Rudeney

Yep, the W163 fuel senders would do this - no fuel = no start and no codes. The exception was when the pump would fail when driving on the highway, and then the codes were usually just misfires or the occasional O2 sensor error.

Mka77

Been there.

bbrain

OP, same thing happend to my c240 well over a year ago while it was still in Arizona mid summer.. after sitting at the dealer for two weeks they could not replicate the issue. So i drove the car again for a couple months, after i bought my CLK i shipped the c240 to my nephew and it has not happened again, the CPS i bought is still in the glove compartment in case my nephew ever gets stranded on the road.

But just the other day my CLK took a second or two longer to start after driving, happened again after dinner. Finally when my DD went to start it Tuesday night it would try to turn over and just give up, next morning it started up right away and i drove it home. Have not driven it since because i will be out of the state. It threw me a CEL but no malfunction codes. =/ Hopefully you find a fix soon and i can thank you for the info =)

bheng

So I had an ase mechanic do the work for me. Got too frustrated and didn't want to make my way back to kragen

Started right up, on the way home it died again and had rough idle...died about three more times...

But now it's running fine and smooth... So was it just getting used to the new cps? I'm leaving it on idle outside my garage. Going to see what happens but so far so good

mis3

For me, after they changed the CPS, it worked right away.

bheng

It did work right away. I let the car run for another 30min and it starts and runs fine. Going for a test run on a cold start when it cools down tonight. Could be just a small hiccup

mis3

It worked right away but I did go for dinner for maybe 2 hours. More specifically, after the tech changed the CPS, it started OK and did not stall. I left the car there for 2 hours before I drove again.

Good luck...

Glyn M Ruck

There is no getting used to a CPS. It should correct things immediately if it was faulty. I hope the problem goes away but I regrettably think there is more than one thing wrong. The old CPS might have been contributing to the problem.

2MCHCAR

Hey Brian! I had my CPS replace not too long ago. My symptoms were the car shutting off at idle and very long cold start cranking. After the CPS was replaced (new OEM), no issues what so ever!

Good Luck!

bheng

This is unfortunately true. I just ran the car for 30 min. A lot of the problems are gone but at stop lights I feel a bit of jerking. It stalled again. I do notice my idle moving slowly up and down but very minuscule... What do you this could be? If my obdii doesn't pick it up, how will I replicate it for a mechanic... Or stealership...

Could it be sparks? I am at 97k

bheng

Sorry for double post but can't find the edit button off the mobile version of the forum...

On the way home, CEL flashed a couple of times and then stayed on. Got home plugged in my obdii scan tool. Came up with the following:

P0300
P0301
P0302

I know 300 is random misfire
301 is misfire in cylinder 1
And 302 is misfire in c2

After searching the forum, possible problems are cats...

If it were the sparks, then wouldn't the misfire be in all cylinders? Any recommendations?
also, just read one of glyn's post on another thread that it could be a cat converter...just revved the car past 3k and i dont hear a rattle. =/

Glyn M Ruck

First mark & then swap your coil packs around. See if the misfire changes cylinder. It could well be coil packs or plug wires on a M112. Obviously check plugs as well on 1 & 2. You are overdue! Change all 12.

bheng

looks like i will be changing all 12 plugs...any recommendations for plugs...
will probably order from autohausaz so they have the bosch oem platinum vs theirs bosch iridium/platinum?

does it make a difference? same price....

i'll sway the coil packs today to see if the misfire changes between cylinders.

how to tell if the wires are bad?


EDIT: I think i will do process of elimination for the coil packs. going to swap out coil packs from 5/6 to 1/2 to see if the misfire moves to those cylinders. if not...then i can rule out coil packs. However, my obdii scanner tool says that it fails to erase the check engine code...will i need to erase the codes? or can i just swap and test.

btw cylinder 1 and 2 are on the passenger side while standing in front of the car right? I want to make sure i change the right coil packs.
ty glyn

Glyn M Ruck

Use the genuine original Bosch. You can read resistance of leads or just toss them.



See pdf's for plugs & coils.

Rudeney

The main difference with iridium plugs is longevity. It takes longer for the electrode to deteriorate thus enlarging the spark gap.


Visual inspection - any cracks or breaks are obvious problems. Broken conductors can be found by testing resistance or trial and error (swap wires to see if the error stays with the wire or plug).

You'll probably want to erase the codes. You might want to invest in a better reader.

Correct. On MBZ engines, cylinder numbering starts on the front right (USA passenger side) and counts up to the firewall (1-3 on a V6, 1-4 on a V8), then starts again on the front left (US driver's side) and runs to the firewall (4-6 on a V6, 5-8 on a V8).

bheng

seems easy enough to at least test the coils. i will be using oem plugs so it says its pre-gapped, so i wont be needing a gapping tool to adjust right?


thanks! funny thing is that i took it on the test run last night. honestly i feel like it has the same power as before. i feel the v6 pull as hard as it did before. maybe im going crazy....

still going to swap the plugs today and see how it goes...still dunno what im going to do about the check engine light tho...doesnt erase...so i dont know how im going to test to see if it gets fixed afterwards...maybe i a trip to the dealer to get it reset?

Glyn M Ruck

No gapping required.

A good OBDII scanner should erase codes.

bheng

so as an update:

as of today, I have replaced the following: CPS and spark plugs. it still stalled at one point while driving. at this point, i am sure that it is the battery. I havent driven the car for very long and always driving short distances....

after i got it to run for awhile, it starts up fine. i went for a long drive this evening to let the alternator do its things. I think i will remove the battery and do a test load at the local kragen. if the battery is going bad, i might just get myself a new one.

seems as though when i have my audio running, it will die out faster... but that could be because the battery voltage was low to begin with...

bheng

another update:

car died on the road today. i started to notice some rough idle again.
i drove it around for a bit more because it was on and off. (tried to mimic the symptoms that i felt earlier).
eventually the CEL came on (what i was looking to happen)

i got codes:
p0300
0301
0302

now that i have eliminated the problems of sparks...and cps. i def think its the coils. because it is def on and off kind of thing. now the question is...should i replace the ones on c1 and c2 OR should i just replace all of them?

EDIT: Also out of curiosity....with cylinder misfires...would it shut out the engine for safety purposes. i only noticed it shut down when i gave it a little extra gas...

Glyn M Ruck

With consistent misfires over threshold the ECU shuts down the injector for that cylinder. I would replace all wires & only affected coils for now & see if this solves the problem. No point in throwing unnecessary money at the thing. If we are successful you can then make the decision. Coil life is a crap shoot. Less so plug wires. I've seen coils fail at 80K Km's or last 700K Km's. Wires on the M112 seem tired at very roughly 100K MILES.

EDIT: loading the engine (accelerating) can cause misfires as the volumetric efficiency increases when you open the throttle. Compression suppresses spark. If the ignition coil/lead/plug combo is at it's max limit it will fail to fire.

bheng

okay. already had 2 coils on order. coming in on monday.
as for the plug wires, i know everyone is using magnacore but autohausaz has karalyn or some of the sort...or should i stick with OEM?

Mka77

Just do the OEM. I have used different wires in the past with no noticeable improve one over the other.

bheng

any place that you would recommend to get oem plugs? seems as tho im looking to rack up 300 just for plugs from parts.com is that a good price to pay for these?

EDIT:bosch website gives part number 09848 but the description says OE type spark plug wire set.

So for OEM, i should head to the stealer?

-B Heng

Glyn M Ruck

+1 - Go OEM! RMeuropean can provide much of what you need.

bheng

+1 but doesnt bosch make most of our parts..?
thats the part where i get confused.
i know the CPS +sparks were both made by bosch.
RMeuropean says that the ignition coil set is made by karlyn sti manufacturer