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Author Topic: Engine start question  (Read 3489 times)
NJT 5573
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« Reply #15 on: May 14, 2007, 08:22:39 PM »

Chaz. Buy some Power Service fuel additive and it will clean the injectors up. If it just started this I think you have some poor quality fuel. I wonder if the rack is out of adjustment. Low fuel pressure will also make them start hard. Does it have the right restrictor orfice in the fuel return? If it were rings it would use a lot of oil. If it is a valve it would miss all the time and take more than one to make it hard to start. If the fuel pump quits on your trip you will have the answer. If you can keep oil in it and the oil isn't contaminated with fuel, either is cheap and it will probably run another 100,000 miles. If it stays 80 degrees around the clock for days I bet it will start. If its 50 degrees at night, the engine will still be 50 at noon. How does it start when its shutdown hot and restarted? My Cummins start hard with stock rail pressure when cold. They start instantly in cold weather if I bump the pumps up. You may also have retarded timing and nothing will help alot except either. If it runs good when it warms up just slam your hand in the door and drive it. (With Power Service).
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« Reply #16 on: May 14, 2007, 08:48:37 PM »

TO MY untraned ear, my 6v71 sounds great. she starts up quickly 1 or 2 revs, and smokes very little.
of course she leaks oil like shes alergic to it.. and is very responsive to the throttle.. would you say off hand its a very good engine ? i have no idea what the milage is on the engine..

sorry no caps here. i have trouble typeing with a cat rubbung his face all over mine and holding him with one arm... he seems not to notice we had his snardlys removerd 2 weeks ago...  Huh


 Grin


Paul...
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« Reply #17 on: May 14, 2007, 11:20:15 PM »

If you're low on compression from bad liner kits, fuel savings will definitely help you pay for the replacements. These Detroits will seem to drive okay when they're worn out, but they will actually be low on power output. A good fuel mileage check will settle the question.

HTH.

Tom Caffrey
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Tom Caffrey PD4106-2576
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Barn Owl
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« Reply #18 on: May 15, 2007, 04:26:52 AM »

I have the same problems Chaz has. Unless I plug it in it will almost always need either. Engine warm it will start in Ĺ revolution, engine cold on a hot day, still a lot of cranking and a lot of white smoke till it fires off. You guys have thrown out ideas that I havenít thought of. Mine does not seem to burn much oil. I had one mechanic say that you can have bad compression rings and good oil rings. My bus sat for years with the owner starting it once in a while. He used either all of the time so he might have damaged some of the compression rings. I have had several mechanics say just run it and live with it like it is. The fuel that was in it was very old so I donít know if it gummed up the injectors over time. I will try the additive.

Question: Can injectors be removed without messing up the rack timing?
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« Reply #19 on: May 15, 2007, 05:11:48 AM »

WHOOOOOAAAAAAA!!!!!!!!!!!!!!!!!!!!!!  THANKS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! GREAT INFO!!!!!!!
  That was a helpful barrage of info!! I feel MUCH more enlightened!
   Here's replys from what you guys wrote:
 
  My battery connections are all good. I made sure of that. I actually went to some great lenghts in making them.
   There is some black smoke before it fires. But again, I'm not overly familiar with diesels so I'm not sure if it's bad or not.
  I did put an additive in it and will do so again. I think it really helped. I also put some tranny fluid in it as I was told it, too, is a good injector cleaner. I'm pretty sure, between the two, it has helped. I also replaced the air filter as it was REEEEEEEEEALLY in need of it.
  The rack is adjusted.
  I'm not sure if it "uses" allot of oil, but I know she's some relation to my Harley, as it loves to "mark it's spot"!!!!!
   As far as fuel pressure and all that................... I dunno.
   I don't *think* I have a miss. (I definitely don't have a Mrs.)  Grin
   The oils is good. I had it tested and he was real happy with it. (Steve Capito. One of our members did it.)
   After it's been run and still warm, she hits right off the bat.
   (I know the ol' finger in the door trick, but that's how I drive anyway!)  Wink
   Fuel savings would be a good thing. I took it to St.Louis and back (600 miles or so) and I got about 6.2 mpg. That doesn't make me all that happy. I know I have heard that allot of you guys get WAAAAAAY better mileage, but a trucker cousin of mine thinks that is about right. I'd LOVE for him to be wrong!!!!!!!!!!!!!!  Wink
  As far as power......... again, I have never driven any other diesel. It doesn't seem to have the power that I think it should, but I don't know. I do know the additive and air filter helped a bunch!!!
  Mine sounds a bit like Barn Owls. It did sit for QUITE A WHILE before I bought it!!! And when he started it, he didn't seem shy about the ether.

  Ok, that is about everything in answer to your questions and comments. (I TOTALLY appreciate it!!!!!!!!!!!!!!!!!!!!!!!!!!!)  Maybe that will help with you guys diagnosis.
  Thanx a million again!!!!!!!! It helps allot!!
       Chaz
   
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« Reply #20 on: May 16, 2007, 08:03:28 PM »

You have described exactly what my 671 does when it is cold. The white smoke shows the fuel is there but the engine is not spinning fast enough. When mine is cold ether makes up for the slow spinning and it starts right up.

Since yours does this in warm weather, as has already been said, I think it is just not spinning fast enough.
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PD4107-152
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« Reply #21 on: May 17, 2007, 04:21:39 AM »

I used ether when I first got my coach, even it warm weather. Then found my 8D's were bad, also the motor turned too slow. Went to the group 31's, big differance. Turned over much faster, and no ether. It now starts on the first revolution in warm weather, block heater used when it's cold, same result.

Paul
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JackConrad
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« Reply #22 on: May 17, 2007, 05:04:51 AM »

You have described exactly what my 671 does when it is cold. The white smoke shows the fuel is there but the engine is not spinning fast enough. When mine is cold ether makes up for the slow spinning and it starts right up.

Since yours does this in warm weather, as has already been said, I think it is just not spinning fast enough.

Remember, the colder the engine, the faster (or longer) it has to crank to generate enough heat to ignite the fuel.  Jack
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« Reply #23 on: May 17, 2007, 05:47:06 AM »

I guess I really need to find somebody or some way to tell if I am spinning fast enough. I may have to wait till June 14th for the Cincy bus rally. (dang)
  But thanx for all the info guys!!!

  "get you motor runnin..... head out on the highway..... looking for adventure...."  opps, sorry.
            Chaz
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« Reply #24 on: May 17, 2007, 06:55:12 AM »

Chaz....
To find out how fast your engine is spinning you may want to get a trgger controlled phototach.
It works by applying a piece of reflective tape to the vibration dampner and shooting it with a laser while spinning the engine over.
I got mine from eBay for less than $30 and it does a very good job.

IHTH,
Dallas

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niles500
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« Reply #25 on: May 17, 2007, 10:12:11 AM »

As said above - if your using 8D's the Group 31's should deliver more cranking amps = more power to the starter = faster spin = more heat and better compression = happy camper - HTH
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Chaz
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« Reply #26 on: May 17, 2007, 10:18:48 AM »

Dang, and I just bought mine about 6 months ago. 8d's that is.
  Sux being a rookie!!  Undecided
 
  BTW, I looked at a photo tach on ebay, but I think I would rather just get a professionals opinion. Out of curiousity, if the starter needs rebuilding, what am I "probably" going to be looking at??

    "get your............" opps, already did that,     Wink
          Chaz
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« Reply #27 on: May 17, 2007, 10:50:43 AM »

As said above - if your using 8D's the Group 31's should deliver more cranking amps = more power to the starter = faster spin = more heat and better compression = happy camper - HTH

How do 31's have more CCA's than 8D's?  Or do the 8D's just have a longer reserve?  Back in the winter, my 8V71 (with 8D's) would start with either one or two pushes (for a second or so at a time) of the starter button.  I tried starting it a couple of mornings when it was in the low 30's (cooler than that at night) and it fired right up.  It does smoke a lot less and for a shorter period of time when that 1,000 watt block heater has been on for a few hours, though.  My 8D's are only about a year old, but I wanted to get them out of the original battery compartment - the generator's gas tank fits there perfectly.  I didn't have any house batteries, so I ended up using my 8D's for that purpose and bought two 31's for starting.  Even if 31's won't crank for as long, all I have to do is flip the 'combiner' relay's switch and the house and start batteries are all in parallel for an instant jump start.

David
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NJT 5573
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« Reply #28 on: May 17, 2007, 09:01:21 PM »

Chaz, A quality rebuilt exchange is around $200. Sometimes new truck dealers sell new MT 40 models for under $250, outright, call around. If you have an older model, upgrade. The only thing that will make one run slow is 1 set of brushes being bad. These brushes are not to hard to change. You may find 1 brush with a broken spring or a brush still cocked for assembly and not running on the armature. If you just need a couple brushes I will send you a couple "good used" in the mail for free. If you exchange your starter, take it apart first and keep the parts that a rebuilder will throw away anyway, for future use. I'm presuming you have a R engine, so make them quote their price for a generic MT40 starter. Its not hard to clock the starter to the engine, but do this before you turn in your core or you'll be lost.
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Gold is the money of Kings, Silver is the money of Gentlemen, Barter is the money of Peasants, Debt is the money of Slaves.

$1M in $1000 bills = 8 inches high.
$1B in $1000 bills = 800 feet high.
$1T in $1000 bills = 142 miles high
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« Reply #29 on: May 18, 2007, 04:55:42 AM »

I think Chaz has a GM.  If this is correct make sure the starter you buy is for a left hand rotation engine.  Jack
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