Injector replacement..whats needed? - PeachParts Mercedes-Benz Forum

DinNC · #1 03-13-2009, 08:53 AM

So I got a really good deal on some rebuilt injectors from the MB dealership and couldnt pass them up. I am going to swap them into my 81 TD, and was wondering what I needed. Can I just pull the old ones out and put the new ones in, or are there assorted parts and pieces that I should replace as well. I was going to do the fuel lines...but what else? Are there any kind of seals or anything? Thanks.

dannym · #2 03-13-2009, 09:43 AM

They need to be pop tested & ballanced. Don't assume MB did this, ask them.

Other than that all you need are new heat shields.

Danny

coonerboy · #3 03-13-2009, 12:19 PM

Wouldn't hurt to get new injector return lines also. There is a good chance they may rip when you are removing them.

klaus kallas · #4 03-13-2009, 02:08 PM

Make sure your deep well 27 mm socket will fit over the return line nubs. Some are definitely more snug than others....

Klaus

#5 03-13-2009, 02:22 PM

I used a autozone special 27mm deep well socket and a breaker bar. +1 to everything everyone said ESPECIALLY about the pop testing.

bgkast · #6 03-13-2009, 02:45 PM

You will also need a 17mm wrench for the injector hard lines.

DinNC · #7 03-13-2009, 04:25 PM

I am getting a socket and return lines...so I also need heat shields? The injectors have been pop tested...

bgkast · #8 03-13-2009, 05:47 PM

Yes, they crush when the injector is torqued down, and must be replaced when ever the injector is removed.

toomany MBZ · #9 03-13-2009, 06:24 PM

Quote:

Originally Posted by bgkast

Yes, they crush when the injector is torqued down, and must be replaced when ever the injector is removed.

Yep.
You can also use a deep 1 1/16 inch socket.

Diesel911 · #10 03-13-2009, 09:25 PM

Torque Wrench

toomany MBZ · #11 03-14-2009, 06:28 PM

Quote:

Originally Posted by Diesel911

Torque Wrench

Yeah, torque the injectors to 55 ft. lbs.

ashedd · #12 04-04-2009, 08:32 PM

I think I need new return lines. Where would I get those locally? They just look like small fuel line. Sorry for the dumb question.

DinNC · #13 04-04-2009, 09:25 PM

so I still havent gotten around to installing the injectors....sad I know...but at any rate, what exactly is 'pop testing'....

Diesel911 · #14 04-04-2009, 10:53 PM

Quote:

Originally Posted by DinNC

so I still havent gotten around to installing the injectors....sad I know...but at any rate, what exactly is 'pop testing'....

The Spray Nozzles on the Injectors are under spring tension and set to open up (begin injecting the Fuel) within a specific pressure and and all of the Injectors are supposed to be within a min and max pressure of each other.
The pressure is changed by changing the size of shims that go inside of the Injectors upper Body.
A hand pumped Nozzle Tester/Pop-Tester with a Pressure Gauge is used to check when the Spray Nozzles open.

While the Factory Service Manual has a worne min spec, and a new min-max range of opening pressures that are acceptable; Bosch has provided a pressure stamped into the upper body of the Injectors. On my Engine as examble it has 135bar.
One Bar of pressure is aproximately 14.5 pounds per square inch.

The importance of the opening pressure is that it has an effect on the Atomization of the fuel when injected into the Cylineder and a slighe effect on the timing.
If the whole set is not close to the same pressure your Engine may not run smoothly.

ichbineinekrous · #15 04-06-2009, 07:42 PM

Quote:

Originally Posted by ashedd

I think I need new return lines. Where would I get those locally? They just look like small fuel line. Sorry for the dumb question.

bought a meter of it at a local VW dealership last time I replaced mine. They have the nice cloth braided line, maybe 6 bucks for a meter. It's either 3 or 4 mm, can't remember, I'm sure its posted here somewhere.