Alright, just an update on my situation here. It has gotten worse, unfortunately :( the car now barely runs and can't really be taken anywhere. There's a misfire at idle and low RPMs when you give it the beans, but once the revs go up it works fine (as stated before). Since it is fairly consistent now I was able to get the duty cycle off of the car WHILE it was misfiring and all associated weirdness. Interestingly, the DC never fluctuated beyond 45-55% while this was happening. When it'd skip, it would go up to about 55% quickly and then come down. Makes sense since there is then unburned fuel going through the system. With this in mind, it is almost certainly electrical. Since I've already gone over the cap, rotor, and wires today, that leaves me with bad plugs, bad coil, or bad ignition control module. I have to dig out the EZL troubleshooting guide (I know I have it somewhere) and rule that out. Not sure how to test the coil other than resistance for the different wire winds.
Also verified:
Wires are low resistance (1k ohms, printed on the terminals and verified as 1.1k though multimeter). Again I have to verify with the manual as to the correct overall resistance spec but from searches on here, having 1kohm wires should necessitate resistor spark plugs, rather than the resistors being in the wire. I don't want this to turn into a resistor v. non resistor post but I am just looking for the TOTAL spec from cap-end-terminal to the tip of the spark plug. I am going to test this out before spending any more money (I am also planning on pulling each individual plug to make sure they're not fouled...the 2 I pulled today looked almost new, which is great since I replaced them 15k ago).
I'm getting there...I'm trying not to throw any more parts on it until I can isolate the issue but everything just seems normal...
Showing posts with label ignition. Show all posts
Showing posts with label ignition. Show all posts
Monday, July 9, 2012
Thursday, March 8, 2012
Intermittent stalling, RPM drop, misfiring...oh boy
So it wasn't the OVP. I replaced that with a brand new unit and the problem persists. To refresh, here's what has been plaguing my 300e.
Very intermittently my car loses RPMs and stalls, but ONLY under load. This first happened once in a parking lot after warming up, then again in the driveway. Not too long afterwards, I parked the 300e for a bit since I didn't have a place for it, and it now does it about 40% of starts. It is fine when cold, but after it warms up, the idle becomes rougher and as soon as you step on the gas a bit (still in park) it misfires and shakes badly up until about 2500 RPMs. However, shift it into drive or reverse and it does the same misfiring but the RPMs drop until it stalls. I thought it was the OVP since that is a very common replacement item, but no luck. Also, during this time I found that my EHA valve (stands for electrohydraulic actuator) began to leak massively. Again there was a glimmer of hope, but even after replacing it with a known good part, the problem persists. Actually, I might as well just list all the stuff I've checked
- replaced ovp with new unit
- replaced cap and rotor, just inspected them again today to see if there was anything wacky there...cap had some usual corrosion on contact points but nothing out of the ordinary
- replaced wires, checked again for arcing today and nothing
- replaced EHA (was leaking wildly, had to be done anyways)
- checked engine temp sensor, appears to be fine
- checked the flywheel crank sensor (which goes to EZL), came out to 880 ohms, which is well within spec
- replaced O2 sensor
- fuel pump is always on during this so that rules out FPR
- replaced spark plugs (proper style - ordered from here)
- checked vacuum connections, seems fine
- duty cycle (checked via X11 diagnostic port) remained within 47-51%, which is very good--Lambda tower does not need adjustment.
Really not sure where I am heading from here. I think I am going to replace all of the vacuum lines that I can find and hopefully fix any leak that might exist. Stay tuned....
Very intermittently my car loses RPMs and stalls, but ONLY under load. This first happened once in a parking lot after warming up, then again in the driveway. Not too long afterwards, I parked the 300e for a bit since I didn't have a place for it, and it now does it about 40% of starts. It is fine when cold, but after it warms up, the idle becomes rougher and as soon as you step on the gas a bit (still in park) it misfires and shakes badly up until about 2500 RPMs. However, shift it into drive or reverse and it does the same misfiring but the RPMs drop until it stalls. I thought it was the OVP since that is a very common replacement item, but no luck. Also, during this time I found that my EHA valve (stands for electrohydraulic actuator) began to leak massively. Again there was a glimmer of hope, but even after replacing it with a known good part, the problem persists. Actually, I might as well just list all the stuff I've checked
- replaced ovp with new unit
- replaced cap and rotor, just inspected them again today to see if there was anything wacky there...cap had some usual corrosion on contact points but nothing out of the ordinary
- replaced wires, checked again for arcing today and nothing
- replaced EHA (was leaking wildly, had to be done anyways)
- checked engine temp sensor, appears to be fine
- checked the flywheel crank sensor (which goes to EZL), came out to 880 ohms, which is well within spec
- replaced O2 sensor
- fuel pump is always on during this so that rules out FPR
- replaced spark plugs (proper style - ordered from here)
- checked vacuum connections, seems fine
- duty cycle (checked via X11 diagnostic port) remained within 47-51%, which is very good--Lambda tower does not need adjustment.
Really not sure where I am heading from here. I think I am going to replace all of the vacuum lines that I can find and hopefully fix any leak that might exist. Stay tuned....
Wednesday, September 28, 2011
The plot thickens...300E stalling
Its been a while since I've updated this because I have been unbelievably busy. School started up again and the 300E began to stall when up to temp. There are so many things that can cause the engine to stall out in this fashion, let me describe my circumstances:
First time it ever did this was in the parking lot of a local supermarket when I was out on a really quick grocery run. I parked the car (only had gone about a mile from my apartment), went inside, got what I needed and came back out in about 5 minutes. Starting up the car, it stumbled just a tad but seemed pretty normal idling. As soon as I put any load on the engine (so basically when I shifted into reverse) it immediately stalled. I was able to push it back into the space, start it up and idle it again. I popped the hood and didn't notice anything out of place...checked the OVP for any visible signs of fuse failure, and nothing out of the ordinary. I got back in and revved the engine a bit and noticed a misfire whenever I had my foot on the gas to rev it (would not misfire coming back down, only under a load). After about 5 minutes it fixed itself and I was able to drive home.
Second time was after I replaced a burst coolant hose. I was terrified that in the process I had blown the head gasket by localized overheating (though the car did not get above 110* on the gauge) and I was suffering from low compression. However I realized it was the same odd issue as I experienced above. I figured in the process of checking everything out under the hood I jostled some vacuum lines...I made sure they were all in their respective places, ordered a new valve cover-to-air cleaner tube and installed it. The problem went away after that so I thought I had fixed it
Now, I have parked my 300E at my parents' for the most part, until I can sort out DMV inspection stuff. I ended up buying a new car about a month ago since I needed something that would not break down at ALL, and would not cost me money to repair if it did (read: warantee). My dad calls me a couple weeks ago and told me how he went out to grab a sandwich from a local deli and the car died after he got back in. Oh great! The mystery lives on!
So far I have replaced the overvoltage protection relay (OVP) which is perhaps the most common failure in these cars at this age...did not fix the problem, but its good to have a spare OVP in the glove box for when it inevitably does fail so no harm no foul. I initially suspected the OVP because it intermittently fails (exhibiting the exact symptoms I had) before an ultimate failure. The signal and power for the engine computer goes through the OVP, which is the reason the car runs like crap upon its failure. My next culprit is the O2 sensor, which is a logical choice seeing as the car only behaves badly after it warms up, then the engine temp sensor. I'm going to have to spend quite a lot of time with my digital multimeter at some point, just have no idea when I am going to find that time, especially considering the fact that the car is a few hours away from me at this point and my semester is in full swing. Oh well, this is the reality of owning old MBs, its a labor of love. My 300SD is still inoperable due to a bad transmission too, so the only thing I have at the moment is my brand new car (which I do love).
First time it ever did this was in the parking lot of a local supermarket when I was out on a really quick grocery run. I parked the car (only had gone about a mile from my apartment), went inside, got what I needed and came back out in about 5 minutes. Starting up the car, it stumbled just a tad but seemed pretty normal idling. As soon as I put any load on the engine (so basically when I shifted into reverse) it immediately stalled. I was able to push it back into the space, start it up and idle it again. I popped the hood and didn't notice anything out of place...checked the OVP for any visible signs of fuse failure, and nothing out of the ordinary. I got back in and revved the engine a bit and noticed a misfire whenever I had my foot on the gas to rev it (would not misfire coming back down, only under a load). After about 5 minutes it fixed itself and I was able to drive home.
Second time was after I replaced a burst coolant hose. I was terrified that in the process I had blown the head gasket by localized overheating (though the car did not get above 110* on the gauge) and I was suffering from low compression. However I realized it was the same odd issue as I experienced above. I figured in the process of checking everything out under the hood I jostled some vacuum lines...I made sure they were all in their respective places, ordered a new valve cover-to-air cleaner tube and installed it. The problem went away after that so I thought I had fixed it
Now, I have parked my 300E at my parents' for the most part, until I can sort out DMV inspection stuff. I ended up buying a new car about a month ago since I needed something that would not break down at ALL, and would not cost me money to repair if it did (read: warantee). My dad calls me a couple weeks ago and told me how he went out to grab a sandwich from a local deli and the car died after he got back in. Oh great! The mystery lives on!
So far I have replaced the overvoltage protection relay (OVP) which is perhaps the most common failure in these cars at this age...did not fix the problem, but its good to have a spare OVP in the glove box for when it inevitably does fail so no harm no foul. I initially suspected the OVP because it intermittently fails (exhibiting the exact symptoms I had) before an ultimate failure. The signal and power for the engine computer goes through the OVP, which is the reason the car runs like crap upon its failure. My next culprit is the O2 sensor, which is a logical choice seeing as the car only behaves badly after it warms up, then the engine temp sensor. I'm going to have to spend quite a lot of time with my digital multimeter at some point, just have no idea when I am going to find that time, especially considering the fact that the car is a few hours away from me at this point and my semester is in full swing. Oh well, this is the reality of owning old MBs, its a labor of love. My 300SD is still inoperable due to a bad transmission too, so the only thing I have at the moment is my brand new car (which I do love).
Wednesday, June 15, 2011
w126 ignition tumbler, not something to mess with!
I realize I haven't posted in a while here so I'm playing catch-up! Here are some details about my ignition tumbler issues that I suffered about 2 years ago.
Here's what happened - my tumbler was "loose" but never had any trouble turning. I figured I'd be a little proactive and completely replace the tumbler before it started wearing out even more. Usually this is a super easy job, consisting of about 5 minutes of your time and an unbent paperclip. Somehow, when I inserted the paperclip and turned the tumbler, it got completely stuck! No movement either way. This would be the same problem and solution for all of you who actually have had a completely stuck ignition tumbler as well, not just my folly. Taking a look at the ignition face, there is no way to actually get the tumbler out without turning the key...unless you've got a good grinder and a drill!
1. Take out gauge cluster using the bent-coathanger method
2. Loosen bolts on the underside of the steering column and let it drop (gives about 1.5"). Taking off the steering wheel can help as well, but most of the time the retaining bolt is stuck on there with an ungodly amount of loctite and torque, I was unable to get mine to budge.
3. Here's where it gets fun. There's a little "pin" maybe 3/8" in diameter that holds the ignition assembly to the steering column. It is part of the steering lock mechanism. Some experienced folks on the internet have had success with punching this pin into the column with a drift, but I gave it everything and the damn thing did not budge. Time to take out the dremel! About 5 minutes with a tungsten carbide grinding bit and the pin was no more. This step is much easier said than done. There is almost NO room to work, and you need to get creative to find an angle that works. I was able to slip the dremel in between the plastic steering column sheath (you can take this off if you get the steering wheel off) and the dash...a large socket was used as a spacer since there is some flex in both materials. It was just enough to get the dremel bit in. After grinding down the pin, you should be able to rotate the entire ignition switch mechanism within the steering lock housing.
4. With the ignition switch assembly freely rotating, it should slide out with some coaxing. It isn't easy and still very tight in there, but I was able to get it out and have the igition switch dangling down below the column.
5. Grind off the heads of the screws that hold the back portion of the ignition switch on (i.e. all the wires and vacuum lines side). This will separate the actual ignition switch from the tumbler and steering lock areas. It will also allow you to work on the tumbler mechanism on the bench and outside of the car. Here is a picture of the stuck tumbler/lock assembly on the left and a new tumbler on the right.
6. The plot thickens. Since the metal ring around the tumbler was not moving, more grinding is in store. Putting the new tumbler next to the old, I was able to figure out where the detent was in the ring and tumbler. I cut the ring's detent lock around that area to free the old tumbler:
7. More grinding. I needed to grind the old tumbler's detent down so that I could more easily unscrew that hardened steel ring. That was a pain, by the way--that steel is TOUGH and it takes a lot of cutting and patience. You can see how the tumbler appears to have completely imploded and fallen apart.
8. Finally, after much grinding and fitting, the old tumbler can come out. Small victory:
The new tumbler went in easily!
9. Reassemble, pretty much the reverse (minus grinding) of disassembly. To get the ignition switch back together, I just tightly wrapped electrical tape around the two portions. It lasted 30k miles until the car was parked with no fuss at all. Even the steering lock still works somehow, the pin that I ground down was still slightly large enough to catch just a bit in the hole and secure the mechanism. I imagine it could be removed with a punch now.
Moral of the whole story is: don't wait too late to replace that sticking ignition tumbler!!
Here's what happened - my tumbler was "loose" but never had any trouble turning. I figured I'd be a little proactive and completely replace the tumbler before it started wearing out even more. Usually this is a super easy job, consisting of about 5 minutes of your time and an unbent paperclip. Somehow, when I inserted the paperclip and turned the tumbler, it got completely stuck! No movement either way. This would be the same problem and solution for all of you who actually have had a completely stuck ignition tumbler as well, not just my folly. Taking a look at the ignition face, there is no way to actually get the tumbler out without turning the key...unless you've got a good grinder and a drill!
1. Take out gauge cluster using the bent-coathanger method
2. Loosen bolts on the underside of the steering column and let it drop (gives about 1.5"). Taking off the steering wheel can help as well, but most of the time the retaining bolt is stuck on there with an ungodly amount of loctite and torque, I was unable to get mine to budge.
3. Here's where it gets fun. There's a little "pin" maybe 3/8" in diameter that holds the ignition assembly to the steering column. It is part of the steering lock mechanism. Some experienced folks on the internet have had success with punching this pin into the column with a drift, but I gave it everything and the damn thing did not budge. Time to take out the dremel! About 5 minutes with a tungsten carbide grinding bit and the pin was no more. This step is much easier said than done. There is almost NO room to work, and you need to get creative to find an angle that works. I was able to slip the dremel in between the plastic steering column sheath (you can take this off if you get the steering wheel off) and the dash...a large socket was used as a spacer since there is some flex in both materials. It was just enough to get the dremel bit in. After grinding down the pin, you should be able to rotate the entire ignition switch mechanism within the steering lock housing.
4. With the ignition switch assembly freely rotating, it should slide out with some coaxing. It isn't easy and still very tight in there, but I was able to get it out and have the igition switch dangling down below the column.
5. Grind off the heads of the screws that hold the back portion of the ignition switch on (i.e. all the wires and vacuum lines side). This will separate the actual ignition switch from the tumbler and steering lock areas. It will also allow you to work on the tumbler mechanism on the bench and outside of the car. Here is a picture of the stuck tumbler/lock assembly on the left and a new tumbler on the right.
6. The plot thickens. Since the metal ring around the tumbler was not moving, more grinding is in store. Putting the new tumbler next to the old, I was able to figure out where the detent was in the ring and tumbler. I cut the ring's detent lock around that area to free the old tumbler:
7. More grinding. I needed to grind the old tumbler's detent down so that I could more easily unscrew that hardened steel ring. That was a pain, by the way--that steel is TOUGH and it takes a lot of cutting and patience. You can see how the tumbler appears to have completely imploded and fallen apart.
The new tumbler went in easily!
9. Reassemble, pretty much the reverse (minus grinding) of disassembly. To get the ignition switch back together, I just tightly wrapped electrical tape around the two portions. It lasted 30k miles until the car was parked with no fuss at all. Even the steering lock still works somehow, the pin that I ground down was still slightly large enough to catch just a bit in the hole and secure the mechanism. I imagine it could be removed with a punch now.
Moral of the whole story is: don't wait too late to replace that sticking ignition tumbler!!
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