Feels like a kick in the gut on my 280SE 4.5

[spyderdog]

My 280SE 4.5 wouldn't start so I replaced the distributor cap/rotor and it started right up, but after driving a while it started to feel like is was starving for gas and began running rough. I replaced the fuel filter, spark plugs and wires and still get the same roughness with what feels like the engine being kicked, or punched hard every now and then. Could it be bad injectors with a cylinder and the piston kicking back? Anyone have this experience with what might be causing the 'kick' feeling? Thanks.

[Tony H]

The trigger points are always suspect as well as the original points/electronic switchgear. I cleaned my trigger points and installed a Pertronix and coil and it cured my drivability issues.

[spyderdog]

Originally Posted by Tony H

The trigger points are always suspect as well as the original points/electronic switchgear. I cleaned my trigger points and installed a Pertronix and coil and it cured my drivability issues.

Thanks, I'll try that next. Would the misfiring cause the kick or bang sensation I'm feeling from the motor?

[TZ_280SEL]

I had the electronic switchgear go bad in my 280SEL 4.5 years ago. It started as a slight backfire going down hill on lift throttle. It turned into a bucking bronco of misfire and lack of power. It ended with a totally dead ignition one morning. I went the Pertonix route for several years before I broke down and did fuel/spark Megasquirt.

[spyderdog]

Thanks for the info, but what's the electronic switchgear?

Originally Posted by TZ_280SEL

I had the electronic switchgear go bad in my 280SEL 4.5 years ago. It started as a slight backfire going down hill on lift throttle. It turned into a bucking bronco of misfire and lack of power. It ended with a totally dead ignition one morning. I went the Pertonix route for several years before I broke down and did fuel/spark Megasquirt.

[TZ_280SEL]

Mercedes put an electronic box between the points and the coil. It takes a lot of the load off the points and prevents having to adjust them. BUT, as the electronics start to fail, you get erratic ignition followed by no ignition when the box finally fails.

[spyderdog]

Ahh.. thanks.

Can anyone post an image of the correct firing order on the 4.5... I seem to find conflicting images. (See attached)

Thanks,
Mark

Originally Posted by TZ_280SEL

Mercedes put an electronic box between the points and the coil. It takes a lot of the load off the points and prevents having to adjust them. BUT, as the electronics start to fail, you get erratic ignition followed by no ignition when the box finally fails.

[cth350]

if you haven't done so yet, remove the battery and look under the tray. There's a bolt that grounds a lot of EFI wires. Undo the bolt, clean up the corrosion and put it all back together.

Is it going to fix your problem? Maybe not. Will your EFI system work better? Probably yes.

-CTH

[Sugar Bear]

Firing order should be cast into the intake manifold or valve cover as "Zundfolge".

Good luck!!!

[auriga]

Ur problem is possibily a fuel vapor lock. Cuz my 108 did the same rhing. Hard to start when off the highway. U can replace ur radiator, there is a radiator for sale on ebay, which is a aluminum one with 2 or 3 role, that is an exact fit and it boosted my cooling. My car used to have vapor lock in NY ,Now im in TX and never ever have the same problem.

[spyderdog]

Thanks for all the input on this. I haven't had much time to tool around but did swap to wires on the firing order and that got rid of the occasional engine 'bang', but the motor still seems to run a bit rough. I purchased the Petronix conversion kit for the points and condenser, so that will be my next step. I noticed there's a fuzzy brush that hits the alternator shaft. Should that be bent away for the pertronix magnet to slip down to the alternator plate?

[rumb]

Im guessing when you say alternator you mean distributor.
The points set in the disti has a rubbing block the the lobes hit to open the points. You remove the points completely to put the petronix unit in.