Had quite the scare while installing my IP today. - PeachParts Mercedes-Benz Forum

bipolardave · #1 01-27-2012, 10:24 PM

I recently got my IP back from being rebuilt and finally had the time and help to get it back on today.

Initially, things were going smoothly. Too smoothly. Even the bottom mounting nut was coorperating.

My mechanic buddy and I got everything back in and started to set the time by the drip method.

When I started to work the hand pump, absolutely nothing was coming out of the drip tube. We full expected it to leak profusely until we dialed in the timing. We worked it for a while thinking it might take longer to refill an empty fuel system.

After 5 minutes, still nothing.

I started to recheck the FSM procedure. 24 BTC... check. Start/stop lever in run...check. Delivery valve and the spring only removed...check. Nothing was amiss, so I started to panic.

Thinking there might be something wrong with the IP, I called the Bosch reman shop. They do too many pumps to remember any specfic one, but they were stumped as to why there was nothing coming out of the drip tube as well.

I was sweating bullets at this point. Not only was it going to have to come back out, but it was going to need to go back to the shop about 100 miles away.

Why wasn't this pump spraying diesel when we worked the pump?

Running out of options, we decided to shift it. Lo and behold, loads of fuel began squirting out.

As it turns out, we were so close to being *spot on* with the timing. Despite it being my first time removing/reinstalling and timing an IP, we were 1mm away from perfection. It was oh so slightly advanced.

After spending a few minutes getting exactly 1 drop per second, we tightened it down and buttoned things up.

I had incorrectly assumed that we'd be off by quite a bit would have to perhaps even reindex the splines once or twice and we prepared ourselves for such. The last thing I expected was for it to be right and proper on the first go around.

Funny how we convince ourselves that things are more difficult than they really are, no?

Anyway, after bleeding the lines, she fired right up. In my brief ownership, it's never sounded or idled so well....like a purring kitten served on a plate of warm butter.

There was some white start up smoke which went away and some black sooty smoke when I blipped the throttle. Before it was all white and diesel smelling stuff that choked up the garage and left a 100yd long vapor trail.

I was going to road test it but it appears as though the thermostat has given up in the last month that she spent in lay up. With the weather wintry for the next few days I won't be able to take it out. Once the t-stat is in and coolant flushed (might as well), I'll take her out and report back. But I'm optimistic that for the first time in a long while, she'll run like the day she came off the assembly line.

New timing chain, fresh injectors, and now an exorcised injector pump. Life. Is. Good.

Thanks for all the help, folks!

tangofox007 · #2 01-27-2012, 11:32 PM

Quote:

Originally Posted by bipolardave

I had incorrectly assumed that we'd be off by quite a bit would have to perhaps even reindex the splines once or twice and we prepared ourselves for such. The last thing I expected was for it to be right and proper on the first go around.

If the IP is installed properly aligned, there is no reason why it should not be very close to start of delivery.

Couper · #3 01-28-2012, 12:16 AM

Quote:

Originally Posted by bipolardave

Thinking there might be something wrong with the IP, I called the Bosch reman shop. They do too many pumps to remember any specfic one, but they were stumped as to why there was nothing coming out of the drip tube as well.

Congratulations. You must be one of the very few driving with a freshly rebuilt IP.

How much did you rebuild cost? What did they do?

I was under the impression that there are very few places that do this for our car and it very expensive. Figure that trucks must have their IP rebuilt all the time, but very little demand for us passenger drivers.

bipolardave · #4 01-28-2012, 05:22 AM

Quote:

Originally Posted by Couper

Congratulations. You must be one of the very few driving with a freshly rebuilt IP.

How much did you rebuild cost? What did they do?

I was under the impression that there are very few places that do this for our car and it very expensive. Figure that trucks must have their IP rebuilt all the time, but very little demand for us passenger drivers.

It cost $766 at Mountaineer Diesel in Charleston, WV. There were initially using Bosch parts until I pointed them toward MB. The price difference between the Bosch diaphragm and the MB unit was almost $150!

That included a new governor diaphragm, rear cover with poppet cam (?), lift pump rebuild (my parts), and whatever voodoo they perform on the flow bench. Their driver makes state wide pickups, so it was also delivered to my door saving me a three hour round trip and half a tank of gas.

They primarily rebuild large pumps from trucks but have the capability to rebuild IPs for our cars, although it's not something they do on a regular basis.

Couper · #5 01-28-2012, 01:14 PM

Thanks for the details Dave.

The price seems like a great bargin. My guess was well over $1,000 as my neighbor spent over $600 twenty years ago.

What symptoms were experiencing to cause you to spend the money and time to have your IP rebuilt?

bipolardave · #6 01-28-2012, 01:37 PM

Quote:

Originally Posted by Couper

Thanks for the details Dave.

The price seems like a great bargin. My guess was well over $1,000 as my neighbor spent over $600 twenty years ago.

What symptoms were experiencing to cause you to spend the money and time to have your IP rebuilt?

Mostly it was the word from the local (realtively speaking) Indy Mercedes shop. When I had it in for a new timing chain, he set the IP timing as well and said that a vacuum check turned up some leaking at the governor. He said that it wasn't a critical issue and I forgot about it until after my car came out of the body shop just before Xmas.

On bright, clear days I noticed streams of a whiteish, light grey smoke out the back at highway speeds. At idle, I could smell diesel and would have a noticeable haze that hung around theback of the car. On overcast or rainy days, the lack of light or the increased moisture masked it and there was nothing in the rear view mirror.

Since a new timing chain had been rolled in, IP timing set, and the PO replaced the injectors last year, I just figured that I'd work down the list and have the IP checked out.

I replaced the coolant and t-stat today, so I was able to get about 25 miles on the clock before the rain picked up and I brought it back in. Salty roads, muddy splashes, new paint and all that.

Because of the light rain we were having I couldn't see imuch in the mirror save for the occaional black soot on acceleration. I also didn't notice any increase in power. However, it does run buttery smooth and there's no more diesely exhaust smell. I no longer hear the engine at highway speeds so much as I do road noise. either. So it may not run like a new car, but it certainly sounds like one.

At the end of the day, it could have been a mistimed injection pump. I didn't really troubleshoot. I took the shop's advice and pulled it. If nothing else, though, rebuilding the IP is good preventive mantenance after almost 40 years.

Couper · #7 01-28-2012, 02:47 PM

You sure treat your cars right. Respect. Good to know that it makes that much of a difference.

As reasonable as your cost, doubt that more than a small handful of us w123 will spend the $750 on rebuilding an IP. A tranny , absolutely, as it is critical to drive.

I'm confused about why the IP wouldn't pump diesel in your original post. Was it because you just need to move it around a little?

Stevo · #8 01-28-2012, 03:08 PM

Quote:

Originally Posted by bipolardave

It cost $766 at Mountaineer Diesel in Charleston, WV. There were initially using Bosch parts until I pointed them toward MB. The price difference between the Bosch diaphragm and the MB unit was almost $150!

That included a new governor diaphragm, rear cover with poppet cam (?), lift pump rebuild (my parts), and whatever voodoo they perform on the flow bench. Their driver makes state wide pickups, so it was also delivered to my door saving me a three hour round trip and half a tank of gas.

They primarily rebuild large pumps from trucks but have the capability to rebuild IPs for our cars, although it's not something they do on a regular basis.

Your 240D is the 74, is that the IP with the goat skin diaphragm?

bipolardave · #9 01-28-2012, 11:54 PM

Quote:

Originally Posted by Couper

I'm confused about why the IP wouldn't pump diesel in your original post. Was it because you just need to move it around a little?

Yes. It was pretty much spot on. The IP was just past the "begin delivery" stage where the IP is pressurizing the fuel line, for lack of a better description. At this point, there would be no fuel leaking past the delivery valve during the timng procedure.

I didn't anticipate it going that smoothy and being that accurate. I automatically and incorrectly assumed something was wrong.

bipolardave · #10 01-28-2012, 11:55 PM

Quote:

Originally Posted by Stevo

Your 240D is the 74, is that the IP with the goat skin diaphragm?

Yes. The old one didn't look too bad. If anything, there was wear on the poppet cam (?) shaft in the governor that was causing the vacuum leak.

79Mercy · #11 01-29-2012, 12:30 AM

you should post a video of this thing starting and running, i'd love to hear the new IP on your 616.

bipolardave · #12 02-02-2012, 06:33 PM

Quote:

Originally Posted by 79Mercy

you should post a video of this thing starting and running, i'd love to hear the new IP on your 616.

You gave me an idea.

Not will I plan on doing this, I'm going to do with different sets of fuel injectors.

The goal is to test fuel economy, noise, smoke, cold starting, and butt dyno performance for each set. I'm hoping to video every step including the spray test in the shop.

I'll compare the existing low mileage Bosch reman to some "salvage" variety that I just bought from another member. I don't know their history, so it'll be a double blind test of sorts.

After that, I'll have the same Bosch shop that rebuilt my IP go through the "salvage" injectors with Monark nozzles and then install them. Lastly, my existing Bosch injectors will be pop tested, adjusted if necessary, and reinstalled.

It make take a few months to put this together, but I'd like to get it done before spring so as to get the same temperatures and same blend of diesel that I start the first set with.

I think we're sort of lacking in data when it comes to injectors. I'm silly enough to attempt to rectify that.