Starting issues 87 300TDT- injection pump or anti-theft?? - Page 5 - PeachParts Mercedes-Benz Forum

1stbenznc · #61 07-12-2010, 11:23 AM

I've read it should be around 10-11 sec or so if all in tune and no mods. The boost gauge will tell me a lot today. I will check for cracks in that metal.

barry123400 · #62 07-12-2010, 11:46 AM

This was a case that may have benifited from a pressure test on the delivery valves in the injection pump using air. There may have been a lot of buildup on the seats. That fuel supply example was nasty to say the least.

If you still have the old pump this test can be easily done with the injection pump off the car. Applied air pressure to a spare hard line connected to the injection pumps elements one at a time. . With a loop of clear plastic in the circuit containing some fluid to indicate any air flow. The clear plastic between the end of the hard line and the air source.

Why not do it out of curiosity? I think you would be the first. A surplus hard line off a wreck is all you need. You will have to rotate the pump to make sure each element piston is at the bottom in turn though to open the intake port for the elements piston. Or at least cautiously inspect them visually. Although I think the visual method is too suspect since I cannot locate the actual point of leakage normally on much larger check valves.

1stbenznc · #63 07-12-2010, 04:02 PM

I am curious to know what was actully wrong with it. I will put that on my "to do" list. I definately will open it up at some point to 1) understand it how it operates better and 2) see what failed.

barry123400 · #64 07-12-2010, 09:14 PM

Quote:

Originally Posted by 1stbenznc

I am curious to know what was actully wrong with it. I will put that on my "to do" list. I definately will open it up at some point to 1) understand it how it operates better and 2) see what failed.

The testing is more revealing than looking sometimes. These are relatively small parts. I based the need for the delivery valve testing on what I saw in one of your pictures.

I could not even properly identify what the contamination was. The solvent you used to soak the injection pump and attempt to clean things may have been far too weak for it.

1stbenznc · #65 07-13-2010, 09:14 PM

vstech - Is this the flex pipe you are talking about? Mine is like swiss cheese on one end and cracked along the seam. I could barely tell until I took it off to examine it. I will do a temp fix with some JB Weld, as the holes are pretty small, until I can source another. Could this be leaking enough pressure to affect the boost?
Also, does anyone know where the vac line to the turbo solenoid(?) goes to? From the looks of it, it's not been connected for a while. I hope these two are where my performance loss is from......

babymog · #66 07-13-2010, 10:39 PM

The first piece looks like the tube from the exhaust manifold to the EGR valve. A little exhaust might escape, I can't imagine it has any significant effect on boost.

The hose you're showing is for the wastegate, with it disconnected your wastegate is not operational so it cannot protect from overboost.

I'm guessing that VS is talking about the flex-pipe between the two exhaust manifolds.

1stbenznc · #67 07-14-2010, 09:36 AM

Yes - It is that piece to the EGR valve. I sealed the holes last night anyway. Should be dry this morning. I think my wastegate is not working, but will test it out today with some pressure. Is this the model that is pressure operated. Meaning if it fails it can only overboost and not reduced boost (like you are implying). Can it be stuck partially open. The arm on it won't budge, but I will put some pressure on it today.

First, I need to see how much boost I an getting. Haven't had time the last two days. I picked up a $25 boost gauge from the auto store. I think it will be a good diagnostic tool

babymog · #68 07-14-2010, 11:37 AM

Pressurize the hose, it should open the wastegate. Yes, failure as in the disconnected hose can cause over-boost, not a lack of boost like the later vacuum-actuated version ('91-up 124 & 92-up 126?).

Where are you located? I've probably got a spare one or two of that tube, might be able to take a load of parts to the Ohio GTG if I go.

1stbenznc · #69 07-14-2010, 12:00 PM

Thanks for clarifying. I will pressure it up and see if it moves or hear it move. No -I am near Raleigh , NC- Thanks for the offer Jeff!
Car time is this afternoon

vstech · #70 07-14-2010, 12:11 PM

heh, I'm just a tad closer to you!
if I have any spares, I'll offer em up to ya!
and the cracked part I am talking about is built of the same material as the egr hose you have that's full of holes, but larger in diameter, and it's part of the exhaust manifold betewen cyllinders 2 and 3. mine was cracked, winmutts was cracked, and I'll bet yours is too. when it's cracked, the turbo builds up almost no boost.
it could have gotten hot from the wastegate hose being off, and overheated, then failed. so be sure to get your wastegate fixed!

1stbenznc · #71 07-14-2010, 08:47 PM

Thanks Vstech! I got the boost gauge hooked up and inspected the other metal piece you are talking about - it looked okay. Before I tested it I cleaned the overboost valve on the fire wall (little dirty), valve bolt on intake and the lines better, just to be sure. I warmed up the car took it out for a ride. To my surprise I was getting good boost. At full throttle and maybe 4000-4500 rpm I was getting 10-11 psi max. The hard part was getting up the rpms (read below)

I put about 25 miles on the car today, each mile seemed to run a little smoother and faster. I think all the Mobil one and Italian tune-up runs are clearing the system.

I think I found where the issue is though. The car shifts through the gears too fast!. At normal acceleration it has shifted through all three gears by 25-27 mph!!!

I read the forums and searched around. I did see talk about the bowden cable to the trans. It did have some slack in it and it adjusted it so that as the throttle linkage begins to move so does the bowden cable. However, this did not work. It still shifts too fast. When I manually shifted the car it really took off.

How can I change the shift points up? This will make the car right. The vacuum box attached to the Injection pump is adjustable. Will moving it do this. What does it do?

BTW - It has nothing to do with the shifting, but what affect does the hole in the turbo manifold have? Just saw this 30 minutes ago while inspecting under the car.

Other points:
-Bowden cable is well secured to the trans
-My trap oxidizer (cat) is straight piped
-Trans fluid is at the right level and does not smell burnt. (I did add 2 quarts to get it right). The car has not run in two years.

babymog · #72 07-14-2010, 08:59 PM

That hole will leak exhaust, which will lower exhaust pressure and boost. It will also make the cabin smell like exhaust.

DO NOT ADJUST VACUUM-RELATED HARDWARE!!!!

The vacuum only changes shift harshness, is the last thing to adjust after everything else works properly.

Does the bowden cable move freely? Is it fully extended at full-throttle?

1stbenznc · #73 07-14-2010, 09:15 PM

So can I just mig weld the hole closed? Is there an exhaust impeller in there? I need to have the straight pipe section welded at the muffler shop soon anyway (where the trap ox/CAT was). I will not mess with the vacuum part. and will double check to see if it is fully extended at full throttle. I didn't check that yet.

The main question to all is how can I extend the shift points up? It seems that 4th gear should shift near 40-50 mph under normal acceleration -not 25mph. Is this cable the only adjustment on the trans.?

vstech · #74 07-14-2010, 09:20 PM

NONNONONTONTONONONOONNONO!!!
do not attempt to mig cast iron!!!
it will shatter as it cools!
yes there is an impeller in there.
you can wrap it with permatex exhaust patch, and seal it up, or you can replace your turbo.
you could pull the turbo from the volute, and braze it up, but I don't know if exhaust temps exceed brazing melting temps...

1stbenznc · #75 07-14-2010, 10:24 PM

This stuff, right? Is it low pressure in there though?

PERMATEX® Hi Temp. Metal Repair Compound

Makes long-lasting repairs to high-temp, low pressure exhaust leaks from the exhaust manifold to the muffler. Gets stronger with heat up to 2000°F. One part, water-based ceramic is safe and easy to use.

Suggested Applications:
Cracked and broken exhaust manifolds, headers, furnaces.