6V92 Detroit

[Cat320]

A number of us would love a thread on the Detroit series engines. Don't know how that would get started.

[FastGlassMan]

Originally Posted by Mikedriggers

I already had a mechanic come out on the side of the hi way and charged me $300 to bypass the water seperate cause he thought it was clogged but when it didn't fix it he just shook his head. It took me 6 total hours to make it ten miles to my house...where it still sits.

Please give us that mechanics information as in my 60 years I have never heard of bypassing a water separator as a solution to a no fuel problem, sounds like a problem with the restrictor in the return line, just my opinion but after owning many detroits ,cats and cummins trucks and doing my own work on them, i'll say that was wasted money! removing two lines and butting them together is a ripoff! Bobby

[Mikedriggers]

Originally Posted by FastGlassMan

Please give us that mechanics information as in my 60 years I have never heard of bypassing a water separator as a solution to a no fuel problem, sounds like a problem with the restrictor in the return line, just my opinion but after owning many detroits ,cats and cummins trucks and doing my own work on them, i'll say that was wasted money! removing two lines and butting them together is a ripoff! Bobby

I agree FastGlassMan, it was hard to give it up, but am new to deisels and had to put my faith in him...I was broke down at a convenience store for 4 days with a store owner that was getting tired of it being in his parkinglot. All you guys have given me some great ideas...I will start trying them out this weekend.

[Ernie Ekberg]

Is your fuel tank full?
Do you fill the filters with diesel before you start?
Reconnect the Racor filter- the fuel/water separator and fill that with diesel. I had a 6v92 mechanical for 10+ years.
These engines are 2 stroke and must use straight 40 weight oil- no blends.

[Cajun2Stepp]

I had the same problem on an 8V71 in a MC-9 - it was algae build up on the inlet screen in the tank.
Have you cut the fuel filter open and looked for debris? Look for globs of jelly.
You can try blowing back through the supply line with compressed air to see if it will clear.
Be sure to leave the filler cap off to avoid pressurizing the tank and splitting it.
It will take a while to prime it up afterwards, so you may need to fill the fuel filter a couple of times.
A restriction in the return line will cause the idle speed to creep up and can actually make the engine speed run away, but won't make it die or lose power.

[halfwright]

Now that makes a lot of sense. I did not think it was an air restriction since that would cause smoke and the emergency shut down would be immediate.

[Ted Lambert]

OK Enough confusion.
Why did you change the fuel filters?
Were you having trouble before or did your problem start after you changed them?
Do you know how to prime and bleed a 6v92 Series Detroit?
If you had a problem before you changed filters what was it?
If you had a problem after? Did you properly prime and bleed the system?
I spent half my life working on 53 series 71 series and 92 series. But until you answer the questions I cant help you.

With that said, when you get roadside service, if the guy does not look at least 60. He probably has no experience with a 92 series Detroit. And probably is looking at the first one he has seen.
Not to offend anybody on this site but by today's standards are old engines.

So what was the complaint from the start? You just teased the curious on this site and now everybody is on the band wagon.
More info please!

[Ted Lambert]

Originally Posted by Ernie Ekberg

Is your fuel tank full?
Do you fill the filters with diesel before you start?
Reconnect the Racor filter- the fuel/water separator and fill that with diesel. I had a 6v92 mechanical for 10+ years.
These engines are 2 stroke and must use straight 40 weight oil- no blends.

D 30 is all we ever used in our 92 Series Detroit. No blends is correct.

[Ted Lambert]

Originally Posted by Cajun2Stepp

I had the same problem on an 8V71 in a MC-9 - it was algae build up on the inlet screen in the tank.
Have you cut the fuel filter open and looked for debris? Look for globs of jelly.
You can try blowing back through the supply line with compressed air to see if it will clear.
Be sure to leave the filler cap off to avoid pressurizing the tank and splitting it.
It will take a while to prime it up afterwards, so you may need to fill the fuel filter a couple of times.
A restriction in the return line will cause the idle speed to creep up and can actually make the engine speed run away, but won't make it die or lose power.

I would not recommend this. If you blow back in the fuel line it is ok but you must pressure the tank and get a good flow of fuel back to the filters.
Having to fill the filters a few times means that you are running the fuel system dry. Detroit s hate running out of fuel. Fuel is the oil lubricant for the Injectors and the transfer pump. DON"T DO IT.
Restricted return on a Cummins can make the engine run faster. It was a trick back in the day to get more HP out of the engine. Especially if being sold to a potential buyer.
I believe the 6v92 series Detroit would handle a restricted return line by relieving pressure at the transfer pump. There is a restriction in the cylinder head to maintain pressure in fuel system. I don't know of any in the return line.

[Ted Lambert]

Originally Posted by Mikedriggers

Twinboat, I have checked the shutoff and they are ok...someone did mention to me that if the return line back to the tank was stopped up it could be flooding itself out. Does that sound right?

Nope

[norcalbruce]

ok my 2 cents worth.. The Detroit was running poorly before the filter change. So after the change it ran the same. So move to another fix..

One test I would also check is the delivery of the fuel.. What is the Fuel Pump's pressure? What's it's suppose to be?
With all these posts on fuel and running poorly, maybe low pressure? Please put a pressure gauge on it to check.

Another test; When you finally get it running, let it run until it dies. When that happens, take off the first Fuel Filter (if you have more than one, the filter closest to the fuel tank) and check it for being full at time of engine dying.
I hope this helps. Bruce.

[Ted Lambert]

Originally Posted by norcalbruce

ok my 2 cents worth.. The Detroit was running poorly before the filter change. So after the change it ran the same. So move to another fix..

One test I would also check is the delivery of the fuel.. What is the Fuel Pump's pressure? What's it's suppose to be?
With all these posts on fuel and running poorly, maybe low pressure? Please put a pressure gauge on it to check.

Another test; When you finally get it running, let it run until it dies. When that happens, take off the first Fuel Filter (if you have more than one, the filter closest to the fuel tank) and check it for being full at time of engine dying.
I hope this helps. Bruce.

Bruce from the OPs experience I don't think he could check the fuel pressure as he would not be able to do it. But if it is running that is what I would do.
Those are such simple fuel system. But very hard to direct the orchestra and such distance. I wish him luck.

[BRex45]

Narampa did you have the "Silver 92?"

Worked on my own 8v71 in the fall of 1976, outside, 8 cylinder kits and rebuilt heads, in the snow. After 400,000 highway miles I got to know it pretty well, then apprenticed in a Kenworth / GMC dealership.

My first assignment in the shop? Pulling the trans on a Western Star with a 12v71 that had all of the flywheel bolts break or come out, raised hell with the flywheel housing.

Hopefully the OP stumbles onto the solution. Would like to know what it is.
The problem would have been found, usually, at our shop within an hour or less.

Bruce

[Mikedriggers]

Ok, to clear things up and hopefully eliminate the confusion, here is the whole story. This rv was given to me by the widow of a friends father who passed away, she had no further use for it. 2 years ago they had traveled all over Texas and was on way home when it started losing speed, but they made it home OK. It has set up ever since. Before I came to pick it up she had a "mechanic" come by and he drained the old fuel out, put 20 gallons of fresh fuel, changed the air and fuel filters and took it for a spin but couldn't get it to go over about 30 mph. When I came to get it I cranked it up and let it idle while it built up air pressure to release the brakes and shortly after air built up it died. It would crank back up but would die if let idle for a minute or two. Trying to get it home I was lucky to get it to reach 20 mph and that was going down hill and it wouldn't climb back up the next hill with out first bogging down and dying midway up. I would crank it and it would slowly climb the hill till I got to the next and it was the same for every hill. I pulled into a convenience store and pulled the air filter out and cranked it up with no change. I pulled the fuel filter off to make sure it was full and it was. I called a "mechanic" and he came and put in another new fuel filter and he then bypassed the fuel water separator because he thought it was stopped up and that didn't help. He followed me home and even rode with me some and drove some which took about 2 hours to go just a few miles. Now that it is home all I have done is checked the shutoffs and everything was good there. I cranked it and went back to the engine to watch the shutoffs thinking it may have been the electric solenoid being bad and it dies without the shutoff being activated. At the request of a friend I removed the fuel filter and cranked it to watch the fuel flow and it had a steady enough stream in the video I sent him that he said I could have driven for miles just on the fuel he saw come out. The exhaust burns clean and there is no air restriction. As it stands, sitting at the house, it will crank and idle every time I walk out there but dies within a minute or two. The only other thing I know that's bad is the alternator isn't charging but I wouldn't think that would affect the engine.

I hope this is enough info so you guys aren't confused, I surely could use the advice. I'm going through a divorce and on disability so calling another mechanic is out of the question.

Thank you all for your patience and advice.