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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: gear jammer on September 09, 2021, 10:54:27 AM

Title: 6v92 low on power
Post by: gear jammer on September 09, 2021, 10:54:27 AM
Just got back from a 7000 mile excursion.  6v92 ddec 2 ran great. Used 1gallon of oil total.  Has 80k miles total. In the last leg of the trip, 250 miles. It Was running good before this.  Didn't notice it  on the highway but after I stopped in Tucson for lunch. It was having a hard time getting going. Have a scan gauge and the boost is around 17-18,prior to this I have seen 28, usually you can feel the turbo kick in and pull before it shifts in 1st gear.  it has always pushed some black smoke on take off. Now it's worse. This all being said I said it ran great before. It did to what I'm used to. But I always felt it could take off better from a stop.   I have changed all fuel filters air filter. Checked fuel pressure at 75 against the governor no load.  And no smoke  no load. I pulled the intake tube and it he was turbo spins free, bearings feel okay.  Hope someone can help. This all happened over  the course of 250 miles so seems like something happened.
Title: Re: 6v92 low on power
Post by: luvrbus on September 09, 2021, 11:00:05 AM
There are 2 -1/4 inch dia rubber hoses that attach to the turbo boost sensor one of those could have cracked ,broken or fell off check those as you aware the DDEC will only allow enough fuel as the air ratio dictates smart little joker isn't it     
Title: Re: 6v92 low on power
Post by: gear jammer on September 09, 2021, 12:52:42 PM
Thanks for the reply
Where is the boost sensor.
Thanks steve
Title: Re: 6v92 low on power
Post by: luvrbus on September 09, 2021, 01:20:55 PM
Quote from: gear jammer on September 09, 2021, 12:52:42 PM
Thanks for the reply
Where is the boost sensor.
Thanks steve

Should be mounted on the end of the blower with a bracket 
Title: Re: 6v92 low on power
Post by: gear jammer on September 09, 2021, 03:00:51 PM
Okay I found it. The line looks okay.  Without taking it off it's hard to tell. By the time I get it off I'm sure it will crack. Looks like special tubing?  How about the blower bypass valve could that cause a problem. Or the air box drain check valves?
Steve
Title: Re: 6v92 low on power
Post by: luvrbus on September 09, 2021, 03:37:02 PM
Quote from: gear jammer on September 09, 2021, 03:00:51 PM
Okay I found it. The line looks okay.  Without taking it off it's hard to tell. By the time I get it off I'm sure it will crack. Looks like special tubing?  How about the blower bypass valve could that cause a problem. Or the air box drain check valves?
Steve

The bypass has a hose too (silicone ) it opens when the turbo reaches more psi than the blower then the blower free wheels sorta of ,1 bolt and you can remove it clean it and try it,it is probably going to the boost sensor the connection could be corroded and not sending info to ECM.something else you need to check is be sure the fuse going to each cylinder bank hasn't blown and you are not running on 1 bank   
Title: Re: 6v92 low on power
Post by: gear jammer on September 09, 2021, 03:40:14 PM
I'll check and clean both.  Replace the  hoses. Anybody know the the part number for a boost sensor
Only going to do this once... I hope
Steve
Title: Re: 6v92 low on power
Post by: gear jammer on September 09, 2021, 04:04:06 PM
Correct me if I'm wrong. On the blower bypass valve, vacuum should pull the plunger up?
I have it out and cleaned it not sure how it works.
Steve
Title: Re: 6v92 low on power
Post by: gear jammer on September 09, 2021, 05:15:13 PM
Huh, where would I find the fuse for each cylinder bank?
Steve
Title: Re: 6v92 low on power
Post by: luvrbus on September 09, 2021, 05:15:52 PM
Quote from: gear jammer on September 09, 2021, 04:04:06 PM
Correct me if I'm wrong. On the blower bypass valve, vacuum should pull the plunger up?
I have it out and cleaned it not sure how it works.
Steve

There is no vacuum on a Detroit air pressure opens the by pass on the blower around 5 or 6 lbs so the blower and turbo are about equal on pressure ,if the bypass slides freely it is good 
Title: Re: 6v92 low on power
Post by: luvrbus on September 09, 2021, 05:22:56 PM
Quote from: gear jammer on September 09, 2021, 05:15:13 PM
Huh, where would I find the fuse for each cylinder bank?
Steve

What bus do you have ? you can check for 1 side not firing with IR thermometer or by hand it has a fuse some place for each bank
Title: Re: 6v92 low on power
Post by: gear jammer on September 09, 2021, 05:43:35 PM
Okay bypass is free.  I'll check to see if both banks are hot,  no corrosion at boost sensor.  If the sensor was bad wouldn't it throw a code? It's a gillig bus chassis, 1994 country coach
Title: Re: 6v92 low on power
Post by: luvrbus on September 09, 2021, 06:16:03 PM
Quote from: gear jammer on September 09, 2021, 05:43:35 PM
Okay bypass is free.  I'll check to see if both banks are hot,  no corrosion at boost sensor.  If the sensor was bad wouldn't it throw a code? It's a gillig bus chassis, 1994 country coach

Not if the hose is broken lol another Country Coach owner I own a Magna 630 with the ISX 15 Cummins
Title: Re: 6v92 low on power
Post by: gear jammer on September 09, 2021, 07:50:16 PM
Magna, beautiful coach, mines a concept. 36 foot. Love the thing.
Both banks are firing.
Title: Re: 6v92 low on power
Post by: luvrbus on September 09, 2021, 08:10:46 PM
Quote from: gear jammer on September 09, 2021, 07:50:16 PM
Magna, beautiful coach, mines a concept. 36 foot. Love the thing.
Both banks are firing.

Ok behind  the pulley that says 6v92 check and clean the connector to the timing sensor those are bad about breaking.I love my Magna too lol even if the guys here call it a sticks and stable job I am not giving it up  8)
Title: Re: 6v92 low on power
Post by: gear jammer on September 09, 2021, 08:34:32 PM
 Yeah I know the feeling. I've had a 4104. A flx vl100 fully restored. And I still have my 1960 starliner. But this concept I had to have.  Beautiful workmanship.  Go it to get a t back to full speed though. 
Title: Re: 6v92 low on power
Post by: gear jammer on September 09, 2021, 08:53:57 PM
Ok I pulled codes using the ddec switch and using the cel.
22
43
44
46
58
Keep in mind I've never seen a cel since I've owned it
Do I have to pull the pulley to check timing sensor?
Title: Re: 6v92 low on power
Post by: luvrbus on September 09, 2021, 09:05:20 PM
Quote from: gear jammer on September 09, 2021, 08:53:57 PM
Ok I pulled codes using the ddec switch and using the cel.
22
43
44
46
58
Keep in mind I've never seen a cel since I've owned it
Do I have to pull the pulley to check timing sensor?

You seem to have a low voltage problem do you know how to count TPS
Title: Re: 6v92 low on power
Post by: gear jammer on September 09, 2021, 09:20:45 PM
No
Title: Re: 6v92 low on power
Post by: TomC on September 10, 2021, 07:56:18 AM
Still like my mechanical injection. Good Luck, TomC
Title: Re: 6v92 low on power
Post by: chessie4905 on September 10, 2021, 08:10:13 AM
don't  panic! usually that many codes indicate a bad connection, many times a ground connection that feeds several sensors. Other times one bad sensor can trigger alarm or codes from other sensors that depend on signal from that particular sensor. I would start with checking computer ground con ections, and or broken one. Age and corrosion can cause typical issues, especially from poor wire repairs in the past.
Title: Re: 6v92 low on power
Post by: gear jammer on September 10, 2021, 08:23:56 AM
Looking at the ddec troubleshooting manual.  Those are historical codes. The cel light doesn't go out until the problem are repaired. But the codes stay here n the computer until cleared. You need a pro link to clear codes.  I may be wrong but I don't think the codes are relevant
I agree on the mechanical injection
Title: Re: 6v92 low on power
Post by: gear jammer on October 14, 2021, 02:31:15 PM
Howdy
Still have not solved the low-power problem.  Hers what I have done
Ran it with no air cleaner,  took the terribly restricted muffler off.  Changed the boost sensor.  Put a gauge on fuel pressure 40 idle.  60@1000 rpm,75 @no load.  All which have accomplished nothing.  Still smokes black when you gun it.  And low power.  I ran it with the boost sensor hose off.  Still same,  smoke no power. Disconnected the plug at the sensor.  Runs the same with the Cel on.  Starts good, runs smooth.  I'm ready to pull my hair out.  Turbo turns good no slop in bearings.  If you put in gear to move forward  it's a turtle and stream of constant black smoke.  Until it gets to speed.  Takes forever. 
Any more ideas.  Scan gauge says it's getting 100 percent on the tps,
Steve
Title: Re: 6v92 low on power
Post by: luvrbus on October 14, 2021, 03:07:28 PM
Quote from: gear jammer on October 14, 2021, 02:31:15 PM
Howdy
Still have not solved the low-power problem.  Hers what I have done
Ran it with no air cleaner,  took the terribly restricted muffler off.  Changed the boost sensor.  Put a gauge on fuel pressure 40 idle.  60@1000 rpm,75 @no load.  All which have accomplished nothing.  Still smokes black when you gun it.  And low power.  I ran it with the boost sensor hose off.  Still same,  smoke no power. Disconnected the plug at the sensor.  Runs the same with the Cel on.  Starts good, runs smooth.  I'm ready to pull my hair out.  Turbo turns good no slop in bearings.  If you put in gear to move forward  it's a turtle and stream of constant black smoke.  Until it gets to speed.  Takes forever. 
Any more ideas.  Scan gauge says it's getting 100 percent on the tps,
Steve

Have you done the injector cut out and see if the smoke goes away and have you checked the pulse width on all the injectors ?.If you have the heat blankets on the manifold and piping I would remove it a check the piping,gaskets and manifold mine blew a chunk out of 1 manifold and I could never find it till I removed the blankets and it fell out   
Title: Re: 6v92 low on power
Post by: buswarrior on October 14, 2021, 04:01:23 PM
I'm just a bus driver...

If it was me...

The boost is being made, and it is being pumped over board.

Find where the boost is leaking.

White shirt and tie carefully hung on the rear view mirror, and into the engine compartment to find the broken clamp, burst hose, cracked manifold, cracked pipe, loose bolt holding it on top, airbox inspection cover come loose...

Restroom wet wipes, be sure to check backs of arms, shirt and tie back on, hero to the customer...

Happy coaching!
Buswarrior
Title: Re: 6v92 low on power
Post by: luvrbus on October 14, 2021, 04:16:45 PM
I think he lost a injector or got a load of real crappy fuel,a pro/link will only tell you what's happening on the top of a injector
Title: Re: 6v92 low on power
Post by: chessie4905 on October 14, 2021, 04:18:31 PM
you sure the turbo isn't missing some or damaged vanes? You have a boost gauge?
Title: Re: 6v92 low on power
Post by: luvrbus on October 14, 2021, 04:37:31 PM
The DDEC is supposed to supply just enough fuel  (AR) for the air it produces DDEC' usually don't blow a lot of black smoke unless something is wrong under the valve covers . The turbo sensor tells the ECM how much fuel is needed   
Title: Re: 6v92 low on power
Post by: gear jammer on October 14, 2021, 06:15:00 PM
no i havent removed the blankets, no broken clamps, yes i have a boost gauge, not guessing, ill have the prolink cable soon so i can check injectors etc,  maybe the fuel this started after a fuel up but i didnt notice it til 200 miles after, i was on the highway for a couple hundred miles, noticed it in traffic, these things move slow off the line anyway, now its real bad.
Title: Re: 6v92 low on power
Post by: Fred Mc on October 14, 2021, 06:48:21 PM
Just watched as video when the bus was down on power because there was an exhaust leak between the turbo and blower.
Title: Re: 6v92 low on power
Post by: luvrbus on October 14, 2021, 06:50:12 PM
Quote from: gear jammer on October 14, 2021, 06:15:00 PM
no i havent removed the blankets, no broken clamps, yes i have a boost gauge, not guessing, ill have the prolink cable soon so i can check injectors etc,  maybe the fuel this started after a fuel up but i didnt notice it til 200 miles after, i was on the highway for a couple hundred miles, noticed it in traffic, these things move slow off the line anyway, now its real bad.

They are slow out the gate and real bad on a slope to get started but once they sense the boost they move on
Title: Re: 6v92 low on power
Post by: gear jammer on October 14, 2021, 07:44:55 PM
Quote from: Fred Mc on October 14, 2021, 06:48:21 PM
Just watched as video when the bus was down on power because there was an exhaust leak between the turbo and blower.

I watched that video.  All my connections are tight it would have To be something broken like a manifold.   Thanks
Title: Re: 6v92 low on power
Post by: gear jammer on October 16, 2021, 11:48:22 AM
Howdy
OK I'm going to wait until I can get the prolink  information when the cord gets here. Hopefully it will let me know if there's us injector problems.  I'm thinking there is because of the smoke....

Then I'm going to pull it apart. Replace the exhaust manifold gaskets. And do a tune up.  I'm seeing on the valve cover the injection timing is at 12 degrees btc  The injectors are set at 1.520. The turbo is tv7512 with a 108 ar. 350 HP.  My question is.  Is this the best tune for this motor.  I see injectors at all different heights.  Anything I can change to get more performance?  . 
Title: Re: 6v92 low on power
Post by: luvrbus on October 16, 2021, 12:05:24 PM
No that is advanced timing for less smoke and cleaner burn and the right setting for a DDEC with your turbo the 1.08 A/R is on the compressor side (cold side) the timing has nothing to with the amount of fuel delivered. You can bump it to 400 hp with a different turbo but you need the DD software to change the calibration on the injectors it's not worth it IMO   
Title: Re: 6v92 low on power
Post by: gear jammer on October 16, 2021, 12:28:48 PM
I thought the 1.08 at is the hot side?  If it needs a turbo.  I'd consider the 400 HP recipe
Thanks steve
Title: Re: 6v92 low on power
Post by: gear jammer on October 16, 2021, 12:33:53 PM
 The more I think about this the more I'm thinking a injector problem  and a exhaust leak,  it always  blew some black smoke getting up to speed.  Time will tell. 
Title: Re: 6v92 low on power
Post by: luvrbus on October 16, 2021, 02:02:05 PM
Quote from: gear jammer on October 16, 2021, 12:28:48 PM
I thought the 1.08 at is the hot side?  If it needs a turbo.  I'd consider the 400 HP recipe
Thanks steve

You need to remove the turbo to see the hot side A/R it is stamped inside the housing at the flange mounting.you would not notice the increase because it only gains a few more foot pounds of torque lol you would notice the extra fuel for the 50 hp though 
Title: Re: 6v92 low on power
Post by: sledhead on October 16, 2021, 02:43:40 PM
ya I wanted more power out of my 6v92ta so I fixed it with a cat 3406e

dave
Title: Re: 6v92 low on power
Post by: gear jammer on February 15, 2022, 01:34:41 PM
Howdy, old post by me I know..
Well I finally found the time to get on this again.  I decided to pull Al the exhaust plumbing off including the exhaust manifolds.  I found a few spots in the gaskets that were leaking.  All the plumbing was good and tight.   No cracked manifolds.  Or broken clamps.   I'm going to do a tune up while I have it apart.  A few questions, to do the valve adjustment I believe the Jake's have to come off.  Is there anything I need to know before I pull them.  Any loose parts that could fall out etc?     Everything under the covers looks good.  I did run the prolink on the cylinder cut out and it all checked out.  I also going to set injector height,  I have the tool. And I'm going to set them at 1.520 as the specs on the valvecovers.  I'm thinking about  changing the hot side turbo housing from 1.08 to. 96, any opinions on this.  Thinking it would spool the turbo sooner.  This idea is coming from a turbo guy
Thanks steve
Title: Re: 6v92 low on power
Post by: lovetofix on February 15, 2022, 08:13:41 PM
Quote from: gear jammer on February 15, 2022, 01:34:41 PMI'm thinking about  changing the hot side turbo housing from 1.08 to. 96, any opinions on this.  Thinking it would spool the turbo sooner.  This idea is coming from a turbo guy
Thanks steve

The guys at Leid Diesel in Newville PA are very knowledgeable with the two-strokes and super helpful. If you have any questions on settings or turbo specs give them a call.
Jonathan just helped me rebuild my 6v92TA and add Jakes. He setup the engine with 9G90 injectors and a different turbo and it ran 350-360hp at 2100 rpm on the dyno with zero smoke anywhere unless you slapped the throttle from idle to wide open throttle (that just gave a small black puff).
We did not put back the delay on the fuel rail and from 800-900 rpm you can snap the throttle wide open with zero smoke. He said that is only possible with the correct turbo.
Title: Re: 6v92 low on power
Post by: gear jammer on February 15, 2022, 09:26:05 PM
Quote from: lovetofix on February 15, 2022, 08:13:41 PM
The guys at Leid Diesel in Newville PA are very knowledgeable with the two-strokes and super helpful. If you have any questions on settings or turbo specs give them a call.
Jonathan just helped me rebuild my 6v92TA and add Jakes. He setup the engine with 9G90 injectors and a different turbo and it ran 350-360hp at 2100 rpm on the dyno with zero smoke anywhere unless you slapped the throttle from idle to wide open throttle (that just gave a small black puff).
We did not put back the delay on the fuel rail and from 800-900 rpm you can snap the throttle wide open with zero smoke. He said that is only possible with the correct turbo.
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Thanks.  I'll give them a call
Appreciate that