Not quite the power I had. (617A) - PeachParts Mercedes-Benz Forum

300 Super D · #1 10-19-2015, 04:38 PM

So I replaced my IP some time back. (I had the massive thread on losing power on the highway and trying to find the cause)

I did the drip timing method and it started and ran perfectly but after doing a short highway trip last week, I noticed I didnt climb a grade or two as well as I used to and I feel like i may be 5-10hp down.

Questions: How do you guys, who tune diesels, know when you nailed the timing just right? I did that technically I think but, like with a gas engine, especially one with higher miles, tweaking it to get it just right is kind of an art (and a lot easier with a gas motor.) Can you tell by how much smoke you get on throttle? I seem to get no smoke no matter what I do... maybe Im a degree or two off?

In that big thread where I described the engine failure, I also suffered a glowing red turbo. Now Im worried my turbo may not be working as perfectly as it did in before this. How can i test it, outside of just feeling it to make sure its spinning easily. Could i have messed up that wastegate system? (I know nothing about the turbo!)

funola · #2 10-19-2015, 05:24 PM

Did you ever find out why the old pump all of a sudden suffered a catastrophic failure? Did it have the rear pump bracket in place with all bolts well secured? Without it, the pump can vibrate itself to death over time.

If your new pump has a RIV port, it can be timed visually (with a mirror) by centering the lug in the port. Did you try measuring turbo boost? Do you hear the turbo whine?

300 Super D · #3 10-19-2015, 07:50 PM

No I dont have the money to take the pump to the Bosch shop and have it checked. It was fully secure, there was some internal failure.

Thanks but Im kinda past the timing mark methods I think. I researched/talked all of that to death, including buying a timing tool which didnt work properly (it was $28 on ebay.. dont buy one!!!). I did the drip method exactly like the merc. book says. I'm looking for indicators that I have it set perfectly to see if maybe the old pump somehow had better fuel delivery and a little more power. Or if it was just timed better than the current pump.

For example, it seems like with the old pump, I could floor it at 60mph and Id get some black smoke and a little more power. When I do that now, I dont really see much smoke at all and I dont get that extra little bit of power im used to. Either my turbo is off or my timing or the new pump is worn out more. (My guesses anyway)

I have never heard a 617A turbo whine, nor mine, before or after my issues. How would I check boost? I dont have many special tools.

mannys9130 · #4 10-20-2015, 12:44 AM

The new pump has its own ALDA. Your old pump ALDA was probably turned up, and this current one is not. That's why you're feeling a lack of power and not seeing smoke. You can pop the cap off the ALDA and dork with it if you want. You should see just a puff of smoke when you floor it, and it should go away as soon as the turbo spools.

Get a tire pressure gauge and make a boost gauge so you can determine the health of your turbo. Guessing ain't getting you anywhere.

300 Super D · #5 10-20-2015, 04:55 AM

Thanks but I believe the ALDA can only affect my off-the-line power and not my full throttle power. ? At 60mph, going up a long highway hill, and flooring it, gives me no more power now where I used to have a little left to apply.

mannys9130 · #6 10-20-2015, 08:47 PM

Nope. The Alda restricts rack travel unless it sees boost. Doesn't matter what you're doing. If the old pump Alda was turned up, and this one is not, even with the same boost it will be slower. If you don't have fuel to go with the air you won't have power no matter how much boost you are running. The Alda is functional at all speeds and situations.

300 Super D · #7 10-24-2015, 01:13 AM

I checked it today and the nut wouldnt tighten all the way. I turned the adjustment all the way out anyway. I did a pressure test and it held 15psifairly well. It also had two copper washers in there. Did someone do that to space it up possibly?

When people get rid of them, what do they put in place?

mannys9130 · #8 10-24-2015, 02:13 AM

The washers are factory spacers. More shims = less fuel reduction. ALDA removed = full rack travel and full fuel available always. Removing the ALDA allows full fuel all the time, however injecting full fuel without the boost will only result in skyrocketing EGTs and lots of black smoke, you don't get the power until you get the turbo online. If you can moderate your foot, fine. If you like to plant it and hold WOT then keep the ALDA on and adjust it till you just start to get barely perceptible smoke and stop.

People don't put anything in its place. Underneath it is a plunger, but it believe it's sealed. There won't be a hole into the IP once it's off, just a cavity.

If you spent a good amount of time getting the timing nailed with the drip method, I'd say it's probably OK.

Try to adjust the ALDA or remove it and try it in that state. See if you get that missing power back.