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2001 SL500
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Discussion Starter #1 (Edited)
2001, M113 engine. I'll keep things in chronological bullets for easy reading so I can get as much help as possible.

-misfires on cyl 1-4 (all of bank one), and O2 + heater circuit codes for bank one, sensor one.

- Jerky gear shifts on accel and decel, rapid rpm drops and car seemingly self braking upon light acceleration and letting go of gas pedal all start the following day

-replaced all 16 spark plugs (bosch platinum), all 16 wires (beru), all ignition coils on bank one, and O2 sensor bank one sensor one (bosch)

- engine light gone for 3 weeks but intermittent rough idle continued

- engine light comes back on for cyl 1,3 and 4 misfires, plus O2 codes po130 and po135, and a new one po442 evap leak

- Had fellow forum member Photodude use his star scanner to diagnose, all ignition components working perfectly fine, fuel injection perfectly fine. Misfires only occur at idle, suggested having a shop check for vacuum leaks. Codes cleared and engine reset

- codes for cyl 1,3,4 misfires return, O2 codes 130 and 135 return. evap code didn't return\

- went to my benz mechanic, told me to take it back to shop that did the repairs due to beru wires(rubber boots).

-went back to the shop that did repairs, had my time wasted with a simple code readout, they're suggesting my few months old magnaflow primary (secondaries cut off, both primaries are magnaflow) is causing misfire and O2 codes despite no catalytic efficiency codes( plus many forum members have gone the magnaflow way with no issues.). I don't see how the cats are relevant if the O2 sensor in question is pre cat......

I have no idea what to do now... I can't keep throwing parts and this damn car. What the hell do I do? I'm considering a MAF replacement, or trying another shop and requesting they check vacuum leaks only.... (my console door lock button and and acceleration self locking have intermittent functionality)

Somebody help.......
 

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2000 SL500, 2001 S600, 2004 E320
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I'm considering a MAF replacement

Somebody help.......
There is nothing wrong with your MAF sensor.

Idle speed adaptations showed near perfect values (~ +0.2 ms), Air Mass reading was perfect 16 Kg/h at idle. Intake manifold pressure perfect. That would pretty much rule out any serious vacuum leaks too.

Fault memory showed that all 4 misfire codes were set at idle speed. Misfires are very random and engine idles very smooth most of the time.

I wouldn't rule out Purge Valve even though Actuation test showed it's working.

Did you replace the gas cap?
 

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2001 SL500
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Discussion Starter #3
There is nothing wrong with your MAF sensor.

Idle speed adaptations showed near perfect values (~ +0.2 ms), Air Mass reading was perfect 16 Kg/h at idle. Intake manifold pressure perfect. That would pretty much rule out any serious vacuum leaks too.

Fault memory showed that all 4 misfire codes were set at idle speed. Misfires are very random and engine idles very smooth most of the time.

I wouldn't rule out Purge Valve even though Actuation test showed it's working.

Did you replace the gas cap?
I was going to order it but when codes were cleared and came back, the evap code was no longer showing up. Should I still replace? And if so, is the OE Blau cap ok? My understanding with part types is that OE is genuine and not the same as OEM
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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I'm with the shop, you have a severely clogged cat. Your symptoms is exactly inline with my experience.

I bet if you removed the B1S1 O2 sensor from the exhaust and started the car, the misfire would disappear.
 

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2001 SL500
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Discussion Starter #5
I'm with the shop, you have a severely clogged cat. Your symptoms is exactly inline with my experience.

I bet if you removed the B1S1 O2 sensor from the exhaust and started the car, the misfire would disappear.
Ok I’ll go get the cat and o2 sensor looked at.

how does a three month old cat get clogged up? And I still have full power when driving ....

Strangely enough I think the left side cat is toast but that bank hasn’t given me trouble....
 

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I was going to order it but when codes were cleared and came back, the evap code was no longer showing up. Should I still replace? And if so, is the OE Blau cap ok? My understanding with part types is that OE is genuine and not the same as OEM
I'm not saying gas cap is your problem but yours looks old and… you had Evap code, which may return… cheap way to eliminate one part of the equation. No brainer AFAIC, I would just go to a MB dealer and get one that fits, rather than guess what might fit. $30-35 is max you should pay at the dealer.

It's hard to imagine gas cap causing misfire directly but… purge valve possibly could. Dumping fuel vapors to intake manifold could cause misfire.

Is there connection between gas cap and purge valve? I don't know enough about evap system…

Like I told you, all vital signs look good on your engine… I would start with new gas cap and see what happens… next part to investigate would be Purge Valve.

I hope someone with more diagnostic experience could help here.
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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Ok I’ll go get the cat and o2 sensor looked at.

how does a three month old cat get clogged up? And I still have full power when driving ....

Strangely enough I think the left side cat is toast but that bank hasn’t given me trouble....
If the left side is toasted, but flows freely, you will get a CEL for cat efficiency bank 2 (think its P0430). But a clogged cat will induce severe backpressure on the engine.

In theory a bad O2 sensor could affect it too, that's why the o2 sensor removal would be a good test. Unplug O2 sensor and remove from exhaust, start the car. See symptoms.

Gas cap or bad purge solenoid won't cause a single bank misfire. Due to how evaporative emission works, if the emission devices are faulty or otherwise malfunctioning, you'd get P0300, which is random misfire. In other words, you'll have misfire on all cylinders, not just bank 1. Or you'd get P0171 and P0174, which is bank 1 and bank 2 running lean.

Clogged cats can happen for any reason, including faulty O2 sensor, leaky fuel injectors or bad secondary air valve.

When you say you have full power when driving, explain that. Do you mean to say that if you took the car right now and went full throttle, you'd have full power right now?
 

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Discussion Starter #8
If the left side is toasted, but flows freely, you will get a CEL for cat efficiency bank 2 (think its P0430). But a clogged cat will induce severe backpressure on the engine.

In theory a bad O2 sensor could affect it too, that's why the o2 sensor removal would be a good test. Unplug O2 sensor and remove from exhaust, start the car. See symptoms.

Gas cap or bad purge solenoid won't cause a single bank misfire. Due to how evaporative emission works, if the emission devices are faulty or otherwise malfunctioning, you'd get P0300, which is random misfire. In other words, you'll have misfire on all cylinders, not just bank 1. Or you'd get P0171 and P0174, which is bank 1 and bank 2 running lean.

Clogged cats can happen for any reason, including faulty O2 sensor, leaky fuel injectors or bad secondary air valve.

When you say you have full power when driving, explain that. Do you mean to say that if you took the car right now and went full throttle, you'd have full power right now?
Yeah I’ve been flooring it recently and power appears to be there. 0-60 is apparently 6 seconds and that’s what I’ve been seeing when I watch speedometer.
 

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Discussion Starter #9
If the left side is toasted, but flows freely, you will get a CEL for cat efficiency bank 2 (think its P0430). But a clogged cat will induce severe backpressure on the engine.

In theory a bad O2 sensor could affect it too, that's why the o2 sensor removal would be a good test. Unplug O2 sensor and remove from exhaust, start the car. See symptoms.

Gas cap or bad purge solenoid won't cause a single bank misfire. Due to how evaporative emission works, if the emission devices are faulty or otherwise malfunctioning, you'd get P0300, which is random misfire. In other words, you'll have misfire on all cylinders, not just bank 1. Or you'd get P0171 and P0174, which is bank 1 and bank 2 running lean.

Clogged cats can happen for any reason, including faulty O2 sensor, leaky fuel injectors or bad secondary air valve.

When you say you have full power when driving, explain that. Do you mean to say that if you took the car right now and went full throttle, you'd have full power right now?
Just double checked today, car is fast as hell like it always was, though initial acceleration has a slight jerk, and deceleration from low acceleration has a more noticeable jerk.

Ill still have the cats and the b1 upstream o2 looked at.

Can you explain what symptoms I’m supposed to look for? Especially in terms of the o2 sensor when the sensor gets removed from exhaust or is disconnected from wiring?
 

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1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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By unplugging b1s1 the ECU goes into failsafe default mode, and it ignores all input from any sensors. Doing it this way will show if you have a physical problem (like a hole in the block) or it's a sensor problem.

Failsafe mode is supposed to run perfectly every time, assuming a healthy engine. It's a baseline that you use to diag.

It's interesting to say that you have full power at full throttle, normally that isn't the case when the catalyst converter are plugged. Then in this case the most likely cause is bad b1s1 O2 sensor.
 

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Discussion Starter #11
By unplugging b1s1 the ECU goes into failsafe default mode, and it ignores all input from any sensors. Doing it this way will show if you have a physical problem (like a hole in the block) or it's a sensor problem.

Failsafe mode is supposed to run perfectly every time, assuming a healthy engine. It's a baseline that you use to diag.

It's interesting to say that you have full power at full throttle, normally that isn't the case when the catalyst converter are plugged. Then in this case the most likely cause is bad b1s1 O2 sensor.
UPDATE:
New shop took a look. Misfire codes changed from 1,3,4 to 2 and 4 and o2 codes didn’t show up.

cat is fine o2 sensor fine but wiring is kind of burned???

The guy who worked on my car said to bring it back next week and he’ll check for vacuum leaks and look at the EGR
 

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Hopefully your shop also does the basic diagnosis and swap the coils and wires with a known good unit (like those from bank 2).
 

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Having all misfires on one bank (passenger side) means you should look for something common to that side, which would be, in decreasing order of probability:
1. Clogged cat - common on the M113/112

2. Cam timing off due to chain stretch: probability increases with mileage

3. Low compression due to head gasket leak: remote chance with no other symptoms.

All of them can be checked for low cost, which I would do before playing more blindfolded basketball with parts.
 

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Discussion Starter #14
Having all misfires on one bank (passenger side) means you should look for something common to that side, which would be, in decreasing order of probability:
1. Clogged cat - common on the M113/112

2. Cam timing off due to chain stretch: probability increases with mileage

3. Low compression due to head gasket leak: remote chance with no other symptoms.

All of them can be checked for low cost, which I would do before playing more blindfolded basketball with parts.
update 3/15/20

went back to the shop, no vacuum leak check done because I didn’t have lean codes. Was told downstream o2 sensor on bank one was weak due to being old and was told replacement would most likely solve problem.

so I ordered the sensor Bosch # 13862 and had them replace. Replaced the gas cap too with a Blau gas cap. Was told two drive cycles would reset adaptations and that would be it. Rough idle reduced but was still there

yesterday as I was about to head out engine light came on and immediately started flashing without the bad shaking typical of misfire. Stopped at autozone for code read aand of course still misfiring on bank one and o2 codes.

I got Po300, 301, 303, 304, 130, and 135. Pretty much the same codes as before. Cylinders 1 and 2 seem to like to take turns every so often to

I just don’t get it. Nearly $800 spent in like 4 months and the problem still hasn’t gone away. Every shop has let me down.

if my cat is fine and the upstream o2 is the culprit, how can that be if it’s just a few months old and the correct Oe Bosch one for its position????

The wiring supposedly is burned?? And the last shop said a milky substance came out of the connector?
Any new suggestions? More diagnosis? Or just replace the sensor? (Maybe I shouldn’t have gotten the one on the car right now from oreilleys even though part # was correct)

I’m just so disappointed right now
 

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update 3/15/20

The wiring supposedly is burned?? And the last shop said a milky substance came out of the connector?
Any new suggestions? More diagnosis? Or just replace the sensor? (Maybe I shouldn’t have gotten the one on the car right now from oreilleys even though part # was correct)

I’m just so disappointed right now
I think I recommended a shop in Fullerton for you to take it to. If anyone can fix it he can
 

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The Real Mechanic Shop? :cool:
Yes Ubaldo Rivera he does all three of my SL's heavy maintenance, very honest and very reasonable even the dealer sends problem cars to him. Instead of throwing parts at it it's worth the trip there to have him diagnose it
I spend every Saturday morning there and have seen a lot of difficult issues repaired.
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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Yeah, he's awesome. I fix my own cars, but he's the real deal.
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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Huh, are you the guy with the bandana? We've met.

Small world. I do keys and other electronics for ubaldo.
 
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