Are w124 injectors DIY'able?
 

I had one replaced by a local mechanic...but I think now after him telling me one of them was leaking...I kinda wanna get them all done for good measure in the attempt to fix my terrible mpg and performance.

I looked in the Mercedes CD for a PDF on it...but couldn't find any?? Did the original CD not come with injector replacement instructions?

Is it DIY'able? The indy that replaced mine said they can be screwed up if not done correctly....

Any other place with instructions? Or did I miss it on the CD?

I did 5 of the 6 on my M104 engine and it is was routine. To get to the last one in the middle, IIRC, I need to remove some air hoses and I want to be ready with replacement parts in case the hoses disintegrate. If your M103 uses seals and insulators, you'll need those too. These things are not cheap and it may be an expensive way to hunt down a misfire.


glenmore
1991 300CE
2000 C280

124 is a chassis which has many different motors and types of injectors. But assuming you're asking about 103 motor injectors, yes they are quite easy, and also quite cheap.

http://mb.auto.pl/wis/w124/CD01/Engine/103/07.3-6520.pdf

Thanks guys. Sorry I have a habit of using w124 too much...gotta stop that!
I saved that PDF....Not sure why I can't find it off my MB CD :confused:

Can someone tell me if the 3L M103 engine requires insulators? I know it uses a seal.

I'm not worried about the cost...because once they are done, I will be covered for a long time on them. I have been saving alot of money and unfortunately as far as I know...there is no way to directly "test" the injectors other than pulling them out. If I am going to have to take them out....I might as well replace them.

That PDF does not mention Insulators...so I assume it does NOT need any...but can someone confirm that for me please?

Parts sites like Fastlane or ********AZ have the engine serial number ranges for the different parts but it still may require you to take one out for a look see to confirm.

glenmore
1991 300CE
2000 C280

I also checked A/H AZ and it only mentions a seal too...but do sell an insulator as well so I still would like to double check. Looks like it is $150 in parts for the injectors + seals.

I haven't done it (yet) but it looks to be almost as easy as swapping diesel injectors....just more smelly. (I hate gas smell, its horrid....)

CD 1 / Model / Engine / Mechanical & Combustion / 7.3 / 6520

Yes, they are DIYable, but you need line (flarenut) wrenches for sure.

You also need hex or torx (depends) drivers.

DIY without proper tools is dumb. All you can save on is labor--you still need the same tools the pros use, or you'll tear stuff up.

Access is limited on some injectors and removal of fuel lines is required. In addition, same limited access increases liklihood of stipping out allen socket on holddown screws.

There are insulater plus seal on the M103 engine that's in your '88.

I think L-Jetronic better than K-Jetronic, but the latter's injectors sure are cheap in comparison.

There's really no need for intructions, as it's simply unfasten/refasten. Don't bend the lines and don't overtighten them.

The instruction on your CD is 07.3-6520, "Removing and Installing Injection Valves."

Could the insulators be used from the current injectors or do they have to be replaced? Any possible consequences to using the current ones if they don't have to be replaced?

I have all those tools so I should be fine.

Did this job last year on my '90 2.6 M103 engine. Pretty simple. Only a little to remove for access. I did not replace the insulators on mine (at 100+K miles) and have not had a problem. The older mechanical style injectors do wear and will leak after a time. Mine had evidently been doing so after engine shut down. When I replaced all 6, under two of them (4&5) there was a wetness in the manifold after removing the injectors. Cured the slight, stumbling, rich-flooded re-start I was experiencing after an hour to a day or so of standing.

A less expensive route is to send them to http://www.cruzinperformance.com/

They'll clean, test, replace seals and provide a flow test report. Call Rich at (231) 796-5705 to confirm scheduling and have questions answered. I've used him 2 times and always been satisfied.

You wouldn't want to send out CIS injectors to be cleaned and rebuilt - it's just too cheap to replace them.

I might replace them on ours this summer if I have the $$ to do so. Ours does the stumbly startup sometimes too. (not often though)

When I changed mine out, I could have reused the old insulators. There was no damage or wear in the plastic other than being discolored. IIRC there is an "O" ring there that should be renewed.

glenmore
1991 300CE
2000 C280

That's what I figured as all I hear is that the O rings can go bad and cause vacuum leaks. I'll pull the insulators and if they look okay I'll reuse them...if I am suspect on any of them for any reason I'll replace them.

Thanks for all the info guys!

My miscue. I priced injectors for my 94 e320. $85 ea for m104 vs $29 ea for m103.

I have read that many injectors never pass flow tests even when new...should I get mine cleaned and flow tested rather than buying new? What would you guys recommend.

The injectors are pretty much the only thing left that could be causing my misfires. I've been through everything else. Am I right in reading that if one injector is opening early, the pressures on the rest of the injectors are thrown off due to the CIS' design?

I think I've got the same problem. I took out #1 injector only to look at (not wet/leaking) but I replaced the small rubber seal with a new one. The insulators are plastic. No need to replace but note the orientation of them (there's a hole through the middle). I've got the stumble at restart too. My idle is also not smooth so I'm thinking a bad spray pattern. I've been reluctant to replace them because of less than 50k miles and with other CIS-E cars never needed to, even after 100k+ miles. Oh well. Maybe I'm lean at idle but without an exhaust gas analyzer I've no way to know. Runs great otherwise so I've 'lived with it.'

I don't think anyone refurbishes CIS injectors - cost with freight would be about the same as buying new ones.

Right...same here. I've driven the 300TE every day for the last 4 years with the problem...It doesn't effect its ability to drive...only the idle quality at the lights.

Fair enough. With new insulators and seals included total is $178 from ********arizona. Not too bad. Glad the K-Jet are so cheap compared to other x-jet systems. Gonna replace the insulators for good measure...last thing I would want is to skimp on $25 and have the problem revolve around leaking insulators...

i just replaced all of the injectors, injector seals, insulators and o-rings today on my m103. cylinders 3 and 4 were the most difficult, but the job was pretty easy.

car seems to drive alot nicer now

Any tips for accessing 3 + 4?

Got done. Injectors were my rough idle misfire problem!
Took about 1hr 30mins to do it....very straightforward.

It seems I did not need the lower bushing that I purchased....Guess ********az was wrong. Oh well only out a couple bucks.

Great news. Congrats. How many were leaking or clogged at idle? Your MPG should be ~20 now. I'm gonna bite the bullet and do this job also.

Not sure...it was getting dark outside so decided to just do them all at once. The insulators looked very tarnished...so I am glad I bought new ones.

Filled the car up yesterday so fingers crossed I'll be spending less at the pump.

Awesome, that's great to hear! Looks like I'll be pestering the wife again to let me change them out on her 300E....it has an occasional rough idle and has been cranky about re-starting (will die unless you give it a shot of gas with the pedal when starting), but once started it runs fine and never stalls. I suspect the injectors are leaky/not atomizing correctly. At 137k and original I bet they are more than due for replacement (as well as the insulators and o-rings)

Yes I recommend spending the extra $20 and getting the insulators.

Mine is only 93k miles and "supposedly" changed just before 60k miles...which now I am doubting.