Todd Edge

My car went into Mercedes for oil change while I was out of town. They called to say that during the QA drive, the check engine light came on. After a diagnostic, it was determined it was due to unmetered air entering the engine. The tech advised that since I grinded the post on my throttlebody that too much air was entereing the motor and tripping the CEL. Does this sound right? Nobody else seems to have had this issue after they modified their OEM throttle body.

I spoke to Shardul and decided to look for any vacum leaks. I removed the tb and reinstalled with no issues found. I then remembered finding a small part the other day that fell into the belly pan. It was a black plastic/rubber piece with a mesh metal screen in it. After more looking, we found a part number on it (A1170780981) and determiened it was a filter/boot that goes on the secondary air injection valve mounted on the front of the passenger valve cover.

It appears to have broken off the lower nipple on the valve. Anyone ever had this happen? I'm trying to determine if this would generate the CEL.

Below are pictures of the valve with the broken nipple and missing filter. Also pictures is the actual filter that I heard fall the other day when I was working on the car.

MBTEK

NO, THAT'S JUST A VENT FOR THE SWITCHOVER VALVE,YOU NEED TO CHECK FOR MORE VACUUM LEAKS,RESET YOUR ADAPT. AND RECHECK FOR CODE TO COME BACK.HOW'S THE IDLE QUALITY/DRIVEABILITY?

Todd Edge

So you are also in agreement that the throttlebody grind mod didn't cause the CEL? I removed it and looked everywhere and can't find any other loose hoses, etc. Any ideas of common areas to look?

Thanks,
Todd

chawkins2001

Those techs are dumb SOB's Todd. Hate that this happened, find a good indo where you are, only way to go.

Todd Edge

Yeah, I've had it with the dealership. They kept uncovering what they said were issues. It never had a check engine light until they touched it. I have an appt. to drop it back off for them to fix the mistake.

I'm going to go ahead and install the new valve covers tomorrow so I can inspect everything and make sure I don't see any obvious vacum leaks. The light comes on and goes off erratically... At this point, it is only an annoyance.

Todd Edge

Also going to put on the stock throttle body back on and will run it to see if the light comes on or not. I think they disconnected some line when they were doing the tranny work and this is the cause of the issues.. Time will tell...

novae500

i'm sure they forgot to reconnect some switch and its throwing the CEL code. But they wont admit to it.

TTMotorsports

Replace the secondary air injection valve(change-over valve p/n A0025401497) if you can't get that cap to seat back on. The port on the bottom is broken and you need the boot to cap it off. This should fix your issue. These cars are EXTREMELY finicky about vacuum.

The TB shaft grind has NOTHING TO DO WITH YOUR ISSUE!!

GL and let us know how you make out.

Todd Edge

Thanks Bruce. I forced the cap back on and after about 15 minutes of driving, the CEL went off. It isn't as much of a cap as a filter. You can see clear through it but, it has a mesh screen. I'll try buying a new one since this one is only on there temporarily. Have you seen this trip a CEL before? Others stated it would not but, you seem to have additional insight.

Thanks,
Todd

Roverron

Bruce has insight outsight and good sight.
He keeps a lot of people "well us" from making big mistakes.

grantwoodtx

When all else fails super glue will keep it on!

benz_addict

OMG NO WAY! I FOUND THE SAME PART ON THE GARAGE FLOOR I DIDN'T KNOW WHERE IT WENT THANKS

guysandiego

our amazing cars come with the one down fall of having **** sensors.

Todd Edge

I just finished installing new plugs and valve covers, in addition to searching for any vacum leaks. None were found. I ran the car for a while to check for leaks and all good. When I went back out later to run an errand, the CEL came back on, just sitting in the garage. I ran up to Auto Zone and scanned the car and got code PO507, which stated idle too high. I did install an OEM throttle body with the shaft grinded the other week. Any chance the throttle body has something wrong with it? Just trying to further isolate where the problem lies.


BTW, the car runs harder than ever. I'm guessing the 60K plugs were on their last legs...

Thanks,
Todd

jcjmw

Any updates?

Todd Edge

Nothing yet. I dropped it off at the dealer after exhausting all efforts to resolve myself. I'll update once I hear if they found a vacum leak or if they just needed to re-orient the throttle body 0 position with the computer.

Todd

Todd Edge

Turns out the throttle body had to be re-adapted to the ECU. It somehow lost the 0 point when I removed it to work on it and then put it back on. Painful lesson as I tore the whole top 1/2 of the motor apart looking for vacum leaks.

Todd

jcjmw

Good to hear. What did you have to do to have the TB re-adapt to the ECU?

Todd Edge

Took it to the dealership and forked over $200 for a 5 minute procedure... I unfortunately already dropped the car off when skratch77 posted to another thread I had going with a DIY to do this at home, without STAR. The Dealership used STAR but, here is the process via the DIY method from skratch77:

Those 2 codes were the ones I was getting with an 82tb.If there is no leaks I think you moves the throttle blade off its track.

do this,put stock tb on and reset the ecu with a scan tool.Dont start the car yet and go over to the throttle body and unhook the cable going to it.Then go back and turn they ket to the stage right before the car turns on.you should get a error on the dash.wait 20 seconds and then turn the key to the first position without taking it out and go plug the cable back in.

Now go put the key to the stage right before the car starts and wait 3 min,the car will re adapt the throttle body and you will hear it move on its on.

this is a trick instead of reseting the throttle body with star.

Regards,
Todd

Forrest Gump 9

Another trick that I do when install the TB is instead of using OEM gaskets, I just use silicon gasket maker material. Never have any problem.

wsybert

I tried this and I can't get it to work. Idle is still high. Any help would be appreciated. I followed the info above.
Cleared fault, unplug tb connector, key to 2nd position, wait 20 sec, then key to first position (one click back, correct?), connect tb connector, key bak to 2nd position, wait 3 min. I can hear and see the throttle plate move.
I know it's not a vacuum leak, at least I have checked until I was satisfied.
Any other input would be welcome.
Thanks
Bill

skratch77

How hi is your idle? I have a stock tb fs and just need to double check the serials because I got it off ebay.

170 hipped if you want it.

wsybert

Varies. I thought I had it. Disconnected the batt and did the tv reset too. Checked all the vacuum lines again. Put a clamp on the eval line. Was a little loose and I just had a gas cap cel. Fired it up. Fixed. Or so I thought. Took it for a spin and stopped and revved it. Idle stayed @ 1500. I put it in drive then it drops and stays. I hate these types of issues.
Bill

skratch77

So your car was stock and started acting up? You can try my tb if you want to rule out the tb.

wsybert

I replaced my valve cover gaskets. While I had the top works off, looked into the TB, and wiped it out. That is the only thing I can think of that screwed things up. Is it bad to open the throttle plate on these cars, by hand?
Car has a Renntech tune and pulley, but I bought it that way. This is the only thing I have done to the car.

Edit: I may take you up on the TB. Need to do some more analysis, and will let you know. Hanging it up for tonight. Thanks
Bill