because the timing circlip had tool marks on it (and near it), and may have been messed with. So, the pump timing is a bit of an unknown. It’s hard to tell what color the smoke is, it’s not a lot, and my shop is small, so I open the doors up pretty quickly or I get headaches . I’ll run it again tomorrow to loosen the lines like Welder Dave said, and put the pump back to where it was, and when I do, I’ll let it smoke up a little more and maybe I can tell what color it is. Thanks for the help!
If u post the pump # I can look that up and tell u what letter it’s supposed to be.. if it’s listed.. The DES # is the CAV # that’s stamped on the inj. body.. (5222108) same w the pump..(name plate) DO NOT SCRAPE THE NAME PLATE.. It sounds as if you know what your doing.. so u should have some “gasket/paint stripper” in a spray can.. U can get it just about anywhere .. (parts store, Walmart)
Did you make sure all the old copper compression seals came out with the old injectors? I have had that happen several times(them staying in the head) in the past and the injectors ends up too high in the sleeve.
I actually did have a problem with that, originally. Cyl 1 exhaust was 100-150 degrees colder than the others, after I installed the injectors again. What I found was the new copper I put in there was leaking. I barred the engine over by hand and could hear a hiss at that injector. Anyway, I was out of coppers at that point, but I had some aluminum washers, and used one of those, and that sealed it up. I was hopeful that was my root problem, but it wasn’t unfortunately. So, yes I did have a copper problem at first, but that apparently wasn’t my real problem. Good idea though!
Good thinking V.., idk why I don’t mention it.. It happens more times than not. When I get a set in that’s missing a washer, THATS the first thing I do is alert the customer.!!
I uploaded some pics of the pump. There aren't many discernible numbers on it. There is a "342" on the pump head. Also what is possibly a 7132A01 written on the inside of the mounting flange. Not much else. My nozzles were DNOSD126, and the injectors, if my notes are to be believed, are SDN 31-1610. There is a procedure in the book about setting the timing circlip in the pump. I performed that procedure, and my circlip was a bit off. I'm putting the pump back on now, and hopefully I can get it running.
Ahhh.. now I get it, there’s no name plate.. Did u take it off.?? How did u check the c clip.?? Put fuel/air pressure on the #1 cyl.. With no name plate and no spec sheet to go by.. I guess u could determine it by the line it hooks up to the #1 engine cyl.. THEN rotate the pump in the NORMAL direction of rotation..again since no name plate, there’s no arrow (on name plate) to point the direction.. & U MUST b standing IN FRONT OF THE PUMP while rotating the drive..
Yep, took it off, put 440 psi into #1, and set the circlip there. Installing it now.
I took a lovely artistic, enticing and visually stimulating video today, that I'll post up this afternoon. Its running better than it ever has, and it might be as good as I'm going to get, but it's still not quiiiite where I'd like it to be.
I taught Steven Spielberg everything he knows. So, it’s definitely running, and it might be as good as I can get, but I’d just like to see it a little smoother.
Did your marks line up behind that little side plate? It looks like the pump housing is all the way to one side of the slots.
It is all the way. Actually, it could have gone a little more. That might mean the gear on the fuel pump is off a tooth. According to the best info I have, it should fire #1 at 18* BTDC. It’s actually closer to 16, so it’s a little later than it technically should be.
Turn the low idle down to 700-800rpm and button it up and send it down the road..
Having the air cleaner hooked up might make it sound a little smoother. The 4-154 wasn't one of the most popular Perkins. They weren't rare but were a little different recipe from the very popular 3-152, 4-236 and 6-354. I had a Miller welder with a 4-154 in it. The rear seal leaked a bit but it started and ran good.
I had the manual for it, so I must have worked on one before, I just don’t remember. Shocking, I know. Funny thing is, I got an old Ferguson coming in a week or so with the same engine. Similar problems too. Anyway thanks you guys for helping me think through this. The root problem was multifaceted, and I had been working on this machine for too long! I guess I couldn’t see the forest for the trees, and got all wrapped around the axle about it. It’s wierd how that happens to me sometimes. I’m scaring 50, and have been a mechanic all my life, and still every once in awhile, I get hung up on something like this, and I need a little help pulling myself out of the weeds. Thanks guys!
Its ok to get hung in the weeds from time to time. It makes you who you are and your occupation still interesting to you . Don't lose that. Im scaring 70 and still enjoy a challenge.
I didn't think a 4-154 was ever put in a tractor.
Might not be exactly a 4.154, but something real close to it. I dunno, we’ll have to see
I was hoping I had it ironed out, but I don’t. Cylinder 1 is still colder than the others, white smoke upon start up, and low power and black smoke while under even a light load. Aside from some mysterious thing that I can’t measure going on in the cylinders, my problem has to be the pump. It seems like I can get one for 500-1500 bucks, but I would need to know the p/n of mine, so I’d know what to order. Since I don’t have a data plate, that’s pretty hard to do. I could call my local Perkins dealer and get the Perkins number, but other than that, is there another way to identify exactly what pump I have?
What is the temp difference? Maybe.........have you swapped the injectors to see if the problem moves? Have you checked the engine compression on ALL the cylinders?
Temp difference is over 100 degrees. Cylinders 2-4 are in the 400 range and 1 is in 300. I’ve moved injectors.
Well there ya go.. If cyl 1 is only at 300 psi.. there’s your white smoking problem.. U could try adjusting the valves but other than that.. ur looking at rings. How many times have you hit it w ether.?? R u talking compression or temp.??
OOPS those were temperatures not compressions The compressions are all in the 360 range. The temp I'm reading with a laser thermometer right on the exhaust port. The temps go up the longer I run it, but the difference stays significant no matter what I do. Cyl 1 is always much lower exhaust temp. Never used ether on a diesel.
Something isnt making sense. You have good compression all the way across, the problem didn't move when you swapped injectors. All it takes to fire is good compression and the right amount of atomized fuel at the right time. Its sounding like the injector pump isn't pushing enough fuel to #1 injector or that injector isn't atomizing the fuel (which would be unlikely since the problem didn't move during the swap)
Right! That’s the core of the matter. The problem with that is, it’s a rotary pump. I have a vague understanding of how they work, and a single cylinder failure seems almost impossible. By that, I mean, if cyl 1 had failed because if a worn out cam, then cyl 4 (or whichever one, I can’t remember firing order) would also fail, because it uses the same cam lobes. How can a rotary pump fail on just one cylinder? That’s my conundrum. This one really has me.
Put a dial indicator on your valves above the pushrods and measure the travel through a cycle by hand. Im wondering if you have a cam lobe or lifter going down and its effecting the air flow
Is there any chance that something is restricting the fuel flow in the injector line ? Just a thought, disconnect the lines on #1 and #2 injectors and get an accurate measurement of the fuel coming through them for comparison.
Definitely worth a look, but I think this type of thing is covered by a compression check. I give it 10 cranks through compression for each cylinder, and take my measurement there. If it takes one cylinder longer to get to 350 or whatever, that’s the one with valve problems. That’s a good idea though, I’ll give it a go possibly tomorrow. Thanks!
I’ve never heard of this. Aside from the line being damaged / bent / kinked, I don’t know what could be in there that would survive those pressures. I can’t really rule anything out yet though.
I had an experience with a minute piece of metal lodged in a line once. It took me a while to find it. I changed out the pump for a new one and the problem persisted. That's when a I smelled a rat so to speak.
Get this - funny little ending to this story. First of all, I tried all the recent suggestions from everyone, I especially liked the dial gauge on the tappet. Very clever on that one! In any case, still no trouble found. Engine still runs a bit rough. The only thing left to do is send the pump out for bench check / overhaul, which could take weeks, and may not even yield any fruit. Not alot of shops even willing to work on this old pump, but there are a few. Anyway, so I had "that" conversation with the guy. You know the one where I say I can't figure out what's wrong, and we need more expertise than I can provide, and this old stuff is hard to find support for etc etc... The kind of phone calls I HATE. I mean, seriously, my stomach was in knots about this. I've been a mechanic for 30 years, and I can count on one hand the number of times I've come up with nothing. Well, maybe I need one more finger now. Anyway, so I call the guy and take him through all this, and he says not to worry, other mechanics have been telling him this for years, and he'll take it the way it is, no sweat. Years? YEARS? and he couldn't maybe have shared this with me before I spent freaking forever trying to figure this old POS out? YEARS? UGH. well its over. Thank you all for your help with this. Imma take the next couple days off - hope you all can too Is it beer:30 yet?