My car now has 50 000 km's (31k miles) and when I pulled the service information it had intake manifold gasket in replaced at 28 000 km (17k miles), which was in 2015 in case it matters what year the gaskets are made. I have no engine light on or anything but the car doesn't seem responsive that first little bit of throttle. For example, if I rev the car in neutral to 2k rpm I have to roll on the gas just a hair before cracking the throttle. I can't just stab the gas and have it rev out. From a dig the throttle response is a bit poor, that first second it just feels flat, but not as if the trans is slipping or anything. Also anytime I got WOT from a roll it doesn't seem to have as much down low power but pulls hard about like 4k rpm. From a dead stop if I punch the throttle to the floor it just kind of falls on its face for about a second and then builds enough power to spin the tires after I'm moving but if I was to roll in the gas pretty aggressively (not just all the way down instantly) it seems to make more power and will spin from a stop. WOT from a dead stop, the tires aren't spinning until the top of first Throttle response seems to be lacking in all these examples. Maybe this is why people suggest to launch off the brake wiry a bit more rpm than idle?

The car is a non performance package car so I'm not sure if that is reason alone for it to feel a bit flat at low rpm. Maybe the 450hp models just have less timing or something to make them have less power? I'm going to tune it regardless in hopes for better throttle response and low end power. I just wanted to make sure that these weren't symptoms of having to do the intake gasket (before tuning it) as I've heard it's a common issue to have. Maybe I'm just expecting too much from the 450hp model but it's almost got a acute feeling of what I'd assume a car with turbo lag would feel like.

Edit: Another thought, could driving around in city traffic all the time affect throttle response at all because it's gotten lazy? Maybe I'll pull my battery terminals over night and see if I notice a difference.

 

Trying resetting the adaptations https://mbworld.org/forums/c-class-w...ml#post2896967

To check for a intake leak, you just get some carb cleaner and spray around and if the idle changes, you have a leak.

 

Thanks for the reply. I don't believe that reset method actually works, I've got by negative battery pulled as we speak to do the same thing though. I'm going to try the carb cleaner trick just for piece of mind, I didn't realize there was a way to check it. I wouldn't imagine it would feel strong at higher rpm if it was an issue? Would there be any tell tale signs though? Would it set off a check engine light if it was leaking? I'm not sure I even have a problem with the car, maybe I just need a tune to be satisfied, I just always read people recommend to rule it out as it's a common issue.

 

 

Well there's good to know at least. Would I have lost any codes from pulling the battery last night? I'll go rip around tonight and take it by my buddies shop tomorrow and see what I can find. Is there a possibility that it's running normal and I'm just expecting too much? Wish I could drive a other non performance model to compare, it just feels like it's got a slight hesitation / bad throttle response . I'm just about to do injectors, plugs and a tune when I can decide what tune to use, as long as I know everything is running right

 

Any codes, once set, will remain in memory until erased.

 

The real question is, do you have the same issue with traction control fully off?

 

perfect, thanks

I don't even want to call it an "issue", I just don't know if this kind of crappy throttle response is normal or not. I was just going to tune it as I assumed that's all it needed but now I'm just wanting to make sure everything is running top notch before I tune i.. so now I'm kind of wondering.

To answer your question, this is always sport traction setting. I'm pretty much always in that from the time I start up the car. I took traction full off once for a burnout and i felt like maybe it held onto the burnout longer, as if sport limits wheel spin after a point? I just was under the assumption sport mostly just stopped the car from getting too sideways. Also, it has the same dead (for lack of better term) feeling under roughly 3500-4000k from a roll too. It's pulls noticeably harder above 4k.

Would it be too far fetched to think that the 450hp models just have too much of a rich factory tune at low rpm/less timing or something going on, to make them that power level versus a PP, 507 edition, etc?

 

New question, if a car was pulling timing for bad gas where in the powerband would it occur? Right across, or? I went down to the states to fill up on 92 octane and I swear the car is feeling like a beast on it. I'm in Western Canada and our gas is notoriously not as as in the states for performance cars. Unless it was just placebo. We can get chevron 94 but it has as lower ron rating than our shell 91, but most tuners and local people know that the 91+ state side is better than anything we can get. Might have to just start feeling up in the states. I saved about 20 bucks on one tank by filling up there.(works out to be 5.50USD/ gallon for what we are paying right now).

 

Surprisingly, my situation is exactly like yours.
When I mash on the throttle, the car doesn't react for a good second until the engine finally responds. (This is in comfort mode, which is the mode I usually use)
Funny enough, my car is also a non-pp model with 49,000 kms on the clock and we live in the same city with the crappy expensive gas.
I personally don't know what's causing the problem but I hope if you find the solution to this then please post back.

Thanks

 

I've filled up in the states with shell 92 the last two times. With such a small tank and almost all city driving it's not practical to think I can keep this up though.

 

Interested to see what you guys end up doing here. I definitely have a intake leak as the engine is whistling once warmed up, which disappears when I pull the dipstick out, so leaking air. Really not convinced it is the gasket yet as no CEL and no IDLE issues, and as far as I'm concerned no power loss of significance. Are you chaps seeing any changes in running temps? I have standard 2008 model. 48k miles, and oil used to run steady at 102-105C and I think it is running a bit higher these days, but may be just me.

 

did you spray brake clean around where the gasket is to see if the idle changes? Could also be the pcv valve. Best to do both if you are doing the IM gasket also.

 

It's the gasket. The whistle is the ONLY symptom until it eventually worse.

The leak is so minor it's only audible right now.

 

Agreed with Jasonoff, the whistle can be the only noticeable symptom without a CEL. I tried the brake cleaner method as well but it didn't pick up on anything, but I replaced mine anyway. Whistle has since been gone and other symptoms as well, but never had a CEL

 

The method I like to use is to wait till the engine is nice and hot, then slowly pour a cup of gasoline or toluene all around the intake. Make sure you cover the gasket area. Fixes the problem every time.

 

Yes, no change in idle at all. Appreciate pointer on PCV valve.

Interesting, thanks for sharing, any negative impact if I leave it for a bit so see what happened?

Nice to know it's not just me, so I might just got the route of doing the gasket and PCV valve.

What is interesting is this has happened pretty much immediately after I had a shredded belt due to a pulley failure and seems a little coincidental for my liking., wondering if they had anything off the front when they did the pulley and created a vacuum leak by not putting it back together again properly, and obvious checks to be done? Appreciate your valued opinions.

 

Normally when you have an intake leak:
the air flow into cylinder/bank differs from MAF sensor so your car runs lean
the O2 sensors notice this and try to add more fuel
This usually ends up with misfires for a cylinder or entire bank.

Can of Ether.
Let engine idle and spray around intake gasket
If engine revs up a bit you found your leak.
IF engine does not rev up probably no leak or you did not spray where is leaking.

Do not go crazy with ether (starting fluid) small sprays go a long way
Also do this outside not in garage
Fire extinguisher handy as always.

 

Can of keyboard cleaner from Walmart works way better.you dont have to spray fuel all over your intake manifold.

 

Thanks for advice and input skratch77 and ygmn.

 

just check the bolts first. See if they are tight. I had 3 finger tight. If they are loose, do NOT retorque them. Thats how they break. Just replace the gaskets and bolts.

 

Well... you don't want unfiltered/unmetered air making it into the engine so it's beneficial to do it sooner rather than later.

It's possible they were leaning on the IM doing the work wiggling it around a bit then didn't let the car get hot enough to hear the whistle. Or they did and ignored it lol.

 

I had a leak, there was a whistle and there was brown residue around the separation area.
Check the bolt torque with a torque wrench. mine were well below.
I replaced the bolts twice.
Seeing that they were loose, I thought that maybe the alloy was not hard enough, but regardless, I can't try to tighten them, because I will break them.
But at the same time, there may be nothing wrong with the gaskets themselves and it's very easy to replace the bolts only without the gaskets.
Then I changed my mind and did a full replacement, with manifold removal.

At the end of this, I had two sets of bolts: The factory set and the first replacement set, which was torqued and then angled properly.

So guess what? Rijad Handanovic did not tighten them properly at the factory. The factory bolts were not elongated enough. I could have just tightened them, but you're never sure, because old Aluminum bolts are not like new Aluminum bolts. They have been heat cycled.