400e injector replacement

[Dirtleg]

Replacing the injectors on my 1993 400e. When I pulled the old injector about half of the plastic holders that the injector goes into pulled out. The others didn't and are pretty brittle. They also seem to be shoved in the pretty tight. So my plan is to replace the holder/insulators (which term is actually correct?) on all of the cylinders once I get the remaining ones out. Upon pulling them out I keep reading about having to replace an o-ring that goes with the holder? These holders didn't have any o-ring, just a plastic piece that tapers to go into the engine. Am I missing something, or are the O-rings part of the holder itself? My new injectors have both o-rings on them and seem to fit snugly into the holders that popped out, so I'm guessing that's good.

Any help/ideas/photos?

Thanks in advance!

[a777fan]

Hi there.

Can you post a photo that illustrates the items you are talking about? The verbal description you have is not translating for me...

[Dirtleg]

These are what the injectors go into. I think maybe the oring is on the piece.. just faded? Some were pushed pretty deep into the intake, others had their top about.level. When I put it back together it seemed like they were too deep for the injectors to go all the way back in. Even when everything was back in place and bolts exactly where they go. Injectors are identical to old ones. I'm stumped.

[MB V8]

Welcome Dirtleg. Glad you got a response already.

[a777fan]

These are what the injectors go into. I think maybe the oring is on the piece.. just faded? Some were pushed pretty deep into the intake, others had their top about.level. When I put it back together it seemed like they were too deep for the injectors to go all the way back in. Even when everything was back in place and bolts exactly where they go. Injectors are identical to old ones. I'm stumped.

Weird. I have no idea what part that is. Was that on the end of the injector that presses into the manifold?


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[Dirtleg]

Yes it was. I've ordered something that appears to be the same thing. Just haven't seen a lot about them. The fact that the injectors seem to come up short led me to believe that the old "sleeves" were pressed too far in. No idea.

[a777fan]

Hrm. What year and specific model are we discussing here?

When I had my ‘94 E420 apart, the injectors looked like this:



The end is a small black plastic ‘hat’. Behind that is a rubber o-ring. Then a small plastic o-ring that you can see in blue. Then its the injector body.

The manifold ports that the injectors pressed into had no other gaskets or rings:






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[Dirtleg]

Yes my injectors are like that. Look down in the manifold port. You can see that plastic piece I'm talking about. That top shoulder is the top of that plastic piece. It is tapered and allows the injector to pop in and stay in place. You can kind of see the little depression where the injector o-ring locks in. 1993 400e v8.

[a777fan]

I might be forgetting, but I’m almost 100% certain that everything you’re seeing in that manifold pic is cast Al. Perhaps there was a manufacturing change at some point?


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[Dirtleg]

They must have, because about half of them came out with the injectors, the other half I pulled out.

[Dirtleg]

https://www.pelicanparts.com/More_In...VSVSI=3422.htm

[gerryvz]

Hi Dirtbag, yes, the nozzle holders that press into the intake manifold IMHO should be replaced when replacing/rebuilding the injectors. They get old and brittle with age, heat and use. Same is true for the M117 engines.

Cheers,
Gerry

[Dirtleg]

Did you put the holders on the nozzles first and then push them in? It seemed to me like the injectors were almost too short when I tried to reuse the holders that were installed. I know this isn't the case and the fuel rail was positioned right.

[Dirtleg]

Update... injectors replaced. Fired car up and had one injector leaking at the top where it goes into the fuel rail. Took it apart, reseated it and now car won't run. Turns over, fires if I spray a little gas in the intake. Fuel is getting to the fuel rail and obviously has spark. Would a cracked vacuum line keep it from firing all together? I maybe have had some brittle lines that run across the fuel rail that need to be replaced now. Ie. they got broken during the install.

[French02chris]

Hello,
I am thinking about replacing my injector on my 1993 400E as well..

Is it really difficult to do? or should I pay my mechanic to do it?
Any photos or write-up on how you did it? and how long did it take you?
Thanks in advance

[little_e]

Why are you replacing your injectors? What symptoms are you having?

[French02chris]

Car seems to want to stall when engine is not at full temperature ( usually the first 5 minutes of driving and when I am stopped at a traffic light)....idle will slightly go up and down.
The car has 219000 miles and the injectors seem to be original ( never changed).....
Plus, today I decided to smell my engine oil cap, and it had a little odor of fuel.

When engine is warm ( therefore around 80 deg), car idle smooth and run fine ( quiet as well)

[little_e]

I’m having the same issue. You’re talking about a wonky idle just below the 80 C mark? When it’s cold and/or fully warm it’s zero issues?

[French02chris]

yes this is correct....only before the engine is fully warm ( basically, I start the car with no issues, start driving for 2 or 3 minutes , and then get to the traffic light...and this is when the engine would act like it's going to stall ( but only in Gear...does not do it in neutral)...then when the car is fully warm ( and within the day), it acts normal ( steady idle )
MAF and Throttle body have been changed 2 years ago ( not the issue)
Wiring is not the issue...
Caps and Rotors, spark plugs and wires as well as ignition coils are new as well...

It's not the huge issue, but sometimes it bother me...lol

[a777fan]

I had the same issue with ‘wonky’ idle, almost exclusively around 60 degrees.

I was never able to track down the exact cause, but a new wiring harness and a replacement of all vacuum and PVC hoses, as well as the intake manifold rubber donuts seems to have cured the problem.

I would suspect an air leak of some sort before replacing injectors.


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[French02chris]

the gas smell in the engine oil might be my fault...I will have to check again tomorrow...

I was revving the engine today while in park ( to check if my small muffler "crack" was fixed : it is btw ...lol)....
so the smell might be normal for the high revving that I did ?!! I will check tomorrow after driving the car normally

[gsxr]

yes this is correct....only before the engine is fully warm ( basically, I start the car with no issues, start driving for 2 or 3 minutes , and then get to the traffic light...and this is when the engine would act like it's going to stall ( but only in Gear...does not do it in neutral)...then when the car is fully warm ( and within the day), it acts normal ( steady idle )
MAF and Throttle body have been changed 2 years ago ( not the issue)
Wiring is not the issue...
Caps and Rotors, spark plugs and wires as well as ignition coils are new as well...

It's not the huge issue, but sometimes it bother me...lol

I didn't see insulators in your list... did those get replaced with the caps + rotors? A bad misfire at idle, where the engine feels like it will stall, 3 minutes after startup... sounds EXACTLY like the fluid-on-the-back-of-the-insulators syndrome. And, the problem normally vanishes after the car is driven 20-30 minutes.

[French02chris]

I didn't see insulators in your list... did those get replaced with the caps + rotors? A bad misfire at idle, where the engine feels like it will stall, 3 minutes after startup... sounds EXACTLY like the fluid-on-the-back-of-the-insulators syndrome. And, the problem normally vanishes after the car is driven 20-30 minutes.

that is right!! I forgot about the insulators...I looked at them, and it was dry, so I did not change them.. i will install new ones next month then..
also problem vanishes in less than 10 minutes

How about the little smell of gas in the oil after revving the engine??

[French02chris]

Also, when it's raining a lot...the car is more sluggish and erratic idle ( even when driving).....would the insulators cause that issue as well ?

[gsxr]

that is right!! I forgot about the insulators...I looked at them, and it was dry, so I did not change them.. i will install new ones next month then.. also problem vanishes in less than 10 minutes

The insulators only have liquid on the back side... if you did not remove them (requires unbolting the rotor bracket) and inspect the back, you may find liquid on the rear. If you DID remove and they were dry on the back side, they may not be the cause of your problem.

How about the little smell of gas in the oil after revving the engine??

That isn't good. It could indicate an overly rich condition, or a "dripping" injector. This would be tough to diagnose, and harder via keyboard as we can't sniff what you are sniffing.

Also, when it's raining a lot...the car is more sluggish and erratic idle ( even when driving).....would the insulators cause that issue as well ?

In general, no, the insulator problem tends to go away after a while at full operating temp. If the engine is always sluggish in the rain, you might have something else going on. I'd start a new thread with your specific symptoms, as someone else may have an idea, but they may not find your question in this injector thread.

[French02chris]

That isn't good. It could indicate an overly rich condition, or a "dripping" injector. This would be tough to diagnose, and harder via keyboard as we can't sniff what you are sniffing.

it is okay today....I have done a lot of short trips recently , less than 5 minutes trips..
the dipstick does not smell gas, and oil level is the same

In general, no, the insulator problem tends to go away after a while at full operating temp. If the engine is always sluggish in the rain, you might have something else going on. I'd start a new thread with your specific symptoms, as someone else may have an idea, but they may not find your question in this injector thread.

yes, problem goes away after a few minutes of driving, when the car "dries"...it is NOT always

[French02chris]

Anyways, I still want to know if there is a "HOW TO" replace injectors on the M119...which is why I posted here ...LOL

[gerryvz]

Anyways, I still want to know if there is a "HOW TO" replace injectors on the M119...which is why I posted here ...LOL

Not aware that there is, though I've done HOW-TOs that include injector removal for the M104 and the M117.....don't know that anyone has ever really needed to. It happens only about as often as the heads have to come off of a 119, which is about......almost NEVER.

Cheers,
Gerry

[a777fan]

Haha. If you’ve searched and not found one then it probably doesn’t exist.

There really isn’t much to it if you’re mechanically inclined however. Disconnect the injector harness from the injectors. The fuel rail is bolted to the top of the manifold via clearly visible bolts. There are two fuel line connections to the fuel rail towards the back of the drivers side of the engine which can be loosened and removed with the appropriate open ended wrench. Expect fuel to leak, especially if you have recently operated the car. If you are going to have the lines off for a bit, make sure to loosen your gas cap so vapors can’t build in the tank and keep the lines pressurized. (Should only be an issue in warm ambient temps).

Once the bolts on the rail are removed and fuel lines disconnected, simply pull up on the rail to pull the injectors out of the manifold ports. They are squished in there pretty well, so it might take a pretty good tug. Working your way around the manifold evenly also helps so you don’t get anything too cock-eye’d

With fuel pressure removed from the rail, you should be able to remove the metal clip that attaches the injector in question to the rail. With the clip removed you can pull the injector off the rail. Again, its a tight fit, so some wiggling might be required.

Make sure you replace all the o-rings on the injectors while you’re in there. And be careful with debris. You don’t want to get junk in the lines that can clog your injectors!

Check out my owner thread for some pics of my upper end ‘rebuild’ and feel free to reach out if you have more questions.


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[French02chris]

Thanks a lot