Trouble in paradise: m50 gone wobbly!

[ColinH]

Hey guys, I love the site, big fan of the great tips!

Now, I parked her (93' 525 m50) one night, and she sounded fine, cept for the louder than usual ticking from under the hood. Next day, I start it up and the whole car shakes. A real night and day difference. Now, she runs rough as hell, as if one piston had a fouled injector/sparkplug/ coil pack... like she's running on 4 or 5 pistons rather than 6! My fuel pump is buzzing, but she always did... She's full of good oil, but maybe i;ll try another weight or brand. Im at 130K and no synthetic. Can i start now?

Any simple suggestions on where to start? Im about to take the Valve cover off and inspect everything. Thanks for any suggestiongs. Anyone know a decent DIY injector test?

Thanks for any help.
Colin. ;)

[Scott C]

Hey guys, I love the site, big fan of the great tips!

Now, I parked her (93' 525 m50) one night, and she sounded fine, cept for the louder than usual ticking from under the hood. Next day, I start it up and the whole car shakes. A real night and day difference. Now, she runs rough as hell, as if one piston had a fouled injector/sparkplug/ coil pack... like she's running on 4 or 5 pistons rather than 6! My fuel pump is buzzing, but she always did... She's full of good oil, but maybe i;ll try another weight or brand. Im at 130K and no synthetic. Can i start now?

Any simple suggestions on where to start? Im about to take the Valve cover off and inspect everything. Thanks for any suggestiongs. Anyone know a decent DIY injector test?

Thanks for any help.
Colin. ;)

Any chance you kept the key on for a long period of time without the engine running? My car will sometimes be this way after this occurs. Mine clears up after driving 5 min.

Scott

[jplacson]

If it sounds like it's running on one less piston...it might actually be running on one less piston. Check electricals, etc. Ignition system? Sparks? Just a thought.

[632 Regal]

the clicking sounds like maybe one of the rockers might be loose or broken. I would start there by removing the rocker cover, checking lash and inspecting.

[ColinH]

I will remove the valve cover/ and the "rocker cover, checking lash and inspecting" This is for an M50, the engine im more familiar with is my e30's m20b25.

This is beneath the Vlave Cover right Regal 632? Would this lash adjustment issue be the kind that could be alright one minute then SNAFU'd the next? I have my bentley but not infront of me. Call me clueless, but this car still has regular valves I can adjust myself?

I know this is all kinda scatter brained but this problem literally developed overnight, could that merely mean 'time for adjustment'? Thanks a million times, ya'll are like a beacon in a dark sea!
Thanks again for time and suggestions.
Colin H :D

[ryan roopnarine]

im pretty sure that all version of the m50 were 24valve models, dohc, with hydraulic valvetrains, ie not adjustable/self adjusting.

[ryan roopnarine]

i drove my car 250 miles on only 4 cylinders to get to the proper snap on computer/mechanic, et cetera. the difference being, i knew that cyl 1 and 6 were dead, and was able to do so by disconnecting the FI s on cyl 1 and 6. i drove it with no spark on 6 and irregular f injection on 1, it didnt shake, perhaps because taking out the end cylinders made things balanced. perhaps one of the middle or more cylinders are "dead", and that's causing the shaking. what's the idle at? what does the exhaust smell like?

[billb]

Hey guys, I love the site, big fan of the great tips!

Now, I parked her (93' 525 m50) one night, and she sounded fine, cept for the louder than usual ticking from under the hood. Next day, I start it up and the whole car shakes. A real night and day difference. Now, she runs rough as hell, as if one piston had a fouled injector/sparkplug/ coil pack... like she's running on 4 or 5 pistons rather than 6! My fuel pump is buzzing, but she always did... She's full of good oil, but maybe i;ll try another weight or brand. Im at 130K and no synthetic. Can i start now?

Any simple suggestions on where to start? Im about to take the Valve cover off and inspect everything. Thanks for any suggestiongs. Anyone know a decent DIY injector test?

Thanks for any help.
Colin. ;)

I'd check there first, especially if it was a little noisy first. Sounds like it was backing out some. The cam covers will cover up some of the sound of an open cylinder, and the plug would be banging up into the coilpack. Check those first (pretty easy with a 10mm socket).

[ColinH]

the idle is regular and pretty smooth at 690~700. No audible fluctuations, just the rough running... it's less rough on giving it gas (rev) and more noticably rough on the way back down to idle after revving. I think i'll start by testing my buzzing fuel pump, anyone have a neat (clear) description of tests? I have a fluke MM, but might have to buy a pressure guage, where should I install it? Before the fuel rail? Is there a nipple for testing or do I have to create one? The more i think the more i'm sure the prob isn't fuel. I need to investigate more...

As for smell, to me it smell'd like gas. nothing too suspecious.

Thanks for your sharing your experiences ryan. BTW, an MB s700 is fictional right? Can you supply a link to specs and photos?

[ryan roopnarine]

Thanks for your sharing your experiences ryan. BTW, an MB s700 is fictional right? Can you supply a link to specs and photos?

if you put mercedes benz 700 v14 into google, you'll get several hundred links to lyrics to the same song. yea, it doesn't exist. the same song also makes reference to putting 30'' rims on an airplane. in 1999, when the song came out, it was released completely as a novelty. it was unheard of to make reference to such utterly riduculous things, it was somewhat "cute" at the time. now every half assed rapper wants to sing about such absurdity as though it was real, and threatens to blow you away if you don't believe him/them.

[ColinH]

Any chance you kept the key on for a long period of time without the engine running? My car will sometimes be this way after this occurs. Mine clears up after driving 5 min.

Scott

No, and I also let her run for a while, just to see... and after 10 min it hadn't changed and naturally i don't want to run her much like that.

[632 Regal]

check the plugs first

[Nzimiro]

ColinH,

I will check for vacuum leaks 1st before I open any covers if I were you. I have just resolved a similar problem on my M60 by checking/re-tightening all hose connections to and from the intake manifold to eliminate vacuum leaks - this after spending $$$ to replace the MAF sensor (which I damaged mistakenly while cleaning it!) because I suspected it was faulty. The failure of the new MAF in stopping the rough idle led me on to vacuum leaks.
Good luck