Help Please - 280SL Euro - PeachParts Mercedes-Benz Forum

romansek · #1 10-13-2006, 11:00 PM

This '83 280SL Euro did not run for five years and I'd really like to get it working.

Symptom #1: At normal operating temperature I cannot idle above 2000rpm the rpms and vaccuum falling down. The same thing happens if I throttle it or if I open the air flow sensor plate manually.

Symptom #2: The car has no power. I can barely make it putter in 1st gear and I cannot accelerate it at all. When I try to accelerate the air flow sensor plate makes a popping sound.

To me it seems that this would be a fuel problem and that both of these symptoms are related to the same problem.

Therefore, I replaced fuel pump, fuel filter, checked and replaced all leaky air hoses, put in new spark plugs, replaced the injector o-rings, and cleaned the plunger from the fuel distributor which operates air flow sensor plate.

On the other hand, when I manually open the air flow sensor plate and trottle valve at the same time I can run up to to 4000rpm.

Has anyone had experience in this area? If so, your input and aid would be greatly appreciated.

Thanks,

t walgamuth · #2 10-14-2006, 08:34 AM

the haynes manual has a check list i believe which you can run through to find out the source of trouble.

all the things you have done are excellent preventative maintenance so you havent lost anything yet.

i would suspect one of the support devices before the actual fuel injection unit. so dont be tempted to monkey around with the richness adjustment or you will be totally lost on mixture when you do find the problem.

i cant find my haynes for the 280 right now so i cant help with hard facts.

tom w

ctaylor738 · #3 10-14-2006, 01:28 PM

Is the sensor plate moving up and down easily? If it doesn't move when you open the throttle plate, then the engine won't get any additional fuel. Maybe something in the mechanism is sticking?

Or you might have a huge air leak between the throttle plate and the mixture control unit, so that the air movement created when the throttle plate opens is not getting "transmitted" to the CSI via the throttle plate.

Also, take a look at the rubber plumbing for the idle and aux air valves for leaks.

romansek · #4 10-14-2006, 02:15 PM

Chuck and Tom thanks for the prompt response. I completely removed the entire intake and cleaned the sensor plate mechanism, replaced rubber plumbing for idle intake. The sensor plate moves easily before priming the fuel and is somewhat harder to move when the engine is running. The sensor plate is opening with the throttle plate, but it only opens a little bit and then it won’t move anymore and the engine starts choking and the vacuum goes down. I definitely don't have a huge air leak because when I disconnect the idle by-pass air hose and plug it at the air guide housing. So when I plug the by-pass hose the engine dies. I have a feeling that problem is with the fuel distributor, since it is to hard for the vacuum to operate the sensor plate. I checked how the sensor plate on my 420SEL felt like when it runs and it is alot easier to move than in my 280SL. I wonder if there is some kind of adjustment on the fuel distributor to adjust the movement of the sensor plate.

ctaylor738 · #5 10-16-2006, 01:27 PM

I can't think of anything off-hand that would cause the sensor plate to not move with the engine running if it is nice and easy with the engine off. Since the car has not run for a while, I suspect that you have some crud in the FD that is preventing the movement. You could try jumping 30 to 87 on the fuel pump relay or running 12v directly to the pump and loosen the fuel line fittings and see what comes out.

romansek · #6 10-16-2006, 10:56 PM

I think I have a timing problem with cylinders #1 & #2. When the car idles for 15 minutes and then I remove the spark plugs from #1 & #2 the spark plug is cold and I see wet stuff on the top of the pistons. I checked the fuel coming to the distributor and it looks alright. I also cheked the compression and it ranges from 170-190psi. Thanks for the help.

ctaylor738 · #7 10-17-2006, 08:23 AM

Then you have bad plug wires or bad injectors or possibly both in those two cylinders. You can test the spark by putting a timing light on the wire and seeing if it flashes. If you pull the injectors out, you may be able to find a shop that will clean them for you inexpensively - be sure to put them back with new seals.

romansek · #8 10-27-2006, 06:02 PM

After adjusting the ignition distributor the car finally has power and is drivable.

However, I still have some oil that should not be there in Cylinder #1. I've idled the car for an hour and after I turned it off and removed the spark plugs I have oil on top of the piston still. (I cleaned the injectors and I'm sure that Cylinder #1 is getting fuel and spark.)

Why is this oil not being burned when the car is operating? I suspect the oil is getting through the valve stem seals because are bad.

I ordered a manual for engine M100 and it's on its way. However, I was hoping in the meantime that someone who has the manual could look up and give me the correct timing for the engine so I could continue on.

I know I have to replace the valve stem seals but my problem is to find the tools to compress the springs inexpensively. Does anyone have any ideas of where I could buy one for less or maybe rent one. Here is a post from another forum member and I've contacted this user but he has not responded. Is there anyone who could help me with a similar offer?

* 280Sbenz

*i make the tool you need to compress the spring to remove the rocker on these engines.

*around $60 AUD if you want one not including post

*makes life a lot easier to remove the rockers and a lot cheaper than the genuine factory part.

Any help is appreciated.

Thanks,

SatRoc · #9 10-27-2006, 09:29 PM

Timing is 10 degrees BTC. Good luck!