As many of you know, I have a coach that wasnt running right on
Our trip from florida to Michigan. I had
Mixed motor oil in with the diesel. Long story but here is the latest list of things I've done and I'm still
Missing some hwy top end. Can't get the coach over 65 mph:
1. Drained fuel tank and added 15 gallons of b100 biodiesel to clean tank and fuel system. Ran it on that for a couple of hours then added $200 worth of diesel to the tank. Coach exhaust is now invisible. Can't see it at all.
2. Motor oil looks great and so does tranny fluid.
3. Checked turbo at inlet and outlet and looked perfect. Spins as it should with no play.
4. Pulled off muffler running straight pipe now and can hear turbo :) love that whistle.
5. Blew air in all fuel lines to eliminate any obstructions.
6. Changed fuel filters
7. Checked to be sure throttle linkage is working properly.
Coach doesn't even smoke a teeny bit on full throttle on the hwy. where is my power? Seems to me like it still isn't getting enough fuel. Anything in the fuel system that would obstruct or reduce flow?
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Wow, start by checking the rpm with a hand held tach your 6v92 should be 2100 to 2250 no load then check the fuel pressure should be 55 to 70 lbs at full throttle ? does your engine have a fuel modulator sounds like you are not getting full fuel position at the injectors.
You really cannot tell if the engine is at full throttle by checking the linkage on the governor housing,the rpm check is a good place to start
If practical, try changing out all your rubber fuel lines with one size larger. Old rubber lines constrict like clogged people heart arteries and restrict fuel flow.
It would sound like your restriction/power problems MAY be waste oil caused....or at least influenced somewhat? "Abandon All hope Ye Who Enter Here." HB of CJ (old coot) :) :) :)
Totally unrelated to fuel issues.....but how about the air filter... Ours plugged and it was a dog discovered some crafty inhabitants ;)
Have fun !
Eric
clogged fuel system --> cleaned out with bio --> now under powered = clog moved further down line = blow out fuel lines, filters, injectors - see what caused Sean Welsh's problem a few years back - HTH
Cliff, I think this is the only way I'll know definitely what my power loss is. I'll work on this. Going to have to purchase the tach. Where does it connect? At the alternator?
HB, problem Exhibited only recently so I doubt my lines are constricting flow enough to cause this but it will be a good idea to replace the rubber lines anyway since I ran on B100 for a couple of hours. I'm not sure the waste oil caused my issues but the jury is still out on that. If so, I'll be the first to share this and save others the aggravation of trying to use it as fuel.
Eric, true true. I forgot to mention it in the above list but we replaced the air filter two weeks ago. Took entire housing apart too and cleaned it and made sure there were no obstructions. Good point and yes did it.
Niles, we did blow out the entire fuel line system all the way back to the tank. Had to reprime but it was worth it to be sure the lines were clear.
Two thoughts:
1. I took apart my engine stop lever/throttle plate assembly to unseize the engine stop lever when we were parked in florida. Any chance I could have put it back together wrong? I merely unbolted the Lid, unseized the stop lever washer and put the lid back on.
2. When changing fuel filters, I noticed that there was a small actuator or little round metal electric solenoid that is attached to the secondary fuel filter housing that has two wires attached with nuts. Does it control pressure or something along those lines?
Thanks once again for the assistance and helpful dialogue.
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Scott,
If you don't have these gauges, turbo boost, exhaust pyrometer, and fuel pressure gauge. I think they could really help you keep an eye on your engine functions. They are the original DDL, no laptop required.
Ken
Scott,, the wires from your filter are for the water detector system,>>>Dan
Ken, I would love to get kitted out with that set of gauges! Love to monitor stuff like that. I will start looking around for them and as we get the $$$ I will start buying them. Can you or Cliff or someone recommend a good place and brand to purchase the following:
1. Pyrometer
2. Tach
3. Fuel pressure
4. Analog or manual water temp.
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For now, buy yourself a hand held tachometer at Harborfreight or similar place. Less than $100. You stick the little white strip of tape that it comes with onto the main pulley, and aim the tach at it, and it shows your rpm right away. Handy tool to have.
And yes, it sounds to me too like it is not getting full fuel from the racks. Look at your stop cylinder and levers again.
JC
Scott make sure you have clearance between the shut down cylinder and lever run it awhile and check that clearance making sure it hasn't closed up MCI's are bad about the skinner valve leaking and let the shutdown cylinder start to close taking away power
Also Scott, I beleive the sensor wires you are talking about on your secondary filter are not a water sensor, but a fuel pressure sensor. It is part of the emergency override system. It disengages the starter when there is fuel pressure. The MCI's have an emergency override system that you can hold the start button to keep the engine running after the safety shut down system has activated.
I've used egauges.com. They carry most brands. If you have some extra wires running up front it would be easier if you used electric senders. I think it might be some benefit if you installed pyrometers in both exhaust manifolds
I would IR gun the exhaust manifold and see if all your cylinders are firing correctly. Although you would probably be seeing something if that was the culprit.
Rick
Yes. I see nothing at the moment. Exhaust is literally invisible. Is my gear pump dying?
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Also, cliff I double checked my stop cylinder skinner. Seems to be backed off just fine but we are parked for a week in ludington Michigan so I'll play with it more later.
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Since no one has mentioned this. If you are smoking underload or pulling a grade might have FOD damage to your turbine wheel OR compressor wheel. It is rather easy to see the blade tips on the compressor wheel. If the edges are rounded off or rough the ability to generate enough air will be greatly reduced. The hot side turbine wheel is hard to view with the cartridge assy installed in the turbine housing. I do remember you mentioning that you installed a new/used downpipe. If anything got kicked into the turbine housing FOD damage would occur.
Last summer I planned on upgrading my S60 turbocharger as a upgrade. Needless to say, I was shocked to see my compressor wheel chewed up. Someone did not clean the air filter canister prior to installing a new filter. It only take a few grains of sand, plastic or XYZ to wipe out the blades that spinning in excess of 75K RPM.
Do your injectors have screens in the fuel inlet?
Zero, thanks for the discussion. I did check the turbo intake and exhaust side thoroughly and there is absolutely no damage whatsoever to the turbo. No play, spins freely, no oil leakage. I was very careful replacing the downpipe and besides any debris would blow out the exhaust not suck in. Anyway there are no shiny or worn spots no turbo dragging, nothing. Checked very very carefully. Still really feeling like its not getting enough juice. I've always seen a bit of smoke when mashed at full throttle but haven't seen that at all lately. Thinking of installing an electronic fuel pump inline and seeing if that helps. If so, I'm thinking the pump is on the fritz.
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Scott before "just" adding a fuel pump inline follow Clifford's advice to the "T" first!
He gives excellent advise for free. The quickest way to get someone to quit helping is to "not" take their advice. (and then to post that you didn't and still have same problem and still wanting more advice!)
Check fuel pressures, rpm's andsuch as Clifford advised then start shooting in the dark!
(trust me I've followed Clifford's posts for a long time and 99.9999999999999999999999999 % of the time is dead on the problem and the fix before most of us can finish reading the original post!)
;D BK ;D
Yes BK! Definitely will do. Just in a campground in ludington for a week and appreciating the continued discussion. Someone posted instructions on where to buy and how to use the remote tach but I need some instructions on where and how to install a fuel pressure gauge.
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Scott on top of the filter base you will find a plug to install a gauge
good luck
Quote from: luvrbus on May 19, 2012, 08:39:52 PM
Wow, start by checking the rpm with a hand held tach your 6v92 should be 2100 to 2250 no load then check the fuel pressure should be 55 to 70 lbs at full throttle ? does your engine have a fuel modulator sounds like you are not getting full fuel position at the injectors.
You really cannot tell if the engine is at full throttle by checking the linkage on the governor housing,the rpm check is a good place to start
Cliff, is this rpm at full throttle? Floored? So I should tape the pulley aim the tach and let Wifey step on the throttle full on while I time it?
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I think that this is a first, :) "exhaust is literally invisible". Usually it is, " i have white, or blue, or black smoke out the tailpipe" ;D
True story. I've always had a little bit of "feedback" from the exhaust color. But nothing now.
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Still haven't purchased the tach yet for my first tests (watching the pennies at the moment until we know what our income is for the month) but noticed driving down the highway last week that when I'm at full floored throttle, I can clearly hear the motor (exhaust is straight piped at the moment) but when I start to descend a long hill and the coach picks up speed, right exactly at 72 mph the noise of the exhaust goes away literally as if I let off the throttle which or course I didn't. Almost like its governed. Any thoughts? I promise cliff I will get the RPM numbers to you via tach but just throwing out another data point.
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Just a thought - on the photo-tach source. Check the e-place - I just bought one for 13.00 brand new. Accuracy is just as good as the hundred dollar items. .
Nice! HF also has them for $30. Doable. So since I'll be doing this, I have to ask again how do I measure the RPM? Should I have wifey floor the throttle and then go measure the speed while throttle is floored?
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I disconnect the throttle cable linkage and do it all from the rear it should go from idle to governed speed (wide open) in just a second and fall back to idle just as fast if not you need a rack adjustment .
If that checks ok then hook the throttle linkage back up if it takes longer to go up to the top rpms and back down you have a linkage problem (careful around the belt)
good luck
Got it! Thanks cliff. Will post results. :-)
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Block the wheels.Use BIG blocks.
Scott-
I don't remember anyone suggesting this, but a cracked exhaust manifold will put you down on power, and sometimes they are difficult to detect, at least the small cracks. On many DDs the manifold will have a tendency to crack at the frontmost bolt area nearest the fuel pump, secondary filter etc.
Robs the turbo to boost, etc.
This actually happened to me, and I went along that way several weeks before someone heard me backing up and thought he heard that funny noise.
Just FWIW
Mike in GA
Quote from: eagle19952 on May 27, 2012, 10:27:15 AM
Block the wheels.Use BIG blocks.
I suggest the big black chocks designed for big vehicles. About $10 each from a truck parts place.
If you need chocks then go buy them. I am not suggesting extra safety is bad. I would think park brake on and transmission in park and some wood chocks would be plenty. The store bought ones look nice and if you need them for other things spend the money. For this test and by reading your posts you may want to save the money and make your own.
John
I think the fundamental reasons (given it worked before, doesn't work now, and nothing was done to change the rack or the governor settings) for lack of power is lack of air or fuel. Lack of air would result in black smoke, but there is no smoke. Lack of fuel would result in no smoke for a given amount of air, so I would continue to look for what is restricting fuel flow. I would, at this point, be measuring fuel pressure, pulling out and replacing (probably not trying to clean) the screen filters in each injector base, and if that didn't change anything pulling and testing each injector for fuel quantity per stroke. And never ever putting anything other than diesel in it (just my opinion, that and two bucks will get you a cup of coffee...)
72 mph is around 2200 rpm in an MC-X with 3.7 diff and 12R-22.5 tires, so that's what I would expect with a normal 2200 rpm governed speed. It should get there no problem, and go faster if you turn up the governed speed. If it can't make that, then I agree you have a loss of power, fwiw.
Brian
Hello Scott--- After reading Brians post saying your problem is fuel shortage have you considered that your tank pick up tube might be partly plugged with some residue from your bad bio fuel mix that you taked about in a previous post? A while back I suspected I had a pick up tube problem. I removed fuel, tank filler connection and fuel sender. With a light and a long inspection mirror I could follow pick up tube in tank. The tube goes down wall, across floor (16 to 18") up an inch or so and through a hole in the baffle plate. After that I do not know.where it goes. This design makes a low spot for things to settle (thick residue).Your unit and mine are both MCI and close to same year. There is a good chance your tank is same design. You could check this with a temporary pick up tube. Check fuel pressure reading now with guage at secondary filter at 1200 rpm say. Rig up a tempory pick up tube with a piece of fuel hose through tank fill and connected to pump suction line outside tank. Reprime engine and start. Check fuel pressure at secondary filter again at SAME rpm as before. If your pressure reading is higher than before or if throttle response is better, you might have a partly plugged pick up tube. Take it for a drive and see if is any better. Wire up hose so can't come out. Stuff rag around hose. wire rag so can't go in tank.
Larry B
Brian, thanks for the info on governed speed. Will be checking RPM this week and posting results.
Larry, I have already blown the lines of the entire fuel system out with 120 psi of compressed air backward from filters to tank (filters removed). Didnt make any difference. I think I'm getting to governed speed but it's slow getting there. Injector screens could be an issue I suppose. But my first checks will be air stop skinner, RPM, and throttle assembly. From there I start thinking rack readjustment Or injector screens. Where do I plumb in a fuel pressure gauge?
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Mike, a cracked
Manifold is something I would see soot buildup from right? Should see soot all around the leak? I do have a small exhaust leak on my elbow joint that is likely 1/16 of an inch. Tiny but it blows out enough to soot the area. But this leak has always been there without this much power loss in the past. Anyway you guys have given me some excellent advice and things I try so I'll get busy and post the results. Thank you so
Much for the help
On this guys.
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You can easily screw a press. gauge into a spare port on top of the secondary fuel filter. That will be under fuel press. downstream of the pump.
JC
You mean the port with a brass fitting and you unscrew a brass cap to get to the fitting? I use that port to prime. What was it for? And did you say it will measure fuel pressure between the filters and the motor?
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Yes and yes. That will tell you the fuel pressure. Make sure you put it on the secondary filter, between the pump and the heads. Putting it on the primary filter would show you a vacuum.
JC
Quote from: lostagain on May 28, 2012, 08:03:26 AM
Yes and yes. That will tell you the fuel pressure. Make sure you put it on the secondary filter, between the pump and the heads. Putting it on the primary filter would show you a vacuum.
JC
Oh dear. That would definitely confuse me.
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Scott, I would highly doubt a cracked exhaust. Low boost (caused by a cracked exhaust) would show black smoke under throttle. Since you say you have no smoke, you are dealing with a lack of fuel, not lack of air. Lack of air will cause excessive smoke, period. You need to figure out why you are not getting full fuel. Start with Cliff's suggestions. These mechanical engines are pretty simple...air plus fuel equals bang bang.
My sentiments exactly! Love the "air and fuel and bang bang". Classic :-D
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Here's a video of my startup and throttle push. Seems to go up to RPM and drop fine....I think. Notice the rough running at the very beginning followed by a brief "burp" and then runs smooth and no smoke? Weird. Never used to do that. :-\
http://www.youtube.com/embed/zzRnI25nYmw (http://www.youtube.com/embed/zzRnI25nYmw)
Here's a better video of the full throttle push...not sure if it's even helpful bus this was wide open. I guess there is a bit of a "roll up to wide open throttle" delay...but not sure what's normal and what isn't.
http://youtu.be/36BXdQkLeIQ (http://youtu.be/36BXdQkLeIQ)
Doesn't sound like it going up to 2200 rpm to me is that a NJT bus ?
Scott,
You need to put the first video back up if possible. Allow someone with more experience than me to listen. I think it was only running on 4 or 5 cylinders for the first few seconds. That's why it was blue smoking so much, that burp you described was the other cylinders kicking in. I've heard this refereed to as "cold ring stick". I don't think it's your problem, you just might want to know. I had this on my 6V92, it was caused by excess carbon build in the ring lands because I was dumping so much fuel in off the bottom and my problem was compounded by a tall first gear.
Ken
It was only running on 5 cylinders Ken it should have never died when it fired the 1st time, not riding a dead horse here but his fuel mixing you can make bet he has carbon build up
good luck
Kinda what I thought but I hate to say anything, because I know some people seem to get away with it. I will suggest that anyone running or considering running alternate fuels should disassemble some injector pumps and nozzles (maybe a local pump shop might some scrap ones). Try to measure the tolerances with standard micrometer, it's amazing they work with perfect fuel. It will certainly give you an ideal why water and trash is not good. I hate spending money on diesel, I guess I'll keep spending.
Ken
It didn't die. It didn't start cause I let off the starter too soon. It normally lights off quick but we are having cold nights here in Michigan. Going to be 46 tonight. But it has been lighting off at the touch of a button no sweat. Also the 5 cylinder then 6 deal literally started a few days ago. What do you think cliff? Oh yes the first video is still up there. First link
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Ok heres what i think,first you need to listen to whoever said put a tach and pressure gauge on it,and then do it.
I have tuned a lot of Detroits and I am here to tell you you can not build full throttle and discern any thing by pumping the throttle in 2-3 second bursts.
Why don't you hold WTO for 8-20 seconds... jeez the motor was made to run full throttle for days. You'd never set no load gov.speed in that short of time,the engine isn't going to self destruct if it has nothing wrong...and if it does ,well better off it does it where it sits.
we used to shut down our 200kw gens for 30 or 40 minutes every 250 hrs to change oil and had kits put in every 4 years.....
IMO you need to run the piss out of it,AFTER you run a tach on it.
Get you a stobe and a piece of tape.
you won't figure out squat till you do...
Ps 46* is not cold...I have had Detroits start as good as that at 35 below.
Compresssion and diesel mix REAL well. even in sub zero temps.
Even with 0w30 syn....but thats a whole different can of worms...depends who wants the motors to start....LOL.
Scott, you are not getting to full throttle by doing your short little spurts. Hold that puppy wide open till it won't go no faster, then take your rpm reading.
Eagle and thomas:
Ok I'll do it tomorrow. Scary doing it when standing right there and arm between a spinning belt. Throttle linkage appears to be moving freely and fine so I'm going to have Heather mash the throttle...I'm a bit skittish. I kind of like my arm :-/
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Scott wrote:
"Scary doing it when standing right there and arm between a spinning belt."
Scott,
Since your bus still has the air operated belt tensioner, this is easy to avoid. You should be able to turn the valve controlling the tension cylinder off and the resulting tension release will allow you slip the belt off the crank pulley and stow it overhead while you perform the rpm tests. A few minutes of running the engine without the radiator fans won't be a problem.
If you're not comfortable doing that, another trick is to use a broom stick to reach in and push the throttle lever.
Bob
I hope that this entire thread serves a great purpose for folks to pause and research alternate fuels greatly before they start running them because it sure looks like the fuel/waste oil mix may have contributed to this situation. I don't like big government/big oil conglomerations and ridiculously high fuel prices as much as the next guy but getting off the grid has it's inherent issues as well. I don't think it's as simple as folks think it is and i think that some folks dislike for being reliant on anyone for anything sometimes clouds the truth of the matter. We have all heard the "I've driven 200,000 miles on nothing but linseed oil" testimonies and they should be heard but Scott's situation should be added to the mix in future WVO, Biodiesel, WMO discussions. Which we all know will continue until the end of time. ;D ;D
Thanks for keeping us informed Scott.
Rick
Well heres the deal you NEED to tach the WOT at both places....at the gov linkage AND the pedal. This will confirm linkage and gov problems.
Just sayin.
All I do is put a brick on the throttle pedal (metaphorically speaking, usually I wedge it down with a stick) and check for full lever movement at the governor. Been setting throttle cables like that for 30 years on race cars, I guess it will work with a bus... ;D
As noted, if the belt worries you just take it off, no harm done. Also note Cliffords advice to disconnect the throttle cable from the engine speed lever and lay it aside - you could get it to hang open or otherwise not return cleanly if you leave it connected.
It's odd that we (me definitely included!) just hate to pull max no-load on the engine just standing there holding it wide open when we know they run like that all day long just fine. The first time I dyno'd a race engine and they did a full power full RPM run I literally ducked under the wall, it scared the life out of me! Operator reminded me that I was 10 feet away behind 1/4" lexan and 10" concrete, and that all the other times I'd done full power, full throttle runs with that same engine I was lying on my back with the cylinder head 6" behind my head with 1/8" of fiberglass between it and me, and I was doing 120 mph on a race course...
Brian
Interesting experience Brian...those cars are loud as all get out too. Ok, here's my latest video with RPM Tach check. Please note the following:
Idle: 500 RPM + or -
1st WOT CHECK: 2003 RPM
2nd WOT CHECK: SAME
3rd CHECK PUT MY WEIGHT INTO THE BROOM HANDLE AND REALLY PUSHED LEVER: 2253 RPM
These tests were done with the throttle pedal linkage disconnected. I think the lever itself wasn't pushing in all the way. It took some serious umph to get it to almost "click" into full throttle. Something I doubt is happening just from mashing the fuel pedal in the drivers' seat.
Any thoughts?
Notice she started up without the burp (5 cylinder burp). Got down to 44 last night. Cold start. Emptied the slobber tube before starting her. Not sure it made a difference but there was a cup or two of oil in there. Please be sure to watch the second video. You'll see me pushing on the stick and getting it to really reach WOT and you'll see my 2250 RPM reading. SEE VIDEOS BELOW:
http://youtu.be/1dWMNFo5Z34 (http://youtu.be/1dWMNFo5Z34)
http://youtu.be/FuDuFCB7oHk (http://youtu.be/FuDuFCB7oHk)
You should be able to get it to full fuel easily, with no need for any unique pressure. The pressure of one thumb pushing simply against the pull of the return spring, perhaps 10 lbs of pressure. I wonder if one injector is hanging up, not letting the rack go to full fuel? 2250 is about perfect for a typical no-load max speed, btw. 2000 is definitely not. The issue between the two is rack adjustment, probably, not power - it takes no power to get the no-load speed.
The irritating thing is I know exactly how to diagnose this by disconnecting the racks from the governor and checking each injector, and how to set them again after - but that's "running the racK" and I don't think I can explain it in an email...
Brian
Another data point is that my mileage is 7.4 mpg consistently. That's too good for my 31,500 pound coach the way I drive it. Brian, when I'm in port Huron again I'll have to get you to cross the border and pay you to run the rack for me :-)
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I think you may have two problems, but first let me say that I think that your "improved" reading was also relatived to the fact the the engine was "warmer" but not at full operating temperature.
One problem is a dirty injector or injectors, and in all likely hood a problem with your linkage/throttle cable.could be inj plunger height too...o
To properly tune a Detroit it's gotta be HOT,to properly check it's rpm...it's gotta be HOT.to run the rack...valves...HOT.
I think you need to chk your RPM at the crank too.
Chking a rack adj is alot easier than adjusting same....start here.
turn pages at the top....
http://miscpartsmanuals3.tpub.com/TM-9-2815-224-34-P/TM-9-2815-224-34-P0486.htm (http://miscpartsmanuals3.tpub.com/TM-9-2815-224-34-P/TM-9-2815-224-34-P0486.htm)
ps how many pieces of tape are on your pulley ?
Just one piece of tape :-) I'm going to check fuel pressure and if that's fine I'm going to have the rack run
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