Re: [MBZ] Diagnosing problems on my '72 250C
The condenser on theses cars is a condenser wire - it has the wire and condenser as a single connected part. There's two different ones - a round hole type and a later square hole type. CD ignition sends very little current through the points and normally the points will last for years. I have some customers with early 70's cars that are still running the original stock systems without any problems. This was high tech in the day. Most of the problems come from a lack of service and the advance will eventually seize up from lack of lubrication. Put a few drops of oil on the felt under the rotor. On EFI cars the trigger points get fouled with oil vapours which is separate from the points but still affects running. Dan
Re: [MBZ] Diagnosing problems on my '72 250C
IIRC, You said you rebuilt the carbs, then tried running the car on old fuel (read varnish). You might want to recheck the carbs for contamination Just my 2ยข Rick Knoble 1985 300 CD Yes, I DID try to run it on the tank, but only for a very short time, and very shortly thereafter, went back to the new gas. I know that this is a possibility, but, again, from much experience, and from the fact that it acts EXACTLY as it did before the carb rebuild, on good and old gas, I don't think this is the problem! But, thanks, I will keep it in mind! Michael
Re: [MBZ] Diagnosing problems on my '72 250C
Joseph Shaw wrote: So I am back to thinking that there has to be a flooding issue. Until this episode, I was thinking non-delivery. (especially since you can usually get a brief run from fueling with starting fluid) And now your thinking is??? I will say that, yes, like everyone else, I don't prefer the starting fluid usage, but at time it lets you know if fuel delivery vs. spark is the problem. I also will say that, with the VERY light amounts I am spraying in there, I really don't think it is enough to run the engine for as long as it is running-just enough to get the first solid turn basically! So, again, are you agreeing that it sounds like flooding now? And, again, it is going through TONS of gas, so it is delivering, that's for sure! Unless it is ALL going back through the overflow hose! Michael
RE: [MBZ] Diagnosing problems on my '72 250C
If it does not fire the starting fluid, you have an ignition problem. Okay-then why did it fire the starting fluid the first time? And why does it often fire the starting fluid several times before it behaves this way? Thanks! Michael
Re: [MBZ] Diagnosing problems on my '72 250C
So, after it stops running, pull a plug and see if it's wet and smells like raw gasoline! However, now that I think about it this way, flooding is something of an ignition problem itself, isn't it? When the plugs get too wet to fire, there is NO ignition, right? But you mean something in the ignition system, correct? -- OK Don, KD5NRO Norman, OK '87 300SDL '81 240D '78 450SLC
Re: [MBZ] Diagnosing problems on my '72 250C
Do you have a fuel pressure regulator in line after the fuel pump. These carbs only need a few pounds of fuel pressure and the floats may not be able to shut off anything over 4 or 5 lbs pressure. A proper fuel pump ( not electric ) might be your first cure. Check your choke flaps to see if they're working right. I don't have a regulator after the pump-if I can get one, what PSI do I want one for, or one set to? Thanks! Michael
Re: [MBZ] Diagnosing problems on my '72 250C
Okay-cannot seem to get a condensor for now. Cannot seem to access any of the connectors to the ignition module under the battery tray for now. I went out and looked, and yes, to whomever asked, there are two small black boxes and two small vacuum diaphragm style modules on the passenger inner fender. Underneath these were two small vacuum hoses that were going to nothing. One of the vacuum modules had a vacuum hose connected, while the other had an open port on its top, and two open ones underneath. Before doing anything, I hooked up a CLEAN fuel supply, and tried to start it-no go on its own. I gave it a spritz of starting fluid and it roared to life, and sounded pretty good for about 10 seconds, then began to dwindle and died after it struggled to stay alive under my feathering of the accelerator pedal for about five more seconds. I tried to start it again-no go, tried to open the choke setting slightly-had it almost completely closed. No start. Tried it like this with starter fluid. No start. Attached the two vacuum lines. No start. Tried this set up with starter fluid. No start. Switched vacuum lines and tried again. No start. Closed choke back down, tried. No. Starter fluid. No. So after the initial run, which was longer than it would have lasted with just the starter fluid, it would not start even when primed with starter fluid. So I am back to thinking that ther ehas to be a flooding issue. Anyone agree, or am I just an idiot? Thanks! Michael
Re: [MBZ] Diagnosing problems on my '72 250C
Joseph Shaw wrote: So I am back to thinking that there has to be a flooding issue. Until this episode, I was thinking non-delivery. (especially since you can usually get a brief run from fueling with starting fluid)
Re: [MBZ] Diagnosing problems on my '72 250C
Just wanted to thank everyone that has piped in with info and suggestions on this project. I have been being VERY concerned about this thing, and to get a little more input is very valuable. I feel much better about the TON of fuel it is drinking, as someone reminded me that it has an overflow line back to the carb, which it does! So thanks to all! I'll keep you updated on how it goes! Michael In a message dated 7/5/2005 11:33:55 A.M. US Mountain Standard Time, [EMAIL PROTECTED] writes: I will also say that it just GUZZLES gas-like if I fill a pint bottle of gas and have it hooked up to the pump, by the time the ten-twenty seconds are over, the bottle is empty. That would equate to a gallon every 2.5 minutes, which would be 2.5 MPG if travelling at 65 MPH! Any suggestions? I have the proper/recommended after-market electric fuel pump on it, but, again, this si the one that is SUPPOSED to be the proper one. It had the same problem before I put this pump on it, but still had an electric-of the same PSI rating. It had not been run for about five years prior to me buying it, if that adds any info of note. Michael, Doesn't that fuel system have a return line back to the tank. That would be where your excess fuel is going. Also, the ones I am familiar with would have a pressure regulator (restrictor) in the return line. If that is not functioning you may not be building enough pressure to overcome the float resistance. Let us know what you find. Jim Friesen Phoenix AZ 79 300SD, 261 K miles 98 ML 320, 136 K miles ___ For used parts email [EMAIL PROTECTED] For new parts see www.buymbparts.com For repairs see www.oldworldauto.com To Unsubscribe or change delivery options go to: http://striplin.net/mailman/listinfo/mercedes_striplin.net
Re: [MBZ] Diagnosing problems on my '72 250C
How's the ignition? Does your car have that bastardized semi-electronic/semi-breaker point setup with the control box conveniently located under the battery tray? If so, an aftermarket electronic ignition like a Pertronix would make a big difference. The stock setup is a huge headache. I'd also second the advisory to look at the fuel cutoff solenoids in the carburetor bases. If they aren't energizing, your car will never run right. Russ M Uhm To bew honest, Russ, I don't know jack about this ignition set-up yet. But I do know that it starts well when it starts, and does give a good spark when I check at the plugs! Now, as for those fuel cutoff selenoids in the base of the carburetor, I don;t suppose those are the long, culindrical items that are sticking into the base of the carbs from thew front side with a red wire running to them? If so, that is a new problem...When removing the carbs I accidentally tore one of them, but figured they were something like the choke, and likely I could at least get things running without them working right. Problem is that I broke the wire RIGHT where it goes into the selenoid, and there wasn't even enough remnant wire to try and splice together or anything. SO, next question-where do I find another fuel cutoff selenoid??? THANKS for mentioning this-I thought I could get a ballpark idea of how well it would run without worrying about this, but apparently this may be a problem!!! Michael
Re: [MBZ] Diagnosing problems on my '72 250C
Thing is, I just did a car with no working return line and no working fuel cut off. It seems to run OK.
Re: [MBZ] Diagnosing problems on my '72 250C
Joseph Shaw wrote: It also supposedly ran fine when parked four or five years prior, which I have come to believe, only because everything else I was told by the prior owners has proven to be true, and they seemed pretty honest about it when I bought it, so I trust them at their word at this point. In a few years, gas can turn into a hard, varnishlike substance. Your carbs may be clogged with this and in need of a good soaking in solvent.
Re: [MBZ] Diagnosing problems on my '72 250C
Joseph Shaw wrote: It also supposedly ran fine when parked four or five years prior, which I have come to believe, only because everything else I was told by the prior owners has proven to be true, and they seemed pretty honest about it when I bought it, so I trust them at their word at this point. In a few years, gas can turn into a hard, varnishlike substance. Your carbs may be clogged with this and in need of a good soaking in solvent. Mitch- Sorry-I didn't include this information again, but that was what I just did-removed, cleaned, and rebuilt the carbs. And I don't mean to poo-poo this idea, but I di think that sometimes this factor is over-rated! I have truthfully, honestly bought cars that have been sitting for fifteen years, and run them on the gas that was in their tank when I got them. It is very pre-sitting maintenance, sitting location and climate related, but I rarely find one that the gas is so bad that it affects this too much. Now I will also say that I NEVER do this on a valuable car, but I am one of those that likes to find some old car sitting in a field and buy it and bring it back to life, so often I am dealing with something that no one thinks can be saved anyway, so it is a low risk situation. But please don't get me wrong, I appreciate the advice, and in this car, I think it is very valid advice! Thanks! Michael
Re: [MBZ] Diagnosing problems on my '72 250C
In a message dated 7/6/2005 5:08:23 A.M. US Mountain Standard Time, [EMAIL PROTECTED] writes: I have had it running well enough to drive-about four months ago-though it would NOT get up to speed at that time-would rev fine when sitting still, and would start out, but would max out at about 20-25 MPH and simply not go any faster. This is when I decided to start with the carbs, as it had been sitting for four or five years. Michael, Assuming you have fuel to the engine: If there is a condenser (small, cylindrical object, about the size of a 3/4 socket), on or in the distributor, consider it a primary suspect. They are prone to fail with age and/or heat, and will often allow small amounts of power, but break down when asked to fire a cylinder under more load. The Pertronic point elimination project should be on your list of things to do, but a condenser is only about $5. Do not just merely remove it, it's purpose is to store energy in the primary circuit for firing the coil. Regards, Jim Friesen Phoenix AZ 79 300SD, 261 K miles 98 ML 320, 136 K miles
Re: [MBZ] Diagnosing problems on my '72 250C
Joseph Shaw wrote: I have had it running well enough to drive-about four months ago-though it would NOT get up to speed at that time-would rev fine when sitting still, and would start out, but would max out at about 20-25 MPH and simply not go any faster. This is when I decided to start with the carbs, as it had been sitting for four or five years. I'm just inclined to suspect the ignition on these cars. When it was running, what did it do when you got to 25 mph? Did it want to shift at that point? Did it choke/cough/sputter? Or did you just lose power? Did it ping or backfire when you tried to climb a hill? I'd pull the battery to inspect the connections at the ignition module below it. Make sure the wiring and connections are intact and clean. Battery acid can eat 'em up!. Are there two black boxes on the passenger fender and a couple vacuum solenoids? They retard the timing at low RPM/cold engine temps. I doubt that a malfunction there could keep you from exceeding 25mph, but it could contribute to a cumulative effect. I'll tell you the driving symptoms I had with one malfunctioning idle cutoff solenoid, which was on the rear carb: The car would idle OK with the front carb's throttle adjusted so it was cracked open a bit. While maintaining 30 mph or so the car would surge slightly. On the highway you wouldn't know there was a problem -- it would cruise at 80 without complaint. With two non-functional solenoids, the car will not idle. You'll probably get it firing by pumping the throttle but it won't stay lit. You can check the remaining wired solenoid on your car with a voltmeter. Hook it up in the solenoid circuit (there should be an easy-to-access connector in the line) and turn the ignition on. You should get battery voltage or close to it. If it's not drawing voltage, it's dead. Good luck Russ
Re: [MBZ] Diagnosing problems on my '72 250C
Do you have a fuel pressure regulator in line after the fuel pump. These carbs only need a few pounds of fuel pressure and the floats may not be able to shut off anything over 4 or 5 lbs pressure. A proper fuel pump ( not electric ) might be your first cure. Check your choke flaps to see if they're working right.
Re: [MBZ] Diagnosing problems on my '72 250C
How's the ignition? Does your car have that bastardized semi-electronic/semi-breaker point setup with the control box conveniently located under the battery tray? If so, an aftermarket electronic ignition like a Pertronix would make a big difference. The stock setup is a huge headache. I'd also second the advisory to look at the fuel cutoff solenoids in the carburetor bases. If they aren't energizing, your car will never run right. Russ M Joseph Shaw wrote: Okay, I have asked several things about this, so you are either probably really tired of hearing about it, or at least really familiar with it by now. I rebuilt the carbs over the course of the past two or three weeks. Started it yesterday, and it started up well. It will idle run for a while (ten or twenty seconds) but then always dies out-regardless of whether I am applying throttle, letting off throttle, etc. Simply will not stay running, though it usually runs smoothly and sounds good while it is running. Any suggestions/ideas on what this could be? Usually after it dies I can restart it, though often I have to pour a little dab of gas into the carbs to get it started-does not like to cold start on its own the first time. I will also say that it just GUZZLES gas-like if I fill a pint bottle of gas and have it hooked up to the pump, by the time the ten-twenty seconds are over, the bottle is empty. That would equate to a gallon every 2.5 minutes, which would be 2.5 MPG if travelling at 65 MPH! Any suggestions? I have the proper/recommended after-market electric fuel pump on it, but, again, this si the one that is SUPPOSED to be the proper one. It had the same problem before I put this pump on it, but still had an electric-of the same PSI rating. It had not been run for about five years prior to me buying it, if that adds any info of note. Any ideas? Help! Thanks! Michael ___ For used parts email [EMAIL PROTECTED] For new parts see www.buymbparts.com For repairs see www.oldworldauto.com To Unsubscribe or change delivery options go to: http://striplin.net/mailman/listinfo/mercedes_striplin.net _ This message scanned for viruses by CoreComm
Re: [MBZ] Diagnosing problems on my '72 250C
In a message dated 7/5/2005 11:33:55 A.M. US Mountain Standard Time, [EMAIL PROTECTED] writes: I will also say that it just GUZZLES gas-like if I fill a pint bottle of gas and have it hooked up to the pump, by the time the ten-twenty seconds are over, the bottle is empty. That would equate to a gallon every 2.5 minutes, which would be 2.5 MPG if travelling at 65 MPH! Any suggestions? I have the proper/recommended after-market electric fuel pump on it, but, again, this si the one that is SUPPOSED to be the proper one. It had the same problem before I put this pump on it, but still had an electric-of the same PSI rating. It had not been run for about five years prior to me buying it, if that adds any info of note. Michael, Doesn't that fuel system have a return line back to the tank. That would be where your excess fuel is going. Also, the ones I am familiar with would have a pressure regulator (restrictor) in the return line. If that is not functioning you may not be building enough pressure to overcome the float resistance. Let us know what you find. Jim Friesen Phoenix AZ 79 300SD, 261 K miles 98 ML 320, 136 K miles
