Dude you need to get some rest and recuperation, you're working way too hard! Thank you for your selfless efforts to bring us a wealth of detailed information from your many years of learned experience. 🙏😍
Another great video and to it, for the benefit of those not familiar with basic operating principals of Kontinuous Jetronic Injection, I'd like to add a bit of clarification… At +/- 1:40 Pierre mentions that this regulator affects pressure to the injectors. I believe he was using professional shorthand for a somewhat more involved process, the description of which would not fit within the confines of a short video format. So here then is the longhand version. (This is really my way of getting Pierre to consider making longer videos, not only as relates to automotive repair but to include more Philosophy... Critiques... Editorials... Pierre eating a hamburger, etc.): Pressure to the injectors is in fact constant and is determined by the high pressure fuel pump. In K-Jet, fuel plays 3 roles: 1) facilitating combustion. 2) Cooling the wet-cell high pressure fuel pump. 3) Acting as a hydraulic fluid… You read that correctly. The regulator that is the subject of this video affects ONLY the fuel pressure that hydraulically opposes movement of the fuel metering plunger inside the fuel distributor, thereby varying exposure of the fuel metering slots that deliver fuel to each injector line. This opposing fuel pressure is called the “control pressure” and the other name for the “warm-up regulator” is the “control pressure regulator”. The fuel metering plunger bears against the pivoting arm that secures the air flow sensor plate. Incoming air exerts a force on the plate which causes the arm to pivot and the plunger to move. This pivoting movement is opposed by the plunger to a greater or lesser extent as determined by the control pressure (hydraulic pressure of fuel). Therefore, air/fuel ratio is varied as a function of the control pressure. That in turn is varied by the control pressure regulator (warm-up regulator) as Pierre explained very well, i.e. via heat/deflection of the bimetallic strip + intake manifold pressure which we typically call vacuum. Bonus section: On post-1980 US market, pre-KE-Jetronic cars, an O² sensor (“Lambda Probe”) was added to monitor air/fuel ratio. Control pressure was then further fine tuned based on info relayed by the O² sensor. That fine tuning was done via a device called a frequency valve. This was essentially an electronically modulated fuel valve (pulse width modulated) that, when open, vented control pressure in very small, precisely controlled quantities (depending on frequency and/or duration of pulses). K-Jet is a very simple form of mechanical fuel injection with a few supporting electrical and electromechanical components. The things that fail are those items whose description includes the words “electric” and “electro”. Feel free to correct me if I'm wrong or have left anything out.
I I’ve been working on Mercedes for the past 27 years. Currently I have two old Mercedes to sell a 1979 450 SEL & a 1980 300TD diesel. I want to find them good homes . I have too many other projects going on at this time I’m in Birmingham Ala.
Love the opening monologue. I have a pair of '87s, 560SEL and 560SEC, and was glad to find out I don't have the warm-up regulator. I have a cold start injector and fuel pressure regulator, but not the warm-up thing. Cool. I'm subscribed and will catch you on the next one.
Thank you for producing this content Pierre. I have started working on a family-owned '85 380SL that has clearly been in the hands of those who would have benefitted from some schooling on classic Mercedes maintenance. I have a lot to learn and your videos have been very helpful. I am hopeful to bring the car down to you in the next few months (from St Augustine) for a thorough inspection. In the meantime, I want to get it running more reliably before I head down. I am overhauling the WUR and have a question. I removed the five filter screens and am wondering if I should bother reinstalling them or leave them out. I thought in later models they were deleted but wanted to get your thoughts. They were soaked in acetone and appear reasonably clean, though they have exceptionally fine mesh making it tricky to evaluate. Thanks in advance and looking forward to meeting you soon.
Where can I find a warm up regulator for a 500SEL 1984 us Spec, I'm having very serious whole engine shaking at start up till 2000 rpm or so, so thinking that might be the problem. Should I have changed the 02 sensor too? No black smoke, just the shaking.
Dude you need to get some rest and recuperation, you're working way too hard!
Thank you for your selfless efforts to bring us a wealth of detailed information from your many years of learned experience. 🙏😍
Agree!!!
👍
Another great video and to it, for the benefit of those not familiar with basic operating principals of Kontinuous Jetronic Injection, I'd like to add a bit of clarification… At +/- 1:40 Pierre mentions that this regulator affects pressure to the injectors. I believe he was using professional shorthand for a somewhat more involved process, the description of which would not fit within the confines of a short video format. So here then is the longhand version. (This is really my way of getting Pierre to consider making longer videos, not only as relates to automotive repair but to include more Philosophy... Critiques... Editorials... Pierre eating a hamburger, etc.):
Pressure to the injectors is in fact constant and is determined by the high pressure fuel pump.
In K-Jet, fuel plays 3 roles: 1) facilitating combustion. 2) Cooling the wet-cell high pressure fuel pump. 3) Acting as a hydraulic fluid… You read that correctly.
The regulator that is the subject of this video affects ONLY the fuel pressure that hydraulically opposes movement of the fuel metering plunger inside the fuel distributor, thereby varying exposure of the fuel metering slots that deliver fuel to each injector line. This opposing fuel pressure is called the “control pressure” and the other name for the “warm-up regulator” is the “control pressure regulator”.
The fuel metering plunger bears against the pivoting arm that secures the air flow sensor plate. Incoming air exerts a force on the plate which causes the arm to pivot and the plunger to move. This pivoting movement is opposed by the plunger to a greater or lesser extent as determined by the control pressure (hydraulic pressure of fuel). Therefore, air/fuel ratio is varied as a function of the control pressure. That in turn is varied by the control pressure regulator (warm-up regulator) as Pierre explained very well, i.e. via heat/deflection of the bimetallic strip + intake manifold pressure which we typically call vacuum.
Bonus section: On post-1980 US market, pre-KE-Jetronic cars, an O² sensor (“Lambda Probe”) was added to monitor air/fuel ratio. Control pressure was then further fine tuned based on info relayed by the O² sensor. That fine tuning was done via a device called a frequency valve. This was essentially an electronically modulated fuel valve (pulse width modulated) that, when open, vented control pressure in very small, precisely controlled quantities (depending on frequency and/or duration of pulses).
K-Jet is a very simple form of mechanical fuel injection with a few supporting electrical and electromechanical components. The things that fail are those items whose description includes the words “electric” and “electro”.
Feel free to correct me if I'm wrong or have left anything out.
I I’ve been working on Mercedes for the past 27 years. Currently I have two old Mercedes to sell a 1979 450 SEL & a 1980 300TD diesel. I want to find them good homes . I have too many other projects going on at this time I’m in Birmingham Ala.
Your insights are gold dust for a DIYer 280CE owner like me who's currently running fuel system diagnostics, THANK YOU! Sharing in progress....
Love the opening monologue. I have a pair of '87s, 560SEL and 560SEC, and was glad to find out I don't have the warm-up regulator. I have a cold start injector and fuel pressure regulator, but not the warm-up thing. Cool. I'm subscribed and will catch you on the next one.
Thank you for producing this content Pierre. I have started working on a family-owned '85 380SL that has clearly been in the hands of those who would have benefitted from some schooling on classic Mercedes maintenance. I have a lot to learn and your videos have been very helpful. I am hopeful to bring the car down to you in the next few months (from St Augustine) for a thorough inspection. In the meantime, I want to get it running more reliably before I head down. I am overhauling the WUR and have a question. I removed the five filter screens and am wondering if I should bother reinstalling them or leave them out. I thought in later models they were deleted but wanted to get your thoughts. They were soaked in acetone and appear reasonably clean, though they have exceptionally fine mesh making it tricky to evaluate. Thanks in advance and looking forward to meeting you soon.
I have this WUR on my 77 280e South Africa 🇿🇦 build and it’s a challenge. The car was sat for 14 years. Engine rebuild therefore it runs now .
I specialize on 1955 to 1985 Mercedes model parts in SA and have plenty new/used/rebuilt K jet parts available if you need anything
Where can I find a warm up regulator for a 500SEL 1984 us Spec, I'm having very serious whole engine shaking at start up till 2000 rpm or so, so thinking that might be the problem. Should I have changed the 02 sensor too? No black smoke, just the shaking.
love it - i prefer to watch you than that guy in the trenchcoat selling junky kits
I’ll stifle my yawns if you stifle yours.
obsess new old stock oem
Take a break, you getting to grubby