Glow plugs
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W211 E320 Diesel OM642
Starting issues, Glow plugs?
Can glow plugs tesr normal with an ohm meter, generate no codes and still be bad?
I just recently had to change my control module and with the outdoor temps dropping below freezing, the car take longer to start and it does run rougher.
no issues when the motor is warm.
I have the 7V glow plugs on my OM642
thanks
I just recently had to change my control module and with the outdoor temps dropping below freezing, the car take longer to start and it does run rougher.
no issues when the motor is warm.
I have the 7V glow plugs on my OM642
thanks
Last edited by GoodByeHonda; Nov 23, 2019 at 11:06 AM.
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1922 Ford Model T / no OBD
GP are straight resistor heater. Not much can happen there. I had my OM642 starting with failed module after about 3 seconds of cranking in 50's F, so this engine doesn't need much of preheating.
Than I just spoke with guy who bought my OM642 and he replaced 1 of the injectors, as it failed, giving occasional misfires with no codes.
In case like that I always start with basics. New filters, running smoothest test, making sure you have good fuel.
Than did you try double preheating?
How long the GP light takes in subfreezing to go off? In my climate I have hard time to see it coming at all.
Than I just spoke with guy who bought my OM642 and he replaced 1 of the injectors, as it failed, giving occasional misfires with no codes.
In case like that I always start with basics. New filters, running smoothest test, making sure you have good fuel.
Than did you try double preheating?
How long the GP light takes in subfreezing to go off? In my climate I have hard time to see it coming at all.
Last edited by kajtek1; Nov 22, 2019 at 03:28 PM.
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From: Lawrence, Kansas
GL320
When the glow module or a glow plug goes out, the ECU is pretty good about picking up on it and triggering a code. However, like any resistor, it can get weaker with age and use. The preheat time is determined by the coolant temp sensor.
The state of your battery has A LOT to do with the ability to turn the engine fast enough to start and the most common problem when issues show up with a cold season change.
A slightly leaky injector would also cause delayed cranking then rough cold idle. The same can be said for the fuel pressure sensor.
Your best bet is to find someone with Star DAS and use it to pinpoint whats going on. Its nearly impossible to diagnose an issue with an OM642 without it.
The state of your battery has A LOT to do with the ability to turn the engine fast enough to start and the most common problem when issues show up with a cold season change.
A slightly leaky injector would also cause delayed cranking then rough cold idle. The same can be said for the fuel pressure sensor.
Your best bet is to find someone with Star DAS and use it to pinpoint whats going on. Its nearly impossible to diagnose an issue with an OM642 without it.
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W211 E320 Diesel OM642
Double preheating makes it all good. In fact if I turn the key and wait 30sec and then turn the engine over, it starts normal. Don't have to preheat the glow plugs again. The glow plug light goes away in 2 seconds.
battery is 2 years old. OEM MB unit. All looks good. Fuel, filter are good.
I'm leaning towards injectors. I have Maxiecu diagnostics and even though this software does not have engine smooth test, i believe it does have ability to see how injectors are doing.
battery is 2 years old. OEM MB unit. All looks good. Fuel, filter are good.
I'm leaning towards injectors. I have Maxiecu diagnostics and even though this software does not have engine smooth test, i believe it does have ability to see how injectors are doing.
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1922 Ford Model T / no OBD
Suppose modern GP module keeps GP running on and off for several minutes even after engine start to keep pollution lower, so your experience that keeping ignition on for some time before cranking, helps in cold star- does confirm that.
But 2 seconds of preheating in subfreezing temperatures sounds short to me.
Check the engine temp sensor with a scanner.
But 2 seconds of preheating in subfreezing temperatures sounds short to me.
Check the engine temp sensor with a scanner.
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From: UK
Mercedes R320L CDI 4MATIC 2007
Double preheating makes it all good. In fact if I turn the key and wait 30sec and then turn the engine over, it starts normal. Don't have to preheat the glow plugs again. The glow plug light goes away in 2 seconds.
battery is 2 years old. OEM MB unit. All looks good. Fuel, filter are good.
I'm leaning towards injectors. I have Maxiecu diagnostics and even though this software does not have engine smooth test, i believe it does have ability to see how injectors are doing.
battery is 2 years old. OEM MB unit. All looks good. Fuel, filter are good.
I'm leaning towards injectors. I have Maxiecu diagnostics and even though this software does not have engine smooth test, i believe it does have ability to see how injectors are doing.
I have same situation, been throught that with my car, engine OM642. Glow plug system was all ok. When you keep ignition on for 30 seconds, the fuel is being primed from fuel tank by fuel pump up to the engine for these 30 seconds. Seemed that was enough for the engine to startup as normal. I did test of the injectors (leak off test), as suggested by one of the forum members. Found out two of the six injectors are faulty. Not replaced them yet, but pretty sure thats them causing hard cold start.
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W211 E320 Diesel OM642
It was just below freezing point this morning. Started on the 3rd time. Looks like keeping the ignition on for 30 sec isn't the magic solution so it's getting worse.
I fired up Maxi Ecu and was observing the coolant temp but there are few areas that maxiecu has it as an option to monitor and the one I chose wasn't reading proper value ( I chose set 1 and it was displaying under -200C) .
when the engine warmed up, I selected maxiecu's Set 4 and it appeared to be giving proper coolant temp.
as far as injectors, with warm engine and at idle I saw the following:
Cylinder 1 fuel trim : mm3/stroke -0.09
Cylinder 2 fuel trim :mm3/stroke -0.16
Cylinder 3 fuel trim :mm3/stroke -0.26
Cylinder 4 fuel trim :mm3/stroke +0.32
Cylinder 5 fuel trim :mm3/stroke -0.19
Cylinder 6 fuel trim :mm3/stroke +0.40
Not sure what to make of it.
I fired up Maxi Ecu and was observing the coolant temp but there are few areas that maxiecu has it as an option to monitor and the one I chose wasn't reading proper value ( I chose set 1 and it was displaying under -200C) .
when the engine warmed up, I selected maxiecu's Set 4 and it appeared to be giving proper coolant temp.
as far as injectors, with warm engine and at idle I saw the following:
Cylinder 1 fuel trim : mm3/stroke -0.09
Cylinder 2 fuel trim :mm3/stroke -0.16
Cylinder 3 fuel trim :mm3/stroke -0.26
Cylinder 4 fuel trim :mm3/stroke +0.32
Cylinder 5 fuel trim :mm3/stroke -0.19
Cylinder 6 fuel trim :mm3/stroke +0.40
Not sure what to make of it.
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1922 Ford Model T / no OBD
The digital troubleshooting is still new to me, but your readings looks pretty wide spread to me. Here is video I found
Is MaxiEcu having injectors programming and adaptations for your engine?
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W211 E320 Diesel OM642
Well, things are getting worse. Now the engine is fully warmed up and does not restart. Definately not a glow plug issue then.With the ignition on position 2, glow light goes off immediately as it should.
Fuel rail pressure with just the ignition on goes upto 6.5 Bar, while cranking goes upto 650 Bar but when I stop cranking, drops back to single digits.
If I recall, no start on hot engine is mostly due to faulty fuel rail pressure sensor.
Observing fuel pressure control valve during cranking, I see it start at 8% and goes all the way upto 35%.
I'm working with MaxiEcu. Any thoughts on getting it diagnosed is appreciated!
Fuel rail pressure with just the ignition on goes upto 6.5 Bar, while cranking goes upto 650 Bar but when I stop cranking, drops back to single digits.
If I recall, no start on hot engine is mostly due to faulty fuel rail pressure sensor.
Observing fuel pressure control valve during cranking, I see it start at 8% and goes all the way upto 35%.
I'm working with MaxiEcu. Any thoughts on getting it diagnosed is appreciated!
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From: V E G A S
1922 Ford Model T / no OBD
I recall my engine idling at about 5000 psi, where your 650 bars is almost double that.
But then your prime pressure shows almost 100 psi, what is about twice.
Allow me some margin error as I never had to go that deep into engine management, but I had several scanners giving me bogus data, so I would not go any farther before getting 2nd scanner to confirm that.
The $5 Bluetooth plugs with $5 TorquePro app can read rail pressure.
But then your prime pressure shows almost 100 psi, what is about twice.
Allow me some margin error as I never had to go that deep into engine management, but I had several scanners giving me bogus data, so I would not go any farther before getting 2nd scanner to confirm that.
The $5 Bluetooth plugs with $5 TorquePro app can read rail pressure.
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From: Lawrence, Kansas
GL320
It was just below freezing point this morning. Started on the 3rd time. Looks like keeping the ignition on for 30 sec isn't the magic solution so it's getting worse.
I fired up Maxi Ecu and was observing the coolant temp but there are few areas that maxiecu has it as an option to monitor and the one I chose wasn't reading proper value ( I chose set 1 and it was displaying under -200C) .
when the engine warmed up, I selected maxiecu's Set 4 and it appeared to be giving proper coolant temp.
as far as injectors, with warm engine and at idle I saw the following:
Cylinder 1 fuel trim : mm3/stroke -0.09
Cylinder 2 fuel trim :mm3/stroke -0.16
Cylinder 3 fuel trim :mm3/stroke -0.26
Cylinder 4 fuel trim :mm3/stroke +0.32
Cylinder 5 fuel trim :mm3/stroke -0.19
Cylinder 6 fuel trim :mm3/stroke +0.40
Not sure what to make of it.
I fired up Maxi Ecu and was observing the coolant temp but there are few areas that maxiecu has it as an option to monitor and the one I chose wasn't reading proper value ( I chose set 1 and it was displaying under -200C) .
when the engine warmed up, I selected maxiecu's Set 4 and it appeared to be giving proper coolant temp.
as far as injectors, with warm engine and at idle I saw the following:
Cylinder 1 fuel trim : mm3/stroke -0.09
Cylinder 2 fuel trim :mm3/stroke -0.16
Cylinder 3 fuel trim :mm3/stroke -0.26
Cylinder 4 fuel trim :mm3/stroke +0.32
Cylinder 5 fuel trim :mm3/stroke -0.19
Cylinder 6 fuel trim :mm3/stroke +0.40
Not sure what to make of it.
Think of it this way. By your numbers, cylinder 6 needs 0.40mm3 hub more than baseline to run smoothly. Cylinder 3 needs 0.26mm3 hub less fuel, and so on.
The baseline is zero with a tolerance of +5.0 to -5.0 so all of your cylinder mm3 hub numbers are as close to PERFECT as Ive ever seen.
There is a manual test that i believe you should perform when the engine is cold. Its a manual cylnder leak off test at cranking. Basically you remove the return hoses from the injectors and replace them with clear hoses. Then you unhook the cam and fuel pressure sensor and crank for 10-15 seconds. If any fuel fills the tube, that injector is defective.
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W211 E320 Diesel OM642
Thank you all for input. It's been a while since I had to trouble shoot a problem on my merc, kind of exciting!
I took it out for a long drive and tested my fuel rail pressure control valve using live data feed from maxiecu. It stays constant, hardly any % deflection at steady throttle. So my fuel rail pressure control valve is OK.
Got some fresh gas.
Thanks Krzysiek. Will try to find the obd2 plug locally. 👍
Thinking now it's my tank fuel pump. The car did run out of diesel once....
I took it out for a long drive and tested my fuel rail pressure control valve using live data feed from maxiecu. It stays constant, hardly any % deflection at steady throttle. So my fuel rail pressure control valve is OK.
Got some fresh gas.
Thanks Krzysiek. Will try to find the obd2 plug locally. 👍
Thinking now it's my tank fuel pump. The car did run out of diesel once....
Member
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Posts: 247
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From: Lawrence, Kansas
GL320
Thank you all for input. It's been a while since I had to trouble shoot a problem on my merc, kind of exciting!
I took it out for a long drive and tested my fuel rail pressure control valve using live data feed from maxiecu. It stays constant, hardly any % deflection at steady throttle. So my fuel rail pressure control valve is OK.
Got some fresh gas.
Thanks Krzysiek. Will try to find the obd2 plug locally. 👍
Thinking now it's my tank fuel pump. The car did run out of diesel once....
I took it out for a long drive and tested my fuel rail pressure control valve using live data feed from maxiecu. It stays constant, hardly any % deflection at steady throttle. So my fuel rail pressure control valve is OK.
Got some fresh gas.
Thanks Krzysiek. Will try to find the obd2 plug locally. 👍
Thinking now it's my tank fuel pump. The car did run out of diesel once....
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W211 E320 Diesel OM642
Looks like that key on fuel pressure of 6.5 Bar varies as some times it starts at 4.3 Bar. It takes 6 seconds of cranking to get to the required approximate 300 Bar for the injectors to fire.
Is that fast enough?
Is that fast enough?
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W211 320CDI -04, W210 270CDI -01
Required pressure is lower than 300 bars (I cant recall but I think its around 150-200bar), but for example all my MB diesels starts about 2 seconds in normal conditions. Very cold (under -20C) it takes longer, and if engine pre heater has been only short time on, even longer when ECU finds warm sensors somewhere but lump actually is still cold.
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From: Lawrence, Kansas
GL320
4.3 bar (63psi) is fine as well. Minimum is 58psi.
minimum fuel pressure to fire the injectors is around 3000psi or 200bar. The ramp up time to go from 63psi to 3000psi during cranking should be roughly 1 second.
minimum fuel pressure to fire the injectors is around 3000psi or 200bar. The ramp up time to go from 63psi to 3000psi during cranking should be roughly 1 second.
Last edited by dhurley; Nov 24, 2019 at 10:53 AM.
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1922 Ford Model T / no OBD
I no longer own 642 engine, but from what I remember it needed 5000 psi, or close to 300 bars to run. And the fuel pump was delivering that pressure in about 0.5 second, but no experience with low temperatures.
The only way warm diesel won't start is lack of fuel, or computer holds it from starting, what would trigger a code.
The only way warm diesel won't start is lack of fuel, or computer holds it from starting, what would trigger a code.
Member
Joined: Dec 2018
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From: Lawrence, Kansas
GL320
I no longer own 642 engine, but from what I remember it needed 5000 psi, or close to 300 bars to run. And the fuel pump was delivering that pressure in about 0.5 second, but no experience with low temperatures.
The only way warm diesel won't start is lack of fuel, or computer holds it from starting, what would trigger a code.
The only way warm diesel won't start is lack of fuel, or computer holds it from starting, what would trigger a code.
GoodByeHonda, What is your cranking speed in RPM's? Are you able to view voltage drop during cranking?
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W211 E320 Diesel OM642
The way I'm monitoring the parameters is by selecting what maxiecu offers and literally video taping while cranking. That's my live data 
I did not select rpms during previous testing. The only parameter that I have with respect to voltage is System Voltage and output either OK or No. I get ok
What's interesting to note is that maxiecu has two parameters that it monitors.
1. Start enabled from transmission control module and
2. start enable
During cranking which to me rpms feel normal, #1 turns to Yes BUT #2 (start enable) stays NO. So it would appear that there is no start go ahead signal.
I think to monitor voltage, I'll crank the car and will monitor voltage at the batery terminals with voltmeter and my camera
I did not select rpms during previous testing. The only parameter that I have with respect to voltage is System Voltage and output either OK or No. I get ok
What's interesting to note is that maxiecu has two parameters that it monitors.
1. Start enabled from transmission control module and
2. start enable
During cranking which to me rpms feel normal, #1 turns to Yes BUT #2 (start enable) stays NO. So it would appear that there is no start go ahead signal.
I think to monitor voltage, I'll crank the car and will monitor voltage at the batery terminals with voltmeter and my camera
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1922 Ford Model T / no OBD
Haven't use MaxiEcu for some time, but doesn't it display voltage on top margin?
Torque Pro allows you to choose the gauges, but than it was showing me 3000 psi exhaust pressure, that is why I am skeptic about accuracy.
Having "no" in start enabling indicate that 1 or more starting parameters is not meet. So the cross-puzzle is narrowing.
Can you open a page showing starting parameters?
Torque Pro allows you to choose the gauges, but than it was showing me 3000 psi exhaust pressure, that is why I am skeptic about accuracy.
Having "no" in start enabling indicate that 1 or more starting parameters is not meet. So the cross-puzzle is narrowing.
Can you open a page showing starting parameters?
Last edited by kajtek1; Nov 24, 2019 at 03:43 PM.
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W211 E320 Diesel OM642
Tried again. Took 4 full starting cycles and it fired up on the 5th time.
RPM
During cranking, it goes up to 143 RPM (this is off Maxiecu, I didn't look at the tach if the needle moves during crank)
Voltage
At batery terminals, volt meter shows 12.14V.
During initial crank, it drops to 10.6V, by the 2nd second goes up to 10.9V and stays that low till the end of crank cycle.
Maxiecu shows 11.6V in top right corner during crank. Hmmm
System voltage Maxiecu measuring parameter stays as OK through out cranking.
This time I observed crank signal as YES and there was no start. I cant seem to get into that option as on Maxiecu you can select a parameter and simply observe it. It doesn't tell me what the actual signals it is monitoring.
RPM
During cranking, it goes up to 143 RPM (this is off Maxiecu, I didn't look at the tach if the needle moves during crank)
Voltage
At batery terminals, volt meter shows 12.14V.
During initial crank, it drops to 10.6V, by the 2nd second goes up to 10.9V and stays that low till the end of crank cycle.
Maxiecu shows 11.6V in top right corner during crank. Hmmm
System voltage Maxiecu measuring parameter stays as OK through out cranking.
This time I observed crank signal as YES and there was no start. I cant seem to get into that option as on Maxiecu you can select a parameter and simply observe it. It doesn't tell me what the actual signals it is monitoring.
Last edited by GoodByeHonda; Nov 24, 2019 at 07:39 PM.
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W211 E320 Diesel OM642
There is a manual test that i believe you should perform when the engine is cold. Its a manual cylnder leak off test at cranking. Basically you remove the return hoses from the injectors and replace them with clear hoses. Then you unhook the cam and fuel pressure sensor and crank for 10-15 seconds. If any fuel fills the tube, that injector is defective.
Thanks
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From: Lawrence, Kansas
GL320
Going to check my injectors hopefully tomorrow. When performing the manual cylinder leak off test, you suggest unplugging fuel pressure sensor. I know there is one on the passenger's side of the fuel rail but is there another on the drivers side? If that's the case, both should be disconnected?
Thanks
Thanks
