1993 6V92 Turbo Wont Boost

Topic: 1993 6V92 Turbo Wont Boost (Read 3232 times) previous topic - next topic

Re: 1993 6V92 Turbo Wont Boost

Reply #25 – September 26, 2016, 06:31:52 pm

Quote from: mike leary – September 26, 2016, 05:09:11 pm

Pardon me, but is that a turbo or a supercharger we're talking about? $:-\$

Brett is right...both! Since the 6v92 is a 2 stroke engine it needs the supercharger to build crankcase pressure at start up. After the engine is running and the turbo winds up there is a bypass for the supercharger. I'm not exactly sure how that works but pretty sure once the turbo builds enough pressure a "waste gate" type valve opens and takes the supercharger out of the air flow. If anyone has more details please speak up.

see ya
ken

Re: 1993 6V92 Turbo Wont Boost

Reply #26 – September 26, 2016, 06:58:47 pm

Quote from: wolfe10 – September 26, 2016, 05:41:29 pm

The DD 6V92 has BOTH. Supercharger for low speed, turbo higher speed.

Depends on the year/model. Some have blower bypass and some don't.

Re: 1993 6V92 Turbo Wont Boost

Reply #27 – September 26, 2016, 07:07:00 pm

Quote from: Kent Speers – September 26, 2016, 03:13:36 pm

... The are checking for air box leaks now ...

There are these valves on the air box on each side that let oil leak out when the engine is off (or at idle) but close up when the engine is running under power. When the engine is off (or at idle) a light spring holds the valve open. When the engine is running hard the air box pressure and flow overcome the spring and it seals so you don't loose boost pressure. See attached.

Re: 1993 6V92 Turbo Wont Boost

Reply #28 – September 27, 2016, 05:52:32 pm

Well, still stuck in Danville, MO.

So far we have changed fuel filters, the air filter, checked fuel pressure (20 psi at idle and 70 psi at 2200 rpm), checked fuel restrictor in fuel return fuel line, pulled the boot and checked the turbo, tightened the exhaust manifold bolts and all turbo flanges, checked the DDEC and cleared any codes, also unplugged all electrical 12V and 110 for an hour to clear DDEC, checked the turbo boost sending unit and tightened the hose, checked the blower housing and the air box inspection plates for leaks, checked the accelerator pedal for full throttle and put in a double dose of diesel injector cleaner. My best guess right now is I got bad fuel from Loves in Booneville, MO or the turbo pressure sensor is bad or less likely may be that something is wrong with the super charger or the fuel line has partially collapsed internally but I doubt that I could get 70 psi at the secondary fuel filter if it was collapsed.

Sooo, if anybody else has any idea, please let me know. I'm going to try to get to Granite City, IL tomorrow. I was able to get the coach up to 62 today. Maybe its healing itself.

Re: 1993 6V92 Turbo Wont Boost

Reply #29 – September 27, 2016, 07:32:33 pm

Kent did they check the Air Box Drain Tube Valves John Fitz posted just above,If these are sticking open you won't build turbo boost.
Thy are open at idle and are supposed to close as pressure builds up. Simple cleanouton them all described in JF's post above.just a thought.

Re: 1993 6V92 Turbo Wont Boost

Reply #30 – September 28, 2016, 01:05:58 am

Had similar issue with my ISM Cummins, turned out to be the intake boost senser. Would not turn on fuel until it saw turbo boost pressure.

Re: 1993 6V92 Turbo Wont Boost

Reply #31 – September 28, 2016, 03:32:45 am

Kent,what exactly was done on your redone,have you checked valve clearence?

Re: 1993 6V92 Turbo Wont Boost

Reply #32 – September 29, 2016, 08:33:56 am

Kent - did you happen to notice the coolant (water) temperature when you started losing power, I don't know about the Detroit but some diesel engines will loose significant power it the thermostat sticks open. As mention earlier an exhaust restriction can cause power loss, baffles can collapse, kids can fill the muffler hole with toys or other stuff. Also check for leaks in the system between the turbo and the intake manifold. Hope you get going, and thanks for taking the time to reply to my questions on your former U225.

Re: 1993 6V92 Turbo Wont Boost

Reply #33 – September 29, 2016, 09:13:16 am

Quote from: stump – September 27, 2016, 07:32:33 pm

Kent did they check the Air Box Drain Tube Valves John Fitz posted just above,If these are sticking open you won't build turbo boost.
Thy are open at idle and are supposed to close as pressure builds up. Simple cleanouton them all described in JF's post above.just a thought.

Drains have been checked by a mechanic but I will check them again today.

Quote from: Dave M – September 28, 2016, 01:05:58 am

Had similar issue with my ISM Cummins, turned out to be the intake boost senser. Would not turn on fuel until it saw turbo boost pressure.

I will be removing the turbo boost sensor today and trying to locate a new one. This seems to be the most likely culprit.

Quote from: Old phart phred – September 29, 2016, 08:33:56 am

Kent - did you happen to notice the coolant (water) temperature when you started losing power, I don't know about the Detroit but some diesel engines will loose significant power it the thermostat sticks open. As mention earlier an exhaust restriction can cause power loss, baffles can collapse, kids can fill the muffler hole with toys or other stuff. Also check for leaks in the system between the turbo and the intake manifold. Hope you get going, and thanks for taking the time to reply to my questions on your former U225.

The coolant temp at the time of the occurrence was 178. I just installed a new auxiliary radiator to improve cooling so I was watching the temps. I had just filled the fuel 60 before and was on the longest and steepest uphill in central Missouri when this started.
Although it appears that there is normal exhaust flow through the muffler, this is still fairly high on the list of suspects.

Quote from: John44 – September 28, 2016, 03:32:45 am

Kent,what exactly was done on your redone,have you checked valve clearance?

What was done in the spring was removal of the heads for new head gaskets, reset the rack and a seal kit for the air compressor. But a two stroke mechanic and I both have inspected and checked all connections and bolt heads for tightness.

Bye the way, we made it out of Danville, MO and are at a friends house in Granite City, IL. just across the Mississippi from St. Louis.
This gives me more access to tools and parts. On the drive here I was able to coax the old girl up to 65 mph but she was still very weak on even the slightest hill. She reached 15 psi turbo boost at 2200 rpm but seemed to have very little low end power. Boost through the lower gears was 5 psi in first, 9 psi in second and again 15 psi shifting from 3rd to 4th. She would run around 9 or 10 psi at 65 doing 1700 rpm. Seems like she's kinda healing herself but she's still to weak for really big hills.

Any Thoughts???

Re: 1993 6V92 Turbo Wont Boost

Reply #34 – September 29, 2016, 10:56:47 am

Kent,
It sounds like this power loss started after about 6 or 7 gallons (60 miles) of that new fuel went through your engine.
You say it seems to be getting better as you drive more miles. Could that be wrong fuel mixing in with what you had in the tank?
I am wondering if you got #2 diesel?
Or maybe diesel and gasoline?
You seem to have checked fuel and air available to the engine but still have low power.
JD

Re: 1993 6V92 Turbo Wont Boost

Reply #35 – September 29, 2016, 11:13:24 am

Thought #2 diesel was the one we want as opposed to what?

Re: 1993 6V92 Turbo Wont Boost

Reply #36 – September 29, 2016, 11:15:21 am

I think something was not assembled correctly when this head work was done.

Re: 1993 6V92 Turbo Wont Boost

Reply #37 – September 29, 2016, 12:50:28 pm

#2 diesel is what we want, but not with gasoline. Gasoline has been dropped into the diesel tanks at a station before.
If that happened at that station I would think they would know it by now!
Still wondering about that fuel. Didn't thIngs really go down hill after the last fuel up?

Re: 1993 6V92 Turbo Wont Boost

Reply #38 – September 29, 2016, 01:21:13 pm

I think I have ruled out bad fuel. The generator runs fine.

Re: 1993 6V92 Turbo Wont Boost

Reply #39 – September 29, 2016, 01:46:04 pm

I took some gas one time (my fault), called Cummins, who told me if it was a couple of gallons, no big. Otherwise, pump it out. Is that a Garrett turbo?

Re: 1993 6V92 Turbo Wont Boost

Reply #40 – September 29, 2016, 04:20:53 pm

Still sounds like the same problem I had with my Pete bad boost sensor.

Roland

Re: 1993 6V92 Turbo Wont Boost

Reply #41 – September 29, 2016, 05:58:55 pm

Here is a old thread on another site
http://www.dieselenginetrader.com/diesel_talk/messageview.cfm?catid=9&threadid=3299

Re: 1993 6V92 Turbo Wont Boost

Reply #42 – September 30, 2016, 08:13:24 am

I ordered a new TBS yesterday. Due in on Tuesday so no more news until then.

Re: 1993 6V92 Turbo Wont Boost

Reply #43 – September 30, 2016, 08:48:49 am

Kent this might sound silly but is the boost sensor wire connector plugged in? I have had mine come off once on my big truck.
I didn't get the clip completely hooked when I reconnected it

Re: 1993 6V92 Turbo Wont Boost

Reply #44 – September 30, 2016, 10:23:13 am

Quote from: stump – September 30, 2016, 08:48:49 am

Kent this might sound silly but is the boost sensor wire connector plugged in? I have had mine come off once on my big truck.
I didn't get the clip completely hooked when I reconnected it

Yes the wire was firmly connected but I still pulled it, cleaned it and reinstalled it. What I discovered is that the Turbo Boost Switch bracket and therefore the switch must be installed no more than 30 degrees from vertical. This is so the tubing is running uphill to the sensor so if any oil or water gets into the tubing from the blower housing it won't drain into the TBS and contaminate it. I found that the switch was mounted almost 90 degrees, vertical, and that the tubing was old and not firmly attached at either end. If air leaks from the tubing the sensor cannot get a good reading. I cut both ends of the tubing to make a new connection and added one clamp that was missing and tightened the other. I did a test drive and still low power. I then ordered the new TBS since I fear the old one got contamination in it due to the faulty install. When the new one arrives I will take off the TBS bracket and bend it to the appropriate angle and reinstall it and add a new longer tube that will allow for the uphill angle into the TBS. I sure hope this fixes the problem. We will find out next week.

Re: 1993 6V92 Turbo Wont Boost

Reply #45 – September 30, 2016, 10:35:35 am

Kent Clark Diesel jn Pontoon Beach,Il might have that switch in stock.
Clarke Power Services | Pontoon Beach- IL

Re: 1993 6V92 Turbo Wont Boost

Reply #46 – October 01, 2016, 09:22:04 am

Quote from: stump – September 30, 2016, 10:35:35 am

Kent Clark Diesel jn Pontoon Beach,Il might have that switch in stock.
Clarke Power Services | Pontoon Beach- IL

Stump, thanks for the lead. We are setting in Pontoon Beach, IL right now. I've already ordered and paid for the part in St. Louis but if I need more help I will contact them Monday.

Re: 1993 6V92 Turbo Wont Boost

Reply #47 – October 05, 2016, 11:42:45 am

Update, Tuesday has come and gone. I did get my new turbo boost sensor (TBS-$150) and installed it yesterday, NO CHANGE. I am now setting at Central Power System, LaDue, MO. They are the Detroit Two Stroke Dealer/Distributor for this territory. Clarke mentioned by Stump is the four stroke Detroit Dealer/Distributor and does nothing on 6V92's. So far Central has been great to deal with and seems to be a first class outfit. I will post again as soon as we find the problem.

Re: 1993 6V92 Turbo Wont Boost

Reply #48 – October 05, 2016, 12:03:55 pm

Hang in there! It's just a machine...somebody will figure it out.

Re: 1993 6V92 Turbo Wont Boost

Reply #49 – October 05, 2016, 08:09:41 pm

Total guess but I had an 89 unihome u300 be slow because the factory had not hooked up the three wires in the engine bay around the edge. The connectors had double sealing rings on the male ends.

Turns out the connectors were from the ATEC trans to the DDEC engine.

Without a trans signal the engine went into limp mode. 80% power.

No fault codes either.

The lack of signal made the motor down adjust to a damaged trans.

Not sure if you have the same connectors or even the same system.

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