How do you replace the ignition coils on 400E

[richardkwon]

I think the ignition coils are located on the driver side right behind the headlamps. For the life of me, I can't get the airbox housing off that sits right behind the headlamps so that I can get some extra room. How do you take this thing off? I noticed there are 2 tabs at the bottom but there is some cable wiring that that feeds into the housing as well as some type of electrical connector.

Second, how do you take off the ignition coil housing covers?

 

[samiam44]

easy,

The wire temp sensor plug ... unplugs. Pop the clips and the back cover comes out. But to answer your question... what you want to do is remove the Headlight assy. Pop the turn signal out, remove the lower trim piece, small screw on the inboard edge, screws in the turnsignal pocket and the ones on the top. Then you'll have plenty of room and it will be easy.

Plan on a few hours and a beer or 2.


Michael

 

[Trae]

Is there one of Gerry's "how to replace coils" somewhere on this site?

 

[ivanned]

I got them out with the headlight in place but it was the most PITA 2 hours of my life. There are some screws that have very little access and it takes magic and lots of motivational curse words to put them back once you have them out.

 

[jhodg5ck]

we Always take the headlight out..to muck about otherwise will just drive you batty.

Plus, gives you a chance to clean up some in there...the drains like to clog w/ miles.

j

 

[gsxr]

+1. Pull the headlight, it will save time, knuckles, and sanity. The job is bad enough even with the headlight out (pic below). Make sure to adjust the headlight beam afterwards, it will need tweaking.

 

[richardkwon]

OMG, I did not think it was going to be this difficult! Looks like I'll have to spend a weekend on the car to do this job. For the air housing, unclip the wire temperature sensor, then there are some wires that go into the housing. How do I take those off?

And then, after we take the headlight out, how do you get the plastic covers off that cover the ignition coils off? Do I have to undo the ABS unit that's on top of the coil area to get access to the coils?

And the Bosch spark plug wire set that I got has 3 wires, I assume 2 for the ignition coils. Where does the 3rd go to?

 

[ivanned]

I should know better than to argue with Dave, but if you have a steady hand and if you don't want to remove the whole headlight, I would just try it by just removing the back cover only. Took me about 2 hours to replace my coils that way, which is way too long for a few nuts and bolts. I also had a third wire in my Bosch set. I assume its extra. I wouldn't worry about it. Use the longest and the shortest.

 

[richardkwon]

I just finished replacing my 2 ignition coils on my 400E last night. Took me about 2 hours. Most of the time was manhandling those two plastic coil covers. There's just not enough space to easily pull those things off so it takes a lot of finaggling to get those off. Just an FYI, I did not need to remove the headlight and did not see any advantage space wise had the headlight been removed. The headlight was not in the way during any part of the procedure. The 500E may be different.

First, remove the long air hoses and the front engine top cover and the distributor cap plastic housing. Then disconnect the air sensor from the headlamp plastic cover. I replaced my air sensor with a new one. To remove the sensor from the housing, use a 90 degree needle nose plier, push down on the two ends of the metal tab and then simultaneously pull the tab from underneath the sensor. The sensor then pops out. I noticed on mine, the plastic tabs broke due to age and the foam washer was also deteriorated to nothing.

Then lift the tabs at the bottom of the headlamp cover and lift up the plastic cover. Make note of the ignition wires. The longest one goes to the right coil from the passenger side distributor cap and the shortest wire goes from the driver side distributor cap to the left coil. I removed the left coil first. The plastic coil cover needs to come off. Pry open the end where the wire goes in. Just use a flat tipped screwdriver to pry it open. Then pop off the wire from the coil. Then separate the plastic cover from the wire and jigger it out. I forgot how I got it out but I turned it around, upside down, turned it around at various angles and finally it will come out. Then move the wire out of the way. 2 10mm nuts and bolts hold the coil to the housing. For the left coil, the 2 nuts and bolts are located on the left side facing the engine. Remove the first bolt and nut closest to the headlight using a rachet. Then to get to the second nut and bolt, you will need an open ended wrench as the nut touches a hose. You will need to keep a finger on the bolts to completely remove the nuts. Then there is an 8mm and 10mm nut that holds the wiring to the coil. Be careful not to lose the washers. Then remove the coil.

For the right side coil, the 2 nuts and bolts are located on the top. The first bolt and nut is very easy to remove. The second one is located toward the fender and access is very limited. Remove the 13mm bolt that holds the horn to the ABS housing and this will give you a lot more room. Then, using either a 10mm crows foot or a very tiny 10mm open ended wrench, undo the nut.

My right coil had been replaced at some point previously but the left coil was still the original. Installation is the reverse and goes much more quickly. Sorry that I don't have pics. I was wanting to take some but it was so damn hot and I really wanted to get this thing done quickly before night fall.

 

[bgalakazam]

The longest time for me was putting back the covers. About 30min per coil total without taking out the headlamp.

 

[jhodg5ck]

with the headlight out R&R'ing the coil covers is about 5 min, combined.
Plus, I do like to have the opportunity to Clean up/around/behind..said light .The drains like to get clogged and all manner of dirt/debris accumulates in the plastic headlight surround.

The light takes about 5-10 min max to remove, install is about 5 min

Jono

 

[richardkwon]

with the headlight out R&R'ing the coil covers is about 5 min, combined.
Plus, I do like to have the opportunity to Clean up/around/behind..said light .The drains like to get clogged and all manner of dirt/debris accumulates in the plastic headlight surround.

The light takes about 5-10 min max to remove, install is about 5 min

Jono

Damn then maybe I should have removed the headlight. The thing that really got in the way was the AC sight glass and the metal line.

 

[jhodg5ck]

indeed they do, but with the light out you have Far more options when it comes to hand placement/angle of attack..;-)

 

[mbzgurl]

the ignition coils on 500E

I think the ignition coils are located on the driver side right behind the headlamps. For the life of me, I can't get the airbox housing off that sits right behind the headlamps so that I can get some extra room. How do you take this thing off? I noticed there are 2 tabs at the bottom but there is some cable wiring that that feeds into the housing as well as some type of electrical connector.

Second, how do you take off the ignition coil housing covers?

Oh no!! Aren't you guys going to finish this thread? Don't stop now... I need more info.
I have to put coils on my 500e. There's no instructions or decent diagrams anywhere on any of the usual sites. I called tech help at a couple of these parts places and they don't know what they're talking about....
Guy: "Your car has only one coil. It's easy."
Me: " my car has two coils."
Other guy: "Hummm, dunno. Can't your mechanic do it?"
Me: "Arhgggggghhhhh!!!!"
Thanks! I'll print this thread, go get a ....then, I'll go outside and stare at my machine.
It's stormy out there, the wind is blowing like a hurricane

BTW~ I paid two different mechanics buko-bucks to fix the rough idle and ABS problem. Now my car runs worse than it did before I took it there. Plus neither mechanic even bothered to check out the caps and rotors or plugs. I checked them out and that was part of the problem. Wasted my money. ��

Then, my roommate and his friend insisted on helping me put the new parts on. The car wouldn't start after they finished it because they put the caps on but forgot to put the rotors or the dust shields on. Plus, they didn't connect the wires right! They got mad at me when I told them....

​

I stayed up all night and fixed it myself. It was really a no brainer. The caps and rotors helped some, but I still have the pulsating/rough idle problem after it warms up about a block away. Now I'm stuck. I can't figure out where the coils are exactly or how to put the new ones on. Next I'll change the spark plug wires and plugs, and have someone install a new fuel filter. Hopefully that cures the problems. What about the ABS light? Can someone plz help me with that?
BBL

 

[gsxr]

Re: the ignition coils on 500E

mbzgurl, check the condition of the spark plugs, and make sure they are the correct non-resistor type (Bosch F8DC4, or equivalent from Champion/NGK/etc). Before wasting money on spark plug wires, measure the resistance of each, should be ~2000 ohms (anywhere between 1800 and 2400, approx, is acceptable... if they are like 5k or 10k ohms, replace them). Is your engine harness original? If you're not sure, check the date code, see the forum Wiki for instructions.

Posts #6 and #9 above show where the coils are. Save yourself headaches and pull the headlight out, trust me, this job is miserable if you try to do it with the headlight in place. Takes 5 mins to pull the headlight.

If you have an ABS light, you'll need to pull diagnostic codes from all modules, clear them, and see which ones return. You'll need to build or buy a blink-code reader if you don't already have one. Details on how to use it are in this thread:
http://www.500eboard.com/forums/sho...s-(Diagnostic-Trouble-Codes)-on-the-500E-E500

After you pull the codes, start a new thread on the ABS light issue. If the new coils etc don't fix the idle issue, start a new thread for that as well. People aren't going to find your rough idle (or ABS) problems buried in a thread on coil replacement....

 

[clarkz71]

Re: the ignition coils on 500E

with the headlight out R&R'ing the coil covers is about 5 min, combined.
Plus, I do like to have the opportunity to Clean up/around/behind..said light .The drains like to get clogged and all manner of dirt/debris accumulates in the plastic headlight surround.

The light takes about 5-10 min max to remove, install is about 5 min

Jono

Dave, Jono, and I all agree on headlamp removal. Having done this job many times
and tried different ways. Take advantage of our experience.

You can also inspect the auxilary fan pre-resistor condition and the supply wire.

The power supply wire end & terminal can start to melt/corrode.

 

[mbzgurl]

Re: the ignition coils on 500E

mbzgurl, check the condition of the spark plugs, and make sure they are the correct non-resistor type (Bosch F8DC4, or equivalent from Champion/NGK/etc). Before wasting money on spark plug wires, measure the resistance of each, should be ~2000 ohms (anywhere between 1800 and 2400, approx, is acceptable... if they are like 5k or 10k ohms, replace them). Is your engine harness original? If you're not sure, check the date code, see the forum Wiki for instructions.

Posts #6 and #9 above show where the coils are. Save yourself headaches and pull the headlight out, trust me, this job is miserable if you try to do it with the headlight in place. Takes 5 mins to pull the headlight.

If you have an ABS light, you'll need to pull diagnostic codes from all modules, clear them, and see which ones return. You'll need to build or buy a blink-code reader if you don't already have one. Details on how to use it are in this thread:
http://www.500eboard.com/forums/sho...s-(Diagnostic-Trouble-Codes)-on-the-500E-E500

After you pull the codes, start a new thread on the ABS light issue. If the new coils etc don't fix the idle issue, start a new thread for that as well. People aren't going to find your rough idle (or ABS) problems buried in a thread on coil replacement....

Hi Gerry~
Thanks! I think I see where those coils are. And I see the plastic covers. How do you take those things off? I'll do it now if you call me. I'll pm you my cell.

I'll take the headlight out too, boy, I better be able to finish this job by tomorrow morning or I'll be in deep doo-doo.

If all goes well and the car runs, I'll get a code reader and check the spark plug wires. Already bought the correct plugs. Do I need to get new copper washers?

 

[gsxr]

mbzgurl, any update on your 500E issues? Did you get it fixed?

 

[2phast]

I will toss in my .02 on the topic, as I recently replaced both of my coils.

As mentioned, remove your drivers headlight, I can't imagine trying to do this with it in place.
The plastic coil covers unsnap and are easily removed.
The bolts holding the coils in place are the problem. If I had to guess, these were installed in the car minus the motor, headlights, radiator support, ABS etc. R&R is a afterthought, but typical of German engineering (sort of like a Panzer). Anyway, your going to need a socket and open end wrench to get the bolts/nuts off. The coil located closest to the drivers fender isn't that difficult, the coil next to the motor is quite difficult. The bottom bolt of this coil is partially blocked by a hose, so you need to be careful taking it off so the nut does not fall into the engine bay. Getting it back on is a nightmare though and I must of dropped the nut 10 times. Its best to have a telescoping magnetic bolt pickup tool at hand, as your going to need it. I also found this project went faster with a extra set of hands holding onto the open end and/or socket while you held the nut/bolts in place or attempted to get the threads started.

Set aside a couple of hours for the project and take a Valium before you start.

 

[emerydc8]

A stubby 10mm ratcheting wrench made this job a bit easier for me.

Maybe the E420 coils are slightly less restricted than the E500E because I can't see how taking the headlight out would make the job any easier. I think someone else with an E420 had the same experience and didn't need to remove the headlight.

I agree about dropping the nuts into a black hole. I actually lost one and had to come up with a replacement. I have no idea where it went.

 

[2phast]

I didn't use a stubby, but agree the ratcheting wrench is very helpful

 

[Maui]

I have a new set of coils just haven't got in the mood yet to replace them.

 

[gerryvz]

I have a new set of coils just haven't got in the mood yet to replace them.

You better have a few Cohibas on hand and a six-pack of beer.....

 

[Trae]

Just replaced both coils on the 93'.

That pesky little nut that threads onto the bolt that holds the mounting bracket closest to the engine for the #1coil was a bear. It is the lower 10mm nut that attaches to the #1 lower coil bolt.

Most of you know me as a man who does not cuss or swear, but that particular nut and bolt was driving me nuts!

Patience is the name of this game and I finally got lucky and threaded the nut onto the bolt.

This did not fix my problem, so I will check the coil wires tomorrow.

I know that I should have inspected the coil wires first, but my blink code reader kept telling me the #1 coil was bad, so I just replaced both coils.

 

[nocfn]

Ugh, always seems to take more effort, the more frustrated you get. Might be wires, you just needed new coils in a month so you got it out of order. Chicken or egg ... Or was it coil or wire?

 

[Trae]

I am keeping my fingers crossed that it is the wire and NOT the EZL.

If the wire is not corroded and reads 0 OHMS, the only thing left upstream is the EZL.

Only things downstream are the cap/rotor/spark plug wires/ and spark plugs.

 

[Klink]

I am keeping my fingers crossed that it is the wire and NOT the EZL.

If the wire is not corroded and reads 0 OHMS, the only thing left upstream is the EZL.

Only things downstream are the cap/rotor/spark plug wires/ and spark plugs.

I'm trying to send you good vibes, Cap, but it is almost always the EZL, and for what it's worth, they usually take themselves out.

I have never seen an EZL damaged by something external. You can dead short the primary wires, and it won't hurt them. People can drive around for years with open plug wire ends causing huge flyback voltage in the primaries, and it won't hurt them.

But one day you may start your car, and find it is missing on four cylinders. Or eight cylinders. It happens both ways. You may be changing the oil on somebody's car, and when you restart it, this is exactly what happens. At least five times to me personally since EZLs existed...

 

[500Eboard]

Yep. My EZL half-died after I parked my car in a lot & went into a store for 10 minutes. When I came out -- BLAMMO !!! No warning. Four cylinders dead.

 

[Trae]

Thanks for the good vibes and well wishes about my EZL, however, it is now confirmed that I have a defective EZL.

Swapped the 92' EZL into the 93' and it ran like a top.

Planning on buying one from GSXR.

 

[Klink]

Thanks for the good vibes and well wishes about my EZL, however, it is now confirmed that I have a defective EZL.

Swapped the 92' EZL into the 93' and it ran like a top.

Planning on buying one from GSXR.

Don't you mean "Planning on buying one from GSXR/Kent?"

 

[nocfn]

Shocking

 

[gerryvz]

GSXR/KentYou mean, "Dave's Uncle" ?




The Bosch EZL units seem to fail much more oftan the the Siemens EZLs; I bet your "bad" unit is a Bosch.

Please post a photo of the failed unit.

Cheers,
Gerry

 

[Klink]

Uncle? Are you sure they aren't the same guy? I can't tell them apart...

 

[gsxr]

I have never seen an EZL damaged by something external. You can dead short the primary wires, and it won't hurt them. People can drive around for years with open plug wire ends causing huge flyback voltage in the primaries, and it won't hurt them.

Klink, the internets claim that failing or defective coils can kill an EZL, including a new EZL... and that MB requires documented coil replacement for the warranty to be valid on a new EZL. Is any of this true, or just urban legend? Unca Kent wants to know!

 

[Klink]

Klink, the internets claim that failing or defective coils can kill an EZL, including a new EZL... and that MB requires documented coil replacement for the warranty to be valid on a new EZL. Is any of this true, or just urban legend? Unca Kent wants to know!

Well, you can tell Kent that I don't doubt that a defective coil COULD hurt an EZL, I've just NEVER seen that happen on any EZL on any model that uses an EZL. And the outputs are supposedly protected against any likely external fault including dead shorts of the outputs.

There is no coil replacement warranty requirement that I've ever heard of, but it is a good idea anyway. It's not like the coils don't go bad, they do. But to repeat, I have never seen a coil kill an EZL. I have seen a number of bad coils, and a number of bad EZLs with never any evidence that one did in the other. I have also never found both the EZL and the coil(s) bad on the same car at the same time. Not ever.

I also find no evidence of them being even remotely thermally sensitive. I've seen body shops leave them laying on the exhaust manifold paste side down!

It is easy to do on a late 107, lots of harness length. Symptom? They shut off after an hour on the highway, restart after 15 minutes sitting, run for another hour, lather, rinse, repeat from California to Tampa. Screw it back onto the inner fender, and they continue as if nothing ever happened. If I hadn't seen it myself, I would never believe it. Got a phone call once from a friend with the same symptom after collision work. Same thing. Unbelieveable.

DON'T try any of this stuff at home! But, I stand by the concept that EZLs are almost indestructable. Some unfortunately are suicidal, and even those are remarkably few...

 

[Trae]

After replacing the EZL today, I drove 10 miles and parked the car.

Ran errands and restarted and the symptoms returned for about 60 seconds, then disappeared for the drive home. Ran great after that.

So, I am not completely sure that I had a bad EZL yet.

Sent a picture to Dave of the EZL that I suspected to be bad.

Oh, I forgot to tell you that I bought an EZL from Newton Autohaus in NC. Part # 013-545-64-32

 

[Klink]

Put your suspect EZL on the "good" car and see how it does. Another thing that I've never seen is an intermittent EZL. Not ever. I'd bet they exisist, but I've never seen one...

 

[Trae]

I know that I have told you guys thanks many times over, but

THANKS! It is great to know that we have such an abundance of resources here on the board..

In all the years I have been on this board, I have never waited very long for answers to any problems.

GSXR, Gerry, Jono, and Klink have all been abundantly patient bringing us newbies up to speed.

 

[Trae]

Will do Klink. I will report back tomorrow.

 

[gsxr]

Trae's mechanic had the nifty pliers shown below, which apparently work wonders to remove stuck boots from M119 distributor caps. Anyone know where we could buy these puppies?

 

[sheward]

I have a set of Gearwrench wrenches. I believe they came from Harbour Frieght, if I may borrow your term. I also think I saw them there.

drew

 

[Glen]

Trae's mechanic had the nifty pliers shown below, which apparently work wonders to remove stuck boots from M119 distributor caps. Anyone know where we could buy these puppies?

Is this what you seek?

http://www.homedepot.com/p/GearWrench-Double-X-Hose-Pliers-Set-3-Piece-82107/204618681

 

[gsxr]

Is this what you seek?

http://www.homedepot.com/p/GearWrench-Double-X-Hose-Pliers-Set-3-Piece-82107/204618681

Yes! I believe you found them, Glen... thank you!

UPDATE: I bought the set from Amazon. Photos attached below. I was not impressed with the quality, the fit and finish are poor. They are closer to what I'd expect from Harbor Freight for $15, not GearWrench at $50/set. The corrosion and discoloration seen in the photos is from the pliers brand new out of the box. But, they do work nicely, and will be fine for occasional use.

http://www.amazon.com/GearWrench-82107-Piece-Double-Pliers/dp/B0012S99ZQ/

 

[Trae]

I am claiming victory and doing the happy dance today.

Drove over 100mi. from 0-100mph. and everything performed flawlessly!

Stoplights, start and go, and highway speed were smooth and normal.

I sent GSXR a picture of the "presumed" defective EZL, so he may post it here.

As for the title of this thread, I corrected the only blink code I ever received with my defective EZL.

"#1 coil defective".

 

[nocfn]

the greatest feat is that you successfully loaded a picture!

 

[gsxr]

Trae, the real test would be to pop the questionable EZL into your other car and see what happens. Lay it on top of the existing EZL and the wires will just reach. If the other car acts up, that mostly confirms it's bad. However, this would be the first "intermittent" EZL that has been spotted in the wild. Might need to send to Klink for some post-mortem!

 

[Trae]

Still don't know how to load pictures, GSXR did that.

OK, I will hook it up to the other car, see if it gives the same symptoms, and report back here.

 

[nocfn]

Uncle Kent strikes again, just like in Castle Wolfenstein! When you open a reply thread, in the dialog box there is a + sign, tap that and you get the camera or photo option to upload.

When you open a reply thread, in the dialog box there is a + sign, tap that and you get the camera or photo option to upload.

 

[gerryvz]

I think that's the first failure I've seen of a Siemens EZL.

 

[Trae]

I can't believe that worked!

I feel very accomplished today.

Maybe I can live in the 21st century with your help Louie.