Injectors Replaced - Chapter II
 

I finally got both the injectors changed in the 260E 124, and 300SE 126.

On the 124:

I noticed a prompt response on the kickdown, and the lightness in touch on the gas pedal. Previously, it was sluggish. Now it behaves more civilised with an even-power distribution at torque. Relatively ease in projecting 0-100 km/h without the sudden surge and slug.

The engine sounded smoother too - not so much like a diesel powered powerhouse.

I felt it was worth the while replacing the injectors - despite the advise of some.


On the 126:

The noticeable difference is in the accelerator. It seems much lighter than it was before, and the delivery of power could be felt - smoother than it was and with a gradual silky acceleration. Response was more sensitive on the depressen of the gas pedal.

I also changed the brake-pads (had original, and refitted original). Applied the brake paste AND cleaned with a generous spray of Brake Cleaner over the disc and within the brake-clips. Noticed silent-braking now. Am wondering how long would it remain silent before the squeaks return.

Summary:

It WAS necessary to change the injectors.

Thank you all for your comments and advise, to which I am grateful and guided.

:)

Glad to hear it worked
 

Nice to hear good news...

--Craig:)

Just changed all 4 injectors on my W124 230E (4cyl). I agree with your observations...well worth it especially on a 13 year old car like mine. The new smoothness of the torque band alone has made me very happy:D

Couldn't agree more with you, yal.

We took the car for a cruise last night and made 2 more observations in the "to-do" notepad.

1. To check the engine combusion.

The engine was last overhauled with pistons and valves change and grind last year. But somehow, carbon still accumalates. Rapid acceleration would blow those carbon away, and after a few successions of acceleration, the carbon built-up is minimal. I only notice this "habit" of carbon building in the W124 260E and wonder if any one else might have a similar "habit".

2. Tuning

It defintely requires a good tune-up with the new injectors. The idling has gone way up to 1.1, and thus the engine rev is a little noisy and burning excessive fuel ...

Kerry,
The high idle might be a sympton of something else...I am guessing it could be your idle valve. It sounds like you are also running rich. You might want to post this problem separately to get some responses.

Yal - The idle valve and OVP has been changed. I too think its running rich and plan to screw the CO down (not literally though). Will do that later and see how ir runs. As it is, I'm convinved that with the lowering of the CO, and thus rpm falls below 1000 - the noise should revert to near normal. I did a preliminary test last night and it sure confirmed my analysis.

I hope it won't lead to anything else or I'd be the first to email you for help and directions.

Keep well.

:)

YMsin. sorry I missed Chapter 1. but what problems did you encounter that made you replace the injectors on the 126?

I've already gotten a fuel filter due for replacement, and I thought I may as well replace the injectors too. Any tips prior to and during the injector replacement?

Thanks!!
:)

Mervyn
1983 W126 (280SEL)

hi Merv - check out the link which would answer all your queries:
http://www.peachparts.com/shopforum/tech-help/26068-necessary-change-injectors.html?highlight=injectors

Hope to meet you and your Benz in Singapore soon.
:)

Hey Kerry,

What kind of mileage are we looking at on the W126?

hi Ted - the 126 we have has about 120K on it. The rolling pin on the running meter died this year, so I think it ought to be about 122K. But its definitely beyond 10 years.

What about your 560?

Hey Kerry,

It has 106,700 miles. No engine work has been performed *yet*, although timing chain and guide rails will replaced at 110-115k miles. Lifters are soemwhat loud and hope to replace them this winter.

It runs and starts like a charm, uses no oil, and beside the noisy lifters issue not much to complain about BUT, the car could be a *bit* smoother at idle when the motor is cold-- first 5-10 mins of running. It doesnt stumble and the tach is rock steady at the corrects RPMs when it's at a stoplight in "drive" or in "park", but it could be a smoother. I did run some Techron through it last winter, but I don't think it did anything.

I was wondering if it might be the injectors? I don't think it's the motor mounts, as it smooth as silk when I rev it...

Ted - you never know. New injectors could do more for a smooth engine.

It would be a luxury replacement - when nothing else needs doing, but the desire and urge to replace something exceeds common logic.

Ted, are you sure it's noisy lifters that is causing your problem? These engines have hydraulic lifters that I would have expected to take up the slack. My 560SEL has 70k on the clock and has valve train noise, not sure exactly what it is yet though.

Matt.

YMsin, I've visited the thread, but I was expecting some technical reasons which made u replace the injectors. Nonetheless, I agree with u entirely on your quote:

It would be a luxury replacement - when nothing else needs doing, but the desire and urge to replace something exceeds common logic.

Looks like I will succumb to this quote very soon. Thanks and continue to enjoy your new injectors!
;)

Mervyn

Ted, mine has somewhat loud, but harmless lifter noise too. I'll leave them alone for the time being.

But I'm gonna do this very soon: replace the 2 engine shocks. I've already replaced the motor mounts, but I can still feel a tad vibration of the engine body transmitted thru the car's chassis. "Blame" it on my creamy smooth idle, and my desire for a vibration-less wait at the stop-lights.

Cheers!

Mervyn:D

Matt,

You are correct sir, I meant the rocker arms. One is quite loud for about 2 seconds when it's really cold (like about 10 degrees F or colder) "tap-tap-tap", then it goes away.

Kerry, thanks for the info, I think I'll hold off injectors for a while. One thing at a time :)

Happy Thanksgiving to all!

no probs Ted, are you looking at replacing the rocker arms? I have heard elsewhere that these do wear over time. Might check the prices of these at fastlane. Update, just had a look on Fastlane and these are between $12 and $20 each depending on the brand chosen. 16 each are needed so cost would be $192 and $320 plus fitting. I wouldn't imagine that these would be too hard to fit, basically just torque them down correctly. Anyone done this?

According to Steve B. of Continental Imports:

"On the 420/560 motor it is most likely that the problem is a rocker arm to cam issue. It can all be done without removing the head. Removing the rocker arms to view their surface would be the first step after removing the valve cover. The removal is facilitated by the special spring depressing tool.

There will be no way to see the bad part of the rocker without removal. If the cam is rough you won't need to remove them for a diagnosis but it will require a cam. MB says that cams and rockers should be done together. In the field the rockers are replaced without the cam, at least till the cam is rough.

Be sure the cam oil tubes are tightly mounted into the cam stands."

There's a procedure in the MB service manual (or CD) for this. I'd hate to have to replace my cams, yikes that could be big $$.

Just checked Fastlane and they list the left camshaft at $263, I am also due for a timing chain and related. I can see this might get expensive :-(

One thing at a time, but on the other hand everything is apart, so might as well do as much as you can once you are in there. How 'bout the valve stem seals?? ;)

True, if you have to use the spring compressor to remove the rocker arms then the seals are quite easily done at the same time. Has anyone had to replace the lifters?

Ted:

Check the two little o-rings on the end of the shaft on the oil filter housing cover -- no one ever seems to change these, and they get old and hard and leak. Oil leaks down from the lifter galleries over night, allowing the lifters to go "flat", and they rattle when you start up.

Cheap easy fix, much better than a camshaft or new lifters! -- cured the noise on my 87 300D.

Peter

Thanks Peter, it crossed my mind, but it's easy to overlook. That'll be the first thing checked before digging into the top end! :)

The problems listed above may have been solved with a stroke of a thorough analysis of the engine.

The throttle cable was jammed at one point, and thus the rev was stuck.

Solution: replaced cable. Now the pedal is so much smoother and lighter, and yes, the rpm is back where it should be and the engine sounds very much quieter.

The black smoke could have been due to badly-needed-to-be-replaced air hose which showed signs of extreme wear and tear.

Got that changed too.

Not, the engine performs as good as new and the response immaculate. Black smoke? Don't see that burp coming out now.

I guess, all is well.

:)

YMsin, great to hear more good news from you.

Could you elaborate on the throttle cable and air-hose pls? I mean, do you have the Part Numbers and prices? I may want to address those symtoms that you mentioned.

Thanks!
:)

Mervyn
1983 W126 (280SEL)

I will hop into the real shop and get the details for you.

But then again, it was done for the 124, and the 126 might be different?

Thanks YMsin! I know its for the 124, but somehow my 126 is experiencing somewhat similar symtoms, so I thought I may as well give it a go like what you did.

Keep me posted on the details, thanks!

:)

Mervyn

I think he means that the part numbers will be different for the 126 than the ones for the 124 so the info you asked for may not be of any use to you.

Matt.

Matt, I realized that. Thanks. But any info pertaining to these 2 parts would be pretty useful, if the 126 does have them.

Mervyn

I called the "real" shop on my mobile and was told that the 126 may not come with the throttle cable. It is bound by a rod.

I will be hoping over for them to have a look and I shall get right back here with details.

Merv - *sorry*.

No cables. The 126 are connected by rods. They would need a good lubing to make it sleek.

:D

Thanks anyway YMsin.

Maybe I'll go check the air-hoses that runs from the idle-control valve. Read somewhere that if they're all dried up or filled with crud, replacing them will help the idling pretty much.

Have a nice day!
:)

Mervyn

Mervyn:

Makes a huge difference -- my 300TE banged and thumped something awful, and stalled all the time until I replaced the idle valve hoses. They were loose on the valve! Rock hard, too.

Clean the idle valve while you have it off -- fill with carb cleaner, shake, and dump until the carb cleaner stays clear. Wear gloves, it contains methylene chloride -- removes all the oils in you skin!

If you've had the idle mixture adjusted recently, you will need to have that re-set, too -- you will eliminate a serious air leak at idle.

Peter

Peter:

Great tips, will do just that, thanks!
;)