300D is a big disappointment - Page 3 - PeachParts Mercedes-Benz Forum

Manual Life · #31 07-21-2010, 01:23 PM

I'm on the verge of repenting. I will beg forgiveness if Injection Pump timing is the fault. I decided to investigate IP timing while I was being a google Nazi after I decided to consider the preignition problem. Allow me to relate the following.

The previous owner of the car (owned for 3-4 months) was a "diesel mechanic." He had advance the pump as far forward as he could for more power. When I purchased the car I asked him to return the IP timing to normal. He retarded it almost back to the punch mark on the block and the IP mark now sits 2-3mm advanced/above the block mark. I know he didn't do the BTDC route or mess with anything else other than loosing the 4 IP bolts and moving the IP as he saw fit.

Now, idle on my 300 feels like bad timing on a gas engine. Upon acceleration it smooths out but has since ownership has acquired the knock.

I've read about the IP timing and have an old Haynes. Between 30-20 BTDC on compression stroke almost nothing happens in terms of fuel. Though I do get a squirt of fuel somewhere between 15 and 20 ATDC. Then nothing after that.

I know or assume to know that the IP pump is well out of timing. But, before I can go any farther I need to know If I need to purchase a new Primer Pump before doing a proper IP timing diagnostic. The current one leaks like a busted fuel line WHEN I TRY TO PUMP IT. Is there a way around using the priming pump or should i go get one?

Stretch · #32 07-21-2010, 01:35 PM

Quote:

Originally Posted by Manual Life

... The current one leaks like a busted fuel line. Is there a way around using the priming pump or should i go get one?

I'd go and get one - it will add air into the system and cause uneven idling!

See this current thread:-

http://www.peachparts.com/shopforum/showthread.php?t=281396

junqueyardjim · #33 07-21-2010, 02:12 PM

First thing most new owners of old Mercedes diesels have to do. Replace the primer! Best first repair you can make and it only cost like $12.00 bucks or find one in the P & P for a $1.00

whunter · #34 07-21-2010, 02:28 PM

Quote:

Originally Posted by Manual Life

I'm on the verge of repenting. I will beg forgiveness if Injection Pump timing is the fault. I decided to investigate IP timing while I was being a google Nazi after I decided to consider the preignition problem. Allow me to relate the following.

The previous owner of the car (owned for 3-4 months) was a "diesel mechanic." He had advance the pump as far forward as he could for more power. When I purchased the car I asked him to return the IP timing to normal. He retarded it almost back to the punch mark on the block and the IP mark now sits 2-3mm advanced/above the block mark. I know he didn't do the BTDC route or mess with anything else other than loosing the 4 IP bolts and moving the IP as he saw fit.

Now, idle on my 300 feels like bad timing on a gas engine. Upon acceleration it smooths out but has since ownership has acquired the knock.

I've read about the IP timing and have an old Haynes. Between 30-20 BTDC on compression stroke almost nothing happens in terms of fuel. Though I do get a squirt of fuel somewhere between 15 and 20 ATDC. Then nothing after that.

I know or assume to know that the IP pump is well out of timing. But, before I can go any farther I need to know If I need to purchase a new Primer Pump before doing a proper IP timing diagnostic. The current one leaks like a busted fuel line. Is there a way around using the priming pump or should i go get one?

Manual Life · #35 07-21-2010, 04:38 PM

so let me get this correct.

For IP timing-
1-Set crank to 24 degrees BTDC on compression stroke
2- Adjust IP until i see some fuel welling up on #1 at a rate that seems to match a drop every 10 seconds. (i would measure a drop by the volume of fuel that accumulates in the "bowl"/tapered area where the injector line plugs into the injector.)

Seems a bit too simple for me to be correct but that's what I narrowed it down to. fix my ignorance in this procedure because i'm sure there is a good amount of it.

Is it worth my time to make a spout? i feel like my fuel measurement method is sufficient.

And, if i really wanted to I could just loosen the IP, run the car and decide what timing I like best WITHOUT hurting anything. Not that I want to do that, just wondering.

whunter · #36 07-21-2010, 05:24 PM

Quote:

Originally Posted by Manual Life

so let me get this correct.

For IP timing-
1-Set crank to 24 degrees BTDC on compression stroke
2- Adjust IP until i see some fuel welling up on #1 at a rate that seems to match a drop every 10 seconds. (i would measure a drop by the volume of fuel that accumulates in the "bowl"/tapered area where the injector line plugs into the injector.)

Seems a bit too simple for me to be correct but that's what I narrowed it down to. fix my ignorance in this procedure because I'm sure there is a good amount of it.

Is it worth my time to make a spout? i feel like my fuel measurement method is sufficient.

And, if i really wanted to I could just loosen the IP, run the car and decide what timing I like best WITHOUT hurting anything. Not that I want to do that, just wondering.

Making a spout is a few minutes effort = a great investment..

Manual Life · #37 07-21-2010, 08:25 PM

Quote:

Originally Posted by Manual Life

so let me get this correct.

For IP timing-
1-Set crank to 24 degrees BTDC on compression stroke
2- Adjust IP until i see some fuel welling up on #1 at a rate that seems to match a drop every 10 seconds. (i would measure a drop by the volume of fuel that accumulates in the "bowl"/tapered area where the injector line plugs into the injector.)

And, if i really wanted to I could just loosen the IP, run the car and decide what timing I like best WITHOUT hurting anything. Not that I want to do that, just wondering.

will make a spout tomorrow. my concept of IP timing is correct?

ik04 · #38 07-23-2010, 12:15 AM

Howdy!

You need not worry about finding donor cars and parts in Central Texas. Austin has some very well stocked used Mercedes parts shops and a decent supply of older cars still running on the road.

Between Houston and Dallas you can find just about anything you could want for an older Mercedes. Craigslist and Google will serve you well.

I am putting my engine back together right now and got most of my parts locally or online from sites in Texas...

Enjoy your car!