Hi Guys,

Thank you in advance for the help.

I just chanced the passenger side coil pack and the power now seems a little funky.

Symptoms: First gear everything seems fairly normal power wise. Second however is where I start noticing changes after 4000+ rpm the power seems to be fading and sometimes in 3rd gear it feel almost no power. Other times in 3rd I would say I get about 80% power (can hear the blow off vulvae or waste gate exhaust, not sure which) 4th feels about the same as 3rd. Likewise with 5th.

I'm really not quite sure whats going on with the power. It's also upper 30's here so I should be feeling more power than when I changed the pack (60's). So i'm not 100% sure if the cold is masking a bigger power loss.

My descriptions aren't the best but if anyone has had some experience with power loss after a coil pack change, I would appreciate any input.

Thanks.

Maybe a boost leak on the turbo outlet.

I'd double check the intercooler connections to the turbo's and intake, could have easily buggered a seal. If no codes throwing thats likely culprit, also check the sensor that goes to the passenger side intercooler, forget what it is exactly, MAP I think, but it's easy to crack or break it when moving the intercooler around.

Does a fualty MAP sensor for the intercooler throw a code?

Not sure if it will or not, I know when I did my plugs I easily snapped where the hose went into it, so I didn't fire it up til I replaced it.

Looked it up, it's not the MAP, it's the Charge Air Pressure Sensor.....atleast on my SL600 it is....pretty much the same layout as the SL65 though.

there are a bunch of small boost hoses. you hooked them up wrong or left one unhooked. check carefully what goes where.

Didn't have to unhook any boost lines to replace the coil pack. I took the air intake off last night to double check for any line troubles and there appear to be none.

This may be a very silly question but what's the best method for checking the coolant level on the intercoolers?

Try hooking up an Innovate LC-2 datalogger to the OBD and see if there is anything goofy under a WOT 3rd gear pull. You may be able to log MAP or charge air pressure voltages. Doing this could isolate the problem as being boost or AFR related.

when cold open the coolant cap at the back of the engine between the intercoolers. you should see the coolant. if not- add some until you see it.

Thanks for the help gents. I really appreciate it. Coolant is definitely low based on your description. I'll start there.

Next on to the datalogger.

AtlantaAMG, in buckhead by chance?

You probably forgot to tighten one of the charge pipe clamps between one of the I/Cs to turbo compressor outlet. Or the 6 point bolt that hoses the compressor outlet eblow in place. It sounds like a boost leak somwhere in that area. This is stuff you took apart to do the coil pack.

Thanks Twingtx for the advice.

I've check all those connections and compared them to the other side. I also took pictures before and after. Compared those and everything matches.

The good news is it's something very simple and you'll figure it out before the weekend is over. This is because the V12TT boost/power loss issues, the key things are easy to account for.

Since you indicated that you hear a BOV or Wastegate type sound when you're on hard throttle, it comes down to 1 of 2 things:

1. You're leaking boost somewhere. Simple, find the source of the leaky air sound and close up the leak. Voila.

2. You could also be dumping boost. a. If the pressure sensors attached to your airboxs are not plugged in (or properly secured), the ECU will cause the engine to dump boost. You will hear a sound along the lines of a swooshing BOV or wastegate type sound. b. if you inadvertently disconnected the vacuum lines going to your compressor bypass valves on the turbo, the moment you hit boost, the valve will lift open and dump boost.

Don't worry, you'll find it!

haha thanks twingtx

I noticed something really interesting today. After flooring it starting at about 2k rpm in second gear, the car BOLTED when it hit 5k rpm (felt like the normal pull i'm use to) then in 3rd gear it felt like normal. huge roar, turbo sounded right and the power was immense. Then little bit later got on it heavy in 3rd gear (about 3k rpm starting) and it felt weak again.

I just want to verify with you gens on the coolant level. I have suspicions the coolant might be a little low for the intercoolers. Can you confirm I should just add coolant until i see it in? there is no reservoir that you can see when adding it just off-shoots to those 2 pipes on each side. should it really be that high?

Thanks again for the help!

update.
definitely not the coolant. levels are all good. after driving it hard the intercoolers are warm to the touch, so I think the pump is ok...

Going to hook it up to a datalogger tonight and see what boost pressure i'm getting.

Thanks again for all the help gents. I'll post some results here.

If it's hard to get a hold of a fancy data logger, use an obd 2 scan tool from the autopart store. The higher end one is probably about $150 and has CAN capability and more importantly Live Data. Plug it in and drive in WOT and look at:

- iat - shouldn't be higher than than low 100's to max 130's wot, if it floats in the 160's then its the culprit and motor is probably pulling timing robbing power.

- tps - it should be close to 100perc and hang there during a wot pull. If it falls to less than 50 percent then its cutting throttle and boost.

- map - boost but its not in psi

Youll find the issue.

What is 'tps' ? (Thanks)

Throttle position sensor. Usually measured by a rotary resistor, but obd computers will show it as a percentage. WOT (wide open throttle) is 100%.

:-)

I had similar symptoms before my repairs, etc....

It could possibly be a bad catalytic converter on that side, so have that checked or possibly, a map or the crank position sensor OR just a bad coincidence happened and the voltage transformer that sits on top of the engine may have gone bad....I had to replace my voltage transformer along with a coil pack to get mine right......and also replaced a cracked map sensor.....hopefully it something you can identify without replacing a bunch of parts.....let us know what happens....

Voltage Transformer is now on my radar as I had 2 backfires (could technically just be a misfire) yesterday. Both under full throttle, both in second gear one at 4.5k rpm other right near 6k. I have doubts about anything wrong with the cats since the problems came immediately after replacing the coil pack. I'm fairly swamped this week so I won't be able to start testing and datalogging until this weeked.

to be continued!

One more thought.

The coil packs sold at the dealer today are of latest revision and superceded the one type. I believe the two sides work in pairs.

If both of your coils packs were OLD type and you replaced one of them (passenger side) with a NEW type coil and neglected the driver side, then you may have a problem with the ECU. It will throw misfires and hold back the motor. Usually the Check Engline light comes on and blink though.

In both cases for me, in my S600 and my SL65, when I went to replace one side, the ECU knows that there is a mismatch between old vs. new. I subsequently bought the NEW coil for the 2nd side and problem went away. I was able to duplicate this issue back to back.

Just some more food for thought.

Look at the P/N for your old coil and P/N for the new coil. Then look at the P/N for the untouched driver coil. Make sure the coil you have on your passenger now and the one still in place on the driver side, are from the same series.

Good luck!

I know you'll find the issue.

Any update??
Have you find the problem yet?

Juha

Still have yet to isolate the problem. It does appear to be intermiten and temperamental.

Attached is a data log from some driving I did with a friend to test for what might be wrong. The best pull to look at is Tab 3 close to the end when you see a rolling 40mph start up to 101. I was on full throttle but trottle position sensor isn't showing 100% for some reason and its also not showing constant trottle, which I'm sure was the case.

Note: I will attach the file later. It's not properly uploading

You will need to have log works 3 in order to view the file.

Look forward to your feedback, or any suggestions you might have / where to look

Link to the entire file - will need data log 3 to open
https://www.dropbox.com/s/dk9vpqmh3yashpy/SL65.log

or CSV format here:
https://www.dropbox.com/s/ywusvf0aot...ession%203.csv

also, one new update. This has happened 2x now. I go to start the vehicle after driving it relatively hard (I did allow the car to run for about 30-45 seconds when I arrived at my destination before turning the car off) with about an hour in-between the stop / start and the car sputtered and wouldn't start. It was a strange sputter. I immediately pulled out the code reader and looked for any codes that may have been thrown, but didn't find any. I then let the car sit in the on position for a 3-4 minutes and tried to start it again. This time it did start but it was a sputtered start.

Has anyone else had this experiences? All these little gremlins started happening right after replacing the coil pack.

Is it worth going in and re-seating the coil pack? Any recommendations? The power loss is still present, but still intermittent.

Thanks.

i may have an answer to your problem. I was at the dealer and the tech told me there is a TSB for misfires but to a electronic component under the drive side IC. I have to part at home and will post the updated part number.