1988 300TE - Misfires - Part #2
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88-300CE TWIN TURBO, 99-C43, 05-G55K, 71-280SL, 94-E320 CAB, 08 CLK63 BLACK SERIES
You could put it to a meter and check it as you would any other electrical sensor. To be honest it is something that is routinely replaced anyhow and if it is not bad now chances are it will be later. On GM's (i know it is not a fair comparison) the CPS is the #1 reason for no starts and stalls. If it is not too much $ i would just swap it out. You will know immediately if it was the issue.
Believe it sees a peak of 1.5V at starting and rises with increasing speed.
M103-12V will not start if the EZL ignition control unit doesn't receive a signal from the position sensor.
You can do a static test by pulling the position pickup plug off the EZL unit and measuring resistance between terminals 31d ( outer core ) and 7 ( center pin. )
Should read 680-1200 ohms, if not it needs to be replaced.
Usually a go or no go situation on the M103-12V....if you start and run, then most times the sensor is fine.
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You need an oscilliscope to check the CPS on the M103-12V as it staggered by 120 degrees as the driven plate ring gear turns.
Believe it sees a peak of 1.5V at starting and rises with increasing speed.
M103-12V will not start if the EZL ignition control unit doesn't receive a signal from the position sensor.
You can do a static test by pulling the position pickup plug off the EZL unit and measuring resistance between terminals 31d ( outer core ) and 7 ( center pin. )
Should read 680-1200 ohms, if not it needs to be replaced.
Usually a go or no go situation on the M103-12V....if you start and run, then most times the sensor is fine.
Believe it sees a peak of 1.5V at starting and rises with increasing speed.
M103-12V will not start if the EZL ignition control unit doesn't receive a signal from the position sensor.
You can do a static test by pulling the position pickup plug off the EZL unit and measuring resistance between terminals 31d ( outer core ) and 7 ( center pin. )
Should read 680-1200 ohms, if not it needs to be replaced.
Usually a go or no go situation on the M103-12V....if you start and run, then most times the sensor is fine.
I looked in my Haynes manual and it mentions no EZL. Does it go under a different name maybe? Where is it located?
Thanks, ps2cho
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From: REHOBOTH BEACH DE
88-300CE TWIN TURBO, 99-C43, 05-G55K, 71-280SL, 94-E320 CAB, 08 CLK63 BLACK SERIES
If you have a 1988 300TE you should have the M103-12V engine with CIS-E and a EZL ignition.
Below from the MB "Service Manual Engine 103 "
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The UK one seems a lot different from the US one.
Thats my next plan of action when I get back home.
....
But a little off topic, the car is a hell of a lot more responsive. I just drove 400 miles north for a 7 hour drive and gave her a real good Italian tune up. I love how at 115mph its still totally smooth and I feel dead safe. Gave her some real hard acceleration onto the freeway and she really pulls now with the new EHA and O2 sensor.
I was expecting after the long drive that the misfires would have felt better....but feels the same. I would definitely get better mpg when this problem is fixed. I also know the car still has more HP available too.
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w211 & w124
What did you pay for the EHA sensor. My wagon is in the shop right now and I think the mechanic is putting in a new one of those for me. He says my distributor cap and rotor will also need to be replaced at some point and also the engine mounts need to be replaced.
I'm thinking I don't want to put more than a grand into keeping this wagon working but I also don't can't afford to just let it die and not be able to sell it or trade it out for something while it still runs. Oh the joys of an old Benz....
I'm thinking I don't want to put more than a grand into keeping this wagon working but I also don't can't afford to just let it die and not be able to sell it or trade it out for something while it still runs. Oh the joys of an old Benz....
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Sounds like bad inlet manifold gasket or some other vacuum leak.. ?
Last edited by 124-Fan; Feb 15, 2008 at 06:23 PM.
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What did you pay for the EHA sensor. My wagon is in the shop right now and I think the mechanic is putting in a new one of those for me. He says my distributor cap and rotor will also need to be replaced at some point and also the engine mounts need to be replaced.
I'm thinking I don't want to put more than a grand into keeping this wagon working but I also don't can't afford to just let it die and not be able to sell it or trade it out for something while it still runs. Oh the joys of an old Benz....
I'm thinking I don't want to put more than a grand into keeping this wagon working but I also don't can't afford to just let it die and not be able to sell it or trade it out for something while it still runs. Oh the joys of an old Benz....
You can do all three yourself without any knowledge and save yourself some money. Its real easy.
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1995 E320 SE, 162,000 Miles (Sold) 2007 CLK350 Cabriolet 2014 ML550
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I´ve replaced more cylinder head gaskets in this engine than I can account for and I´ve never seen a cracked inlet manifold. But I´ve seen the inlet gasket torn and even partly disintegrated on several occasions. When that happens, the symptoms are excactly as described here.
Cheers,
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1995 E320 SE, 162,000 Miles (Sold) 2007 CLK350 Cabriolet 2014 ML550
Of couse it could be a cracked manifold. Theoretically. I would still rather bet on the gasket. Replacing it doesn´t require removing the inlet manifold. You just have to undo all the bolts and brackets at the rear to nugde it slightly away from the head.
I´ve replaced more cylinder head gaskets in this engine than I can account for and I´ve never seen a cracked inlet manifold. But I´ve seen the inlet gasket torn and even partly disintegrated on several occasions. When that happens, the symptoms are excactly as described here.
Cheers,
I´ve replaced more cylinder head gaskets in this engine than I can account for and I´ve never seen a cracked inlet manifold. But I´ve seen the inlet gasket torn and even partly disintegrated on several occasions. When that happens, the symptoms are excactly as described here.
Cheers,
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From: REHOBOTH BEACH DE
88-300CE TWIN TURBO, 99-C43, 05-G55K, 71-280SL, 94-E320 CAB, 08 CLK63 BLACK SERIES
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Where should I take the car to have this done? Should every mechanic shop be able to do this efficiently or is it specialized? I live in Southern California.
EDIT: This is what I followed:
http://www.mercedesshop.com/Wikka/M103VacuumLeak
Last edited by ps2cho; Feb 21, 2008 at 03:26 PM.
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From: REHOBOTH BEACH DE
88-300CE TWIN TURBO, 99-C43, 05-G55K, 71-280SL, 94-E320 CAB, 08 CLK63 BLACK SERIES
I have personally tested for vacuum leaks using the O2 sensor with the brake booster, etc...disconnected and it proved no leaks there. Is this limited though?
Where should I take the car to have this done? Should every mechanic shop be able to do this efficiently or is it specialized? I live in Southern California.
EDIT: This is what I followed:
http://www.mercedesshop.com/Wikka/M103VacuumLeak
Where should I take the car to have this done? Should every mechanic shop be able to do this efficiently or is it specialized? I live in Southern California.
EDIT: This is what I followed:
http://www.mercedesshop.com/Wikka/M103VacuumLeak
Many of the symptoms you have mentioned tend to lean toward a vacuum leak.
Unfortunately, I don't believe that MB has ever published a vacuum diagram for the W124.
You mentioned that when you turned your heater on your economy gauge moved.
The gauge is actually a vacuum gauge so possible the movement of an air flap indicates a leak?
Look behind your brake booster and you should see a vacuum manifold, with about five lines branching off.
One of the lines goes to the economy gauge.
See if you can detect a leak in this area.
Smoke testing is probably the best way to detect a leak anywhere in the system.
We used it prior to starting my engine after the twin turbo install.
Concerned that a leak could cause a lean mixture and possible detonation on the dyno.
You'll have to call around to find a shop that has the equipment and specializes in leak detection.
I found an article that better explains all the methods of leak testing, some of which you have used.
http://www.asashop.org/autoinc/may/TECH2TEC.HTM
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Many of the symptoms you have mentioned tend to lean toward a vacuum leak.
Unfortunately, I don't believe that MB has ever published a vacuum diagram for the W124.
You mentioned that when you turned your heater on your economy gauge moved.
The gauge is actually a vacuum gauge so possible the movement of an air flap indicates a leak?
Look behind your brake booster and you should see a vacuum manifold, with about five lines branching off.
One of the lines goes to the economy gauge.
See if you can detect a leak in this area.
Smoke testing is probably the best way to detect a leak anywhere in the system.
We used it prior to starting my engine after the twin turbo install.
Concerned that a leak could cause a lean mixture and possible detonation on the dyno.
You'll have to call around to find a shop that has the equipment and specializes in leak detection.
I found an article that better explains all the methods of leak testing, some of which you have used.
http://www.asashop.org/autoinc/may/TECH2TEC.HTM
Unfortunately, I don't believe that MB has ever published a vacuum diagram for the W124.
You mentioned that when you turned your heater on your economy gauge moved.
The gauge is actually a vacuum gauge so possible the movement of an air flap indicates a leak?
Look behind your brake booster and you should see a vacuum manifold, with about five lines branching off.
One of the lines goes to the economy gauge.
See if you can detect a leak in this area.
Smoke testing is probably the best way to detect a leak anywhere in the system.
We used it prior to starting my engine after the twin turbo install.
Concerned that a leak could cause a lean mixture and possible detonation on the dyno.
You'll have to call around to find a shop that has the equipment and specializes in leak detection.
I found an article that better explains all the methods of leak testing, some of which you have used.
http://www.asashop.org/autoinc/may/TECH2TEC.HTM
I actually emailed someone close by this morning about leak detection. I'll now throw around a few more and see what comes back. I mentioned the problem, what I have replaced and asked if they have the right equipment needed to be absolutely 100% I am vacuum leak free. I'll make sure to mention the smoke test for the other's that I will email/call.
I'll take a sniff around that brake booster line and see if I can spot anything.
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One easy way is also to buy a can of starting spray. It should be available at any local auto store. Which kind doesn´t matter.
Remove the air filter case altogether and let the car idle. While the misfire is happening, gently spray some starting spray all over the intake manifold without spraying into the mechanical airflow sensor. Spray some onto the inlet gasket and the hoses near the idle speed stabilizer.
If the misfires stop or engine rpm changes, you have a vacuum leak.
Cheers,
Remove the air filter case altogether and let the car idle. While the misfire is happening, gently spray some starting spray all over the intake manifold without spraying into the mechanical airflow sensor. Spray some onto the inlet gasket and the hoses near the idle speed stabilizer.
If the misfires stop or engine rpm changes, you have a vacuum leak.
Cheers,
Last edited by 124-Fan; Feb 22, 2008 at 07:44 AM.
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One easy way is also to buy a can of starting spray. It should be available at any local auto store. Which kind doesn´t matter.
Remove the air filter case altogether and let the car idle. While the misfire is happening, gently spray some starting spray all over the intake manifold without spraying into the mechanical airflow sensor. Spray some onto the inlet gasket and the hoses near the idle speed stabilizer.
If the misfires stop or engine rpm changes, you have a vacuum leak.
Cheers,
Remove the air filter case altogether and let the car idle. While the misfire is happening, gently spray some starting spray all over the intake manifold without spraying into the mechanical airflow sensor. Spray some onto the inlet gasket and the hoses near the idle speed stabilizer.
If the misfires stop or engine rpm changes, you have a vacuum leak.
Cheers,
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Well I have been saving up some money and bought a Cylinder Leakage Tester as per suggestion of my dad. This should detect any head gasket, cylinder wall/rings, intake valves leaks.
Will report back with the findings soon. Hopefully something shows up.
Will report back with the findings soon. Hopefully something shows up.
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Oh and will I need to lock the crankshaft?
Found out a few weeks ago that the inside of my rear tires were showing too much wear so had to get them both replaced....I should get back to figuring this out this weekend.
Spring break wooo!!
My goal is to figure this damn thing out over Spring Break. Going to rip out the CPS and measure the ohms and check vacuum leaks with regards to that fluctuating economy gauge.
Last edited by ps2cho; Mar 12, 2008 at 01:47 AM.
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From: Orland Park, Illinois
1994 E320 (current)
[QUOTE=ps2cho;2704204]Guess on Saturday we shall find out!!
Oh and will I need to lock the crankshaft?
If you are doing a compression test all you do is get a socket on the main bolt on the front main pulley. Take the spark plug out of #1 and fix the pressure tester into that plug position. Slowly rotate the crank (make sure you go in the normal direction of the engine) When you get it to the top your compression will spike. When the compression spikes take that reading and then watch for how quickly it blows off compression. It should hold it fairly well. Do this for each cylinder and compare to spec psi and compare all cylinders too each other. If you have a compression issue that bad then often times you can tell because the engine will have oil blow past the rings and the plugs will be "wet". Because of your previous statements about the problem being intermittent I doubt you will find any major issues with compression, or at least issues that are effecting the idle. Good luck, let us know what you find.
Oh and will I need to lock the crankshaft?
If you are doing a compression test all you do is get a socket on the main bolt on the front main pulley. Take the spark plug out of #1 and fix the pressure tester into that plug position. Slowly rotate the crank (make sure you go in the normal direction of the engine) When you get it to the top your compression will spike. When the compression spikes take that reading and then watch for how quickly it blows off compression. It should hold it fairly well. Do this for each cylinder and compare to spec psi and compare all cylinders too each other. If you have a compression issue that bad then often times you can tell because the engine will have oil blow past the rings and the plugs will be "wet". Because of your previous statements about the problem being intermittent I doubt you will find any major issues with compression, or at least issues that are effecting the idle. Good luck, let us know what you find.
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300E a couple 1994 w124wagon E320 Wagon/,1971MGB Track/Rally, MG Midget Autocross ,2000 E320 wagon.
Have
you lowered the wagon?Rear camber might be way negative if those tires were shot on the inside.
CPS if fouled can trigger the misfire as stated but since it is only a $40 part toss one in to rule it out
http://www.autohausaz.com/search/pro...ition%20Sensor
Have you checked the resistance in the spark plug wires and made sure they are good and that the insulation is not leaking spark at low rpm?Have you had it on a scope and actually seen that the misfire is random?
always check www.autohausaz.com for prices,someone mentioned $140 for the cps at autozone and that is a big piece of change more and most times autozone carries non oe or non oem parts.
ohlord
good luck on the hunt,you will solve it
have you ruled out a broken engine mount as a possibility of the misfire feeling at idle?Common on the w210's don't know on your model but worth a check.
CPS if fouled can trigger the misfire as stated but since it is only a $40 part toss one in to rule it out
http://www.autohausaz.com/search/pro...ition%20Sensor
Have you checked the resistance in the spark plug wires and made sure they are good and that the insulation is not leaking spark at low rpm?Have you had it on a scope and actually seen that the misfire is random?
always check www.autohausaz.com for prices,someone mentioned $140 for the cps at autozone and that is a big piece of change more and most times autozone carries non oe or non oem parts.
ohlordgood luck on the hunt,you will solve it
have you ruled out a broken engine mount as a possibility of the misfire feeling at idle?Common on the w210's don't know on your model but worth a check.
Last edited by ohlord; Mar 12, 2008 at 02:35 AM.
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you lowered the wagon?Rear camber might be way negative if those tires were shot on the inside.
CPS if fouled can trigger the misfire as stated but since it is only a $40 part toss one in to rule it out
http://www.autohausaz.com/search/pro...ition%20Sensor
Have you checked the resistance in the spark plug wires and made sure they are good and that the insulation is not leaking spark at low rpm?Have you had it on a scope and actually seen that the misfire is random?
always check www.autohausaz.com for prices,someone mentioned $140 for the cps at autozone and that is a big piece of change more and most times autozone carries non oe or non oem parts.
ohlord
good luck on the hunt,you will solve it
have you ruled out a broken engine mount as a possibility of the misfire feeling at idle?Common on the w210's don't know on your model but worth a check.
CPS if fouled can trigger the misfire as stated but since it is only a $40 part toss one in to rule it out
http://www.autohausaz.com/search/pro...ition%20Sensor
Have you checked the resistance in the spark plug wires and made sure they are good and that the insulation is not leaking spark at low rpm?Have you had it on a scope and actually seen that the misfire is random?
always check www.autohausaz.com for prices,someone mentioned $140 for the cps at autozone and that is a big piece of change more and most times autozone carries non oe or non oem parts.
ohlordgood luck on the hunt,you will solve it
have you ruled out a broken engine mount as a possibility of the misfire feeling at idle?Common on the w210's don't know on your model but worth a check.
Engine mounts are not the problem as the misfire is inconsistent and the engine sounds like a tractor some days. Some days it misses like an earthquake or your driving on a gravel road, and other days its reasonably smooth (still feelable though).
Been through about 5 sets of plugs (prior to fixing valve stem seals leaking oil all over the plugs) but since we fixed that, no oil consumption/plug fouling and I have the correct H9DCO's (OEM). We have gapped as well.
If you are doing a compression test all you do is get a socket on the main bolt on the front main pulley. Take the spark plug out of #1 and fix the pressure tester into that plug position. Slowly rotate the crank (make sure you go in the normal direction of the engine) When you get it to the top your compression will spike. When the compression spikes take that reading and then watch for how quickly it blows off compression. It should hold it fairly well. Do this for each cylinder and compare to spec psi and compare all cylinders too each other. If you have a compression issue that bad then often times you can tell because the engine will have oil blow past the rings and the plugs will be "wet". Because of your previous statements about the problem being intermittent I doubt you will find any major issues with compression, or at least issues that are effecting the idle. Good luck, let us know what you find.
I'm building a list of things that I am capable of doing over Spring break.
Gotta see where I can find that center console around the gearstick too...mines showing cracks. Not to confuse the thread and go off course, but a quick question: Wheres the best place to find this type of interior dash/console stuff? Junkyard? Ebay? Any other places?
Thanks alot guys! Maybe I'll get this figured out once and for all. Been going on too long
Last edited by ps2cho; Mar 12, 2008 at 02:59 AM.
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ALRIGHTY!!!!
FINALLY have done that Leak Down/Cylinder Leak Test.
Results:
15% leak on cylinders 2-5
25% leak on cylinder 1
^ We may have found the problem!
But listen to this:
When the pressure is inserted into Cylinder 1, it seemed to be that we hear air coming from cylinder 2, but not vice versa. Is this odd or is there a logical explanation to that?
Could this be the problem right here???
FINALLY have done that Leak Down/Cylinder Leak Test.
Results:
15% leak on cylinders 2-5
25% leak on cylinder 1
^ We may have found the problem!
But listen to this:
When the pressure is inserted into Cylinder 1, it seemed to be that we hear air coming from cylinder 2, but not vice versa. Is this odd or is there a logical explanation to that?
Could this be the problem right here???
Last edited by ps2cho; Mar 16, 2008 at 08:29 PM.
