Question on my spare inj. pump for 617A - PeachParts Mercedes-Benz Forum

300 Super D · #1 12-03-2017, 09:26 PM

I have an inj. pump which was rebuilt in the recent past. I have it off the engine due to losing power one day on the highway and finally having no power at all and having to be towed in. There was a long thread on this incident a couple years ago.

I only recently started looking at the pump again and took off the fuel vacuum shut-off solenoid.

Am I right in that this lever, which I assume the solenoid hooks to, should easily move with your finger, forward and back? I reached in there and tried to move it and it took all the strength in my finger to get it to move an inch. It felt like it was lubed with molasses on a freezing cold day.

Maxbumpo · #2 12-04-2017, 02:40 PM

Sounds like you've identified the problem with that injection pump. The shut-off valve is supposed to be connected to the fuel rack, so that when vacuum is applied to the valve, the fuel rack is pulled all the way back to shut off all fuel. If your fuel rack is very stiff, neither the shut-off valve or the governor can move it as needed to control the fuel going to the engine.

300 Super D · #3 12-04-2017, 03:00 PM

Yeah there's no way that shut-off could move that thing. What could cause this? It had WVO run through it but it was long before this problem occurred and never had any other issue.

I also wonder what the solution could be. Soak the inside with gasoline?

Maxbumpo · #4 12-04-2017, 03:01 PM

Does this injection pump have a good working ALDA?

Maxbumpo · #5 12-04-2017, 03:10 PM

WVO will gum-up the elements, and cause exactly this. True biodiesel is a good solvent, and a good soaking may free it up.

300 Super D · #6 12-04-2017, 04:47 PM

Yes it has a good (looking) ALDA. It wont hold a vacuum though.

Im confused about how this is built inside. How would you soak it? It seems like heating up to 200 degrees in an oven might be the only way to really dissolve that stuff. ?

I assume the internals are bathed in oil to some degree so the part that could theoretically be affected by the WVO would be only exposed to the fuel path. So I'd soak it via sucking in solvent at the intake and turning it by hand until full?

How would the WVO have affected this if it showed no issues months after having just one tank of WVO put through it? What I can see at the outlet and inlets show no signs of any crud. This also had a purge treatment or two until it was finally pulled off the motor.

Diseasel300 · #7 12-04-2017, 06:56 PM

Having dealt with a seized up IP, you're better off scrapping it or sending it off as a core for a rebuild. There are lots of moving parts that can gum up and stick and no amount of purging or cleaning is gonna get it clean enough to work satisfactorily. When they get gummy inside, they need to be torn down entirely and cleaned up right.

The WVO turns into a nasty gummy goo, sort of like partially cured polyurethane. Any of it that leaks past the pumping elements (and there will always be some leak) will react with the engine oil and polymerize it and the heat in the IP turns it all to a solid. Nasty nasty.

300 Super D · #8 12-04-2017, 07:17 PM

Hmm, well just seems weird that people run WVO for years and this pump had ONE tank of partially diluted WVO ran through it. It may have parked overnight once so I guess that's why? I know other WVO users who dont flush it with diesel after every run.

Something doesnt add up exactly but maybe a trip to the Bosch shop for an inspection will be worth it.

Diseasel300 · #9 12-04-2017, 08:01 PM

How well processed was that WVO? I mean did they just run fryer fat through a sieve and dump it in the tank? If it was contaminated, all bets are off...

eatont9999 · #10 12-04-2017, 11:05 PM

Quote:

Originally Posted by 300 Super D

Yeah there's no way that shut-off could move that thing. What could cause this? It had WVO run through it but it was long before this problem occurred and never had any other issue.

I also wonder what the solution could be. Soak the inside with gasoline?

I was going to as about WVO after reading the first post on this thread. That's your problem. The stuff will ruin the injection and fuel system. It leaves a gum-like deposit on everything it touches and it is very hard to remove.

300 Super D · #11 12-04-2017, 11:08 PM

Uh, no, not that stupid pal. It was sent through a centrifuge, as well as filtered down to whatever the micron rating is that's popular. It also sat in the sealed jug for several days before pouring and the bottom 2% wasn't poured in. Pretty much as clean as can be.

Again, not adding up.

300 Super D · #12 12-04-2017, 11:10 PM

Quote:

Originally Posted by eatont9999

I was going to as about WVO after reading the first post on this thread. That's your problem. The stuff will ruin the injection and fuel system. It leaves a gum-like deposit on everything it touches and it is very hard to remove.

Yeah, but anyone can admit that one tank compared to the rest of the guys that do it with their 100+ tank-fulls with no trouble makes little sense.

Whatever the case. I guess it's screwed.

eatont9999 · #13 12-04-2017, 11:16 PM

Quote:

Originally Posted by 300 Super D

Yes it has a good (looking) ALDA. It wont hold a vacuum though.

Im confused about how this is built inside. How would you soak it? It seems like heating up to 200 degrees in an oven might be the only way to really dissolve that stuff. ?

I assume the internals are bathed in oil to some degree so the part that could theoretically be affected by the WVO would be only exposed to the fuel path. So I'd soak it via sucking in solvent at the intake and turning it by hand until full?

How would the WVO have affected this if it showed no issues months after having just one tank of WVO put through it? What I can see at the outlet and inlets show no signs of any crud. This also had a purge treatment or two until it was finally pulled off the motor.

Unfortunately, it needs a complete and total rebuild. Any solvent that will remove that crud will certainly destroy any seals in the pump. WVO is very expensive to run. Cheap at first but then bang, you get to rebuild an IP every few thousand miles.

eatont9999 · #14 12-04-2017, 11:19 PM

Quote:

Originally Posted by 300 Super D

Yeah, but anyone can admit that one tank compared to the rest of the guys that do it with their 100+ tank-fulls with no trouble makes little sense.

Whatever the case. I guess it's screwed.

Maybe it has something to do with when they switch back to dino fuel. I know WMO and WVO do not mix.

Diseasel300 · #15 12-04-2017, 11:22 PM

Quote:

Originally Posted by 300 Super D

Uh, no, not that stupid pal. It was sent through a centrifuge, as well as filtered down to whatever the micron rating is that's popular. It also sat in the sealed jug for several days before pouring and the bottom 2% wasn't poured in. Pretty much as clean as can be.

Again, not adding up.

Obviously not as clean as it could have been. Some types of foods can leave behind high glycerine content and acids in the oil that is very hard to filter out without chemical processing, even then it's always possible to get a bad batch.

If the car was running and driving well before the WVO, and the IP was damaged while running the WVO, there was something about that batch that was not injection-pump friendly. There could have even been some sort of chemical reaction between something in the WVO and any residual diesel left in the fuel system, or the viscosity of the WVO being high enough that the IP starved for lubrication. Hard to tell...