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Author Topic: Smoking 8V92TA DDEC II  (Read 5644 times)
stevet903
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« Reply #45 on: August 08, 2012, 06:13:13 AM »

The boost pressure sensor has a hose on it that connects to the top of the blower to get the pressure reading from the engine.  Maybe this hose is loose or cracked, or the hose fitting on boost sensor is cracked, causing the sensor to read the boost lower than it really is, and that causes the ECM to overfuel the engine causing the smoking?  It's close enough to the ECM that the hose could have been hit and damaged when they R&Red the ECM...

http://miscpartsmanuals2.tpub.com/TM-9-2320-360-20-2/TM-9-2320-360-20-20306.htm

Easy and cheap to check.....

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Sam 4106
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« Reply #46 on: August 08, 2012, 06:49:39 AM »

Thanks, Steve, I saw the boost pressure sensor this morning when I was looking for a place to hook up a boost pressure gauge. Could I put a tee in the line to the boost pressure sensor for a gauge? I have an appointment at the local DD shop but I think I am going to cancel it and do more on my own before paying $140/hr at a shop. If the boost pressure sensor isn't seeing enough boost why would the ECM be over fueling the engine? Or is it that the boost pressure sensor is showing boost that isn't there? How expensive is a boost pressure sensor and would it be practical to just replace it? I don't like throwing parts at a problem to see if that fixes it, but that may be an option in this case. If I have an injector problem, as some suspect, I will have to take the bus to a shop because I don't have the tools, nor am I physically able to do the work. I will be better off taking the bus to a shop if I can tell them specifically what is wrong. Please keep the ideas coming.

Thanks, Sam
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1976 MCI-8TA with 8V92 DDEC II and Allison HT740
ojgetaway32
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« Reply #47 on: August 08, 2012, 07:30:06 AM »

Sam:

I had some trouble with a DT466 in an IH truck.  I knew it was fuel problem or an air problem or a sensor problem.  After much time and effort spent, I finally got an infared gun and shot each exhaust port after a long pull up a hill.  I just pulled onto the shoulder as soon as I could, put on the 4 ways and rolled the hood forward.  1&6 should be close to each other in temp, 2&5 should be close and 3&4 should be close.  My number 6 was way cooler than any others.  I replaced the injector and then each pair was close to each other.  I actually replaced 1 and 6. 

Please be safe on the roadside...the way your posts are written, you read like a pretty smart guy, I am sure you will find a solution.

Josh
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Josh Miller, Attorney, hockey player, son, brother, friend and busnut...
1983 MCI MC9 8V71 and a 5 Speed
Wheeling, WV
luvrbus
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« Reply #48 on: August 08, 2012, 07:35:28 AM »

Sam, there are 2 plugs in the air horn (right under the turbo) to hook up a boost gauge and fwiw I have never heard anything but good about Curt not from this board but from people that have used him  

A DDEC can not read a over fueling injector it fuels according to the boost I have seen the 60 series smoking like a freight train also with a bad injector with 30 lbs of boost like Ken stated a bad sensor should flash a code


good luck
« Last Edit: August 08, 2012, 07:43:04 AM by luvrbus » Logged

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hargreaves
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« Reply #49 on: August 08, 2012, 09:27:29 AM »

Sam, we used to troubleshoot low power DDEC engines by fooling the ECM by supplying air pressure to the turbo boost sensor. It fools the ECM into thinking it has lots of turbo boost and it will deliver more fuel, if the engine has lots of power we change the boost sensor. Lots of smoke on acceleration but it clears up as rpm picks up .

In your case it sounds like you are getting smoke all the time which would be air filter,  turbo or injectors.In the case of air filter or turbo you would experience low power. To cut out one cyl. without a MPSI reader is a pain in the @$#. you have to remove the rocker cover and disconnect the wires to that injector and then intall the cover and road test.    Cheers Gerry
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now as of Feb 2012 series 50 B400  . Sunshine Coast British Columbia
Sam 4106
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« Reply #50 on: August 08, 2012, 10:34:29 AM »

Thanks, Rick for recommending Curt. I have an appointment with him at Central Truck on Monday. I spoke with him this morning and he is able and willing to work on the engine. Since his shop is about 175 miles from me he said I could stay in the bus if he has to order injector(s) so that will save me having to drive home and then back to pick up the bus. I think I will be in good hands at his shop.
I tried doing a little investigating this morning, but I injured both arms reaching into the turbo area so it just isn't feasible for me to try any further. I bleed very easily since my platelet count is so low, but the drug that causes low platelets is keeping me alive so I will continue taking it.
Thanks for all the suggestions and advise. The bus has good power and there were no codes stored when checked at Fargo. It just smokes a lot and is using more fuel than it used to. I will update after my trip to see Curt.
Thanks everyone, this group is great. Sam
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1976 MCI-8TA with 8V92 DDEC II and Allison HT740
Don Fairchild
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« Reply #51 on: August 08, 2012, 01:14:12 PM »

Sam, I don't think it will be a boost sensor as usually when they go out they won't let the ecm fuel the engine much over 1200rpm. (it will go into limb home mode. Always an exception to everything). I will stay with a bad injector or two. BK. has offered a rebuilt DDEC II ECM if you need it at a reduced price if it turns out that is still the problem.

I will be out around your place sometime between the 10th and the 17th of Sept. That's as close as I can get right now. I will let you know as this gets closer and if you are around maybe we can get together for a glass of icetea.

Keep us posted on what Curt find to be the problem.

Thanks

Don
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Sam 4106
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« Reply #52 on: August 08, 2012, 05:51:33 PM »

Hi Don,

The ECM has a 6 month warranty from Interstate DD but since they put another ECM on at Fargo and that didn't cure the smoke problem I think that the ECM is OK. Thanks for the offer BK. Very appreciated. From talking to Curt this morning I am quite confident that he will find and fix the problem, whatever it turns out to be.
We will be gone from Sept. 6 thru 16. I certainly would enjoy meeting you if you are in the area after the 16th.
Thanks, Sam
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1976 MCI-8TA with 8V92 DDEC II and Allison HT740
RickB
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« Reply #53 on: August 09, 2012, 09:35:08 AM »

Sam,
Curt is an exceptional mechanic and an honest man. All the guys working there are top notch. Sometimes we go to big shops and they put the just-graduated hungover guy who started two weeks ago and didn't know what an impact wrench is in charge of mounting our tires. That does not happen at Central Truck, these guys are all really experienced and capable mechanics because Curt understands what's at stake with heavy equipment. He grew up on a farm working on tractors and I have actually watched him set liners, test injectors and his attention to detail is just great.

You are in good hands and I would be more than happy to come get you and spend the day with you if you don't feel like sitting in the bus all day. We are about 45 minutes away.

Good Luck Sam

RB
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I will drive my Detroit hard... I will drive my Detroit hard.
Sam 4106
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« Reply #54 on: August 09, 2012, 12:27:44 PM »

Hi Rick,

Curt asked me to be at his shop at 8:30 Monday morning so we will be coming up Sunday. He said we  could stay in the bus at the shop so that is the plan. We may have to stay over if he has to order injector(s) but he said he has some 6V92 engines that he can rob injectors from if they are the same. I gave him the serial and model numbers from my engine and maybe he already used that information to order injectors. I like to stay close to the bus while at the shop in the event there are questions or decisions that need to be made. If we have to stay over it would be nice to get together. I have your number and will give you a call if that can happen. We also have other bus friends in the area so if we have the chance we will visit them. One lady recently lost her husband and I'm sure she would enjoy visitors. Charlet may do some shopping on Monday since we will bring the car. If we can get together you will not have to pick us up.

On a side note, do you, or anyone else, reading this post think I will be doing further damage to the engine by driving it 175 miles to the shop?

Thanks again for recommending Curt, Sam.
« Last Edit: August 09, 2012, 12:32:09 PM by Sam 4106 » Logged

1976 MCI-8TA with 8V92 DDEC II and Allison HT740
RickB
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« Reply #55 on: August 09, 2012, 01:17:50 PM »

What did Curt say about driving it?

Rick
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I will drive my Detroit hard... I will drive my Detroit hard.
Sam 4106
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« Reply #56 on: August 09, 2012, 02:39:53 PM »

Hi Rick,

The topic didn't come up in our short conversation and I didn't think to ask him. I didn't want to bother him with another phone call because I had decided to drive it to his shop anyway. Of course, Charlet wants to know, so I asked here to satisfy her. It didn't seem to bother the service writer or mechanic at Fargo because they thought the black smoke was normal. My concern then and now was/is could all that extra fuel cause me to score a cylinder or put an injector tip through a piston. It didn't happen in the 475 mile trip home so maybe that is not a valid concern. I guess I'll know when/if I get to the shop Monday.

Wish us luck. Sam
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1976 MCI-8TA with 8V92 DDEC II and Allison HT740
Sam 4106
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« Reply #57 on: August 13, 2012, 08:25:43 PM »

We went to Central Truck today to have Curt diagnose our smoking problem. He cut out the cylinders one at a time and didn't find any bad injectors. He did find a burned out exhaust manifold gasket so he replaced the gaskets for both manifolds. So, you guys that said to get a turbo boost gauge led me in the right direction. He removed a plug in the air horn and installed a fitting and 1/8" plastic line to the area of the rear electrical panel. I will complete the installation of the rest of the line and dash gauge when I get home. The turbo checked good. He also found an oil line to the air compressor leaking along with seeping oil from the water pump weep hole. They made a new oil line and rebuilt the water pump. Also adjusted the injectors, valves, and jake brakes. Had to replace one jake solenoid and put the wire back onto another. Since the engine was drained I elected to put in new antifreeze.

There is still a little smoke with pedal to the floor acceleration but Curt thought that might be because the Reconditioned ECM might be programed without the throttle delay that the old ECM had. We will see if my fuel milage returns to the level it was at before the ECM change.

We thought we had all the air bled out but we only made it a few miles before the low coolant sensor shut the engine down. Fortunately a man from a house near where we were on the side of the road came to our rescue. He used his Bobcat to pull the bus back to a side road to get us out of the traffic lane. That leveled the bus so I could get more antifreeze into the surge tank. That incident delayed our trip home long enough for the traffic on I35 to decrease enough so we had easy driving through the Twin Cities. We are spending the night at a casino near Red Wing, MN and will complete our trip home tomorrow baring any further problems.

Overall I would rate Central Truck A1. Curt was very diligent about checking things and let me watch and help with the little I could do. I learned a lot by watching and asking questions. Curt is a very pleasant man to be around and so were his helpers. If you need work done on your Detroit Diesel Central Truck is a good place to go. His rate is currently $80/hr, which is very fair as shop rates go in this area. I know I will return there as the need arises. Thank you RickB for recommending Curt, and thanks to all of you who responded to this thread.

Sorry for the long post, but I thought you would like to know the outcome from my trip to the shop. Thanks, Sam

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1976 MCI-8TA with 8V92 DDEC II and Allison HT740
RickB
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« Reply #58 on: August 14, 2012, 06:52:51 AM »

Sam,

All good news. Still kind of puzzled as to what may have "fixed" your heavy smoking... For what it's worth, I think every DD smokes a bit at full throttle. I know mine does. Did Curt think that the valves or injectors were way out of adjustment and that adjusting them correctly was part of why it quit smoking so much?

Curt's a good man and I stay in touch with him enough to know that there are occasional lean times they go through. I'm always hoping that he doesn't ever experience enough lean times to go out of business. That would be a great loss indeed.

Sounds like you're back on track and that's a good thing my friend,

Rick
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lostagain
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« Reply #59 on: August 14, 2012, 07:03:26 AM »

Sounds good. Things are looking up!

With regard to routing a line to the front for the boost gauge, I am doing the same thing in my 5C. Finding a way over the rear axle is not easy. I tried going through the tunnel with no success. I found an unused copper pipe that used to carry refrigerant for the old air conditioning. Today I will push an air line through it. I cut that copper pipe about half way into the front baggage bay so I can exit it with the air line. From there, I will go to the driver's side and up through the floor, then along the heater lines behind the couch, then through the electrical compartment to the left of the driver and under the dash. I am thinking of using hydraulic oil line from the air horn to the engine bulkhead, then plastic. I would be worried about engine heat on the plastic line.

I did that in my old Courier 96, and it works very well.

Good luck with it.

JC
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JC
Invermere, BC
1977 MC5C, 6V92/HT740
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