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  #46  
Old 01-22-2010, 01:52 PM
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Location: Woodstock, Georgia
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no fuel from return line?

Here's where I am now after several days of working on this thing and wanting to give up on it several times.

Completed the swap of the 617 NA IP with the 617 turbo IP.

It started after several attempts but then it would die.

It had too much air in there from somewhere I guess, because after it would start I would use the hand pump and bubbles would come out of the return line which was submerged in a jar of straight diesel. It ran and idled beautifully on the straight diesel for several minutes then die.

I thought it was sucking air from the line attached to the primary filter so I hooked it up to the (50/50) tank and clamped it down and tightened down on the lines to and from the secondary filter and on the IP. Hand pumped again till all the bubbles came out the return line still in the jar. There must have been air in the injector lines because it took several more times on the starter to get it started again. Just almost got it started and the started failed.

Swapped the starter from the 617 NA on my engine stand and cranked again. It started up and ran and idled beautifully.

I got real brave and ventured out about 3 miles. I almost got it home and it died again. Fortunately, it was in walking distance from my house. I let it sit for the night then today I walked back and hand pumped it cranked it about 6 or 7 times and drove it home.

It was running and idling perfect by the time I got it home. I pulled off the return line while it was running to put it back into a jar and see it there would be air when I hand pumped. There was NO fuel coming out of the return line at all. I hand pumped while the engine is still running and just a very little fuel is flowing through return line. The engine is still running perfectly even when rpms are high and retuning to idle normally. little to no fuel retuning from the return line. I pulled the return lines off each injector and a very tiny amount is coming out in some cases none.

Does this mean bad injectors? But, the IP must not be releasing the fuel from the IP either since no fuel is coming out the return line.

What do you think????
Thanks for your comments!!!

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  #47  
Old 01-22-2010, 06:07 PM
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Plugged filters, tank strainer, tired lift pump, air leak, Fuel line obstructed. My guess is the fuel filter as the car runs for awhile until the junk in the primary or secondary filter gets stirred up and totally obstructs. The filter is obviously always partially obstructed.

I think your injectors are not the cause of your symptoms at all. They might not be perfect with age but cannot give you the present problem themselves.

That why even with your 14 pound output electric fuel pump you had such poor readings in the injection pump. If your gauge is not a fluid dampened type gauge you are on your own as the non dampened ones are almost useless for troubleshooting in that application.

Read the pressure close to the electric pump. Than the injection pump base. If there is a large difference I think the secondary filter you never changed or mentioned you did since the problem started is a possible culprit.

You have been mixing fuels in that car as well. This would get a lot of junk in motion. A secondary filter required every two weeks or so would not be unusual.

Last edited by barry123400; 01-22-2010 at 07:02 PM.
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  #48  
Old 01-22-2010, 08:58 PM
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Thanks Barry for your comments.

Not using the electric fuel pump any more.

Did change both filters in the process of working on these problems.

The gauge is a water pressure gauge. It is also not hooked up.
I used a hard plastic line from the spin-on filter to the IP.

The tank strainer was cleaned also when I changed the filters about a month ago.

Fuel line can't be obstructed because the primary filter fills up with fuel when the hand pump is used.

I tend to think that its the lift pump, so tomorrow I'll use the one on the turbo IP that I took off and swap them. Then I'll see if there is a difference in the fuel from the return line. There must be air also getting into the system from somewhere since it quit after about six miles.

On the IP that I removed I intend to take apart the lift pump and see if there is a problem I can recognize. Also, I am in the process taking apart the turbo IP. I finally got the ALDA off. Took the back plate off the IP I see how the shut off works. I'll be getting deeper into this thing. I don't know the correct terms for all the parts but I can see and feel resistance
when opening the throttle all the way. Maybe, I'll take some pics and post them.

Thanks again!
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  #49  
Old 01-22-2010, 11:49 PM
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You really must have some type of supply problem as a non dampened pressure gauge slams against the stops if things are normal fuel pressure wise. Your indication from 0-5 pounds was very poor. That slaming occurs when reading the pressure after the second fuel filter. You cannot read the gauge at all the needle is moving so fast. When the injection pump elements are being supplied properly there are strong reflected pulses present in the injection pump causing that.

The water pressure gauge is usually always a non fluid dampened unit. If you cannot see an air bubble floating at the top of the liquid internally it is not fluid dampened. I think you really need a proper gauge to try to establish what is right and what is not.

The lift pump by design should not be intermittent. Yet once again anything is possible. At this point with so little valid information it might still be very weak though.

A good lift pump will give 30 lbs pressure directly into a gauge. You cannot hurt the pump by stopping the flow for a pressure check with a gauge. Your crude gauge will accuratly read the lift pump output pressure I think. Once again a dampened gauge would be better.

You are running out of things to check and might have passed over the problem already. Even worse is you do not yet have any valid indication of how much pressure or quantity of fuel is there.

Try switching the return and supply lines from the tank up front if you have more than 1/4 tank of fuel. This will clear from the front to back at least. Do not neglect to prime until fuel comes up the return line. Things have to be positivly eliminated in a fashion that leaves no doubt at this point. Otherwise it may not be solved. Or it will become very painful to do it.

Something is desperatly wrong here. I thought when you switched injector pumps you switched the lift pump at the same time. It is bolted to the pump and normally goes along for the ride.

The wild card is still the use of different fuels. This means a lot of junk probably got loose in the system at some point. Thats the main reason I suggest switching the supply and return lines. Even fuel lines become obstructed with the resultant crud. Valve seats in the lift pump are not immune either.

When I suggested you feed one type of fuel to the injection pump and then the other type for comparison originally. I meant feed the injection pump. Not the lift pump as a lift pump could get a little more pressure going with vegatable oil as it would seal the valves in the lift pump better than the much thinner diesel fuel. Your aproach may have led to an unrequired change of the injection pump. Or I was not clear enough.

Do change the lift pump though before proceeding as you mantioned you where going to. It is still a good candidate from what I can tell so far.

Last edited by barry123400; 01-23-2010 at 12:29 AM.
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  #50  
Old 01-23-2010, 12:28 AM
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The gauge is non fluid dampened, so I'll try to find one that is. and measure it again.

Your are right the lift pump is from the 80 NA engine so I will be removing it and going back with the original lift pump that I know was working, because of previous tests before I switched the IP's. It did have some pressure and the return line was dumping fuel at a good rate.

I know things are getting some what confusing since I've done so many things. As you said before in a "shotgun approach" But, I am getting a better handle on whats going on here. Now I have a better feel for what to test and how to test it.

I read a thread about a stuck rack in an IP and soaking it with gas to remove the junk in it. That could be my problem with the original (turbo) IP. I can see the rack with the alda moved over and it does not seem to be moving back and forth smoothly. I'm going to try and clean that IP and purge it with gas for a few weeks as was suggested in the thread. It seems to me that rack could be stuck in the open position when it gets hot thats why the linkage is at idle but the engine remains running at a high rpm. As it did in the video I posted.

Also I think I'm going to replace all the soft fuel lines and clamps just to eliminate the possible sucking of air. I'll switch the return line with the fuel line also as you suggest to clear out the line.

in a previous post you said:
"Your engine will run with the non turbo pump if required . Just no fuel enrichment on demand." What does no fuel enrichment on demand mean exactly?
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  #51  
Old 01-23-2010, 12:46 AM
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Paul. with a turbo engine. As the air pressure from the turbo builds the engine needs more fuel to utilize it. So a device on the injection pump, the alda is altered by the pressure in the line. Called boost pressure I believe. This enriches the fuel amount per injection. As the pressure changes the additional fuel amount is increased or reduced. With your normal pump now present with no alda or boost connection it will not enrich when the boost pressure increases. There is an altitude compensator on the non turbo injection pump instead.

One thing is for certain once you get through this adventure the fuel supply system will be much easier for you to deal with the next time. You in fact did carry the normal pumps lift pump over. I assumed that was done anyways originally. That was what the vast majority would have done..

The chances of both lift pumps being problamatic are small. Swap the return and supply lines first and pump until you have fuel up and try the engine.

Last edited by barry123400; 01-23-2010 at 12:55 AM.
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  #52  
Old 01-23-2010, 01:07 AM
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Quote:
Originally Posted by paul46 View Post
The gauge is non fluid dampened, so I'll try to find one that is. and measure it again.

Your are right the lift pump is from the 80 NA engine so I will be removing it and going back with the original lift pump that I know was working, because of previous tests before I switched the IP's. It did have some pressure and the return line was dumping fuel at a good rate.

I know things are getting some what confusing since I've done so many things. As you said before in a "shotgun approach" But, I am getting a better handle on whats going on here. Now I have a better feel for what to test and how to test it.

I read a thread about a stuck rack in an IP and soaking it with gas to remove the junk in it. That could be my problem with the original (turbo) IP. I can see the rack with the alda moved over and it does not seem to be moving back and forth smoothly. I'm going to try and clean that IP and purge it with gas for a few weeks as was suggested in the thread. It seems to me that rack could be stuck in the open position when it gets hot thats why the linkage is at idle but the engine remains running at a high rpm. As it did in the video I posted.

Also I think I'm going to replace all the soft fuel lines and clamps just to eliminate the possible sucking of air. I'll switch the return line with the fuel line also as you suggest to clear out the line.

in a previous post you said:
"Your engine will run with the non turbo pump if required . Just no fuel enrichment on demand." What does no fuel enrichment on demand mean exactly?
Not a bad ideal to soak your turbo pump. It will do no harm and indeed you could have a valid ideal there. As the govenor pulls the rack it may be sticking. This I imagine could cause the revs to build as you experienced.

You will also have to get the alda back as it was. Maybe you have already. I do not understand all the internal mechanics in the pump well enough to express an opinion. Or if that area has affected things since being tampered with. It might have since it has to do with fuel enrichment or greater quantity of fuel.

Adding a small percentage of laquer thinner to the gas used in soaking internally will clean easier. There are no rubber parts to dry out or upset internally with the addition of a small amount of thinner.

Switching the fuel lines is not to clear out the line. It just establishes if there is a problem in the supply line or tank screen. Even though you checked the screen awhile ago.

The vegatable oil can loosen up a ton of crud in the tank. The rubber connecting hose at the back could be leaking air, there might be a small perforation in the line or the line itself could be almost totally obstructed with crud and close off with fuel flowing up the line after a short time running.. Yours would not be the first to have an obstructed fuel supply line by the way.

By the same token it is unlikely that both injection pumps have bad relief valves. Your turbo pump may have had a bad one.

Last edited by barry123400; 01-23-2010 at 01:59 AM.
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  #53  
Old 01-24-2010, 12:19 AM
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Today was a good day although it was cold working out there. I remove the lift pump from the turbo IP an checked it with my thumb it definitely was working well. I cleaned it up a little.

Then I removed the lift pump from the 80 IP That was diffiicult to say the least since those 10 mm nuts are hard to get to and they are cold.
When I got the lift pump off I could see that the pump was not funtioning at all since the plunger was stuck in the pump.

It is really amazing that the engine would run at all with a non functioning lift pump. I went 3 or so miles with no lift pump, amazing. Anyway, after I put the one that worked on and hand pumped up the pressure, the car ran again beautifully. I was brave enough to drive to the store about a 14 mile round trip. No problems with the engine at all, it runs great now. Hopefully it will continue to run great for a long time. I put more diesel in the tank diluting the svo that was in there and there was no change in the way it ran at all.

My problem now is the vacuum line to the tranny, its shifing hard so I need to figure out how to get that back together the right way.

I'll be putting the NA engine back together and playing with the turbo IP on the stand till I can work out that problem with the rack or what ever it is, but at least now I can go and get what I need.

I'm very satisfied with the way this 83 300SD is running now.

Barry what ever happened to the car you bought that had the problem of stalling every so often? Did you locate the problem?
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  #54  
Old 01-24-2010, 12:24 AM
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paul46,

What part broke on your lift pump? Can you post a picture if you get a chance?

...and congratulations, nice work.
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  #55  
Old 01-24-2010, 06:28 PM
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Barry what ever happened to the car you bought that had the problem of stalling every so often? Did you locate the problem?[/QUOTE]

The main electronic control module (ecm) was heating up and dropping out.. As soon as it cooled down a little the car would run for quite awhile then repeat.

I also found it hard to think properly when it is cold where I am working years ago. For a long time now I just refuse to do it. If the car is in a heated space I am more than willing to tackle it. Necessity and my age do play into it of course.

I am also purchasing a string of used cars for resale as the warmer weather approaches. Gotten some really nice ones so far. . Car auction prices are still remaining low. Although did not buy even one last week.

You have to be very careful and I only try to buy low milage cars. To add to the mysery the cars have to be selected on the basis of what will sell easily. Not what I like myself in many instances.

I do not know where you live but the cost of living has been rising fast here. Safest way I could put some money at work getting a good return at this point in time. I just will let my wife drive one at a time until it sells. Most people will buy a used car from a nice older lady.

As you are now only too well aware a good working pressure gauge is a good trouble shooting tool. At least the car is now serviceable. The frustration is now past. Let us know how the adventure with the turbo injection pump works out.
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  #56  
Old 01-24-2010, 07:33 PM
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Here are pics of the lift pump. The bar that holds the wheel that rides on the cam inside the IP should be flush with the outside edge of the groves that hold it in place. It is stuck all the way in, thus it was not contacting the cam in the IP that forces it in.

The other picture is my next project: getting into the governor linkage and rack, etc.. and getting my NA engine to run with that pump and that lift pump on an engine stand. Eventually to hook it up to a 24KW generator.

I still need a picture of the vacuum lines setup for the IP and transmission, if anyone can point me to one. Still runs great today. Starts right up and accelerates nicely with plenty of power, shifts hard because of vacuum line setup.
Attached Thumbnails
83 - 617 will stall at 2000 rpms-fuelpump1.jpg   83 - 617 will stall at 2000 rpms-fuelpump2.jpg   83 - 617 will stall at 2000 rpms-turobopump.jpg  

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