Serial num 3zj-59548 Only has 15psi boost, power is close to being ok but does a little more black smoking than I think it should, My question is, is there anything inside the pump that could raise turbo pressure? I was going to send it to fabick cat to get tuned up but they said the pump didnt have anything to do with psi and that the first thing they would do would be change a turbo........... No holes in boots, charge cooler or anything else, motor does not burn any oil and has good oil psi. Pj
Yair . . . powerjoke I saw a 3406 on a dredge with missing/broken manifold studs . . . just a thought. Cheers
The turbo needs a complete inspection and probably replaced. I disagree that the pump has nothing to do with boost pressure. The more fuel the pump gives it and the harder the pull the engine is under all make exhaust heat which spins the turbo faster which makes more boost psi, assuming the turbo is working properly. So obviously the pump and the turbo work together...
If it's "rolling coal" then it's getting more fuel than it needs. The fact that it's not making boost and smoking would hint at an air intake or compressor issue. Hate to bring up the obvious but have you checked the air filter. I don't know big diesels all that well, does it have a waste gate. For some reason I was thinking they didn't.
Scrub, I haven't noticed any broken studs or lost gaskets there is no under hood smoke as of yet either, so hopefully both int and exh are ok but ill check it out. Markat, I have visually inspected the intake side.....compressor housing and fins look fine but not saying they aren't worn..... I agree that the pump has a lot to do with boost, I was mainly wondering if timing had anything to do with boost because I am sure someone has been inside of it that didn't know what they was doing hell every old truck n the world has been tinkered with. Blmreject, lol yeah I've checked air filters but believe it or not it wasn't the first place I looked....... I even took one of the filters completely out and went for a test ride just to make sure I didn't have a faulty filter gauge. Does anyone have a guide to checking and setting the pump by sound or feel until I'm able to get it into a good fuel shop, we are working and I can't afford to be without the truck for even a single day, it's my lowboy truck and its not un-common for it to gross 150k lb, I also should add that the pyro will read about 950-1000* on a hard pull. Pj
3406 doesn't have a wastegated turbo for a start. Another vote for checking the air cleaner. Have you checked it yet,because lack of air can make black smoke just as easily as too much fuel..? Also is the black smoke a recent thing or has the engine "always done that"..? What's the engine installed in..? Have you checked all the lines between turbo and engine for leaking joints that could lose you boost pressure..? Also I'd suggest pulling the hose off the inlet side of the turbo and see if you can feel any play in the bearings or see any evidence of the compressor wheel having rubbed on the inside of the housing. 950-1000 isn't exceptionally high for an engine under full load. I'd only get worried if it topped 1150. I'll check the system and see how much boost the engine should produce. Back later on that one.
Thanks
Did you pressurize the intake piping to check it or just do a visual? It would surprise you what 15 psi of air and a bottle of soapy water will show you.
No I just visually inspected it, I would think that a small leak wouldn't affect it that bad, most of the times when we blow boots it'll start with a small hole and expand to a total blow out within just a few seconds. There is no hissing noise at all coming from it that I can tell but it's awful hard to hear it when your rolling down the road with the twin straight stacks rattling lol Pj
check the aneroid valve diaphragm on the pump had one doing the same on a pete and timing and more fuel will create more boost just don't get carried away and watch the exhaust temps or you can melt it down on a hard pull
Great, this is the post I been waiting for ,,,,, now....... What's the procedure for setting the pump? Lol do you have w breakdown of it and the aneroid valve ?
Google THE DIESEL GARAGE.COM fellows handle is YNOT he has answered a lot of the same questions your asking and has pictures and one other thing he knows his **** all you have to do is read thru his posts or others questions and just like here there are a lot of very knowledgeable friendly people and you can get step by step procedures and they already have it printed out and good luck
Yeah I registered there but they haven't turned my acct on yet. Hopefully someone here can help
don't need it to read thru the posts and do searches but here's some things to start on follow the boost line down to the back end of pump pull line and then you have 4 bolts on a thing shaped like a stretched out boob your aneroid diaphragm is in there check it for holes or tears
On a CAT what you are talking about is called an air/fuel ratio (same function as anaroid) but a leaky diaphragm will limit fuel delivery which would limit black smoke. This engine is getting plenty of fuel the way it sounds but not enough air! I would go back to air filter, turbo or boost leak. What RPM are you measuring boost at and I assume your at full throttle?
According to the SN this is a 425 HP at 1900 RPM which is where you should measure boost. Boost spec is 22 PSI which is under dyno room conditions. I would expect at least 18-19 PSI. Is your boost gauge accurate?
+1 - even it if just ticks a box that says "no leaks". According to the test spec nominal boost pressure at full load RPM (1900) is 22.00psi. However the floor of the spec is 18.65psi. At Torque Check RPM (1200) the nominal boost should be 21.1psi, the floor spec is 17.9psi - not a million miles away from what you're measuring. Considering those boost figures and your assertion that all appears to be well with the air filter, inlet piping/joints, & turbo I'd say you are looking at fuel pump/injector issues. A faulty diaphragm in an air/fuel ratio control would just make the engine smoky before the turbo fully spools up. At constant RPM & full load the smoke should clear.
Thanks for the replies, ill try to answer the q's..... Obviously I don't have a dyno so I am reading the gauge while trying to keep a 13' wide load in the middle of the road lol.... No load boost is less than anything my gauge will read >5p.s.i. I guess.. I haven't read boost gauge while at 2200rpm but all I have ever seen out of it is 15psi at about any rpm @ Koecon, I don't know if they are accurate or calibrated but I have 3 gauges on it. 1 dash gauge and 2 extra gauges zip tied to the visor for the time being ( I had a Tee fitting and no pipe plugs so I used another gauge lol) I haven't had a chance to look at the diaphragm yet but will ASAP, what is the procedure for setting timing ? Is this something that could cause this issue ? Something else that's strange is that, under no load and at WOT it will shoot a steady but faint stream of black smoke out of the pass stack only ( I am sure it's just the path of least resistance on the exhaust no big deal) This is a straight stack truck, is there any reason that installing a muffler/adding back pressure would change anything ?
I can send you PDF files for finding T.D.C. for # 1 comp. stroke and static fuel timing if you send me your email address.
Yes please. Ill pm u my email
I am also curious about this, I have a very similar problem. only get about 8 pounds of boost, does not smoke very much either. I have not checked the hoses or the turbo yet but I will be. a friend had told me about the diaphragm. Is there some where I can get a parts break down to see what to look for?
koecon, honestly, what HATCHEQUIP said about YNOT's posts on THEDEISELGARAGE.COM is true. The guy has written literally volumes about Cat mechanical engines. I believe that he was also involved in turbo design for Cat. With your pyro temp getting over 900 post turbo, and assuming that you indeed have no air cooler leaks, clean filters, and have smoke that does not clear up, I would start by looking at the turbo itself. Then I would try to get it in and have the valves adjusted and have it meter timed, and probably have a pop test done on the nozzles. You may have one or more bad nozzles that are not closing. Next could be the timing advance which is prone to wear and can cause problems if it is hanging up. From what I have learned from others, proper timing is essential to these engines in order to produce power without smoking after the turbo has spooled up. There are instructions on the aforementioned forum for setting static timing, but dynamic timing with a meter should be done. As mentioned before, the air to fuel ratio diaphram, if bad, should not let the engine go to full rack because it requires manifold pressure to allow full rack. 15 psi boost is a bit low for stock fuel settings, but not terribly so with warm ambient air temperatures. I would first figure out why it doesn't clean up after the turbo spools before worrying too much about the boost pressure. I adjusted my air to fuel ratio such that it does'nt smoke too heavy when shifting. It takes longer to get the horsepower, but it does not smoke black when shifting. I am not a mechanic, and hopefully others on here will correct me if I have given bad advice, but I have owned a couple of 4MG 3406B's and know how they should run. The fuel and torque screws have a tremendous amount to do with how much boost pressure you get, but I would want everything else to check out okay before I messed with them. I hope that this helps!
I'm getting ready to tear into it next week because I finally have a spare lowboy truck but honestly the timing instructions are about as clear as mud to me. I have read and re read the post that I think koecon sent me but am at 752pages I loose interest after about an hour of reading lol does anyone have a more simple or an idiot version ? Lol Pj
Truck wraps up quick there is defiantly no throttle slag at all. Honestly it could be ok but I would like to see more than 15psi to clean it up a bit and simple logic tells me that hp will come hand in hand with boost psi ?