Car not accelerating properly, and cutting out - PeachParts Mercedes-Benz Forum

jbach36 · #1 11-02-2012, 01:18 AM

Sometimes on my car on the highway, the car sort of cuts out for just a quick second, then is fine. Maybe 30 minutes later, same thing. I thought maybe the turbo was going.

Today, I was driving in the moutains on a 12 hour drive to PA, and had trouble going up some of the steeper and longer inclines! I've driven those roads many times with no problems, and today, the car just couldn't do it. The roads are 60-70 mph, and (cough) 40 mph is all I could do! The car was just dying.

Again, I thought it must be the turbo going, but I called my mechanic, he said it sounded like a fuel issue, maybe a clogged injector or something

After the high part of the mountains, already doing 40 mph, I was going on a slight DOWNHILL, and the car was having trouble accelerating! So I thought, can't be the turbo. Must be a fuel issue after all. If I REALLY step down on the pedal, it will then accelerate more like it normally does, but there's obviously something wrong with the car.

I changed the pre-filter and main filter a week ago (the engine cutting in and out was happening prior to that), and cleaned the injectors directly 2 years ago.

Any other guesses or possible solutions?

1991 300d 175k

whunter · #2 11-02-2012, 02:17 AM

Diesel911 · #3 11-02-2012, 12:41 PM

If an IDI Injector gets plugged there is no place for the Fuel/hydraulic pressure to go so most often it puts a hole or entirly cracks off a Fuel Injection hard Line.

On Direct Injection Injectors it is possible for one or more of the Holes in the Injector Tip to get plugged; but you don't have those.

It is possible for the Pintel on IDI Injectors to stick or stick briefly when they are in the open/upward position and that causes a miss. But, that does not happen unless something had gotten inside like dirt of water (the Injector can pass Water but if Water sits in the Injector it can cause Rust and Rust can cause the Pintel to stick).

But, I don't think this is what is happening to you.

Change the Filters and cut open the Spin-on Filter over a Pot or Bowl so you can see what is inside of it.
However, that won't help if the Tank Screen is also restricted.

jbach36 · #4 11-02-2012, 01:34 PM

Why the feel that the engine is cutting out then, just for a quick second?

jeff

Diesel911 · #5 11-02-2012, 04:46 PM

Quote:

Originally Posted by jbach36

Why the feel that the engine is cutting out then, just for a quick second?

jeff

You could also have an Air (Leak) or Water passing through the Injector; neither will burn and either one mixed with the Fuel will not burn well and the Engine will miss

If it is suff in the Fuel Tank your Car bouncing around could shif the crud in the Tank around and open up the Screen.

Tank Vent plugged or restricted?

Issues with the Fuell Supply Pump or Fuel Pressure Relief Valve?

Any Diesel Repair book with a trouble shooting section is going to have plugged Fuel Filters at the top of the list when a Diesel Engine has a loss of power.

winmutt · #6 11-02-2012, 08:31 PM

I'd bet either your overboost is kicking in OR you have an intermittent leak in your vac system which is keeping the p2 flap from closing....

PS- I am closer to you now, in ecobb just over the river. I will work for beer.

whunter · #7 11-03-2012, 03:54 AM

Quote:

Originally Posted by winmutt

I'd bet either your overboost is kicking in OR you have an intermittent leak in your vac system which is keeping the p2 flap from closing....

PS- I am closer to you now, in ecobb just over the river. I will work for beer.

Good point RE: vacuum issue.

Here is an easy test..
Remove the vacuum line from the mixer housing, plug the hose with a golf T.
Test drive the car.

If performance improved, you have:
* A failing vacuum transducer. MB# 0005450327
* One or more vacuum system leaks.

Please open your air filter box to verify rodents have not built a nest = blocking air flow.

.

jbach36 · #8 11-03-2012, 07:40 PM

I keep the car up pretty well (within my skillset), and changed the air filter maybe 9 months ago. Fuel pre filter and main filter changed just maybe 2 weeks ago.

jbach36 · #9 11-03-2012, 07:41 PM

Quote:

Originally Posted by whunter

Good point RE: vacuum issue.

Here is an easy test..
Remove the vacuum line from the mixer housing, plug the hose with a golf T.
Test drive the car.

If performance improved, you have:
* A failing vacuum transducer. MB# 0005450327
* One or more vacuum system leaks.

Please open your air filter box to verify rodents have not built a nest = blocking air flow.

.

What/where is that, and what does it look like?

whunter · #10 11-03-2012, 09:46 PM

Quote:

Originally Posted by jbach36

What/where is that, and what does it look like?

Look at post #7 again, I just attached the forgotten picture.

.

jbach36 · #11 11-16-2014, 11:08 PM

This is now written some 2 years after I posted the problem. In between, I'd tried certain things and still had the same problem. I never know if the changes I made will work, until I'm in the mountain areas again.

Thankfully, and by accident, I saw Kent Bergsma's video on YouTube about cleaning your TANK filter. I didn't even know the car had one. I had my general mechanic take the filter out, and sure enough, it was fairly clogged. He cleaned it, put it back in, and the car makes it up the hills of Va/W. VA again.

If you do this, MAKE SURE you have a NEW FILTER and a proper tool on hand, because it's tight to get into that area. You don't want to have your car apart, and find out your filter got damaged when you took it out, and it's going to take 3 days to get one. If anyone needs one, please buy mine. I have the tool and a new filter on hand just in case, but I (thankfully) didn't need it. Email me (not message) if you need it. (this written Nov. 2014)

toomany MBZ · #12 11-17-2014, 09:14 AM

Sounds like a maintenance item to be completed at your leisure as opposed going through your experience.

If there is visible grit in the primary filter, have the above procedure on your to do list.