You know, the more I think about this, the more I would like to see you remove the vacuum shut-off from the back of your IP and see if the stop lever is free. That is the only thing I know of that will shut off the fuel....

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Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

Thanks again everyone. I love that so many people are throwing ideas at me. I hope tomorrow its nice so I can really test out as many of these ideas as possible! As soon as I get more info, I will post on it. Please keep the ideas coming. And thank you all!

Set up to deal with a runaway engine situation if you are going to be working on the fuel shutoff setup. Basically a way to deny air to the engine if it takes off rpm wise by itself after starting.

If it were my car I would start by pumping the injection pump full of laquer thinner or acetone. Let it sit for a day. Then pump diesel fuel in to drive any junk and thinner out the return line after it has dissolved. Collect it so you can have a look at it.

This because you have no ideal of the quality of fuel used by the last owner. There could be a lot of crud in that pump.

That it did run on diesel was good. It means the elements of the pump are not ruined. My suggestion is based on you have to start somewhere. Ex wvo cars should have their fuel systems cleaned out just as general maintance anyways. One question is do you have a lot of blowby?

Before my whole rant, I just realized, could this be caused by an issue with the pressure relief valve at the IP? Any thoughts? I have an idea to test it. Put the end of the line right before the relief valve into a container and crank. Compare how much comes out to how much was coming out the return line. If a lot more comes out, the relief valve could be stopping flow more than it is supposed to (does this seem reasonable?

Rant: Everyone, I will do my best to keep up with this (although I injured my hand moving something last night). This morning I went out and took pictures of some things a did a few tests. I think we may have an answer (or be close). To start, I took a picture of the fuel from the spin on fuel filter. Then I went down to the car and took a picture of the setup I have been using (which I will explain in more detail at the end of this post). Then I put the return line into a clean quart container and pumped the hand primer. I didn't time myself, but I found in short time, the quart container was 1/4 full. I then dumped the quart container and tried cranking the car fro about 10 seconds. Took a short break and cranked again for 10 seconds. After 20 seconds or so of total crank time, the quart container had a very little amount of fuel in it (see picture). Is my lift pump the issue here?

Setup: The current set up I have been using for testing purposes is pictured, but if you can't make everything out in it. I have a cleaned out coffee can filled with clean diesel. Submerged in that diesel coffee can is a fuel line which goes down to the hand primer pump (an lift pump right?) then, a line from the hand primer, goes into the spin on filter. Then, from the spin on filter, I put in a clear hose going down to the IP pressure relief valve. There is definitely clean fuel making it as far as the IP pressure relief valve, but when I crank NOTHING comes out of the IP on the top (I have removed the 5 hard lines which go to the injectors so I can monitor what is coming out of each more readily). I also tried removing the brown vacuum line going to the IP and cranking (as someone either on here or elsewhere had suggested that). It didn't help.

As always, thanks again everyone. I will try to get more done today, although working with this injured hand makes this a little less fun... If I can't suck up the pain today, I certainly will do more in the following days.

Here are the pictures mentioned in my last post.

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Block the cigar hose (return to tank) with vise grips and see....

__________________
Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

Wow,

My 617 will fill that cup in a few cycles.

__________________
Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

You could also have crud in the lift pump. As you pump a solvent in it will soak/clean the lift pump as well remember. One way or another until you are pretty certain things are not just gummed up not much sense in doing anything else.

Yes even the return valve can get stuck open with garbage. Basically it cannot be ignored that the car may have run on fuel of questionable overal quality animal fats and all. Anyways it never hurts to clean the fuel system out or at least parts of it now..Especially after running on alternative fuels.

Once again you are lucky that since the car ran on diesel fuel your injector pump elements themselves where not damaged. Your issue I believe and hopefully is pretty minor in nature. Even if it is not crud buildup. Still you have to start somewhere.

Another way to look at this say the injection pump or lift pump or even the relief valve are gummed up? Yes even two out of three are possible even if unlikely.How do you prove it one way or another without cleaning them out? Not technically difficult to do either. If not cleaned out say you do get it running somehow and down the road another clump of fat gets loose and causes issues. This you do not want..

Right now you almost appear to have a problem of an intermittent nature. Some of your tests indicate the rack may be bound up or sticky as well. More likely the lift pump or it's supply is though. I believe the throttle controls the govenor and this in turn controls the rack so there is a possibility of something gummed up or sticky. Also could be crud under the valves in the lift pump. Gummed up relief valves are not unknown either.

I am not stating cleaning the partial system out is going to get the problem solved. To me it is kind of a first step though on the way. Just in case it both is the problem or presents possible issues later clean them. If you do not do things in a systematic fashion it may come back to life with you not knowing exactly what it was. That is a bad senario as it may then come back sometime when you least want it to.

One member I remember posting saw globs of stuff pumped out of his return valve with the solvent soak. Had to clean it a couple of times to get rid of the crud. In his case it did get the engine running.

A car that has used wvo sitting around for a time seems to solidify things more in the fuel system as well. You can never assume that the old owner used high quality wvo or just quickly strained what he got from almost any source and dumped it in the tank. The vegatable oil burner I purchased just used new vegatable oil. Yet it resulted in him having a road breakdown and replacing the car.

I believe what I found that caused the stoppage may not have occured on diesel fuel. Or there would have been far less likelyhood. I am not dead set against people burning alternative fuels. Still many doing so do not attempt to do it properly. It also can complicate troubleshooting and those same people that use really bad wvo seem to lack the knowledge to deal with the resulting issues..

Barry is the return valve king. Heed his words....

__________________
Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

In response to Doktor Bert, will yours fill the cup right up when running, or just from cranking (keep in mind mine is not running)?

In response to barry12345, I appreciate all the advise. I tried to be thorough in my posts, but I have forgotten to mention one thing up until now. I did do a diesel purge when the car was still running (using the usual set up) and two bottles of Lubro Moly Diesel Purge. Should that be enough of a clean, or should I still be pumping in something stronger (like acetone) and leaving it over night?

Thank you both!

When I change my filters, I apply vacuum from a hand pump to the shutoff pod and crank the engine for 5-10 seconds and it will nearly fill a small container like yours in that span of time...

I have a small plastic paint cup, maybe a pint????

__________________
Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

I do not know what the base solvent lubro molly uses. A twenty hour soak of more agressive solvent is far more effective and concentrated though. Laquer thinner also breaks down a lot of crud that lubro molly may not touch. Acetone may even be more aggressive. Yet laquer thinner is adaquate. Remember that it is highly flameable as well.

If you have the same fuel filter as when you did the lubro molly thing. You may have filled it with garbage if you did the recycling method of using it. Both return and feed line in the same container that is.

The nice thing about the soak and pushing the solvent and junk out the return is there is no possibility of saturating the fuel filter with it. Thats is if there is signifigant garbage present.

What we are discussing here is just what my approach would be before getting into the actual fault if the soaking did not clear things up. For example I would not want to waste time only to find out later I had a crud problem. It is quite possible and even much more so on an ex wvo burner.

As soon as the partial system is cleaned out if the system does not work it will be easier I believe to establish what is going on. There can be reasons the flow may be much reduced from your relief valve with the lift pump. While still able to get much better flow with the hand priming pump.

At this time I am still suspicious that the stop circuit is not opening up when it should as another member posted. That is especially why I think the soak now is a good ideal. Also crud on the valve seats in the lift pump might also be present.

If the car had not been on wvo there is a quick test to localise the problem I believe. If when using the primer pump a noise or squeel is felt and heard. The primer pump should become harder to push as well. This results from the fuel pressure required to overcome a normal relief valve.

Have someone crank the engine while still hand pumping. Fuel should exit quite noticeably from the element ports as you have the hard lines off. May squirt quite high in fact. If not it is pretty certain the difficulty lies in the shut off circuit for the pump. You know the crankshaft in the injection pump is turning as there is some output from the lift pump.. You can still do this quick test but if it fails soak the pump before trying anything else. The best test for fuel volume from the lift pump is to collect the output at the lift pump.

As lift pumps age their output pressure may decline enough to barely if at all to overcome a good relief valve. So low fuel volume out the relief valve is not good but still non conclusive as to it being the cause of your current difficulties. You have to add any possible existing restriction of the filters into that reduced delivery equation as well.

i think there is only 1 rubber part inside the IP that might be affected if using laquer thinner or acetone? anyone know; i forgot

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1983 300SD (daily driver)
1991 420SEL (work in progress)
1979 300SD (future replacement for 83 SD)

RIP:
1983 300SD (totalled)
1986 420SEL

Yesterday, I tried to see if the shut off was the problem (jiggled it and looked at what was external-I know this isn't enough to know). I didn't take everything off (but I will if people still think this is the issue, but I removed the IP pressure relief valve (I think, see pics) and cleaned it. I also primed the hand primer with the line from the spin on filter to the IP off. I put it back together and cranked. Fuel came out of the 5 holes atop the IP. So, I put the hard lines back on, and it ran again! But then, it died when reving. I think lots of air was getting in/a line was leaking because I a lot of bubbles in the clear line. I called it a night, because it was dark and cold.

Today, I believe I located the cause of air getting in and replaced the line with a pinhole in it (it was the small return line from the first injector to the top of the spin on filter). The engine seemed to run and not create bubbles in my clear line, but would sitll die when reved (also, at one point, NOTHING was coming out of the return line I had going into my coffee can). As it was suggested that my spin on filter might be in trouble, I dumped it. It was nasty (some small chunks and some brown). So I bought a new one. I put it on and got then engine to start, but then it died. Any thoughts on why the return line stopped returning? It was doing great for a minute or two. I will continue to tinker tomorrow, but I am very confused. I am thinking there is either a clog somewhere or the lift pump may be sluggish (can this happen?). Any input is appreciated, but I think the IP is fine.

Thanks everyone!

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Could it be that your previous purge did not clean out the engine fully (especially since it ran WVO)? Could it be that you jut got the "easy" gunk and that the gunk that was not purged has now gotten loose, causing the current issues?

I'm a newbie, too, so take everything I say with a grain of salt

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"Senior Luna, your sense of humor is still loco... but we love it, anyway." -rickymay ____ "Your sense of humor is still loco... " -MBeige ____ "Señor Luna, your sense of humor is quite järjetön" -Delibes

1982 300SD -- 211k, Texas car, tranny issues ____ 1979 240D 4-speed 234k -- turbo and tuned IP, third world taxi hot rod

2 Samuel 12:13: "David said to Nathan, “I have sinned against the Lord.” And Nathan said to David, “The Lord also has put away your sin; you shall not die."