You're very good at this! I've a collection of early aircooled vw-s. Just bought a 260E in good mech condition, no rust (aust delivery) nice and clean inside, but l'm already sceared because it's too complicated. I want to sell it while it's running and stick with the much simplier beetles and kombies.
Hi, could the symptoms you mentioned at the beginning of your commentary, could that also apply to a fault with a potentiometer but in reverse. i.e my 300SE (W126) is fine on cold start up but once it reaches operating temperature (or even sooner in warm weather, the idle seems low (but okay). However it feels as if the car is going to stall. Through an expensive process of elimination I have replaced the coil, the HT leads. distributor cap and rotor arm and spark plugs. Although it runs betterbecause I have replaced those items it stills has that fault. Sorry this is a bit long winded.
Hi, Tom Maybe it's the oxygen sensor, it might be dirty, (covered in carbon). If it is the ECU thinks that the engine is running rich and cuts the fuel delivery, especially in the idle position. Take it out & give it a clean. Cheers, Paul.
Hi Paul, have you bought any other replacement parts form china?? I am looking at the ICV valve (23$ form china) could be worth a gamble...what do you reckon? .....by the way keep the videos coming, cheers from the czech republic!!
Hi, wesley there is no problem with the parts from China, the biggest problem is the amount of time it takes to receive the part, it can take 2 months for us in Australia, might be faster for Europe but I doubt it. Worth it if it's not urgent, cheers, Paul.
For others performing this task, you may want to use the following link as a reference. It has instructions on how to not only replace, but also adjust your airflow sensor potentiomter properly! www.sg-motorsports.com/AFS%20Pot%20write-up.htm
Hi, This is a hard one, could be lots of things. Faulty cold start valve, faulty coolant temp switch, vacuum leak, auxiliary air regulator faulty, airflow sensor plate rest position incorrect, control plunger in fuel distributor binding. I took these from the workshop Manual. Good luck, Paul.
how is the new potentiometer running so far since the instal? I may have to get one for my car and its been hard to find them new and for a good price. Thanks for the videos they are always a great help!
trader_alex23 Hi, Alex The potentiometer is fine, I don't think the car needed it so I'm keeping the old one as a spare. I got that part from Aliexpress which is products from China, it cost $11.50 US including postage, you can't beat that except that it takes a while to receive postage wise. Regards, Paul
Hi, I haven't thought about it since I changed it, car runs fine. That's why it's been ages since I have done a video on this car, if the sensors, etc are maintained the car will go forever. cheer, Paul
RRJ wondereing how the cars going since you replaced the potentiometer - no low or hi revs if you tell me = its be running like dream since you replaced with your china made part which china potentiometer part sold you just 1 potentiometer -look your videos-i have a 1990 260 e which they tell uses the same potentiometer as the 3oo e----cheers- sunrise
Hi, Sunrise, I have had no problems on that side of the car since I changed it. The car just recently did an approx 3,000 km drive no problems. Cheers, Paul.
May ask help to fix idle high 2000rpm , changed idle valve but same problema , unplug wide from idle valve , motore run 800rpm , chat can i cheek?? Mercedes 260e y1985. grazie
MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} Check the throttle linkage adjustments to be sure that the throttle switch is closing when you return to idle. It sounds like the idle valve is getting stuck open. You might also try disconnecting the idle control valve and see if it still wants to idle low when the valve is disconnected. If it doesn't then it tells you that the valve is probably getting stuck. Clean the intake throttle bore with some carb cleaner, also a faulty over voltage protection relay can cause the idle speed to be erratic. Normal 0
MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} You can try disconnecting the oxygen sensor also to see if it is causing the problem.Regards, Paul.
riffraffjazz disconnecting idle valve wire , the idle is normal around 800rpm , also i have changed the idle valve but same problem , with idle valve wire disconnected all is working well , reconnecting wire idle up to 2000rpm. could be the potenziometer? how can check it? grazie emilio
Check the throttle linkage adjustments to be sure that the throttle switch is closing when you return to idle. It sounds like the idle valve is getting stuck open. You might also try disconnecting the idle control valve and see if it still wants to idle low ( should drop right down or stall not 800 rpm) when the valve is disconnected. If it doesn't then it tells you that the valve is probably getting stuck. Clean the intake throttle bore with some carb cleaner, also a faulty over voltage protection relay can cause the idle speed to be erratic. If the potentiometer was faulty you will have a flat spot when you accelerate where the pot resistance wires are worn. Have you checked the air intake plunger to make sure it is closing properly.
Hi, Darryl It's been so long I can't remember, I know I kept getting junk mail from them for months, there is one web site that I just looked up that has 300E parts, alibaba.com, type in 300e mercedes parts on search. Good luck, Paul.
What do you mean by backwire? Can you explain the testing procedure a bit. I appreciate your Mercedes videos. I'm working on a 1991 300ce I've had in garbage for 7 years. Thanks. ddrayper@gmail.com
Darryl S. Draper Sr.I borrowed this information from the internet, you need two fine probes connected to a multimeter and connect them to pins 1&2, I was going to put a piece of wire on each pin then put the plug back on and connect the multimeter on the ends:-
Normal 0
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MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} With a digital multimeter hooked up to read DC volts, start the car and let it warm up to a steady warm idle. With the engine at idle adjust the potentiometer body by pivoting it slightly until 0.70v (plus or minus 0.10v) is obtained. This is a very fine adjustment and it doesn't take much movement to make a big difference, so be sensitive and move it slowly and gently. Then gently tighten the 4 screws in a cross pattern, being careful to not change the adjustment while tightening. With the sensor tight and adjustment within spec, shut the car off and install the black plastic screw covers on the sensor and reinstall the air cleaner. The fine adjustment screw next to the 3-pin connector should not be used for adjustment as it is only for very minor adjustments and should only be used in conjunction with a flow bench tester. I hope this helps, regards, Paul.
@0:51 Thats not the fuel pressure dampner, thats the fuel pressure regulator.
The fuel dampner is near the fuel pumps at the back of the car.
Very good videos you put on youtube . Nice and clear, . And very informative .Thank you ..
You're very good at this! I've a collection of early aircooled vw-s. Just bought a 260E in good mech condition, no rust (aust delivery) nice and clean inside, but l'm already sceared because it's too complicated. I want to sell it while it's running and stick with the much simplier beetles and kombies.
Its an elegant system once you understand it and simpler than it looks, but yeah its still alot of parts and quite a steep learning curve.
i love this guy
Paul just another quick question: what type and brand of spark plugs do you use on your 300e?
Thks.
Darryl
thanks changing the poteziometer my idle problem is now solved cost 19$
Hello.
I good it yesterday from China. It looks good, I am unable to change my part. I only did what you did it works OK.
Thanks
Hi, could the symptoms you mentioned at the beginning of your commentary, could that also apply to a fault with a potentiometer but in reverse. i.e my 300SE (W126) is fine on cold start up but once it reaches operating temperature (or even sooner in warm weather, the idle seems low (but okay). However it feels as if the car is going to stall. Through an expensive process of elimination I have replaced the coil, the HT leads. distributor cap and rotor arm and spark plugs. Although it runs betterbecause I have replaced those items it stills has that fault. Sorry this is a bit long winded.
Hi, Tom Maybe it's the oxygen sensor, it might be dirty, (covered in carbon). If it is the ECU thinks that the engine is running rich and cuts the fuel delivery, especially in the idle position. Take it out & give it a clean. Cheers, Paul.
+riffraffjazz Thanks Paul I appreciate your advice. I will try that over the weekend.
I thought the pressure damper you are referring to on this video is called primary pressure regulator. Sorry but you can correct me if I'm wrong.
You are correct, the pressure dampner is at the back with the fuel pumps.
Hi Paul, have you bought any other replacement parts form china?? I am looking at the ICV valve (23$ form china) could be worth a gamble...what do you reckon? .....by the way keep the videos coming, cheers from the czech republic!!
Hi, wesley there is no problem with the parts from China, the biggest problem is the amount of time it takes to receive the part, it can take 2 months for us in Australia, might be faster for Europe but I doubt it. Worth it if it's not urgent, cheers, Paul.
riffraffjazz US $17.00 | AP02 Idle Air Control Valve 127238 4612738 for Mercedes-Benz C124 W124 S124 W126 R129 W201 W461
a.aliexpress.com/_dYShIzS
For others performing this task, you may want to use the following link as a reference. It has instructions on how to not only replace, but also adjust your airflow sensor potentiomter properly!
www.sg-motorsports.com/AFS%20Pot%20write-up.htm
Hi, Thanks for adding that great write up, cheers, Paul.
This link no longer works 😢
Hello,
I have a 1990 300se, I starts at 1200 down to 700 goes ok fore 30 minieits dies at stop.
Thanks
Hi, This is a hard one, could be lots of things. Faulty cold start valve, faulty coolant temp switch, vacuum leak, auxiliary air regulator faulty, airflow sensor plate rest position incorrect, control plunger in fuel distributor binding. I took these from the workshop Manual. Good luck, Paul.
Filter stoped up on fuel distributor wear the gas line hooks up
how is the new potentiometer running so far since the instal? I may have to get one for my car and its been hard to find them new and for a good price. Thanks for the videos they are always a great help!
trader_alex23 Hi, Alex
The potentiometer is fine, I don't think the car needed it so I'm keeping the old one as a spare. I got that part from Aliexpress which is products from China, it cost $11.50 US including postage, you can't beat that except that it takes a while to receive postage wise. Regards, Paul
riffraffjazz Thanks for the info on where to order it! Thanks again for the great films on the Mercedes and the music!
Cheers!
8 years on, how did the chinese potentiometer hold up and how many did u go through?
Hi, I haven't thought about it since I changed it, car runs fine. That's why it's been ages since I have done a video on this car, if the sensors, etc are maintained the car will go forever. cheer, Paul
RRJ wondereing how the cars going since you replaced the potentiometer - no low or hi revs if you tell me = its be running like dream since you replaced with your china made part which china potentiometer part sold you just 1 potentiometer -look your videos-i have a 1990 260 e which they tell uses the same potentiometer as the 3oo e----cheers- sunrise
Hi, Sunrise, I have had no problems on that side of the car since I changed it.
The car just recently did an approx 3,000 km drive no problems.
Cheers, Paul.
cheers paul -thats good news-thank
You didnt calibrate this at operating temperature and engine running.
Didn't have too.
May ask help to fix idle high 2000rpm , changed idle valve but same problema , unplug wide from idle valve , motore run 800rpm , chat can i cheek?? Mercedes 260e y1985. grazie
Emilio Bonvi
Hi,
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Check the throttle linkage adjustments to be sure that the throttle switch is closing when you return to idle. It sounds like the idle valve is getting stuck open. You might also try disconnecting the idle control valve and see if it still wants to idle low when the
valve is disconnected. If it doesn't then it tells you that the valve is
probably getting stuck. Clean the intake throttle bore with some carb cleaner, also a faulty over voltage protection relay can cause the idle speed to be erratic.
Normal
0
MicrosoftInternetExplorer4
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You can try disconnecting the oxygen sensor also to see if it is causing the problem.Regards, Paul.
riffraffjazz disconnecting idle valve wire , the idle is normal around 800rpm , also i have changed the idle valve but same problem , with idle valve wire disconnected all is working well , reconnecting wire idle up to 2000rpm. could be the potenziometer? how can check it? grazie emilio
Check the throttle linkage adjustments to be sure that the throttle
switch is closing when you return to idle. It sounds like the idle valve
is getting stuck open. You might also try disconnecting the idle
control valve and see if it still wants to idle low ( should drop right down or stall not 800 rpm) when the valve is disconnected. If it doesn't then it tells you that the valve is probably getting stuck. Clean the intake throttle bore with some carb
cleaner, also a faulty over voltage protection relay can cause the idle
speed to be erratic. If the potentiometer was faulty you will have a flat spot when you accelerate where the pot resistance wires are worn.
Have you checked the air intake plunger to make sure it is closing properly.
Emilio BonviAlso check the rubber hoses from your idle valve for cracks and make sure they are connected properly, could be sucking air in.
Paul.
Hello,
I do it today..
Thanks
Might be s stopped up cat converter
What china company do you order your parts from???
Hi, Darryl
It's been so long I can't remember, I know I kept getting junk mail from them for months, there is one web site that I just looked up that has 300E parts, alibaba.com, type in 300e mercedes parts on search. Good luck, Paul.
Thank you,,,,
Lot's of them on Ebay for between 11 and 60 dollars from US and China.
Hello, how are you?
What do you mean by backwire? Can you explain the testing procedure a bit. I appreciate your Mercedes videos. I'm working on a 1991 300ce I've had in garbage for 7 years. Thanks. ddrayper@gmail.com
Darryl S. Draper Sr.I borrowed this information from the internet, you need two fine probes connected to a multimeter and connect them to pins 1&2, I was going to put a piece of wire on each pin then put the plug back on and connect the multimeter on the ends:-
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be careful so that the 2 contacts aren't
touching and shorting during the adjustment process. You'll need to back-probe
pins 1 and 2 (the top 2 pins) and then reinstall the electrical connector.
Normal
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font-size:10.0pt;
font-family:"Times New Roman";
mso-fareast-font-family:"Times New Roman";}
With a digital multimeter hooked up to read DC volts, start
the car and let it warm up to a steady warm idle. With the engine at idle
adjust the potentiometer body by pivoting it slightly until 0.70v (plus or
minus 0.10v) is obtained. This is a very fine adjustment and it doesn't take
much movement to make a big difference, so be sensitive and move it slowly and gently.
Then gently tighten the 4 screws in a cross pattern, being careful to not
change the adjustment while tightening. With the sensor tight and adjustment
within spec, shut the car off and install the black plastic screw covers on the
sensor and reinstall the air cleaner. The fine adjustment screw next to the
3-pin connector should not be used for adjustment as it is only for very minor
adjustments and should only be used in conjunction with a flow bench tester.
I hope this helps, regards, Paul.
GARAGE....