Car suddenly having trouble starting - PeachParts Mercedes-Benz Forum

1981_300sd · #1 09-09-2009, 11:09 AM

Hey all,

My car has been running great all summer. Yesterday, I drove to work, and when I got done with work my car would not start. The starter cranks, but no ignition.

The thing that I am lost on is the car has always started right away. Never struggles to start. Im also in the Phoenix area and temps are still above the 100 degree mark so its not like I am doing cold starts.

I had my wife drive over to pick me up - told her to bring some WD-40. Sprayed into the intake, and got the car to start that way (huge cloud of smoke once started. Once started, and warmed up, seems to start right back up.

Next morning, same thing.

So I was thinking glowplugs possibly, even though the temps were so high outside, but I am not getting a glowplug flashing light or anything.

What are possible issues that could cause my car to not start up, with high outside temps and no history of it being hard to start previously?

Thanks,
Spencer

kerry · #2 09-09-2009, 11:13 AM

Malfunctioning glow plugs. Go to dieselgiant.com and follow his troubleshooting procedure.

TMAllison · #3 09-09-2009, 03:07 PM

Then check for fuel leaks allowing air into the system if prob persists. Old style primer pumps are common culprits.

Graplr · #4 09-09-2009, 03:43 PM

My glowplug light was behaving normally and I was having rough starts. Found two bad glow plugs (use dieselgiants' method). Replaced them and the starting was normal again.

benhogan · #5 09-09-2009, 03:46 PM

I'd check to see if you had a bad batch of diesel

nhdoc · #6 09-09-2009, 04:31 PM

My own guess is the GP's are OK but do check them first. I say this because at 100F ambient that car should start without GPs working though you might have to crank it for 5-10 seconds or so to get it to start. If it were GPs it still should start.

When was the last time you adjusted the valves? You might have a combination of poor compression due to tight valve clearance and bad GPs that is causing the problem (it might have been masked by the GPs but now you are seeing both issues crop up).

So, in short you might have a GP problem but if it were the only problem you should still be able to start the car with a bit of cranking...if it would not start then I would say you might have more than one problem.

nhdoc · #7 09-09-2009, 04:36 PM

Quote:

Originally Posted by TMAllison

Then check for fuel leaks allowing air into the system if prob persists. Old style primer pumps are common culprits.

X2, especially if the tank was low when this happened. The primer can leak, causing the system to lose its prime.

Diesel911 · #8 09-09-2009, 06:50 PM

To check for an air leak in the Fuel Supply system pump on the Hand Primer a bunc of times and continue pumping as your Wife trys to start the car.
If the car starts like that you know you have a Fuel Supply problem like that dreded air leak.
Old Style Hand primer is the one with the Shiny Aluminum Body and hard plastic knob.

1981_300sd · #9 09-10-2009, 12:13 PM

Thanks for all the responses so far. Have not had time to do much with the car doing 12 hour days this week

Ive been able to get the car to start with my trusty wd-40 each time I need to go to and from work. It will get me by till I have troubleshooting time this weekend.

Im assuming its the glowplugs from the responses. When the car would not start, I had already taken off the return line and the primer pump pushes out fuel every pump. Also I already replaced the primer pump last year so im pretty sure its working correctly.

As for the valves, they were done less than 10,000 miles ago so it should not cause the car to start fine one day and then not at all the next.

I also wonder if its bad diesel tho.... because this did happen the day after a fillup. The strange thing is that once the car is heated up it starts right up. If it was bad fuel, seems like it still would not start up even when warmed up would it?

moon161 · #10 09-10-2009, 12:45 PM

Ring clearances snug up when hot and the motor will crank faster when hot = better starts, no surprise.

Seems like glows because of the sudden onset. With good compression, in warm weather, you should be able to start with the accelerator on the floor and 10-15 seconds of cranking, glows or not.

brainlair · #11 09-10-2009, 02:57 PM

Quote:

Originally Posted by Graplr

My glowplug light was behaving normally and I was having rough starts. Found two bad glow plugs (use dieselgiants' method). Replaced them and the starting was normal again.

Ditto, my rough starts were completely eliminated (er, the roughness that is, not the starts) when i replaced a trio of glow plugs. With regards to the glow plug light, I think (but am not certain) that the light only reacts to the integrity of the glow plug on the #1 cylinder.

#12 09-10-2009, 03:01 PM

Quote:

Originally Posted by brainlair

Ditto, my rough starts were completely eliminated (er, the roughness that is, not the starts) when i replaced a trio of glow plugs. With regards to the glow plug light, I think (but am not certain) that the light only reacts to the integrity of the glow plug on the #1 cylinder.

The light will tell you if you lose the #1 GP, it will also tell you is you lose any other two GPs. I don't know why.

kerry · #13 09-10-2009, 03:04 PM

The glowlight/test system compares current draw(?) between plug #1 and the others. If plug #1 goes out along with another one, the system sees no problem since the draw is the same. In other words, the test system can be fooled by some kinds of failures.

brainlair · #14 09-10-2009, 05:18 PM

Interesting, let me make sure I understand what you're saying Kerry.

When I refer to the glow light coming on, I mean when it turns on for ~5-10 seconds depending on ambient temp, engine temp etc. when you've put the key in the ignition, before cranking the engine. I've never seen it come on while the engine is running.

The glow light will NOT come on if only #1 is out.

The glow light will NOT come on if any two or more of #2-#5 are out, AND #1 is good.

The glow light WILL come on if all five are good.

The glow light WILL come on if #1 is out AND any of #2-5 are out.

Am I understanding properly?

1981_300sd · #15 09-10-2009, 06:18 PM

Wow, and all this time I thought the light came on when any of them are not functioning.

Ill find out this weekend.

Another subject, and maybe I should just start a new thread, is I know at least one of my injectors is having trouble.

Ive been doing searches all day on the subject, and wondering should I clean them, and take them apart according to the DieselGiant website? Or should I get new injectors? Also if I clean them, do I need to do anything like get them pop tested? What about if I do new injectors?

Seems very simple but could not get clarification on what the best decision would be.

One thing that I did find by searching, is to for sure replace the heat shields with new ones