2006 C230 2.5 V6 - Random/Multiple Cylinder Misfire Detected
 

Hi all, really hoping that someone can help.

My C230 threw a P2006 (Intake Manifold Runner Control Stuck Closed Bank 1) error code and after removing the Intake Manifold I discovered the whole unit needed replacing, so sadly the cheap fix went out the window. I also found that the MAP Sensor was broke, so I replaced that, along with the Shut-Off Valve gasket, as I had to remove that to allow me to get the Intake Manifold out.

I purchased a new Intake Manifold and gaskets and went about refitting everything last night, following WIS. Everything went smoothly and it was back in one piece after a few hours, no bolts left over and all connectors clipped in place.

However, when I started the car up it kicked up easily but then instantly ran rough, misfired and cut out. I thought it might not have fueled properly, as I'd had to remove and refit the fuel rail so had depressurised the system, so gave it a few more goes. It revved throughout the range and revved easier higher up, but still misfired, and would eventually continue running, albeit very lumpy, stilling missing and sounding like it was very underpowered.

I tried resetting the throttle position (Key to position 2, pedal down for 5 secs, key to off but left in for 3 minutes) but this had no effect.

I've read the codes it's now showing and they are:

• P0103 - Mass Airflow (MAF) Circuit High Air Flow and HIgh Voltage Output
• P0300 - Random/Multiple Cylinder Misfire Detected

I also noticed, during refitting, that one of the clips on the Throttle Housing connector was broke. To ensure it stayed in place, after clipping it on, using the one working clip, I zip tied it in place. This might not be relevant, but I'm trying to cover all the bases in one post.

I'm really hoping that I don't have to go through removing the whole thing and refitting it again - or worse taking it to a mechanic - but I'll do what I need to do to get back on the road before Christmas.

Thanks for any help or suggestions, in advance.

Sy

I would unplug the MAF and see if there is a change. Also if there is air leaking on the down stream side of the MAF your not going to have a good time.

Cheers, I'll give it a go this afternoon whilst I'm checking everything else. I'll check the housing too whilst I'm there.

We have the exact same vehicle. 2006 C230 V6. I just finished replacing my intake manifold as well and I am experiencing the EXACT SAME ISSUE regarding the misfires. Mine are on cylinders 4, 5, and 6 which are all on the same bank. I am also getting the random Misfire code "P0300". Did you figure out a fix for this issue???
Thanks,
Travis

We have the exact same vehicle. 2006 C230 V6. I just finished replacing my intake manifold as well. I am experiencing the EXACT SAME ISSUE regarding the misfires. Mine are on cylinders 4, 5, and 6 which are all on the same bank. So I have codes P0304, P305, and P0306. I am also getting the random Misfire code "P0300". I have tripled checked every hose and connector. No parts were leftover. I cleaned the MAF sensor to death with MAF cleaner and let it dry for about an hour before reinstalling. I have cleared the codes several times but the CEL starts flashing right after start up, and the codes remain after turning the car off, plugging in scanner, and turning key to on position to scan for codes. Did you figure out a fix for these misfire issues???
Thanks,
Travis

Cleaning a bad MAF will do nothing. Unplug it and see if there is a change.

I will give that a shot. I must have checked 5 times to ensure my new Intake Manifold gasket was seated properly. I also used fishing line to secure the gasket while installing the manifold. I checked each bolt hole to ensure the manifold was in place and hadn't fallen out. I have seen you can spray brake cleaner along the intake Manifold on the bank to see if the gasket is leaking air? What do you think about that? Also the fuel injectors were all switched over to the new Manifold with fuel rail. I am leaning toward fuel injectors or manifold gasket since that is what I handled during the repair.

I will try unplugging the MAF connector, then run the vehicle, and update with new findings!

Thanks

You can use brake clean or starter fluid. You are looking for an increase in RPM when spraying. If there is you have a leak. When you swapped the injectors did you install new seals?

Got it. I unfortunately did not.....I bought some from local oreilly auto parts store but diameter was off and they went on waaaaaay too tightly!!

Perhaps if the brake cleaner or starter fluid doesn't produce a change in the RPM at idle then maybe the fuel injectors are the culprit? Is that what you are thinking???

The injectors don't appear to be leaking and we're seated properly with bottom of the injector extending beneath the surface of the manifold when I swapped them over. Should I take a screwdriver and listen to see if they are "clicking"? Probably wouldn't hurt to order new original seals

Thanks for the help

seems like vacuum leaks on these cars are very common, cause great havoc, and are really hard to track down!!

Use starting fluid not brake cleaner

UPDATE: I sprayed WD 40 all along the manifold where it meets the head. Heard a noticeable change in idle as it sucked the WD 40 into the intake. I will take it apart and use a new Manifold gasket if necessary. Any tips on getting these to stay in place???? Tried fishing line to secure but maybe it came loose. It's a really tight fit once you move the manifold into place so it is tough to reposition the gasket at that point. They are only held on by a small nipple at the bottom ofor the intake. On my 4runner, there is a stud on the head in each corner to hold the intake manifold gasket securely in place. This is much more challenging

I also sprayed the WD40 along cylinders 1, 2, and 3 and they were all fine. Displayed no change in idle when sprayed.

Took out the manifold...again! Haha the gasket on the driver side where cylinders 4, 5, and 6 are located had partially fallen off, primarily at Cylinder 6. It was bent and mangled up. I figured this was the problem and have a new one to arrive Thursday. Thanks for the help guys. I'll post again once it's fixed and misfires codes are gone!

I was about to post that your gaskets likely moved. Glad you figured it out. To keep them in place you can use a drop of super glue in various spots (avoid sealing surfaces) and stick the gaskets to the manifold. Works beautifully.

Super Glue can eventually eat away at the gaskets. Also, Super Glue dries hard. The rubber gaskets and the aluminum surface need to flex/expand/contract.


Imho, it's a good idea to use the stuff specifically made to hold gaskets in place.


For rubber gaskets, use something like:
https://www.permatex.com/wp-content/...6/02/85409.jpg

https://www.permatex.com/products/ga...lant-dressing/

Formulated specially for rubber gaskets, it conditions gaskets for longer life and seals potential leak paths. It also functions to hold gaskets in place during installation. The non-hardening, soft-setting formula makes gasket repositioning quick and easy. Provides outstanding oil and fluid resistance. Temperature range -65°F to 400°F (-54°C to 204°C).

Suggested Applications: Designed for use on all cut and formed rubber gaskets, but also great to condition and extend the life of composite, paper and cork gaskets.


Amazon Link:
https://www.amazon.com/Permatex-8540.../dp/B000HBM3I4
Permatex 85409 Ultra Rubber Gasket Sealant and Dressing, 1 oz. tube
Non-hardening, soft-setting formula makes gasket repositioning quick and easy
Condition gaskets for longer life and seal potential leak paths
Provides outstanding oil and fluid resistance
Temperature range -65F - 400F




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For non rubber gaskets, (paper, cardboard, cork), mechanics sometimes use the old stuff...
https://www.permatex.com/wp-content/...6/02/20539.jpg

https://www.permatex.com/products/ga...llac-compound/

Permatex 20539 Indian Head Gasket Shellac Compound, 2 oz.
The original quality formula, a hard setting, economical sealant. Seals all common gasketing materials in low temperature and low pressure applications. Temperature range -65°F to 350°F (-54°C to 177°C); resists diesel fuels and most shop fluids.


Amazon link:
https://www.amazon.com/Permatex-2053.../dp/B0008KLOG6

Permatex 20539 Indian Head Gasket Shellac Compound, 2 oz.
Size: 2 Ounce
Hard setting, economical sealant
Formulated to lubricate under the most adverse brake conditions
Seals all common gasketing materials
Resists diesel fuels and most auto shop fluids
Designed for temperature range -65 F to 350 F



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As an FYI, for other engines, depending on the application, mechanics may use a fine film of Permatex Ultra Copper or Ultra Blue, let the sealant start to "skim", then lay the gasket on to the Ultra Copper.
However, as far as I know/can-remember, using Ultra Copper as a gasket holding sealant does not apply to any of the W203 engine components.



Good Luck!

Fair point. I used super glue, but only on the nipple where the teeth of the gasket bite. It's recessed and is not part of the mating surface between the intake and head so it's okay.

Anyway, job is DONE! Thing runs like a dream. Got it up to 65 on city street but problem is solved. Most importantly.....no engine codes after driving the car for 30 minutes. There is now a noticeavle difference on engine performance because tumbler/Runner flap is free to move, which allows the 6 intake flaps to move. Thanks for the replies! Unfortunately didn't have time to wait and had to struggle through this without help lol

The guy above assumed you were working on the 4cyl with rubber gaskets. You put the glue in the exact right spots. Glad it worked for you.

Good to hear. I didn't mention this but I used kite string to secure the gasket, then tied it to the fuel rail! These gaskets bend easily.

Anyone reading this before they perform the job should TAKE THEIR TIME and make sure there is ZERO MOVEMENT possible in the gasket after securing it with kite string. Then simply cut the string one at a time and thread in the intake bolt for that hole. That's how I did it at least.