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speedybenz
11-22-2003, 10:48 AM
I have have been using my PDA Scanner and I hae found a performance trend that seems to affect the performance of the engine.

While on steady state cruising on the highway or other roads at low engine loads the ignition timing is running at 28-32 degrees BTDC, but when you tip in the throttle for a little extra go the iginition timing drops off to as low as 12-14 degrees BTDC. This retarding of the ignition timing just takesthe performance right out of the engine.

At full throttle 90-100 percent load the ignition timing comes back up to 25-26 degrees BTDC which is about what a very effienient engine would make good power at.

But as I said above the retardation of the timing when pressing the throttle from 1/8 open to 1/3 open causes the timing to drop all the way down to 13 degrees BTDC and that is a killer for performance. I wonder what Mercedes is thinking!

Anyone have any thoughts on this?

Jeff

manny
11-22-2003, 06:04 PM
Well, think of the " old days ".
When you had a distributor with a vacuum advance unit.
As the load ( throttle increased), the amount of vacuum initiated advance would decrease.
Cylinder pressure ( and chances of detonation ) increases proportional to throttle increase.
If the advance stayed up near 30 degrees with a fair amount of throttle opening, you would have some major pinging in the engine. ;)

moebiusgold
11-22-2003, 06:35 PM
I know what you mean. In my C36 I am only seeing 10 deg. at 5000 and WOT. I am peeking at 22.5 to 24.5 at 6200. In and out of the gas over 5,000 can make the timing jump between -3.5 and 34.5. Now I know why J Irwin likes his chip.

Denlasoul
11-23-2003, 03:01 PM
From one of my books:

"....The variable valve timing sproket assembly is operated by engine oil pressure. The assembly retards valve timing at low speeds for smooth operation and advances timing at high speeds for more power."

Seeing our cars are MB's, it would make sense the engineers would want smooth transitions among the powerband. Maybe in some way the valve timing is correlated to the ignition timing, in that at lower speeds it is retarded and at higher speed it is not. You are right though, it does make the car suffer in the lower range.

CKlasse
11-23-2003, 06:46 PM
Cruise rpm --> WOT rpm requires a jump in the RPM = less time for air intake/exhaust aka less psi in the chamber = ICM retards ignition to compensate 'til the air intake volume is adjusted. Note, this only happens for a fraction of time!

This is one of the reasons why Lambo or VW applies the 2 intake valve and 3 exhaust valve technology.

Correct me if I am wrong :)

moebiusgold
11-23-2003, 09:09 PM
Originally posted by CKlasse
Cruise rpm --> WOT rpm requires a jump in the RPM = less time for air intake/exhaust aka less psi in the chamber = ICM retards ignition to compensate 'til the air intake volume is adjusted. Note, this only happens for a fraction of time!

This is one of the reasons why Lambo or VW applies the 2 intake valve and 3 exhaust valve technology.

Correct me if I am wrong :)

It is all about Temperature and pressure. The more you have the less the timing has to be or you will gover over that majic octane contyrolled point when all the remaining mixture burns at once, autoignites, whatever. If there is low PSI in the combustion chamber the timing can be more advanced than when at the pumping efficiency max. point, which is usually the max. Torq. RPM. Above this rpm the pumping efficiency falls off and there is less initial volume to be compressed with the same compression ratio, so you give it more advance to compensate. You would want to be as close as you can to the autoignition parameters at TDC under most load conditions. That is the hightest thermodynamic efficiency. Ping is the last couple percent of mixture that is left when everything crosses that Temp and pressure point. Whatever is available at that point burns within millionths of a second and creates a pressure spike. A couple of percent sounds nasty.

moebiusgold
11-23-2003, 09:18 PM
.
Originally posted by speedybenz
I have have been using my PDA Scanner and I hae found a performance trend that seems to affect the performance of the engine.

While on steady state cruising on the highway or other roads at low engine loads the ignition timing is running at 28-32 degrees BTDC, but when you tip in the throttle for a little extra go the iginition timing drops off to as low as 12-14 degrees BTDC. This retarding of the ignition timing just takesthe performance right out of the engine.

..... I wonder what Mercedes is thinking!

Anyone have any thoughts on this?

Jeff

Yeah, they don't want any pings. They want long engine life. I am cringing looking at my advance curves. I logged quite a few today and they are the same as I said. I don't have squat at any load below 5,000:( :( . I want to now what J Irwins power chip does. When I get my wife out of the hospital I'll take the time to post some of my runs on a web page. I am considering unbolting the knock sensor:D

speedybenz
11-23-2003, 09:56 PM
CKlasse,

This retardation of the timing is not when going to WOT. It is just when you push down the throttle from like 1/8th to 1/4-1/3rd throttle. The timing will stay down at 12-14 BTDC for long durations of time at this load and throttle position.

At WOT the timing jumps to 28 degrees BTDC pretty fast and goes like hell. In the first mode the engine feels like it lost 4 cylinders and is just dead.

Jeff

Denlasoul
11-26-2003, 07:30 PM
Jeff:

I read some of the responses from other sites regarding this post. Have you tried any of the suggestions? Change fuel, for example?

DLS

moebiusgold
11-26-2003, 08:13 PM
Originally posted by speedybenz
CKlasse,

This retardation of the timing is not when going to WOT. It is just when you push down the throttle from like 1/8th to 1/4-1/3rd throttle. The timing will stay down at 12-14 BTDC for long durations of time at this load and throttle position.

At WOT the timing jumps to 28 degrees BTDC pretty fast and goes like hell. In the first mode the engine feels like it lost 4 cylinders and is just dead.

Jeff
In general I have to dissagree. The more load, the less timing. Pumping efficiency can alter this a little bit and give a little more to squeeze (which is really load) so the timing drops off at the torque peak and then cklimbs a little bit. Sorry, this is a very simplified version. If I go to ~1/8 th throttle at anything above 5K I see 34.5 dgrees of adv. That seems about correct to me. As the speed decays (not moving the throttle) the R's drop but the load goes up and the timing falls off back to the steady state of 18 to 24 deg., 3k RPM, and ~ 70 MPH (~= approximately)
This is how vacuum adv. from the old days worked. High intake manifold vac. as in little load part throttle gave extra adv. More throttle = less vac. = less adv.

speedybenz
11-26-2003, 08:46 PM
Well at 5000rpm I think my timing also advances, but I will have to check my charts.

But at 2500-3000 rpm if I slowly add throttle and load I see the timing retard to the stated 12-14 degree BTDC. And the load can continue to go up and the throttle can continue to be applied but the engine will not acelerate with any authority or in some cases not at all.

Only when the throttle gets pressed to the point where it causes the transmision to shift down does the engine come alive and get going.

Jeff

CKlasse
11-26-2003, 08:52 PM
What's your foot doing at 1/4 throttle anyway???? :D

speedybenz
11-26-2003, 09:15 PM
CKlasse says: What's your foot doing at 1/4 throttle anyway????

Well I don't spent much time down there slumm'in but every once and a while---.

More of a minor fustration with what appears to be a simple fix for MB, if they had just programmed the ECU correctly.

Jeff

moebiusgold
11-26-2003, 09:44 PM
Originally posted by speedybenz
Well at 5000rpm I think my timing also advances, but I will have to check my charts.

But at 2500-3000 rpm if I slowly add throttle and load I see the timing retard to the stated 12-14 degree BTDC. And the load can continue to go up and the throttle can continue to be applied but the engine will not acelerate with any authority or in some cases not at all.

Only when the throttle gets pressed to the point where it causes the transmision to shift down does the engine come alive and get going.

Jeff
Jeff,
This is exactly my complaint. Except you are getting about 4 degrees more than me on the bottom end. Speed of throttle change seems to have something to do with my tranny deciding to down shift. Yesterday I mashed it at 68 and it went into second gear.:) There are times when I'm going 50 and I could sware that I'm mashing just as fast and it will only go into 3rd and act wimpy to 5K, then it decides to act like it should. I wish it had an EPROM and you guys had tricked out S/W to burn.;) I run a 11.7:1 chevy with vortech heads with almost twice the advance below 5 k on 92 octane. Same fuel in the C. Thats why I want to know what J Irwins curves look like. The chev has a lot more cam and at least equal if not a little more heads than the C36 (sorry). The cam is big enough to take some of the cylinder pressure out on the bottom end which allows for a little more advance. The benz's combustion chambers might be more efficient/ faster burning. At least I hope so. This Benz doesn't have a hope of being as fast but that's not the point, I know it can run a lot harder without hurting it. You have to understand that I didn't buy the C to go "fast", I am an engineer who can't leave good enough alone and who knows that it can be better.;)
Bottom line, for how good it is from 5 to 65+ KRPM, it ought to run harder below 5.
BTW, I have played with my TPOS and come to the conclusion that the ECU is moddin' the input and telling me that it is only 91.8. If I try and give it a little more travel this high pitched eletrical whine stops and it suddenly will only read exactl;y half of what it was before. 1% to 45.5%. I wonder if that is limp mode?
While I am at it ther is one other pecularity that I have noticed. If I am cornering right onthe edge where the ASR light would just start flashing but it is swithched of so ASR is supposed to do nothing, and I WOT fast, the is a huge, like .5 second hesitation, with the sound of the intake wide open, but no power increase, then bang. Hard to be smooth when it acts like that.:( All that it accomplishes is spinning the inside rear.:( :(

kameraguy
11-27-2003, 03:04 PM
When ASR is switched "off", you do kill rear braking for traction issues. However ASR always maintains engine control and if needed it will kill torque to the rear wheels when traction is lost. Engine braking? I forgot the exact terminology. But I think this is what you are experiencing when cornering and see the glowing yellow triangle blinking.

Remember the good 'ol days when an "off' button really meant OFF, and not sort-of off? :(

moebiusgold
11-27-2003, 04:47 PM
According to my wimpy paper owners manual. This is a 95 C36 I am refering to. If you turn the ASR off with the switch up to 90% of the power will be avaiable. If the light flashes for 30 seconds continuously full power will be avaiable. This implies that Kameraguy is correct. the:mad: :mad: compuiters have thier fingers in it. It acts like there is a G sensor (accelerometer) in the mix. If I hit bumps in turns it causes the same bogus engine performance even if there is no slip. With ASR on hitting the same bumps makes the light flash even at steady state low load conditions. MB did this to keep people who haven't/can't performance drive. This is bad enough that:
1) It takes a lot of fun out of the way I want and try to drive the car every day.
2) It causes the car to push at the least opportune times, which is a SAFTEY issue in my book. But then, they did it to make us safer:(
3) Makes me wish that I had bought one of those M3's instead. Sorry folks. ;)
This is by far the most irritating thing to me cuz I'm used to tweaking just about any and everything and for me to fix this I'd have to learn alot and spend some money on electronic stuff that I don't really want to buy.
Now if some chip tuner offered engine / chassis computer chips that fixed this, unsted of gust ECU engine HP, I would gladly cough up the ridiculus $800 to $2k that they seem to want.
So,
You chip users out there (I know there are more than J Irwin out there) Do you have the same problems or was there any before /after differences in any of my complaint area's? Too me any performance gain is mostly worthless if I can't use it in a turn.;)
Yep, I grew up in the analog off is off and on is on days. You had more control in those days and there were a lot less laws and Officers of the law.........:) and almost every gas station had some
real good Hi Test.
BTW, anyone try octane booster? I'm tempted to fill er up with Trick unleaded 100+ octane, just to see what it does. Too bad I can't use the 50 Gal of Metanol I got laying around. That stuff is like 140 or so octane and very forgiving on tuning errors.

CKlasse
11-27-2003, 06:05 PM
Originally posted by moebiusgold
I'm tempted to fill er up with Trick unleaded 100+ octane, just to see what it does. Too bad I can't use the 50 Gal of Metanol I got laying around. That stuff is like 140 or so octane and very forgiving on tuning errors.

Cocktail time!!! Mix them up!

moebiusgold
11-27-2003, 07:54 PM
Originally posted by CKlasse
Cocktail time!!! Mix them up!

Ah, they put some chemical in it just so you can't do that. It can't be distilled out once it's in there. Methanol. I need a blleeeeepoing new keyboard.

Urban Legend: Doesn't stop Russian's from drinking it (or Ethanol). They go blind in a couple years but I think that's what there after.

speedybenz
11-27-2003, 07:55 PM
moebiusgold,

I will bet you lunch that some 100 octane gas will not do a damn thing to fix this. May give you a little better response but the main problem will still be there.

But please try it and report back.

Jeff

moebiusgold
11-27-2003, 08:29 PM
Jeff, Your probably correct. But, it is relatively cheap to try and gives me some data to think about. I am more hesitant on unbolting the knock sensors and isolating them in rubber. The ASR crap bothers me more actually. I bought it to go around turns fast. I started off thinking that the timing map might be the easier thing to understand. I'm starting to think that ASR is wrapped into almost everything that the ECU does. I wonder how the supercharger and turbocharger folks get around this? Standalone engine managment?
http://www.myhps.com/c43/dynoc43after.html
This is a car that is my home town. Wish I could find him.
This seems reasonable for 7K$ vs the 19 Hp Brabus kit for 5K$

J Irwan
11-27-2003, 09:35 PM
moebiusgold


There is a thread at mercedeshop forum about this kill switch.

One of the 500E (W124)owner came up with it and its way way way way cheaper than $1200 Renntech ASR kill switch.

However it would take some a little changes to adapt it to C36 ASR module (since they may have different color code than W124 500E).

And I didn't pursue further to find out more, since there aren't enough interest for C36 :(



Regardz,

Denlasoul
11-27-2003, 11:00 PM
Originally posted by moebiusgold
This is a car that is my home town. Wish I could find him.


I got his number if you want it. He's pretty cool and very open to talking to forum people.

moebiusgold
11-28-2003, 06:28 AM
Originally posted by Denlasoul
I got his number if you want it. He's pretty cool and very open to talking to forum people.
Yeh!! Please E-Mail it to me. Thanks DLS!!!:)

moebiusgold
11-28-2003, 06:48 AM
Originally posted by J Irwan
moebiusgold


There is a thread at mercedeshop forum about this kill switch.

Regardz,

Thanks for the lead. I saw that thread when I was chasing my EGR low flow and before I joined 202. With my wife and some other stuff I spaced it off. That and there was no mention about C's and the fact that MB changed the way ASR works a couple of times since my 95. It's a real good lead and I'm going to chase it anyways. I have lots of high tech resources as a byproduct of work so if I just know what to do the rest should be easy. (relatively so) If it manage to pull that off I'll have to have a posi. Wonder who knows if it possible to transplant a 560 SEL/SL one into a C?
As a side, What are the specs on your Penske shocks? Everyone I new that raced and had them swore by them. They were 2K apiece and I have a hunch that you might not have the same thing, not that yours aren't good, just hopefully cheaper. I just could not stomach paying half as much as I did for the car to buy the best shocks. Mine is awfull harsh, tends to unload too much over minor pavement breaks that everything else I own takes in stride. And one of them has 4X the stock spring rates and Konis that i have to pull /push with all my might to make them move. 100K on the Bilistiens on the C. Paint strips line up on all 4.
So J, I am assuming yuou don't know what your timing curves look like?

Renn 208
11-28-2003, 07:14 AM
Mobius,

Just to clear up some confusion, it is speedybenz who has the penske 7500 dampers.

You can read up about them

here (http://www.club202.com/forums/showthread.php?s=&threadid=472&highlight=penske)

moebiusgold
11-28-2003, 07:38 AM
Originally posted by Renn 208
Mobius,

Just to clear up some confusion, it is speedybenz who has the penske 7500 dampers.

You can read up about them

here (http://www.club202.com/forums/showthread.php?s=&threadid=472&highlight=penske)
Oops My aplogies to J and Jeff for spacing. I feel like a dummy for not using the search fuction. I must need more Coffee.:confused:+coffee= :)

Renn 208
11-28-2003, 07:45 AM
Originally posted by moebiusgold
Oops My aplogies to J and Jeff for spacing. I feel like a dummy for not using the search fuction. I must need more Coffee.:confused:+coffee= :)

It's all good man, but yeah, there's good info abound hidden within the search button.;)

moebiusgold
11-28-2003, 08:48 PM
Every one on M shop forums said short out pins 1 and 6 on the X11 diagnostic connector. I read this months ago when I thought that My C was OBD I and too different. Well as you might know its OBD II but different then W124's and 129's. I may be conmfused but it appears when they do this it also affects their ABS. I like the ABS because it can be forgiving even to a good driver. Well on my 95 the ASR MIL light came on and stayed on because it is now endlessly looping in diagnostic mode.:D But the big surprise was no ABS MIL. Hmm time for a test drive.:D :D . Its been rainging on and off all day here so it was easy to check without being too obnoxious. The biggest difference in the car to date nest to fixing the EGR port. There was only hesitation when it decided to shift first to second (when I was) at part throttle and I would try to force it back into first because I can't hold it in first. It is only about .1 sec. so I can handle it. It was totally consitant which is another plus. It has something to do with the Electronic throtlle control or ATA. It doesn't run any stronger anywhere but then its not being choked off.:D The only problem is that this is going to generate an error code every time the system cycles. I don't know if that's going to make anything else be weird if the codes pile up but that jumper's staying put for the moment. My time was well spent with a penny of wire. Maybe I'll throw a toggle Sw. in the under the dash.
This helped me have courage to do it:

http://pages.prodigy.net/jforgione/MB_asr.html

I have brooken too much stuff in my days because I didn't quite know what I was doing. Course, that's how I seemed to learn best in the long run.:o :)

Thanks all, My C will appreciate the newly found attention that it will be getting. It suddely has me wanting a real posi and maybe someday even doing an E55 AMG Transplant. :D

Oh Mike's HPS C43 is now Titanium Silver. He owns this Co. and does the high speed camara work from his C.

http://www.gripvideo.com/

I hope that the vids are better than the StarzBoyz bike vid I saw a couple of years ago. Those guys were truly insane and ubelivably stupid. I wonder how many of them are still with us?

moebiusgold
11-29-2003, 06:56 PM
Oops, Mike does not own grip video, he was just doing pic. shoots for them. He does own his own Co. and has one heck of a nice C43. 50k kilometers on it BTW.

Denlasoul
11-29-2003, 09:10 PM
Moebiusgold:

Where did Mike (or HPS) relocate the coolant resovoir(sp)? I still cannot decide on what to do with my car, but based on your comments....I might HAVE TO get a supercharger. :)

I cannot go from having the fastest C class to the slowest!

J Irwan
11-29-2003, 10:35 PM
Originally posted by Denlasoul
Moebiusgold:

Where did Mike (or HPS) relocate the coolant resovoir(sp)? I still cannot decide on what to do with my car, but based on your comments....I might HAVE TO get a supercharger. :)

I cannot go from having the fastest C class to the slowest!


Base on those picture if I am not mistaken the coolant reservoir is next to the ABS module (on the driver side) :)



Regardz

moebiusgold
11-29-2003, 10:44 PM
Yep, that's where the coolant res. went oh and there's a big old K&N sitting behind the foglight. I want to drive it with an intercooler and a new dif. I want one exactly like this. My Mind is made up and the wife is smiling.:) :) :) actually!

moebiusgold
11-29-2003, 10:50 PM
It has real AMG headers too! H&R cup kit suspension mod. Ah I can't stand it I can't even think straight.

speedybenz
12-12-2003, 08:31 AM
I had a bad Belt tensioner in the front of the engine that would make some rattling noises when the climate controls were on. I let the problem go on for several weeks even though I had the part to fix it.

Well yesterday I had it replaced, took all of 30 min and while I was not expecting any change to the engine performance there is a marked increase in the engine response. I am still sort of shocked that the belt tensioner would have this sort of effect. But I have driven the car enough now to know for certain the extra response is there.

moebiusgold
12-12-2003, 10:07 AM
Wwoww. Maybe the the ECU knew that the idle compensation was too+ and decided that something was wrong and therefor limited output. When I bought a bad MAF last week even thought the fuel trims went way out it ran smoothly, just with a fraction ofthe poser that it should have had. When I put the scanner on it I instantly noticed the WOT would only result in engine loads in the 40% to 50% ranges. (fuel trims were climbing out of site in the plus direction. over 35 % it triggered the CEL, would have had to gone to +300% to make up for how far off the MAF was.) I am still upset over that ordeal.
Just remember that some of the best engineers are trying to save us from our foolishnesses and mistakes.;)

speedybenz
12-12-2003, 05:17 PM
I thought I would just make it clear that fixing the belt tensioner did help the engine become more responsive it did not fix the bigger problem of slow acceleration and performance that is the main topic of this post.

I just cannot figure out why the ignition timing will drop all the way to 14 degrees BTDC when the throttle is applied to 1/3-1/2 down; when at cruising speed and throttle position the igintion timing is at 28-34 degrees BTDC.

Jeff