Author Topic: Update: Sluggish Acceleration Solved:Vibration over 45mph, Solved No Start  (Read 459 times)

Diesel 617

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Following parts are new
Plugs NGK Bp6es
Wires
Coil
Both Ballast Resistors
Ignition Control Modual
immaculate fuel tank
Bled lines
Rebuilt WUR
Rebuilt FD
Replaced all Vacuum
New Filter
New Accumulator
New Fuel Hoses
Original Fuel Pump
Injectors Cleaned and tested 1 New Bosch

I Took the plug off the center of the distributor and put a spark plug into it and placed it on the ground near the left headlight and no spark.

The blue ballast resistor gets very warm to the point I can feel heat when I put my hand near it I tested the voltage on the coil and it registered about 4.5-5volts. And between the two red wires on the ballast resistors it registered .6ohms at start then crept up to .79 the longer I left it on. Also sanded off the contacts inside the cap, and its all shiny inside now. Used a light grit sandpaper.

key was in the 'on' position the whole time.

I Tried swapping in the old coil as well as a modual from a 450sel k-jet to no avail.


The very first time i started the 280SE it wanted to run, but it did not want to start running if I let my foot off the accelerator, the last time I got it started it barley stayed running when my foot was depressed all the way to the floor.

Right now I can smell the fuel when I open up the throttle plate, and I can hear the fuel pressure build if I manually push it down with the key in the 'on' position.

Should the ballast resistors be overlapping each other to be screwed in? Thats how I picked up the car, with the blue one nearest the fender and the white nearest the engine. With the double wire going to the blue resistor.

Update: As it turns out the correct wiring is to match the Ignition Distributor numbers to the correct cylinder, not the firing order. Nothing like a rookie mistake.
« Last Edit: 21 April 2019, 12:56 PM by Diesel 617 »
1980 300SD Worn out Engine
1979 280SE Euro Spec Import Crank Windows and Cloth Seats, needs head rebuild, and WUR rebuild
1979 300CD


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TJ 450

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Re: Another no spark K-Jet
« Reply #1 on: 20 April 2019, 01:11 AM »
If the resistors are wired in how you found them, it shouldn’t be a problem. Overlapping the brackets is fine, and then getting hot is also normal.

I would be looking at issues with the pickup in the distributor first, or a break in the green wire. Check for continuity in the pickup coil and the green coax wire.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

Diesel 617

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Re: Another no spark K-Jet
« Reply #2 on: 20 April 2019, 02:05 PM »
Were making progress. Turns out I had the ignition wires in the wrong order. But i'm not out of muck yet.

Now I can't keep the car idling and it only starts when I give it gas at the pedal . And once I get over 40mph the car starts to shudder roughly and I can feel it in the steering wheel. It has almost no pick up like I'm towing a boat. Fluids are all at optimal levels. Is this the cold start valve going out? Wur and FD have been rebuilt by CIS flowtech and fuel tank is immaculate inside and all rubber vacuum connectors replaced. I have premium fuel in the tank.

Solution to hot stalling and starting by adjusting idle mixture adjustment.
« Last Edit: 20 April 2019, 09:51 PM by Diesel 617 »
1980 300SD Worn out Engine
1979 280SE Euro Spec Import Crank Windows and Cloth Seats, needs head rebuild, and WUR rebuild
1979 300CD


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Diesel 617

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Re: Another no spark K-Jet
« Reply #3 on: 20 April 2019, 03:18 PM »
Update: Turn out the idle needed to be adjusted (its a plastic spring loaded screw on the left side of the engine, snake a screw driver between the Ignition Distributor wires).

However, the shudder remains. Its as though the engine mounts are loose. I did verify they are tight and even manual rocked the engine and it was solid. Going to adjust the idle some more see if it offers any improvement. The engine mounts look nice still, some fine cracking, but engine is solid when rocked by hard shoving by hand. Only rear flex disc has been replaced. Trans mount seems okay, I have seen much worse.
« Last Edit: 20 April 2019, 03:24 PM by Diesel 617 »
1980 300SD Worn out Engine
1979 280SE Euro Spec Import Crank Windows and Cloth Seats, needs head rebuild, and WUR rebuild
1979 300CD


Inventory of w116 Parts
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daantjie

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Have you checked for vacuum leaks?  Maybe vacuum advance on the distributor is faulty?
Daniel
1977 450 SEL 6.9 - Astralsilber

TJ 450

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Make sure the ignition timing is correct too.

Failing that, you also have the idle mixture adjustment at the air flow meter, but it’s best not to touch this until everything else is confirmed ok.

Easy way to check is be pressing or raising the meter plate and observing.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

Diesel 617

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Shudder problem solved  ::) flat spots on tires.

Did a test on the vehicle acceletartion though and did 0 to 60pmh in 18 seconds. 8 seconds to slow from factory. Going to verify timing, as we did minor adjustment to it and it impoved performance, but still lack luster take off, still very much towing a boat. Acceleration is very sluggish.

Will try and add sea foram to oil to clean up engine and do oil change again, pickup screen was 25-30& covered pre-change, Sat for years. And will verify vacuum.
1980 300SD Worn out Engine
1979 280SE Euro Spec Import Crank Windows and Cloth Seats, needs head rebuild, and WUR rebuild
1979 300CD


Inventory of w116 Parts
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revilla

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Hi
When I had a similar acceleration issue it ended up being a simple problem with a simple solution: the accelerator mechanism that transmit movement to the transmission bar on right side of engine that passes on top of Cyl5. Such bar was sloppy as the plastic piece next to transmission was broken. Once I tightened it up the engine became very reactive, the kickdown function came back, the transmission held to high RPMs all that resulting in a healthy acceleration of the little M110.
I must add that before I arrived to that fix, I played with many things including timing, mixture, etc etc etc...It was part of the fun learning experience though.
Hope it’s useful for your case.
Good luck
Robert
W116 1977 280SEL & 1979 280SE

Diesel 617

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Suggestions noted so far:
Verify and adjust timing
Adjust Throttle Linkage
Adjust Idle Mixture

The 280SE has a very hard time starting up after sitting for a while, hot or cold doesn't matter. Adjusting the idle doesn't have any effect.

This 280SE does not have the RPM in the instrument cluster unfortunately, and to the best I can understand it might be possible to use a multimeter. But I don't know where to connect the positive lead.

I read through the FSM on setting the timing and I'm quite lost. It seems I need to purchase a timing light tool, and I understand how to adjust the distributor with minor adjustments, other than that I am at a loss. These gasoline engine are much more complex than diesel, albeit much cleaner.

As for the throttle linkage, I am working on that after I post this.
1980 300SD Worn out Engine
1979 280SE Euro Spec Import Crank Windows and Cloth Seats, needs head rebuild, and WUR rebuild
1979 300CD


Inventory of w116 Parts
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Alec300SD

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My guess is the check valve on the fuel accumulator, but it could be a number of things.
There are many components on a K-jet system.
The fuel distributor in particular does't do well if it sits for too long.
Good basic guide for troubleshooting:

https://www.benzworld.org/forums/1576889-post4.html

79 W116 300SD 'Stormcloud' new as of 10/22/2017
78 W116 300SD 'Desert Rose' new as of 01/26/2014
83 W126 300SD 'Rena 2.0' with engine from 82 W126 300SD Rena' (SOLD and crushed 11-20-2017)

revilla

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Timing:
The manual states the parameters at idle/1200/3000 vacuum hoses disconnected. But for a start, you can set it up at TDC at idle hoses connected. That will get you roughly where you need to be. Later you can set it up more precisely to spec. You need a stroboscopic lamp for that. Let the idle alone for now.
If cold/hot start are difficult, your static/running/control pressures might be off. To adjust that you need a pressure gage and to play with the WUR. But that’s a bit more complicated.
As suggested by Alec, remove and check the condition of the pressure regulator at the distributor. It could be stuck. Clean it up and see if things improve. Don’t change the shims for now. That you can do once you install the pressure gage.
Good luck.
Robert
W116 1977 280SEL & 1979 280SE

Diesel 617

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Fuel accumulator is brand new bosch, other one was loaded with varnish and original.
Replaced 760CCA amp battery with my 1000CCA diesel battery no improvement
Throttle Linkage all to spec

The vehicle starts great if I let it warm up to operating temp turn it off and turn it back on with in 10 minuets, starts after 2 seconds, very normal.

After any significant cool down period (10+minuets) Its only starts when the pedal is floored and cranked for a minuet up two two minuets. The longer is sits the longer it takes to start, up to approx 2 minuets. If it sits for 30 Minuets, it'll take approx 20-30 Seconds to start.

I checked vacuum canister on the side of the ignition distributor and it held vacuum around over 20HG/-75KPA. No leak. I tested the lines coming from the intake to the ignition distributor canister and they do not hold any vacuum,

Purchased timing light tool and a photosensor tachometer.
Rpm at idle at operating temp is min 779, max 838 avg 813 that is in spec I read 750-850 somewhere.

When using timing light I connected to first cylinder/plug wire I can see a small knob on the harmonic balancer and It looks like that is the TDC marker. If it is I believe it is in spec as it barley moves much, as the FSM states +/- 3. My distributor is 0 237 302 005 I found this thread: https://forum.w116.org/mechanicals/280se-correct-ignition-timing/msg140703/#msg140703

I assume for the 1500 and 3000 that is rpm and as long as it is within the specs my timing is on point. I am unsure how to test for the the vacuum control values and adjusting value of ignition.

Lastly, the list from benz world, my answer are in bold

Engine turns but won't start

1)No fuel pressure;
(I can smell the fuel build up and the engine revs high once started burning off excess fuel)

2)Jammed and/or sticking airflow sensor;
(freely moving, no biding)

3)Auxillary valve is sticking;
(Possibility, need to locate and test somehow?)

4)Defective cold start injector;
(Possibility, need to locate and test somehow?)

5)Shorted or defective thermo time switch;
(Possibility, need to locate and test somehow?)

6)Control plunger sticking;
(Moves freely, no binding)

7)Restricted injectors;
(Cleaned a tested injectors)

Hot starting difficulty


1)Loss of rest pressure;
(idles fine, and I can drive, just like towing a boat, no oomph.)

2)Airflow sensor adjusted incorrectly;
(Verified according to FSM)

3)Sticking or binding of the control plunger;
(moves freely)

4)Injectors leaking;
(Cleaned and tested)

5)Cold start injector leaking;
(Possibility, need to locate and test somehow?)

6)Shorted thermo time switch;
(Possibility, need to locate and test somehow?)

7)Incorrect control pressure;
(Possibility, need to locate and test somehow?)
Do a pressure test and verify that the warm control pressure is within spec.


Rough idle (cold)
(No issues with cold idle)

1)Cold control pressure incorrect;
The movement of the control plunger will be limited if the cold control pressure is too high.This in turn will limit the amount of fuel able to be delivered through the injectors.The result will be a lean ratio and will cause rough idle.

2)Auxillary air valve defective;
If defective and not opening,idle cannot rise and results in rough idle.

3)Airflow sensor adjusted improperly or binding;
If the movement is not smooth,it will result in air-fuel ratio errors.

4)Leaking cold start injector;
If the cold start injector is leaking,the engine will be overfueled even if cold.If the cold start injector is leaking,the idle will get worse as the engine temperature increases.

5)Injectors have an unequal flow or spray pattern;
Do an injector flow test and replace any that do not deliver the correct amount of fuel or have a poor spray pattern.


Runs rough (warm)
(Runs great warm, just no oomph)
1)Warm control pressure incorrect;
Incorrect warm control pressure that is too high or low will cause an incorrect air-fuel ratio,thus resulting in a rough idle.

2)Airflow sensor adjusted improperly or binding;
If the movement is not smooth,it will result in air-fuel ratio errors.Check for centering and correct rest height.

3)Leaking cold start valve;
Again,will result in overfueling the engine,resulting in a rough idle.

4)Injectors have an unequal flow or spray pattern;
Do an injector flow test and replace any that do not
deliver the correct amount of fuel or have a poor spray pattern.


Stalls after starting (warm)
(Where to test fuel pressure, which line to disconnect?)
1)Warm control pressure;
If the warm control pressure is too high,the air-fuel
ratio will be lean.

2)System pressure incorrect;
If too high or low,the air-fuel ratio will be incorrect.


Idle speed high
Idle speed is good, as are RPMs
1)Check auxillary air valve;
Ensure that it is closing.

2)Vacumm leaks;
Self explainatory.

3)Check the minimum air;
Self explainatory.


Backfire in intake
(No backfires)

1)Check that CO adjustment is correct;
If incorrect,backfire will result if started and under a load.

2)Boot between airflow sensor and throttle defective;
Will result in a lean mixture due to secondary air(false air)

3)Vacumm leaks;
Self explainatory.


Misfires
(No misfires)
1)Ignition;
Inspect the cap,rotors,wires and plugs.

2)Fuel delivery inadequate;
Check for binding of airflow sensor,control plunger,
incorrect control or system pressure and restricted injectors.

3)Injectors;
Unequal delivery or poor spray pattern.Do a test and
replace any that are defective.


Poor power

1)Control pressure too high;
(How to test for this?)
If the control pressure is too high,the control plungers travel will be limited,resulting in a lean running engine.

2)Check ignition components;
Verify that the spark plugs,wires,cap and rotor are not worn.

3)Injectors restricted;
Do a test for delivery.If an injector is restricted,fuel delivery will be limited,thus power will suffer.


Sag or stumble when accelerating

1)Airflow sensor plate binding or sticking;
(free moving)

2)Control plunger binding or sticking;
(free moving).

3)System pressure or warm control pressure incorrect;
If too high,the travel of the plunger will be limited.
(Possbility)

4)Injector flow unequal;
(Cleaned and tested)

Videos working on upload
First is of running at operating temps

Second is starting
« Last Edit: 22 April 2019, 01:01 PM by Diesel 617 »
1980 300SD Worn out Engine
1979 280SE Euro Spec Import Crank Windows and Cloth Seats, needs head rebuild, and WUR rebuild
1979 300CD


Inventory of w116 Parts
https://www.ebay.com/usr/vintagepartsandstuff/

revilla

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Hi
For your poor acceleration issue:
Assuming you have checked:
Injectors not clogged (even if uneven flow)
Transmission rod adjustment/no sloppy. I’m not referring to throttle linkage on left side of engine, but to the trans rod itself on the right side. Adjust it fully tight to check improvements.
Air plate moving freely
Fuel pump flow
Pressure regulator at fuel distributor
Timing
Fuel filter next to pump (new)
Fuel filter inside tank.
Fuel mixture (3mm hex screw inside fuel distributor)
If problem of acceleration persists it’s time to check your system pressure and control pressure. If they are off that could cause poor responsiveness alone with cold/hot start difficulties. To do that you need to connect the pressure gage to the control pressure line on top of distributor. When valve is closed you’ll be measuring system pressure, when valve open you’ll be reading control pressure.
This vid shows the procedure on k-jet:
https://youtu.be/kukvaGYRRrM

This link contains the CIS manual (recommended reading):
https://www.dmcnews.com/Techsection/Bosch%20K-Jetronic%20Fuel%20Injection%20Manual%20-%20boschtech-12d.pdf

Finally, this old-fashion vid shows the CIS ops principles. Good to understand in order to troubleshoot:

https://youtu.be/a4fJAfXYxWk

If your pressures are off, the adjustment is done at the WUR which is installed in an odd position on M110 engines next to oil filter. Be VERY careful when disconnecting the lines. They are weak and impossible to find replacement old or new.

Adjustment of the WUR involves tapping an insert with a hammer. We’ll get there depending on your SP and CP readings. Static pressure too. I read you changed the fuel accumulator. Good, however that doesn’t guarantee static pressure will hold in case of, for example, a leaking injector. When you’re at the WUR you can also check a small filter located there that’s prompted to clog causing the pressure readings to go off.

Let us know

Good luck

Robert
W116 1977 280SEL & 1979 280SE

Diesel 617

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Thank you to everyone who has helped me along here. I watched the video and it was fascinating and gave me a few clues. I still have the manual to finish reading I am very interested in it.

It looks like I have found two maybe three major issues. The first being this cracked vacuum hose connector going to the Auxiliary Air Idle Slide Valve (below) part number: 1100941882
https://mega.nz/#!xJ90XKwL!6Wn9rqdaM9sHqFvUwbHh4kNPX0GkrSC7JXQdqF6hRtE

The second being the rookie mistake of the year. That would be failing to clean the fuel pressure regulator resulting in vanish like mud flowing directly into the rebuilt WUR and FD. At least I know the next stages of the project. It never even occurred to me to clean that one part. Talk about a rookie mistake. I'll be sending the parts back into the be rebuilt a second time. Here is a photo of the horror show.
https://mega.nz/#!cFlwTCBL!dAxn0KoBmqhQKjkx5wDP3psAoM4pMrbDlayDQ6km-Ic

Lastly, I tested the vacuum on my WUR, it only has two possible connections. One on the side and one on the face. The connector on the side slowly release vacuum and the one on the face doesn't hold vacuum. I'm going to have the shop verify the vacuum is functioning properly on the WUR. My question is should the WUR hold vacuum? The line on the side going to the hose with the crack above, and the connector on the face leads to the bottom of the intake manifold. In the EPC it shows the hose on connector on the face leading to a vacuum connection on a hose going to the aux slid valve, I do not have that hose set up. picture attached. The Fuel Pressure regulator DOES hold vacuum.
https://mega.nz/#!cZlW2AhI!BmUgmhQmm8BZsadK9104kAEfY74Ltb3GaGCAD5y0GRs
« Last Edit: 02 May 2019, 08:14 AM by Diesel 617 »
1980 300SD Worn out Engine
1979 280SE Euro Spec Import Crank Windows and Cloth Seats, needs head rebuild, and WUR rebuild
1979 300CD


Inventory of w116 Parts
https://www.ebay.com/usr/vintagepartsandstuff/