Another hot shakes query... - Page 2 - PeachParts Mercedes-Benz Forum

vwnate1 · #16 01-29-2019, 02:14 AM

Thanks for this .

I too discovered light rust on my delivery valves and reddish looking fuel in the D.V. well after I removed them, cleaned ever so carefully with Q tips and no change so I harvested set of DV's from some core injection pumps, tried them, no joy, most were somewhat worn although none had the rust so I bought a set of new DV's from the Classic Center and installed the, the engine is smoother but recently broke yet another air cleaner 'T' bracket, this one was an aftermarket one , I found the $ to buy the new M-B factory one ($110 OUCH) and it's in there, I hope it lasts a while if not forever .

Shern · #17 01-29-2019, 01:26 PM

Any idea what causes that corrosion? Or the reddish fuel?

Diseasel300 · #18 01-29-2019, 06:17 PM

Quote:

Originally Posted by Shern

Any idea what causes that corrosion? Or the reddish fuel?

Water.

Shern · #19 01-29-2019, 07:11 PM

Quote:

Originally Posted by Diseasel300

Water.

Reasonable, though I have a tough time getting my head around the source.
It was primarily in bore one... if it was water in the fuel, surely I’d have a systemic issue? Wonder if this came from cleaning my engine a few months ago.

Also, did you manage to completely polish the ring off your plunger?

Diseasel300 · #20 01-29-2019, 08:03 PM

Quote:

Originally Posted by Shern

Reasonable, though I have a tough time getting my head around the source.
It was primarily in bore one... if it was water in the fuel, surely I’d have a systemic issue? Wonder if this came from cleaning my engine a few months ago.

Water is always present in some quantity in the fuel system. It comes in with your fuel from the pump, it collects from condensation in the tank, etc. The only fuel/water separator on these cars is the spin-on fuel filter and it is not perfect. Even if the fuel you're buying is clean, it should be changed at least annually just to get rid of the water trapped in it. The rust and red fluid you saw is probably from where water settled around the sides of the DV holder where there is not much fuel flow. Since it's heavier than the fuel and the gap around the DV inside the DV holder is not an area of much flow/turbulence, it would stand to reason that water could collect there and cause rust over time. It only takes a drop.

Quote:

Originally Posted by Shern

Also, did you manage to completely polish the ring off your plunger?

No. My goal was to smooth it out and try to polish the faces to each other to improve the sealing surface. I'm not about to shell out for new DV's when for 50% more money I could have a calibrated and rebuilt IP.

vwnate1 · #21 01-29-2019, 08:05 PM

I know my Coupe had water in the tank when I bought it years ago, I could -see- it in the clear plastic intake screen .

Once it actually chugged to a halt on a Sunday morning in front of a Korean Church, I was embarrassed as all get out as I removed that screen. blew it out and was able to get going again .

Because of this reddish crud and rusty delivery valves I hunted up a pristine 1985 300SD that a semi had run into the back of, it had clean fuel in all the filters (no black crud at all) so I bought the injection pump and steel injector pipes and installed them after I got all the crud out of the fuel tank .

I can't see anything but water causing rust or reddish fuel ~ I live in the city so died farm Diesel isn't anywhere near me .

That's purple anyway, IIRC .

Shern · #22 02-01-2019, 01:24 PM

Very helpful, thank you! I guess this is something to keep an eye on from time to time.

PDeputy · #23 12-02-2019, 06:21 PM

Quote:

Originally Posted by Shern

Alright, it appears I've gotten to the bottom of the shakes –at least for now.

I pulled the hardlines and removed each valve assembly for inspection and cleaning.
What I found within the assembly was interesting. Unfortunately, the environment was dark and difficult to photograph. There was a bit of fine particulate in bores 2-4, but nothing too bad(?). I was able to clean them with q-tips, followed by a thorough priming.
Bore one however contained quite a bit of reddish, I'm assuming rust. That took a bit of swabbing but was eventually returned to a clean state. Injector 1 had been nailing a bit (confirmed by loosening hardline) during cold starts.

The valve holders were all a bit rusty/reddish, though valve holder 1 had the most of this stuff on the outer surface. I have no idea from where or how it came to form.

The surface of each plunger was fairly smooth. No varnish or crud. There was a thin line however that marked the spot the plunger made contact with the valve holder. I then employed Diseasel's cerium oxide method for polishing the bevelled edge of each plunger and holder. I polished until the line stopped catching on my finger nail, though I was never able to remove it entirely.

Here's a photo of each assembly (the detail on the plungers was impossible to capture).

As you can see, number three's body is very scored, I assume, from spinning within the bore.
One and two aren't terrible and four seems okay, though my assessment is arbitrary.

I reinstalled each DV along with new valve springs and crush washers.
So far so good. The side to side oscillation is gone.
It seems the issue did in fact lie somewhere within the Injection pump, though too many variables were affected to pin anything to a single cause.

Has anyone else tried this? What did you find?

I have been posting about my surging idle that only happens when engine is hot. I have already addressed virtually every cause in the last few months. See "Surging Idle" if you want to see.

I read the posts with the one I quoted above. And the one item I haven't addressed is delivery valve replacement. I have a parts car that I can pull delivery valves from. Just messaged you to see if there is anything I should look out for when removing and replacing the valves. I have ordered new crush washers.

I am asking because I read an older forum where a man used a magnet to remove his valves and turned into an rats nest to resolve.

Shern · #24 12-02-2019, 07:26 PM

Didn't get your message, but nothing too crazy pulling them out. Remove the valve holder/flare attachment (not sure what that part is called -basically what you're hardlines screw into) slowly as the spring underneath may want to pop out. Take the spring off and remove the DV assembly. Believe I used pliers to remove the pintle, and the body of a ballpoint pen to remove the barrel. They are not under any pressure, nor are they fixed to anything.

On occasion, you may find a stubborn crush washer. Prod at it gently, without scratching anything, and you should be in business.

vwnate1 · #25 12-03-2019, 08:54 PM

I did this before giving up and buying a BOSCH rebuilt IP, I used a magnet to remove the old DV's, they're two pieces that are machined as pairs so don't mice them up ! .

I had to search a lot of old IP's to find un rusted DV's, eventually I bought new DV's from the M-B Classic Center, they were not terribly expen$ive, too late I discovered you're supposed to replace the little springs too....

.

Yes, the new DV's helped a lot but I think that IP was toast in spite of coming from a low mileage 300SD that had clear clean fuel in it .

I spent some time tweaking the ALAD's adjustment to get decent power and little smoke, this pump is apparently doing O.K. in another member here's car ~ I gave it to him and he's well pleased with it .

Many have said that new DV's & springs helps smooth up both hot idle and overall running so might as well give it a try .