Rough Starting / Rough Idle...Ongoing Problem - Ideas please! (yes i've searched....) - Page 3 - PeachParts Mercedes-Benz Forum

Burnzy · #31 09-10-2009, 01:38 PM

Not that you don't have enough things to consider..................................I feel compelled to give you another, if it passes scrutiny of some of the smarter guys you may want to give it a shot. Could it be a bad shut off valve or vacuum switch on the "ignition" assembly? Try disconnecting the hose to the shut off valve befor you start it next time. Just throwing it out there.

Good luck!!!!

Squabble · #32 09-10-2009, 04:24 PM

Quote:

Originally Posted by Burnzy

Not that you don't have enough things to consider..................................I feel compelled to give you another, if it passes scrutiny of some of the smarter guys you may want to give it a shot. Could it be a bad shut off valve or vacuum switch on the "ignition" assembly? Try disconnecting the hose to the shut off valve befor you start it next time. Just throwing it out there.

Good luck!!!!

can this be explained in greater detail? i just followed the black vacuum line that goes from what i think is the shut off valve through the firewall and found it just hanging there up under my dash. is this normal? where should it go / be connected to??? could this loose vacuum line have anything to do with my trouble starting?

i see what everyone is saying about the compression test and it is the next thing i plan on doing, but i still will track down any leads i have in the mean time. i finished the complete diesel giant glow plug testing and hooked all the gp's up to the jumper cables: all five glowed perfectly...

Burnzy · #33 09-10-2009, 04:36 PM

The line should be brown, and it comes out of the firewall on the drivers side and connects to the back of the IP. Disconnect it and and try to start your car. If it fires right up that would indicate that the vacuum switch on your "ignition" (where the key goes in to the steering column) is bad. That black line you are refering to is a vent line most likely and doesn't connect to anything as far I know.

Squabble · #34 09-10-2009, 04:50 PM

Quote:

Originally Posted by Burnzy

The line should be brown, and it comes out of the firewall on the drivers side and connects to the back of the IP. Disconnect it and and try to start your car. If it fires right up that would indicate that the vacuum switch on your "ignition" (where the key goes in to the steering column) is bad. That black line you are refering to is a vent line most likely and doesn't connect to anything as far I know.

disconnect it and leave it open or disconnect it and plug the line?

things are looking up though, i think you just solved the question as to why i'm not getting anything out of my floor vents....

EDIT: Wait a minute.....

i just went out and took the brown line out of the connector running through the firewall, left it hanging there, and started her up...

with NO stumbling!!! now, this could be a false positive as the car was a little warm from some vacuum line work i was doing but, it was the best sounding start i've had in a LONG time. i'm not really going to be able to test this theory until tomorrow morning though as i've got some driving to do tonight and it'll probably keep the car warm until past my bed time, but...i like where this might take me! thanks!

Burnzy · #35 09-10-2009, 05:02 PM

Disconnect it and leave it open.

Squabble · #36 09-10-2009, 05:04 PM

^^^ check my edit ^^^

if this checks out, what is the next step? do i need to fix something or replace something and what is that thing called?

Diesel911 · #37 09-10-2009, 05:24 PM

Quote:

Originally Posted by Squabble

^^^ check my edit ^^^

if this checks out, what is the next step? do i need to fix something or replace something and what is that thing called?

If you remove that Brown Hose at the Vacuum Shutoff on the Fuel Injection Pump and your Engine starts up and runs like it is supposed to; it would be an indication that the other Vacuum Valve that is attached to your Steering Wheel Lock behind the Dash needs replacing.

If after pulling the Brown Hose off your Engine still has the same problem it indicates that that Vacuum Valve attached to the Steering Wheel Lock has nothing to do with your problem.

Squabble · #38 09-25-2009, 06:04 PM

UPDATE: the vacuum hose was not the problem. got my cleaned up, rebuilt, monark nozzle filled injectors back, all five for $167.00. put them in today with only one old heat shield giving me any problems. had to tear it up pretty good to get it out of there. all my old injectors were thick with black soot all over the nozzles and pretty cruddy and dirty too. new ones went in just fine. tomorrow morning is the real cold start test!

snookwhaler · #39 09-25-2009, 06:50 PM

Quote:

Originally Posted by Craig

By the way, when were the valves adjusted last? If the valves are far enough out of adjustment you will lose enough compression to make starting difficult.

I can vouch for this one. I put it off for a while because of the special wrenches. I finally got the wrenches and did it. The start up problem was solved immediately in my case.

The PO stated that he had put off having it done "because the car ran so good?"

What an idiot.... So, if the car runs good why change the oil either? Anyway....

"Going out on a crumbly, rotted, moldy, termite infested limb here"

Sounds like you have (had) major glow plug issues.

Squabble · #40 09-26-2009, 08:09 AM

nope. another rough start this morning, with all new injectors. not quite as bad i think, and it was the coldest morning yet. glowed it for one cycle and then glowed again for the duration of the glow light. same deal: starts up then kinda chugs along and slowly "kicks in." finally smooths out after 10 to 30 seconds. I'm going to post a video tomorrow so everyone can see what i'm talking about.

so, compression test next i guess. my indy suggested replacing the timing chain, said he could do it for about $50 plus parts.

let's say i do a compression test and the numbers are low, what is the next step and how expensive is that?

Brian Carlton · #41 09-26-2009, 09:53 AM

Quote:

Originally Posted by Squabble

it'll stumble and cough out gray/white smoke each morning and will idle roughly for about 5 to 10 seconds. if i give it a little fuel, maybe bring the engine up 100 or 200 rpms, it smooths right out. i'll usually feather the accelerator and hold it until things feel better and then it idles just fine.

all five glow plugs replaced with five new bosch glow plugs (and i glow them twice to start by force of cold winter habit).

that's all i can think of.....what do you think?

Back to basics.

Have you confirmed that you have 12V at each of the glow plugs during the glow cycle?

Are you positive that the 80A fuse is intact?

I have the sense that this engine is running on four cylinders for 10-15 seconds or so. Either one glow plug is not working...........or it's not getting voltage............or compression is low in one cylinder.

Squabble · #42 11-07-2009, 08:00 PM

well, i finally bit the bullet: bought a set of wrenches, a gasket, and got to checking to see if those valves were adjusted properly or if they had slipped. what an annoying PITA job! it took me 3 hours to get the valve cover off and get 7 valves adjusted.

patience fully tested, back ready to give out, all light gone with the sun, not enough light or patience to continue. tomorrow morning i go out to finish the job and try to remember what my linkages looked like.

so far, EVERY ONE of my valves was tight. i'm talking REALLY tight, as in, no feeler gauges of any size could fit, let alone the correct ones. i think i may have discovered my problem. we'll see tomorrow though...

soothappens · #43 11-07-2009, 09:24 PM

Hello all still new at this posting stuff so bear with me . My 240 has had problems since day one ( 5 years ago) rough start and bad idle . Ive done filters valves and injectors even the head gasket to no avail . went on the performance forum and found relief spring thread readjusted and it ran better. Found thread on balancing cylinders by turning barrels on injection pump amazing things happened car starts on 3 turns of starter and after warm up you could set a glass of water on the valve cover . power band is better also. Note though bosch does not recommend doing this on the car needs to be on test bench . remember I said 5 years of this and countless hours under the hood so I threw caution to the wind on this one. worked so good even the wife is driving it now !!

Brian Carlton · #44 11-08-2009, 12:17 AM

Quote:

Originally Posted by Squabble

valve adjustment done about 3 months ago.

Quote:

Originally Posted by Squabble

so far, EVERY ONE of my valves was tight. i'm talking REALLY tight, as in, no feeler gauges of any size could fit, let alone the correct ones.

Sorry, but there is information here that is incorrect. NFW that the valves get to the point of no clearance in three months.

Either the valves were never adjusted or the current measurement of the valves is wildly incorrect.

Squabble · #45 11-08-2009, 10:04 AM

Quote:

Originally Posted by Brian Carlton

Sorry, but there is information here that is incorrect. NFW that the valves get to the point of no clearance in three months.

Either the valves were never adjusted or the current measurement of the valves is wildly incorrect.

well, technically it was 5 or six months ago as i wrote that in sept, but i was probably exaggerating a little bit....

.

but it is very possible that my indy was doing the job with his mind on something else, as this happens from time to time. either that or he had the specs wrong, i don't really know but it's all possible.

so the job is done, finished it this morning. taking a break seemed to make it easier/better. i added .05 mm to the intake clearance as per the FSM suggestion with the temps being so low and staying so low in the winter. however, thinking back, i might have added .05 mm to the exhaust clearance as well. what's the worse that could happen because of that? should i go back and re-adjust the exhaust down .05 mm? i really don't want to...