300SDL - IP Issues? - Page 2 - PeachParts Mercedes-Benz Forum

DieselGuy53 · #16 09-26-2016, 02:24 PM

Have you changed delivery valve O-rings and the copper washers inside the each delivery valve?
If you have R&R the O-rings, bleed/purge the system off of trapped air.

I had the same issue with mine and this is what I did.

Diseasel300 · #17 09-26-2016, 03:38 PM

I have done the O-Rings and copper washers in the delivery valves. Not to say something didn't go wrong, though there has been no change in behavior at all from before I did it. When checking the internal elements, they'll be done again, so who knows what the outcome may be.

In order of what I'm gonna try on this recalcitrant dinosaur:

1: In-Place solvent soak (24-48 hours)
2: D/V inspection, O-Rings, copper washers
3: Diesel Purge
4: Apologize to my wallet and hunt down an IP

Diseasel300 · #18 09-27-2016, 11:32 AM

I'm starting to suspect issues with the lift pump. I emptied the "redneck gas can" of diesel and filled it with lacquer thinner and moved the return hose to another basin to catch the diesel as it pushed out.

It took almost 5 minutes of cranking to get ANYTHING to come out the return line. I finally did get the IP to start pumping lacquer thinner (could smell it), but in all that time of cranking, I only got about 1/2 cup of fuel through the return hose into the other container. This just doesn't seem right to me.

With the old PRV installed that had no restriction, I never had a problem with return flow, I have to wonder if the lift pump is just at the pressure of the PRV and causing issues with priming and fuel supply? Possibly leaking/bypassing internally?

funola · #19 09-27-2016, 11:44 AM

You have to be careful the type of solvent used and compatibility to seals in the fuel system. As far as I know, the inline IP does not have any rubber seals that are in contact with fuel. I do not remember the type of seals in the lift pump but there are definitely rubber seals in it. Stretch may know, I think he has a post on it taken to bits.

edit: OOPs, you said there are 0-rings in the delivery valves so there are rubber seals in the IP in contact with fuel.

funola · #20 09-27-2016, 11:55 AM

Rubber Chemical Resistance, Rubber Chemical Compatibility, Page 3 - Mykin Inc

Lacquer thinner is listed as unsatisfactory for just about all types of rubber seals.

Diseasel300 · #21 09-27-2016, 01:03 PM

Lacquer thinner is hard on a lot of things. The idea here is to try to dissolve any varnish or sludge present in the IP. The O-Rings are already slated to be replaced afterwards, so no loss there.

The lift pump was still pumping diesel when I was trying to re-prime it with lacquer thinner. This is where my suspicion of the LP came/comes into play. All things being equal, I'd have expected it to quickly prime and push fuel out of the system since all the hoses and filter were full already. This wasn't the case.

funola · #22 09-27-2016, 01:29 PM

If you replace all the rubber seals/ o-rings after a lacquer thinner soak, then no big deal. Make an adapter with a spare banjo bolt/ hook up a fuel pressure gauge to it and see where it's at. Or just rebuild the lift pump.

Diseasel300 · #23 09-27-2016, 02:04 PM

I think it's time to throw in the towel on this IP. Was talking with a friend of mine, who is a Powerstroke guy (sigh), before lunch and he suggested finding out if the IP is capable of popping the injectors. I feel stupid for not having though to do this:

Use a spare hard line, tie an injector on the end, and test each DV to see if it pops the injector.

So I did just that on my lunch break. # 1, 2, and 3 all bled out and fired as you'd expect. #5 bled and fired, but a very short spurt compared to 1, 2, and 3. #4 and #6 bled out, but never fired the injector. #6 dripped a couple of times, but never sprayed, #4 never did anything. I tried to re-bleed, followed by 4 30 second crank bursts with the rack wired full-fuel, and nothing....4 and 6 never fired. No leaks present at either end of the injector line.

Since this was the same injector and line on all 6 D/V i think that pretty conclusively puts the final nail in that coffin... I can try rebuilding the D/V, but as it's already been done and #4 and 6 have been a thorn in my side since Day 1, I don't think I'm going to see any improvement.

I did crank the engine over with the D/V ports all uncovered, and they all shoot fuel up in the air, but for whatever reason 4 and 6 don't develop enough pressure to pop the injector.

Diseasel300 · #24 10-21-2016, 09:45 PM

So I figured I'd post an update on the IP issues with this car.

The Lacquer Thinner soak did do some good to the IP, but did not solve the issues with the violently hunting idle, random missing out, stalling, and difficult starting.

On an unrelated note, I gave the cylinders a nice long soak with Marvel Mystery Oil to try to de-gunk the rings to some extent, which seems to have been successful. The first day, all the MMO drained out the oil pan. The 2nd day, some leaked out, but not nearly as much. Rotated the engine 180˚ and repeated the MMO treatment. Continued rotating the engine and refilling every 2-3 days for a week or so and finally got to the point that the MMO no longer drained past the rings at all. Compression is up slightly, 380-400PSI instead of the 360-380PSI I had before, so slight improvement in compression, but that wasn't an issue, the oil smoke was! Happy to say the oil smoke is 90% less after the treatment, so worth while.

While the injectors were out to do the MMO soak, I took a day to balance the pop pressures using the best holders I had with a new set of Monark nozzles I bought for the old crusty holders. Got them all balanced to 1950 PSI +/-25PSI with perfect spray patterns and excellent leak-down behavior.

After deleting the MMO, clearing out the cylinders, and refilling the engine with oil and IP with diesel fuel, it was time to try again. The usual rocking, hunting, and erratic operation was still present, but occasionally the car would run on all 6 cylinders for 1-2 seconds, and when it did it was buttery smooth, then go right back to rocking and rolling. At this point, it was blatantly obvious that the IP was the issue here, so I tracked down a good-used unit and got it coming this way.

Flash forward to today, I went out to pull the old IP and get the car prepped for the new one. Once the IP was removed from the car, I decided to take the side and bottom plates off to check out the insides. The side cover plate didn't reveal anything too unusual, lots of black gunk inside and a sticky fuel rack (slow to respond when the throttle was returned to rest).

The bottom plate revealed what the problem had been all along: Catastrophic bearing failure. Front ball bearing is intact and tight, but the rear ball bearing has had the cage come apart and the balls have ground down into rough little egg shaped bits. This explains so many things.....the reduced fuel on cylinders 4,5, and 6, the rocking/hunting, the random missing out, the stalling. Having that camshaft wobbling around in there blows my mind that the thing even ran! There was shrapnel everywhere in the bottom half, yet the cam faces still looked ok!

I've attached a few photos taken with my phone. Quality isn't very good unfortunately, but shows some of the larger metallic chunks I pulled out, the metallic grit on the sides of the sump walls (there was quite a bit on the bottom cover, but I forgot to snap a photo), and the rear bearing. On the photo of the bearing, look closely at the top left ball and you can see where the cage has come apart and the ball is in sad shape. The rest of the balls underneath it are worse, but I couldn't get a photo to turn out! You can see the rough condition of the ball cage on the bottom right, looks almost like a serrated knife.

The new IP was supposed to arrive on Monday, but showed up this evening (early delivery, yay!), so I'll post back once the new one is installed and tested.

Apologies for the long post, but I can't stand threads that end in the middle of a diagnostic procedure!

Diseasel300 · #25 10-27-2016, 10:46 PM

So I figured another update is in order. I sourced a "known good" IP from a "running" car and swapped it in. Engine starts, revs, then dies. If the rack is held full fuel, it will start and run at elevated speed, but when the rack is released, RPM takes a dive and the EDS and fuel rack cannot increase speed again, eventually stalling the engine. (The internally grenaded IP had no real issues changing speed, but was missing out randomly and stalling with BIG smoke). If RPM is kept above 1800RPM, everything is peachy, though RPM increase is very slow (5-10 seconds to increase from 1800 RPM to 3000 RPM with the rack slammed against the full fuel stop!!!!), drop below 1500 RPM and there's no hope of increasing speed again, the car will stall, and you can clearly hear the EDS solenoid clattering trying to maintain RPM.

Clearly the IP has an internal fault, got in touch with the seller, and received a refund and was told to keep the parts. Somewhat of a score, I guess, spare parts! Now I'm back at square one with a grenaded IP, and an IP with a sticky/seized governor or gummed up rack.

Some good news did come of the "known good" IP though. The car DOES run on all 6 cylinders, and runs beautifully on them. Amazingly smooth (as in I was surprised how smooth that engine runs).

I've posted a WTB thread in the parts subforum, if anyone has a truly "known good" IP from a truly "running" engine, please get in touch so we can talk.

sixto · #26 10-27-2016, 10:50 PM

The known not so good IP doesn't just need a less tired pressure regulator? Swap it from the grenaded IP.

Sixto
83 300SD

Diseasel300 · #27 10-27-2016, 11:00 PM

Quote:

Originally Posted by sixto

The known not so good IP doesn't just need a less tired pressure regulator? Swap it from the grenaded IP.

Sixto
83 300SD

Forgot to mention in the earlier update (sorry, tired this evening), the pressure relief valve was bad. Replaced with a good one. No change. Tested fuel pressure, slightly low coming from lift pump (about 8 PSI). Swapped out lift pump with the one off the grenaded IP. Pressure slightly higher (12 PSI), no change in operational behavior whatsoever.

Engine runs smooth as a baby's back side on all 6 cylinders, fuel supply pressure is good (a couple PSI low, but shouldn't be causing these issues), injectors are all fine, but it won't rev. I should clarify, when I say it won't rev, I mean you can slam the rack to "full fuel" and wait until the fuel tank drains, and you won't get 1 RPM more out of it. Grenaded IP with all sorts of other operational issues would rev up, but this one won't. Says to me the IP has a problem here.

Diseasel300 · #28 11-04-2016, 11:22 PM

And now to put this thread to bed. Injection Pump #3 went in this evening and the engine runs like a top. Once the lines were purged it fired right up, runs smooth as a baby's ass on all 6 cylinders, revs without any delay, smoke, or roughness. Restarting takes only a single compression hit and it's off to the races, just like it was designed to do!

I have to say though, getting that IP to line up and go into the timing device is a B*#¢h, I hope I never have to do it again, already done it 3x and that was 3x too many...