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#16
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So we're all on the same page with regards to the idle-descent problem, here's how mine was behaving prior to new caps (for reference, I have my idle set ~650 RPM):
When operating "normally", a quick blip of the throttle would have the idle return to ~750 RPM, pause for a second or so, then drop back to ~650 RPM where the idle is set. When "misbehaving", a quick blip of the throttle could have the RPM drop to ~1000 RPM and quickly (3-5 seconds) taper back to 650, or it could have the RPM hang at ~900-1000. Sometimes it would slowly (we're talking 15-30 seconds) return to idle, or on occasion, it would just stick indefinitely (several minutes). No amount of throttle manipulation would get it to quit what it was doing, but unplugging the ELR solenoid would immediately drop to ~550 RPM where the mechanical governor is set. The "stuck at 1000 RPM" idle was truly a random occurrence, generally at traffic lights or drive-thrus where a small amount of throttle was required to move the vehicle, then remaining stationary. It's so random, that I've never fully worked out exactly what has to happen to make it stick. I know that slow speed and gentle throttle movements were required. Generally when it would stick, the RPM was less than 2000 RPM prior to the sticking event. With the capacitors replaced in the ELR, the 'delay' returning to idle appears to be gone. When blipping the throttle, the idle speed drops back to ~650 RPM immediately, and without the pause at the higher RPM. Whether or not capacitors have solved the "stuck at 1000 RPM idle" issue remains to be seen. I typically had that behavior 2-3 times a week and while irritating, didn't hold a candle to the car rocking (that was REALLY irritating). If I make it a week or two without a "stuck at 1000 RPM" idle, we can assume the capacitors were a fix.
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Current stable: 1995 E320 149K (Nancy) 1983 500SL 120K (SLoL) Black Sheep: 1985 524TD 167K (TotalDumpster™) Gone but not forgotten: 1986 300SDL (RIP) 1991 350SD 1991 560SEL 1990 560SEL 1986 500SEL Euro (Rusted to nothing at 47K!) |
#17
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I had a laundry list of errands to run this afternoon, both personal and for work. I deliberately went through town to hit all the stop/go areas and slow traffic zones (2 school zones). My car rocking idle has not returned, but more importantly:
1: My WOT A/C cutout switch is actually functioning now. The switch was good, but the A/C would rarely cut out. Now when it does, that car's like a rocket. Very different behavior compared to it's usual sluggy self with the A/C on! 2: You can actually tell the ELR/EDS is actively correcting idle speed when the A/C compressor cycles. There's a mild "bump" when the compressor cycles on or off and I no longer get RPM droop with it on. 3: This one is important: THE KICKDOWN SWITCH WORKS NOW!!! Since I've had the car, the kickdown switch has always been flaky. A hotline to Ms. Cleo would have been helpful to know whether or not it would work, there was no rhyme or reason to its behavior. Over ~2500 RPM, it would not work at all, regardless of load, you'd have to manually downshift using the gear lever. Now it's working 100% of the time I hit it. I even took it on the highway and it'll downshift at highway speeds! It's NEVER done that! It's worth noting that on the '86, the downshift has an RPM sensitive circuit in the KLIMA relay. I don't think the later cars have that, this one does and the KLIMA I have installed has the relay in it for that function. Still not hot enough to test the A/C cycling on the highway, but it wasn't doing it when I went for my highway run this afternoon.
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Current stable: 1995 E320 149K (Nancy) 1983 500SL 120K (SLoL) Black Sheep: 1985 524TD 167K (TotalDumpster™) Gone but not forgotten: 1986 300SDL (RIP) 1991 350SD 1991 560SEL 1990 560SEL 1986 500SEL Euro (Rusted to nothing at 47K!) |
#18
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What a great thread, tremendous contribution here. Should become a DIY thread!
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Respectfully, /s/ M. Dillon '87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted '95 124.131 (E300) "Sapphire", 380k miles '73 Balboa 20 "Sanctification" Charleston SC |
#19
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My KLIMA relay would never work, so I ended up removing that and replacing with a work-around relay that restored AC compressor function. I also had the rough idle from EDS/ELR. I really need to try your fix and see if I can restore the whole system to operation. My engine wiring harness is looking rather poorly, with a big of insulation flaking off because it has gotten brittle and cracked when flexed, so I'd attributed my issues to that. Now I need to try this fix.
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Respectfully, /s/ M. Dillon '87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted '95 124.131 (E300) "Sapphire", 380k miles '73 Balboa 20 "Sanctification" Charleston SC |
#20
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My original KLIMA relay had the contacts welded on the compressor relay, which ultimately fried the compressor when it ran out of refrigerant (it was UGLY). The replacement KLIMA relay has been working, but the kickdown has never worked properly and the A/C cutout microswitch wouldn't disconnect the compressor, even though the wiring and switch were good. Both functions work now. It's hot today, so I plan on testing the A/C on the highway after getting off work. Hopefully no more rapid-cycle.
It is worth noting that the ELR/EDS will not fix a rough/lumpy idle caused by mechanical problems. If the engine runs rough with the EDS solenoid disconnected, it's gonna run rough with it connected as well. If it smoothes out with the EDS solenoid unplugged, it's likely to be issues in the EDS computer contributing to the shake. My idle is not perfectly smooth and never has been, but now that the EDS computer is serviced, any roughness I have is completely ignorable, I've been at a couple stop lights where I thought the thing died, but was still running fine, just without the familiar stomach-jiggling shake!
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Current stable: 1995 E320 149K (Nancy) 1983 500SL 120K (SLoL) Black Sheep: 1985 524TD 167K (TotalDumpster™) Gone but not forgotten: 1986 300SDL (RIP) 1991 350SD 1991 560SEL 1990 560SEL 1986 500SEL Euro (Rusted to nothing at 47K!) |
#21
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EDS re-cap took care of the rapid cycling A/C compressor on the highway too. Was 87˚ today, and on a 20 minute highway trip, it only cycled once the fan was ramped all the way down to maintain temp in the cabin.
Still no recurrence of the 1000 RPM idle.
__________________
Current stable: 1995 E320 149K (Nancy) 1983 500SL 120K (SLoL) Black Sheep: 1985 524TD 167K (TotalDumpster™) Gone but not forgotten: 1986 300SDL (RIP) 1991 350SD 1991 560SEL 1990 560SEL 1986 500SEL Euro (Rusted to nothing at 47K!) |
#22
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Day 5 and still no high stuck idle. The things that started working with the re-cap job are still working, and the car-rockingly rough idle still hasn't returned. I've been doing a LOT of in-town driving to test that thing out, so far it seems to have solved several mysteries.
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Current stable: 1995 E320 149K (Nancy) 1983 500SL 120K (SLoL) Black Sheep: 1985 524TD 167K (TotalDumpster™) Gone but not forgotten: 1986 300SDL (RIP) 1991 350SD 1991 560SEL 1990 560SEL 1986 500SEL Euro (Rusted to nothing at 47K!) |
#23
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Pictures
It's been a week now and none of my problems have returned and no stuck high idle. I'm calling the recap of the EDS board a success.
For those folks out there who need a photo, I pulled the EDS module out and took some quick shots to reinforce what I said earlier in this thread. Photo 1: When you pull the EDS computer, make sure you note which way the latching clip (red arrow) faces. The boards inside can go back into the plastic box either direction, but if you get it backwards during reassembly, you won't be able to reattach the wiring harness since it'll be "upside down". Photo 2: Once you remove the 4 screws that hold the module together, pull the boards out of the plastic box and arrange as shown with the latching clip (blue arrow) at the top right. Remove the 2 screws (red arrows), and squeeze the 2 plastic clips (purple arrows) to release the boards. Photo 3: At the bottom end of the board pair, you have 2 plastic clips. Separate them at the bulges (red arrows). They should pop apart with a small effort. At this point you should be able to fully separate the boards and lay them open like a book. Photo 4: With the boards laid open, you will see the 5 electrolytic capacitors you need to replace. They are marked with their values, but they are also given here for reference. I used 63V capacitors for all of my replacements because they were the easiest (and cheapest) to find. These boards are double-sided circuit traces, so take your time de-soldering. If you get impatient and start ripping and tearing, you can destroy the circuit card. You may need to wick the solder out of the hole, then use the soldering iron to maneuver the old leads out of the holes. The polarity of the capacitors is marked on the silkscreen of the circuit card. The positive end of each capacitor is marked with a "+" symbol. The capacitor itself will have the negative end marked, usually with a white stripe or with a series of "-" symbols. As is usually the case, reassembly is the reverse process of disassembly.
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Current stable: 1995 E320 149K (Nancy) 1983 500SL 120K (SLoL) Black Sheep: 1985 524TD 167K (TotalDumpster™) Gone but not forgotten: 1986 300SDL (RIP) 1991 350SD 1991 560SEL 1990 560SEL 1986 500SEL Euro (Rusted to nothing at 47K!) Last edited by Diseasel300; 06-19-2021 at 10:06 PM. |
#24
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Again, that's for a very useful thread.
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#25
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That's the idea of a forum isn't it? People sharing/transferring knowledge?
__________________
Current stable: 1995 E320 149K (Nancy) 1983 500SL 120K (SLoL) Black Sheep: 1985 524TD 167K (TotalDumpster™) Gone but not forgotten: 1986 300SDL (RIP) 1991 350SD 1991 560SEL 1990 560SEL 1986 500SEL Euro (Rusted to nothing at 47K!) |
#26
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Quote:
I was hoping for dry linkage lol. I'll grab the electronics and get to work. Thanks again! PS...I just love this kind of fix. Kind of like my clock repair. Thought it'd be big bucks to get a new clock. Couple bucks in capacitors and it keeps perfect time. Thank you Diseasel!
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1986 300SDL 440,xxx |
#27
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I figured I'd follow up since it's been about a month since I started this thread:
Still not one instance of the high idle issue since re-capping the EDS computer. Not one. Considering I was having it happen 2-3x per week, I'm reasonably confident in saying that repairing the computer solved that issue. A/C still has not done it's rapid-cycle behavior on the highway. It cuts in and out as you'd expect it to based on temperature in the cabin. It stays engaged until the fan cuts way down and it reaches setpoint, then begins to cycle. Currently not really an issue since the weather is nice enough for windows-down and/or Economy mode. Kickdown switch has been working like a champ! Gone are the days of repeatedly mashing the pedal and praying for a downshift. Poke it and let the transmission do the work. Idle improvement is still there too. I occasionally get a rough idle, which I think I tracked down to an air leak in one of the fuel lines to the lift pump. Since replacing it, the idle has been much improved for the last few days. Even with the leak, I still was not having the car-rocking idle issues I had before the EDS computer was re-capped. Through and through - improvements all the way around in terms of refinement.
__________________
Current stable: 1995 E320 149K (Nancy) 1983 500SL 120K (SLoL) Black Sheep: 1985 524TD 167K (TotalDumpster™) Gone but not forgotten: 1986 300SDL (RIP) 1991 350SD 1991 560SEL 1990 560SEL 1986 500SEL Euro (Rusted to nothing at 47K!) |
#28
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Quote:
Where is this connector ? Thanks And Does 350SDL has ERL adjustment knob? Just curious.
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91' MB 350 SDL, with 961 engine and #14 valve head 09' ML320 Bluetec Last edited by phlfly; 12-10-2017 at 09:36 PM. |
#29
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The ELR plug is on the back of the injection pump. It's a red solenoid with a plug on top. If you unplug it and the engine speed suddenly drops, you know the ELR is doing something.
Not sure if the 350 has the ELR adjustment knob or not. If you do, it's on the firewall behind the fusebox. It's numbered 1-7
__________________
Current stable: 1995 E320 149K (Nancy) 1983 500SL 120K (SLoL) Black Sheep: 1985 524TD 167K (TotalDumpster™) Gone but not forgotten: 1986 300SDL (RIP) 1991 350SD 1991 560SEL 1990 560SEL 1986 500SEL Euro (Rusted to nothing at 47K!) |
#30
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Shamelessly bumping this thread. 1) It's a good read and 2) it references Ms. Cleo in post #17.
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1991 300D 2.5 "Rocinante" 2002 Golf TDI "Teen Spirit" -------------------- 1984 300D 1966 Mustang I6 3sp 1985 Mazda RX-7 GSLSE 1982 Toyota Supra 1977 Datsun 280z 1971 Datsun 240z |
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