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#1
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I looked at the accelerator linkage on the 250C (under the front carb). There is a bracket on the pivot with an adjustment that varies the travel of the pedal. If the screw that secures the adjustment were loose or missing, the two pieces could just flop around and not open the carbs. There is also a slider on the linkage that has to be "taken up" before the carb linkage moves.
I agree with Charlie that this is unlikely to be the cause, since the pedal would have to be near the floor if the linkage were 'way out of adjustment. But I cannot think of anything else that would cause the condition. Chuck |
#2
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In addition to my points being shot...my distributor cap has a crack in it!!!
Think fixing these things will help?? ~Christy and Chuck...my pedal IS way near the floor.... |
#3
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Yup
especially the cap, the crack(s) hold dirt and stuff which tends to be conductive. The crack becomes a path to bleed off some or all of the spark to ground resulting in weak or no spark at the plug.
Just to update my escapades, I put the front back on on Sunday (with the secondary vaccuum passage blocked till I get the new diaphram), and fired the car up, but it ran horrible. I left the thing before I put a wrench through something expensive. I went back to it last night took a look and noticed the brake booster hose still disconnected. I optimistically hooked it back up. Cranked it and it fired up strong and smooth even considering my monkeyed settings! It seems way fast on the idle but thats better than falling through the floor. While in the garage, I looked at one of my boxes of old BMW parts and spotted the dual barrels of an old Sole poking out of one. I picked it up and lo and behold, it also has a vaccuum actuated secondary. I took it apart, and the diaphram is a match for the Zenith....except for the threaded hole, it has an M4 I need an M3. But I have JB Weld (a metalized two part epoxy) so I mixed some up, filled the hole and left it to dry. Tonight I'll drill it out and retap it, I have M3's here at work. I'll let you know how it goes. Mark |
#4
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The pedal "falling through the floor"...
THAT is EXACTLY what my car was doing...and what I expect it to do once I can get it started again... WHY would it do that?? Is that an accelerator PEDAL adjustment?? Flooring that pedal will NOT cause the engine to rev...what do I do???? ~Christy |
#5
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More
Ok new diaphram is in started it up and ran it to warm up.Still idling fast and a bit uneven (unbalanced?) One thing I'm noticing thats disturbing is a sucking sound fronm the front carb and a noticable dribble from the preatomizer. From the rear nada, no sound no dribble, which is closer to right?
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#6
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Mark:
The rear carb is closer to right. There should be NO fuel coming from the pre-atomizer. NONE. This means that the throttle plate (hence, idle screw adjustment) is open too far and is allowing to much air past the throttles. This is causing a small venturi effect which is what draws fuel through the preatomizer circuit. There are two (yes two) adjustments for idle. The MAIN one is the thumb screw between the throttle shaft arm and the pivot arm. You need to work the thumbscrew (either clockwise or counter) to get the idle speed set. This will mean that as you adjust the front carb you will probably have to adjust the rear one also. This is one of the reasons a flow-meter is used. Try to get the idle speed in the 800-900 rpm range. The second adjustment that will effect idle speed is the idle mixture screws. NOTE: No matter where those screws are set it WILL NOT cause the condition you describe in the front carb. If you don't have a flow-meter you can get sort-of close to a balance on the carbs by using a short piece of heater hose or a tube from a roll of paper towles. Hold the tube (or hose) to your and stick it (the tube or hose - not your ear) into the PRIMARY of each carb and try to get the sounds balanced. That is what a flow-meter does except it has a graduated scale to give a more accurate reading. Good luck.. Dan edited stuff: Actually I had to re-think this a tad after I wrote it. You should have SOME sound from the rear carb. Probably it is metering fuel at idle or it would not idle well at all. As I remember when I had the Zeniths it took me a while to get mine set anyhow. As I remember, I set the throttle plate openings so that 4mm feeler gauge would pass between the plate and wall. Had them off when I did this. What I think I determined I needed was just so each carb had close to the same amount of initial plate gap. I know they should be open "a tad" but not how much. I set this opening using the idle stop screws on that project down from top plate of the carb (just next to the vent thing). Then I set each thumbwheel adjustment in the middle of its range. I figured this would allow enough hi-low range to adjust everything. I think (been 3 years) that I had to give each carb maybe another 1/2 turn IN on EACH idle stop screw so that I ended up with enough adjustment left on the thumbwheel. When you get this initial adjustment right it doesn't (or shouldn't) take a lot of thumbwheel movement to affect the idle - remember we are working with two carbs - so if you need +200 more RPM then you are trying to adjust so that each carb adds +100 to the total. Dan (again) [Edited by DANTRCAV on 05-16-2001 at 01:24 PM]
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Dan Taylor/ Tulsa, OK MBCA '84 300D/'90 Jaguar XJ6/XJ40 |
#7
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CHRISTI: (regarding distributor cap and points)
You really need to replace the cap, points AND condenser then reset the timing. Knowing one element (ignition) of the system is suspect only lessens the chances (hence odds) of correcting what may (or may not be) a problem in another element. You do have some problems with the carbs yes, but why wonder if the crack in the cap and the bad points are adding to the problems or not. The ignition components are an easy fix and, done correctly, will take that elememt out of the problem mix. Please don't ask how I really know that for a fact - but it is so. Hang tough. Dan
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Dan Taylor/ Tulsa, OK MBCA '84 300D/'90 Jaguar XJ6/XJ40 |
#8
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Ignition parts
Christi,
I thought from an earlier thread that you had replaced cap/rotor/points/condenser/plugs/wires?? If you have a cracked cap that's fairly new, your rotor may be incorrect or it may be hitting something. I would replace it as well. A bad cap can DEFINATELY cause the problems you describe. Not sure I should mention this right now... you might want to look at an electronic ignition...
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Bill Streep San Antonio '57 190SL (toy) '08 S5500 (mine) '09 CLK550 (wife's) '06 SLK350 (daughter's) '11 GLK350 (daughter's) '03 CLK310 (spare) |
#9
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If any of you folks is interested in a parts car ('67 250S), see the for sale section for a car here in San Antonio.
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Bill Streep San Antonio '57 190SL (toy) '08 S5500 (mine) '09 CLK550 (wife's) '06 SLK350 (daughter's) '11 GLK350 (daughter's) '03 CLK310 (spare) |
#10
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Idle Adjustment
Mark -
You are in good shape! If you are getting gas from the pre-atomizer, you probably have a plugged idle circuit on that carb. Dan has excellent instructions on how to check it in the Carb4 post. Chuck |
#11
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Actually Chuck, when I was fiddling with the settings I was able to flip the conditions between carbs. That tells me A:I'm very close, B:My idle circuit is probably OK. I may take off the top cover and clean things out anyway. The bigger thing is probably the ignition timing now, and There was a couple good replies to my post on that also.
Car ran great this morning in the cool damp air. (its raining today which must mean this is a long weekend) Need to pick up a cheap tach for checking the timing, (may mount it under the hood permanently for diagnostic purposes) The car also accelerated easily from 80 to 85 mph yesterday when I let it out a bit on the highway. I think my cheap guy fix of the secondary diaphram is working well. So after the ignition timing comes the timing chain and the hanger bearing. (the source of a ton of drivetrain noise right now) Then I ought to be safe to ditch the beater Integra for good! Thanks for the help everyone. Mark |
#12
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A cheap tach that can't show you a 30 rpm change isn't going to help you much.
Sears has a really, really good little meter for about 50$. It's digital. -CTH |
#13
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UPDATE...
The car still won't start.
~Christy |
#14
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Did you do something to it that raised the expectation?
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Chuck Taylor Falls Church VA '66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe |
#15
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Christy,
Did you try new distributor cap, points, and rotor? Even if it isn't the problem now, a cracked distributor cap will cause you problems sooner or later. After I put new carbs in a few weeks ago, I couldn't get my car started because my ignition system was not working right. As far as the accelerator pedal goes, if you pull and push it with your hand, how far can you move it? If you disconnect the accelerator linkage, can it move even further?
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Hemant '57 190SL '86 560SEC AMG |
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