STD Tuning Engine Does anyone have any idea why my OM617 begins to run extremely rough when hot

Does anyone have any idea why my OM617 begins to run extremely rough when hot

Does anyone have any idea why my OM617 begins to run extremely rough when hot

 
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Echo575
Naturally-aspirated

23
07-29-2023, 06:32 PM #1
My car has a N/A om617 that has been turbocharged with a Holset HE221W and has the stock M-pump turned up to max. The car is as fast as I would expect it to be with the fueling I can get from the 5.5mm elements.

The thing is that it runs fine when cold but after it warms up real good (has reached max coolant temp for over 15 minutes) it starts to idle extremely rough like you can see the whole front end of the car shake around and this change in how it runs comes over quite suddenly. I can notice it getting a bit rough and after 2 minutes it's crazy rough.

Revving the engine smooths it out but not completely. It sounds like it's not running right on one of the cylinders. I have a straight pipe and the sound is like when you run a gas engine without 1 spark plug wire, doesn't sound like a 5 cylinder at all but in the higher rpms it seems to fire on that cylinder again at least partially.


I have just checked the valves again and set the clearance to what a 617A would use but it made no difference. Previously I checked the injectors and all were at stock N/A 115 bar
pressure and spray was good. 

I haven't checked compression but don't see a reason for that being the issue in this case.

Opening any of the injector lines results in the engine somehow running even rougher and I can't spot which of the cylinders runs rough if it's related to a specific cylinder even.

I assume it can't be a fuel delivery issue to the pump because it can accelerate just fine without any issues expect that you can notice it's a tiny bit slower than when cold. 

The only thing I can imagine causing this is something going wrong with an element or a delivery valve after the engine oil gets hot (M-pump uses engine oil for lubrication) 

Please suggest anything that I could try to find the problem. This has been an issue for a long time and I want to get it fixed.   Confused
Echo575
07-29-2023, 06:32 PM #1

My car has a N/A om617 that has been turbocharged with a Holset HE221W and has the stock M-pump turned up to max. The car is as fast as I would expect it to be with the fueling I can get from the 5.5mm elements.

The thing is that it runs fine when cold but after it warms up real good (has reached max coolant temp for over 15 minutes) it starts to idle extremely rough like you can see the whole front end of the car shake around and this change in how it runs comes over quite suddenly. I can notice it getting a bit rough and after 2 minutes it's crazy rough.

Revving the engine smooths it out but not completely. It sounds like it's not running right on one of the cylinders. I have a straight pipe and the sound is like when you run a gas engine without 1 spark plug wire, doesn't sound like a 5 cylinder at all but in the higher rpms it seems to fire on that cylinder again at least partially.


I have just checked the valves again and set the clearance to what a 617A would use but it made no difference. Previously I checked the injectors and all were at stock N/A 115 bar
pressure and spray was good. 

I haven't checked compression but don't see a reason for that being the issue in this case.

Opening any of the injector lines results in the engine somehow running even rougher and I can't spot which of the cylinders runs rough if it's related to a specific cylinder even.

I assume it can't be a fuel delivery issue to the pump because it can accelerate just fine without any issues expect that you can notice it's a tiny bit slower than when cold. 

The only thing I can imagine causing this is something going wrong with an element or a delivery valve after the engine oil gets hot (M-pump uses engine oil for lubrication) 

Please suggest anything that I could try to find the problem. This has been an issue for a long time and I want to get it fixed.   Confused

NZScott
HX30W 73/44mm

398
07-30-2023, 04:26 AM #2
I've heard of pouring cold water over the injection pump if it won't start when hot...similar thinking here maybe


1978 300D, 373,000km... OM617.912 with a Holset HX30W, 7.5mm IP, 711.113 5 speed (project car, 7 years off the road and counting ;/)
1977 250 270,000km (parts car)
1977 300D (ex 280) 500,000km

1981 240D 498,000
1975 HJ45 ???,000
2001 2.8TD Rodeo 4x2 - 456,000 - DD




NZScott
07-30-2023, 04:26 AM #2

I've heard of pouring cold water over the injection pump if it won't start when hot...similar thinking here maybe



1978 300D, 373,000km... OM617.912 with a Holset HX30W, 7.5mm IP, 711.113 5 speed (project car, 7 years off the road and counting ;/)
1977 250 270,000km (parts car)
1977 300D (ex 280) 500,000km

1981 240D 498,000
1975 HJ45 ???,000
2001 2.8TD Rodeo 4x2 - 456,000 - DD




Alec300SD
K26-2

32
07-30-2023, 01:13 PM #3
(07-29-2023, 06:32 PM)Echo575 Please suggest anything that I could try to find the problem. This has been an issue for a long time and I want to get it fixed.   Confused

Slow air incursion into fuel lines (prior to the injection pump) or from cavitation of fuel due to excess suction through clogged filters.
The accumulated air in the injection pump will eventually cause a stumble at idle.

Shine a light though the clear(ish) hard line going from the fuel filter outlet to the injection pump while the car is running.
If present, a small stream of random bubbles will increase in frequency when you raise the engine speed.

Usual culprit is the small rubber fuel hose on either side of the clear primary fuel filter and/or the clear primary fuel filter itself.

The best primary fuel filter I've found is the Hembuller (001 477 79 01) which has the brass inserts.
Best practice is to change both fuel hoses on either side of the primary fuel filter when it is replaced.
This post was last modified: 07-30-2023, 01:15 PM by Alec300SD.
Alec300SD
07-30-2023, 01:13 PM #3

(07-29-2023, 06:32 PM)Echo575 Please suggest anything that I could try to find the problem. This has been an issue for a long time and I want to get it fixed.   Confused

Slow air incursion into fuel lines (prior to the injection pump) or from cavitation of fuel due to excess suction through clogged filters.
The accumulated air in the injection pump will eventually cause a stumble at idle.

Shine a light though the clear(ish) hard line going from the fuel filter outlet to the injection pump while the car is running.
If present, a small stream of random bubbles will increase in frequency when you raise the engine speed.

Usual culprit is the small rubber fuel hose on either side of the clear primary fuel filter and/or the clear primary fuel filter itself.

The best primary fuel filter I've found is the Hembuller (001 477 79 01) which has the brass inserts.
Best practice is to change both fuel hoses on either side of the primary fuel filter when it is replaced.

Echo575
Naturally-aspirated

23
07-30-2023, 02:13 PM #4
(07-30-2023, 01:13 PM)Alec300SD
(07-29-2023, 06:32 PM)Echo575 Please suggest anything that I could try to find the problem. This has been an issue for a long time and I want to get it fixed.   Confused

Slow air incursion into fuel lines (prior to the injection pump) or from cavitation of fuel due to excess suction through clogged filters.
The accumulated air in the injection pump will eventually cause a stumble at idle.

Shine a light though the clear(ish) hard line going from the fuel filter outlet to the injection pump while the car is running.
If present, a small stream of random bubbles will increase in frequency when you raise the engine speed.

Usual culprit is the small rubber fuel hose on either side of the clear primary fuel filter and/or the clear primary fuel filter itself.

The best primary fuel filter I've found is the Hembuller (001 477 79 01) which has the brass inserts.
Best practice is to change both fuel hoses on either side of the primary fuel filter when it is replaced.



Thanks for the reply. 

This would make sense. I've replaced all the fuel lines from the fuel tank to the injection pump and the fuel filter but there could still be something wrong.

I will check this soon.
Echo575
07-30-2023, 02:13 PM #4

(07-30-2023, 01:13 PM)Alec300SD
(07-29-2023, 06:32 PM)Echo575 Please suggest anything that I could try to find the problem. This has been an issue for a long time and I want to get it fixed.   Confused

Slow air incursion into fuel lines (prior to the injection pump) or from cavitation of fuel due to excess suction through clogged filters.
The accumulated air in the injection pump will eventually cause a stumble at idle.

Shine a light though the clear(ish) hard line going from the fuel filter outlet to the injection pump while the car is running.
If present, a small stream of random bubbles will increase in frequency when you raise the engine speed.

Usual culprit is the small rubber fuel hose on either side of the clear primary fuel filter and/or the clear primary fuel filter itself.

The best primary fuel filter I've found is the Hembuller (001 477 79 01) which has the brass inserts.
Best practice is to change both fuel hoses on either side of the primary fuel filter when it is replaced.



Thanks for the reply. 

This would make sense. I've replaced all the fuel lines from the fuel tank to the injection pump and the fuel filter but there could still be something wrong.

I will check this soon.

Echo575
Naturally-aspirated

23
07-30-2023, 03:29 PM #5
(07-30-2023, 01:13 PM)Alec300SD
(07-29-2023, 06:32 PM)Echo575 Please suggest anything that I could try to find the problem. This has been an issue for a long time and I want to get it fixed.   Confused

Slow air incursion into fuel lines (prior to the injection pump) or from cavitation of fuel due to excess suction through clogged filters.
The accumulated air in the injection pump will eventually cause a stumble at idle.

Shine a light though the clear(ish) hard line going from the fuel filter outlet to the injection pump while the car is running.
If present, a small stream of random bubbles will increase in frequency when you raise the engine speed.

Usual culprit is the small rubber fuel hose on either side of the clear primary fuel filter and/or the clear primary fuel filter itself.

The best primary fuel filter I've found is the Hembuller (001 477 79 01) which has the brass inserts.
Best practice is to change both fuel hoses on either side of the primary fuel filter when it is replaced.


You were right there is a lot of bubbles coming from the pump return line. Air bubbles are entering from the injection pump fuel pump on the side. Not sure if from fuel pump being broken or fuel line issue before pump. 

I'm surprised it runs because there is a constant stream of small bubbles and a few larger ones now and then and from my previous experience, any air causes the engine to shut off.
This post was last modified: 07-30-2023, 03:29 PM by Echo575.
Echo575
07-30-2023, 03:29 PM #5

(07-30-2023, 01:13 PM)Alec300SD
(07-29-2023, 06:32 PM)Echo575 Please suggest anything that I could try to find the problem. This has been an issue for a long time and I want to get it fixed.   Confused

Slow air incursion into fuel lines (prior to the injection pump) or from cavitation of fuel due to excess suction through clogged filters.
The accumulated air in the injection pump will eventually cause a stumble at idle.

Shine a light though the clear(ish) hard line going from the fuel filter outlet to the injection pump while the car is running.
If present, a small stream of random bubbles will increase in frequency when you raise the engine speed.

Usual culprit is the small rubber fuel hose on either side of the clear primary fuel filter and/or the clear primary fuel filter itself.

The best primary fuel filter I've found is the Hembuller (001 477 79 01) which has the brass inserts.
Best practice is to change both fuel hoses on either side of the primary fuel filter when it is replaced.


You were right there is a lot of bubbles coming from the pump return line. Air bubbles are entering from the injection pump fuel pump on the side. Not sure if from fuel pump being broken or fuel line issue before pump. 

I'm surprised it runs because there is a constant stream of small bubbles and a few larger ones now and then and from my previous experience, any air causes the engine to shut off.

Alec300SD
K26-2

32
07-31-2023, 07:10 PM #6
(07-30-2023, 03:29 PM)Echo575 You were right there is a lot of bubbles coming from the pump return line. Air bubbles are entering from the injection pump fuel pump on the side. Not sure if from fuel pump being broken or fuel line issue before pump. 

I'm surprised it runs because there is a constant stream of small bubbles and a few larger ones now and then and from my previous experience, any air causes the engine to shut off.
Easy to tell if the air incusion is between the lift pump and the fuel tank.
Just  supply fuel from a clean plasic bottle (mini fuel tank) that bypasses the metal feed line from the main fuel tank.
If the bubbles are absent with the mini fuel tank, the problem is aft of the lift pump.

The lift pumps tend to leak air at the old stlye primer pump handle.
The rubber seal on the piston/handle dries out.

The hollow bolt on the fuel filter head seals with an upper aluminum crush washer and a lower rubber o-ring on the "01"
fuel filter head (6150920108) or 2 o-rings on the later "02" fuel filter head (6150920208).
If these seals are inadequate, air can be introduced fom the small bleed hole on top of the fuel filter head.

Hairline cracks on the clear(ish) hard lines tend to happen near the transition into the barbed  fittings.

The aluminum crush washers on the banjo fittings can let air leak in.
Any fuel unions that were disturbed previously are also suspect as possible air incursion points.

As mentioned before, the rubber fuel  hoses on either side of the primary fuel filter can leak.
The test is to see if they leak is to try and rotate them by firmly twisting them by hand.
If they do rotate, they will leak air.
Alec300SD
07-31-2023, 07:10 PM #6

(07-30-2023, 03:29 PM)Echo575 You were right there is a lot of bubbles coming from the pump return line. Air bubbles are entering from the injection pump fuel pump on the side. Not sure if from fuel pump being broken or fuel line issue before pump. 

I'm surprised it runs because there is a constant stream of small bubbles and a few larger ones now and then and from my previous experience, any air causes the engine to shut off.
Easy to tell if the air incusion is between the lift pump and the fuel tank.
Just  supply fuel from a clean plasic bottle (mini fuel tank) that bypasses the metal feed line from the main fuel tank.
If the bubbles are absent with the mini fuel tank, the problem is aft of the lift pump.

The lift pumps tend to leak air at the old stlye primer pump handle.
The rubber seal on the piston/handle dries out.

The hollow bolt on the fuel filter head seals with an upper aluminum crush washer and a lower rubber o-ring on the "01"
fuel filter head (6150920108) or 2 o-rings on the later "02" fuel filter head (6150920208).
If these seals are inadequate, air can be introduced fom the small bleed hole on top of the fuel filter head.

Hairline cracks on the clear(ish) hard lines tend to happen near the transition into the barbed  fittings.

The aluminum crush washers on the banjo fittings can let air leak in.
Any fuel unions that were disturbed previously are also suspect as possible air incursion points.

As mentioned before, the rubber fuel  hoses on either side of the primary fuel filter can leak.
The test is to see if they leak is to try and rotate them by firmly twisting them by hand.
If they do rotate, they will leak air.

Echo575
Naturally-aspirated

23
08-02-2023, 01:36 PM #7
(07-31-2023, 07:10 PM)Alec300SD
(07-30-2023, 03:29 PM)Echo575 You were right there is a lot of bubbles coming from the pump return line. Air bubbles are entering from the injection pump fuel pump on the side. Not sure if from fuel pump being broken or fuel line issue before pump. 

I'm surprised it runs because there is a constant stream of small bubbles and a few larger ones now and then and from my previous experience, any air causes the engine to shut off.
Easy to tell if the air incusion is between the lift pump and the fuel tank.
Just  supply fuel from a clean plasic bottle (mini fuel tank) that bypasses the metal feed line from the main fuel tank.
If the bubbles are absent with the mini fuel tank, the problem is aft of the lift pump.

The lift pumps tend to leak air at the old stlye primer pump handle.
The rubber seal on the piston/handle dries out.

The hollow bolt on the fuel filter head seals with an upper aluminum crush washer and a lower rubber o-ring on the "01"
fuel filter head (6150920108) or 2 o-rings on the later "02" fuel filter head (6150920208).
If these seals are inadequate, air can be introduced fom the small bleed hole on top of the fuel filter head.

Hairline cracks on the clear(ish) hard lines tend to happen near the transition into the barbed  fittings.

The aluminum crush washers on the banjo fittings can let air leak in.
Any fuel unions that were disturbed previously are also suspect as possible air incursion points.

As mentioned before, the rubber fuel  hoses on either side of the primary fuel filter can leak.
The test is to see if they leak is to try and rotate them by firmly twisting them by hand.
If they do rotate, they will leak air.

Ok.

Today I first ran the engine from a bottle and bubbles were still present even after over 15 minutes of revving and idling. 
 
After that I took off the lift pump and took it apart, went over the parts and there was 1 issue which was that 1 of the valves had a foreign object stuck in it so it wouldn't seal. No problem I removed it and tested the valves and they seal now. I cleaned everything in an ultrasonic cleaner and replaced the orings and copper washers and put it together.  The object that was stuck in the valve had probably gotten in because I had no filter before the lift pump so I added one of those small filters used in small gasoline engines. Anyway it made no difference in the air in fuel lines. Surprised no issues were caused by the valve not sealing. 

Tomorrow I will check the other stuff like the filter housing and seals etc.

I added a picture where you can see the air bubbles coming from the injection pump return line.       

There don't seem to be many if any air bubbles at idle but giving it a slight rev to 2500 rpm and letting it return to idle results in air bubbles such as in the picture coming from the injection pump back to the filter where the fuel returns to the fuel tank. There is a sudden stream of these bubbles and they stop coming after returning to idle.

I'm quite certain no air bubbles come from the fuel tank. These air bubbles are quite large and I have seen even bigger bubbles come from the pump.


The shake is horrible still but increasing the rpms by 300 results in a silk smooth idle. If I increase the revs slowly I can feel that 1 cylinder picking up at around 850 rpm and at 1000 rpm it doesn't shake at all. If it matters I think cyl 4 is the issue because after cracking the fuel line and revving it I don't feel that 1 cylinder picking up at all anymore. It's also not like it doesn't run on cyl 4 at all because it does. Disconnecting the fuel line makes the engine run extremely bad. Reminder that this happens only after the engine has ran for some time and it stops doing it after sitting for a few hours.
Echo575
08-02-2023, 01:36 PM #7

(07-31-2023, 07:10 PM)Alec300SD
(07-30-2023, 03:29 PM)Echo575 You were right there is a lot of bubbles coming from the pump return line. Air bubbles are entering from the injection pump fuel pump on the side. Not sure if from fuel pump being broken or fuel line issue before pump. 

I'm surprised it runs because there is a constant stream of small bubbles and a few larger ones now and then and from my previous experience, any air causes the engine to shut off.
Easy to tell if the air incusion is between the lift pump and the fuel tank.
Just  supply fuel from a clean plasic bottle (mini fuel tank) that bypasses the metal feed line from the main fuel tank.
If the bubbles are absent with the mini fuel tank, the problem is aft of the lift pump.

The lift pumps tend to leak air at the old stlye primer pump handle.
The rubber seal on the piston/handle dries out.

The hollow bolt on the fuel filter head seals with an upper aluminum crush washer and a lower rubber o-ring on the "01"
fuel filter head (6150920108) or 2 o-rings on the later "02" fuel filter head (6150920208).
If these seals are inadequate, air can be introduced fom the small bleed hole on top of the fuel filter head.

Hairline cracks on the clear(ish) hard lines tend to happen near the transition into the barbed  fittings.

The aluminum crush washers on the banjo fittings can let air leak in.
Any fuel unions that were disturbed previously are also suspect as possible air incursion points.

As mentioned before, the rubber fuel  hoses on either side of the primary fuel filter can leak.
The test is to see if they leak is to try and rotate them by firmly twisting them by hand.
If they do rotate, they will leak air.

Ok.

Today I first ran the engine from a bottle and bubbles were still present even after over 15 minutes of revving and idling. 
 
After that I took off the lift pump and took it apart, went over the parts and there was 1 issue which was that 1 of the valves had a foreign object stuck in it so it wouldn't seal. No problem I removed it and tested the valves and they seal now. I cleaned everything in an ultrasonic cleaner and replaced the orings and copper washers and put it together.  The object that was stuck in the valve had probably gotten in because I had no filter before the lift pump so I added one of those small filters used in small gasoline engines. Anyway it made no difference in the air in fuel lines. Surprised no issues were caused by the valve not sealing. 

Tomorrow I will check the other stuff like the filter housing and seals etc.

I added a picture where you can see the air bubbles coming from the injection pump return line.       

There don't seem to be many if any air bubbles at idle but giving it a slight rev to 2500 rpm and letting it return to idle results in air bubbles such as in the picture coming from the injection pump back to the filter where the fuel returns to the fuel tank. There is a sudden stream of these bubbles and they stop coming after returning to idle.

I'm quite certain no air bubbles come from the fuel tank. These air bubbles are quite large and I have seen even bigger bubbles come from the pump.


The shake is horrible still but increasing the rpms by 300 results in a silk smooth idle. If I increase the revs slowly I can feel that 1 cylinder picking up at around 850 rpm and at 1000 rpm it doesn't shake at all. If it matters I think cyl 4 is the issue because after cracking the fuel line and revving it I don't feel that 1 cylinder picking up at all anymore. It's also not like it doesn't run on cyl 4 at all because it does. Disconnecting the fuel line makes the engine run extremely bad. Reminder that this happens only after the engine has ran for some time and it stops doing it after sitting for a few hours.

Echo575
Naturally-aspirated

23
08-11-2023, 07:04 AM #8
(07-31-2023, 07:10 PM)Alec300SD
(07-30-2023, 03:29 PM)Echo575 You were right there is a lot of bubbles coming from the pump return line. Air bubbles are entering from the injection pump fuel pump on the side. Not sure if from fuel pump being broken or fuel line issue before pump. 

I'm surprised it runs because there is a constant stream of small bubbles and a few larger ones now and then and from my previous experience, any air causes the engine to shut off.
Easy to tell if the air incusion is between the lift pump and the fuel tank.
Just  supply fuel from a clean plasic bottle (mini fuel tank) that bypasses the metal feed line from the main fuel tank.
If the bubbles are absent with the mini fuel tank, the problem is aft of the lift pump.

The lift pumps tend to leak air at the old stlye primer pump handle.
The rubber seal on the piston/handle dries out.

The hollow bolt on the fuel filter head seals with an upper aluminum crush washer and a lower rubber o-ring on the "01"
fuel filter head (6150920108) or 2 o-rings on the later "02" fuel filter head (6150920208).
If these seals are inadequate, air can be introduced fom the small bleed hole on top of the fuel filter head.

Hairline cracks on the clear(ish) hard lines tend to happen near the transition into the barbed  fittings.

The aluminum crush washers on the banjo fittings can let air leak in.
Any fuel unions that were disturbed previously are also suspect as possible air incursion points.

As mentioned before, the rubber fuel  hoses on either side of the primary fuel filter can leak.
The test is to see if they leak is to try and rotate them by firmly twisting them by hand.
If they do rotate, they will leak air.

A bit of an update and bad news still.

I replaced all the fuel lines after the lift pump, I wet sanded all sealing surfaces just in case, replaced all crush washers, put proper hose clamps in all lines. Also replaced the oring in the filter housing.

After I put a pre filter before the lift pump I can see bubbles entering the lift pump from the prefilter. I don't know if bubbles are supposed to form there. I will check the fuel lines before the lift pump when my fuel tank is close to empty so I can take the fuel out and test with compressed air.

No change in the previous behavior. Runs very good for the first 15-20 minutes and after that idle literally shakes the whole front end of the car.
This post was last modified: 08-11-2023, 07:06 AM by Echo575.
Echo575
08-11-2023, 07:04 AM #8

(07-31-2023, 07:10 PM)Alec300SD
(07-30-2023, 03:29 PM)Echo575 You were right there is a lot of bubbles coming from the pump return line. Air bubbles are entering from the injection pump fuel pump on the side. Not sure if from fuel pump being broken or fuel line issue before pump. 

I'm surprised it runs because there is a constant stream of small bubbles and a few larger ones now and then and from my previous experience, any air causes the engine to shut off.
Easy to tell if the air incusion is between the lift pump and the fuel tank.
Just  supply fuel from a clean plasic bottle (mini fuel tank) that bypasses the metal feed line from the main fuel tank.
If the bubbles are absent with the mini fuel tank, the problem is aft of the lift pump.

The lift pumps tend to leak air at the old stlye primer pump handle.
The rubber seal on the piston/handle dries out.

The hollow bolt on the fuel filter head seals with an upper aluminum crush washer and a lower rubber o-ring on the "01"
fuel filter head (6150920108) or 2 o-rings on the later "02" fuel filter head (6150920208).
If these seals are inadequate, air can be introduced fom the small bleed hole on top of the fuel filter head.

Hairline cracks on the clear(ish) hard lines tend to happen near the transition into the barbed  fittings.

The aluminum crush washers on the banjo fittings can let air leak in.
Any fuel unions that were disturbed previously are also suspect as possible air incursion points.

As mentioned before, the rubber fuel  hoses on either side of the primary fuel filter can leak.
The test is to see if they leak is to try and rotate them by firmly twisting them by hand.
If they do rotate, they will leak air.

A bit of an update and bad news still.

I replaced all the fuel lines after the lift pump, I wet sanded all sealing surfaces just in case, replaced all crush washers, put proper hose clamps in all lines. Also replaced the oring in the filter housing.

After I put a pre filter before the lift pump I can see bubbles entering the lift pump from the prefilter. I don't know if bubbles are supposed to form there. I will check the fuel lines before the lift pump when my fuel tank is close to empty so I can take the fuel out and test with compressed air.

No change in the previous behavior. Runs very good for the first 15-20 minutes and after that idle literally shakes the whole front end of the car.

Hercules
GT2559V

219
08-11-2023, 01:56 PM #9
I would suggest problem is in the pump. Smooth idle until warm, if cold weather, shake may take several hrs. to start.
Engine had dead miss, traced to #4 cyl. idle only. removed delivery valve lapped all parts, reinstalled miss gone .
Shake did return after several weeks, not as bad ,miss has never returned been several yrs.
Hercules
08-11-2023, 01:56 PM #9

I would suggest problem is in the pump. Smooth idle until warm, if cold weather, shake may take several hrs. to start.
Engine had dead miss, traced to #4 cyl. idle only. removed delivery valve lapped all parts, reinstalled miss gone .
Shake did return after several weeks, not as bad ,miss has never returned been several yrs.

Echo575
Naturally-aspirated

23
08-11-2023, 04:13 PM #10
(08-11-2023, 01:56 PM)Hercules I would suggest problem is in the pump. Smooth idle until warm, if cold weather,  shake may take several hrs. to start.
Engine had dead miss, traced to #4 cyl. idle only.  removed delivery valve lapped all parts, reinstalled miss gone .
Shake did return after several weeks, not as bad ,miss has never returned been several yrs.

I'm thinking it's a delivery valve too. 

A forum member gave me a set of 6mm elements that I will be putting into my pump. I will lap the parts and replace all the seals when I get to that.
Echo575
08-11-2023, 04:13 PM #10

(08-11-2023, 01:56 PM)Hercules I would suggest problem is in the pump. Smooth idle until warm, if cold weather,  shake may take several hrs. to start.
Engine had dead miss, traced to #4 cyl. idle only.  removed delivery valve lapped all parts, reinstalled miss gone .
Shake did return after several weeks, not as bad ,miss has never returned been several yrs.

I'm thinking it's a delivery valve too. 

A forum member gave me a set of 6mm elements that I will be putting into my pump. I will lap the parts and replace all the seals when I get to that.

Echo575
Naturally-aspirated

23
08-13-2023, 01:57 PM #11
It seems to definitely be a fuel pump issue. Began using wvo again and runs like it should no matter how hot it gets.
This post was last modified: 08-13-2023, 03:56 PM by Echo575.
Echo575
08-13-2023, 01:57 PM #11

It seems to definitely be a fuel pump issue. Began using wvo again and runs like it should no matter how hot it gets.

Niko
K26-2

47
08-14-2023, 03:06 AM #12
I'm having something similar on may daily with an EDC pump . Starts fine, runs nice, warms up and does the shake . Nothing serious, but not mercedes-like .
It also had a smoking problem under full load and high RPM but that seems to have cleared up by changing the fuel pressure bolt on the pump .
Niko
08-14-2023, 03:06 AM #12

I'm having something similar on may daily with an EDC pump . Starts fine, runs nice, warms up and does the shake . Nothing serious, but not mercedes-like .
It also had a smoking problem under full load and high RPM but that seems to have cleared up by changing the fuel pressure bolt on the pump .

Echo575
Naturally-aspirated

23
08-17-2023, 05:15 PM #13
(08-14-2023, 03:06 AM)Niko I'm having something similar on may daily with an EDC pump . Starts fine, runs nice, warms up and does the shake . Nothing serious, but not mercedes-like .
It also had a smoking problem under full load and high RPM but that seems to have cleared up by changing the fuel pressure bolt on the pump .

Yes. I also own a Volvo 240 diesel and that had a constant shake at idle caused by a delivery valve. I think our issues are caused by delivery valves too but can't really say why only when warm. 

I have driven a few hundred km with only WVO with the om617 and no more shake. Of course would shake with diesel again but thicker fuel fixes it for me.
Echo575
08-17-2023, 05:15 PM #13

(08-14-2023, 03:06 AM)Niko I'm having something similar on may daily with an EDC pump . Starts fine, runs nice, warms up and does the shake . Nothing serious, but not mercedes-like .
It also had a smoking problem under full load and high RPM but that seems to have cleared up by changing the fuel pressure bolt on the pump .

Yes. I also own a Volvo 240 diesel and that had a constant shake at idle caused by a delivery valve. I think our issues are caused by delivery valves too but can't really say why only when warm. 

I have driven a few hundred km with only WVO with the om617 and no more shake. Of course would shake with diesel again but thicker fuel fixes it for me.

Niko
K26-2

47
08-18-2023, 01:26 AM #14
Any idea which oil is a better additive for diesel ? The debate was between two stroke oil and ATF, and somewhere I came across the statement that one improves the burn and reduces ash .
Niko
08-18-2023, 01:26 AM #14

Any idea which oil is a better additive for diesel ? The debate was between two stroke oil and ATF, and somewhere I came across the statement that one improves the burn and reduces ash .

Echo575
Naturally-aspirated

23
08-19-2023, 04:08 PM #15
(08-18-2023, 01:26 AM)Niko Any idea which oil is a better additive for diesel ? The debate was between two stroke oil and ATF, and somewhere I came across the statement that one improves the burn and reduces ash .

I would say 2 stroke is better because it's designed to burn in 2 strokes too. ATF is probably cheaper since most of us probably have at least some laying around from oil changes on automatics.
Echo575
08-19-2023, 04:08 PM #15

(08-18-2023, 01:26 AM)Niko Any idea which oil is a better additive for diesel ? The debate was between two stroke oil and ATF, and somewhere I came across the statement that one improves the burn and reduces ash .

I would say 2 stroke is better because it's designed to burn in 2 strokes too. ATF is probably cheaper since most of us probably have at least some laying around from oil changes on automatics.

Kevy
Naturally-aspirated

11
01-21-2024, 11:35 PM #16
(08-18-2023, 01:26 AM)Niko Any idea which oil is a better additive for diesel ? The debate was between two stroke oil and ATF

Neither. They don't do anything and they aren't made to be used in diesel fuel.
Kevy
01-21-2024, 11:35 PM #16

(08-18-2023, 01:26 AM)Niko Any idea which oil is a better additive for diesel ? The debate was between two stroke oil and ATF

Neither. They don't do anything and they aren't made to be used in diesel fuel.

 
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