Tusc

Key Question: Is there a way to diagnose whether it is the coil pack or the voltage transformer which has failed prior to renting/buying from v12icpack? Also, what are my options for plugs since if I'm going to do the job I may as well toss a new set in. I did already find a source for the red boots.

Here's the full BOOK, since sometimes details are important:

Several days ago, my girlfriend saw a light on in my car parked outside and told me about it (I was dead to the world at 3am when she got in) but she didn't take it upon herself to go fix it. I'd replace her, but she has other good uses!

The battery was dead in the morning, so I jumped it. I am 100% certain that there were no lights on in the car when I parked it the night prior.

That night when I got home and parked, I ensured no lights were on when I locked it and went inside.

When she got back from taekwondo, I looked out and an interior light and one single driver side headlight was on (one of the ones which blink when you lock the car.)

I cycled the alarm lock and it went away.

The next day, I was coming home from work and noticed that when I pressed the pedal to pass on the highway there was a hesitancy before the car reacted. Five minutes later I received the following codes:
P0203 - Injector circuit open #3
P0301 - misfire #1
P0303 - misfire #3
P0305 - misfire #5
P0400 - EGR flow malfunction
P0603 - PCM keep alive memory (KAM) error - "limp home mode?"
P0444 - EVAP emissions control system purge valve C open
P0300 - Random/Multiple cyl misfire detected

There were no mechanical noise changes when this occurred. I pulled over and looked for leaks / checked fluids, etc. Deemed the car safe enough to get the remaining 7 miles home at an idle.

In reading online I see that the Coil is the primary suspect. That the voltage transformer is a possible alternate - but I don't know if cyls 1/3/5 reflect one "half" of the TV going or not per what I read. And one reference states that battery issues can cause misfires.

My primary concern is resolving the misfires so I can return the car to daily driver status instead of bringing my weekend project car to the building where I have taken over a wildly enflamed union facility and I don't trust them not to key/damage it.

Is there a way to diagnose which piece has failed prior to renting a unit or units from v12icpack?

Thanks, guys!

Tusc

P0203 - Injector circuit open #3

Wiring / ground issue? Failed injector? What should I read into this one?

Tusc

I did also add 1 liter of oil several days before the issues began. Not quite due for an oil change, but if I have it in the garage I will go ahead and do that also.

tusabes

kraut56

Don't change any parts - get an SDS check (not using another tester type).
The ign. transformer can be checked for correct output voltage (about 280 volts) as per WIS at the connector to the coil pack.
Good luck!

tusabes

Tusc

It was not the battery in the least. Though in learning to reset the windows, I did fix my sunroof which had given me fits.

I'm thinking right side coil has got to go.

Tusc

What is SDS, and an SDS checker?

I plugged in my ultra gauge scanner to get the codes previously. It's just a BT obd2 adapter.

Astro14

Wait - you had a dead battery...but you think the problem now is NOT the battery???

The coil didn't cause the light to be on, and the coil didn't croak your battery. A weak battery causes all sorts of problems, so, now that yours has been fully discharged, you need to either:
1. Fully charge it (this takes hours on a good charger, no, a jump and driving for 30 minutes will not fully charge it)
2. Replace it.

Until the electronics are operating with proper voltage, there is no way to be certain if the faults are from the modules (including the coil) or from low voltage.

Fix the battery first - then see what you've got.

Tusc

I replaced the battery first.

Then I went ahead and ordered a pair of new coils, plugs, boots, and a rental VT.

ItalianJoe1

More likely to be coils than anything else. That doesn't explain your lights on.

I would check your front SAM's, the left side one first, for water intrusion, if the lid isn't sealed it can get wet easily and cause all sorts of havoc. Shouldn't cause the misfires but may be keeping lights on and draining battery.

tusabes

SDS is star diagnostic system aka the Mercedes computer (or Chinese clone ) which is far more advanced than a obd scanner

Tusc

Like a Tech2 scanner for my corvette. Gotcha.

What's the piece at the front you are talking about?

And come to think of it, the outside temp sensor/gauge does not work... But when it rains and I drive, it displays - 136 when it obviously gets wet.

wallyp

I would start by carefully checking and cleaning the connector for the sensor. Deoxit is good stuff...

Tusc

What sensor? Where? I am not up on the mercedes acronyms for parts. The only work I've done on this car was to replace the cooling system. I do have years of wrenching, wiring and general garage hijinkery behind me as well as a full tool box, so I can walk the walk once you edumacate me.

wallyp

The temp sensor for the outside temp that you were complaining about in your last post. It is located in front of the AC condenser. The fact that it changed in the rain hinted that the connection is faulty...

tusabes

Tusc

I purchased a pair of exchange coils from V12icpack. I had also rented a VT, but it never arrived??? In any case, I installed the right side coil last weekend along with new plugs and the problem was immediately rectified. I am just wrapping up installing the left side coil tonight (pre-emptively - it still functions, but why not run a matched pair and be ahead of any future issues?) along with new plugs.

I do have a question: Towards the front of the left side (driver side) coil there is a small vacuum line which snakes behind it and across to the other head area. What is this vacuum line for?

On the passenger side, it was broken at the T junction near the intercooler. On the driver side, it was broken at the metal connection by the coil. I believe it may be cracked elsewhere in-line between the two. The yellow plastic hardline is brittle and seems to have been made so through years of heat cycles. I believe I have it resolved at either "end" at least on top of the engine but it also dives down on the driver side. Could this be anything like a vacuum referenced bov connection? If so, I'd say it has not been working for quite some time.

It does appear someone has been under the hood before on the car. The right side boots were newer and supple. The left side were mildly brittle. I saw a few zip-ties for wiring, etc. But nothing bubba'd up, thankfully.

Once I am done with the coil project I will look up how to flush the ABC fluids. I can see the cannisters in the front driver area appear to have slight overflow. They are tacky with fluid in a 1" circle around the caps so I wonder if they can blow fluid out, they may have sucked back dirt in right?

Another project for another day.

ItalianJoe1

There are some zipties on the harness from factory, but it's not surprising at this age that the car was worked on before.

Those vacuum lines go to the turbos and BOV's, yes. Replace them, they are always brittle/broken due to the heat/age. The plastic line is airmatic line, it's very cheap and available by the foot, get plenty and replace all you can find.