Good Afternoon
I know this is way too long but describing everything that happened without understanding it is really difficult. Even my observations probably are wrong or have a simple explanation.
I’ll try to remember all of my observations and conclusions when I examined the rack on my pump.
When I removed the bolt in the photo that I posted above in reply #9 a few days ago, I was surprised to find it wasn’t a bolt but a threaded cap with a hex, which, of course, you all knew. Probably expensive to make, which I suppose is why they eventually changed it to a rubber plug. My pump is a PES 6KL70/120RL11 in a late 1966 Italian version 230SL manual transmission car.
I also discovered that the threaded hole in my rack is not an M4, but probably an M5. An M4 screw worked by just side loading it a little.
When I removed the cap, the end of the rack was flush with the end of the threaded tube within which it slides and onto which the cap screws. That rack position is shown in photo #1.
From that position, when I pulled on the screw, the rack pulled out about 5 or 6 mm, but was stopped by something internal to the pump. That position is shown in the photo #2. That protrusion distance agrees with the design of the screw-on cap, which provides just about that much space for the rack to protrude from the tube within which it slides. As I pulled out the rack with the screw, I could feel resistance of two types. The pull out effort was resisted by the progressive feel of a light spring as well as a light smooth and constant resistance that felt like a slip fit with a thick lubricant. A few months ago, I filled the injection pump with Castrol GTX 10W30 engine oil before ever turning over the engine. NOTE: I used Castrol GTX 10W40 for the engine initial fill and for priming the engine. My pump oil supply is self-contained and separate from the engine. I was afraid the 10W40 engine oil would be too heavy for the injection pump. When I released the tension on the screw, the rack returned to its initial position smoothly by the force of the spring(s) that resisted its forward movement.(photo #1).
Once again, from the initial rack position, I inserted the screw and pushed the rack farther into the IP housing. And again, I could feel the “drag” of a heavily lubricated slip fit of the rack in its hole as well as the progressive resistance of a spring. The rearward travel of the rack from photo #1 position was limited internally to about 12 or 13 mm. This position is shown in photo #3. It was obvious to me that the normal (for the moment) position of the rack is with its end flush with the tube within which it slides, and that that any movement from that position is resisted by spring(s). When the rearward force on the screw was released, the rack moved smoothly back to its photo #1 position by the force of the spring(s) that resisted its rearward movement.
Thus far, all rack movements were initiated manually by the use of the machine screw. Since none of the previous rack movements had any effect on the IP throttle lever, I checked to evaluate the effect of the IP throttle lever movements on the rack movements, if any.
With the rack in photo #1 position (apparently the normal, for the moment, position), when I opened the IP throttle lever (without any linkage connected) from its closed throttle stop position to its Wide Open Throttle position, the rack moved smoothly and continuously from the photo #1 position to about one mm short of the photo #2 position. Without releasing the IP throttle lever, and with the use of the screw, it was possible to pull the rack that extra millimeter farther forward to the photo #2 position. But when the screw was released, the spring forced it back to the photo #2 minus 1 mm position achieved with the IP throttle lever.
NOTE: No relationship test is valid without evaluating the relationship forward and backwards, so I continued the backward test.
When I smoothly and slowly allowed the IP throttle lever to return from its Wide Open Throttle position to its closed throttle position, the IP throttle lever, driven by the torque of a return spring, moved relatively smoothly back to ½ throttle where it hung up, as I have discussed in a previous post. Strangely, to me, the rack did not follow the movement, but remained at the photo #2 minus 1 mm position. Everything was hung up at that condition. When I exerted enough return spring type force to un-stick the IP throttle lever, I was able to move it relatively smoothly back to a ¼ throttle position, but the rack position did not change. It still stayed at the photo #2 minus 1 mm position. When I exerted slightly more closing effort to the IP throttle lever, it “draggingly” returned to its closed throttle position against its closed throttle stop. Amazingly, to me, during that last ¼ throttle movement of the IP throttle lever, it “dragged” the rack from the photo #2 minus 1 mm position all the way back to the photo #1 position. This is the series of movements that describe the relationship that, in my previous post, I referred to as French Mathematician René Thom’s Catastrophe Theory (in English, this time). I have included a graph that describes the discontinuous function of the IP Throttle Lever/IP Rack relationship. The graph is 100% IP throttle lever travel large and approximately 100% rack position tall. The fact that it can be called a catastrophe theory type graph is not important. The important thing is that the behavior is difficult to understand in that it behaves differently going up than coming down. I assume that the entire lower two thirds of the graph is controlled to some extent by the Barometric Compensator, the notched screw on the back of the IP and the Warm Running Device (assuming what is shown about the rack is what it is supposed to be). Maybe the whole relationship is shifted up or down by those devices. My purpose here is to describe something that I don’t understand so completely that those of you who know how these pumps work can see what might be wrong, if there is something wrong.
Anyway, I hope what is here helps you to help me. I’m completely baffled as to where the fuel is coming from – if it’s fuel and not antifreeze as I mentioned a couple of days ago. I'm hoping you can see the problem and it's just that I haven't yet adjusted the WRD and BC yet, because I have not yet found a leak among the other Cold Start Devices.
Thanks for any insights you might provide.
Tom Kizer
