injection Timing control solenoid purpose

Does your Mitsubishi L300 make a strange noise? Need wheel alignment specs?
weelsey
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injection Timing control solenoid purpose

Postby weelsey » Tue Nov 14, 2017 7:45 am

injectiontimingcontrol.jpg
grab of l300 fuel injection systems manual
injectiontimingcontrol.jpg (272.46 KiB) Viewed 96 times

What do you suppose this solenoid does? I'm looking at pumps, concerned something may have changed after I had the pump cover off to replace the top seal, judging by the exhausted fuel under load.
The purpose of the throttle position sensor is a mystery yet on my manual trans 1990, and I'm wondering if both this solenoid and the TPS are there simply to replace the cold starting timing advance done mechanicaly on previous models and other ve type pumps. And not to time the injection, which is done mechanically with governor. Any thoughts?

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injection Timing control solenoid purpose

Postby Growlerbearnz » Tue Nov 14, 2017 1:16 pm

weelsey wrote:What do you suppose this solenoid does?
Weelll... that section of workshop manual is from an L200, and not entirely applicable to our vans. You shouldn't have one of those- and I want photos if you do! On an L200 that solenoid changes the pump's internal pressure, which changes the injection timing. It's used to retard the timing under high-load situations to allow more boost and power. It was an attempt to get more control and power out of an old pump without having to spend the money on an electronically-controlled unit (and all the wiring and ECUs).

Not your pump:
VE-Fancy.JPG
VE-Fancy.JPG (86.33 KiB) Viewed 88 times


weelsey wrote:...concerned something may have changed after I had the pump cover off to replace the top seal, judging by the exhausted fuel under load.
As in, black smoke out the exhaust? You probably put the control lever back on one spline out. Did you have to change your idle speed screw a lot to get it to idle at 750rpm again? (and did you change any other setting screws?)

weelsey wrote:The purpose of the throttle position sensor is a mystery yet on my manual trans 1990, and I'm wondering if both this solenoid and the TPS are there simply to replace the cold starting timing advance done mechanically on previous models and other VE type pumps. And not to time the injection, which is done mechanically with governor. Any thoughts?


The TPS connects to the glow plug ECU, and cycles your glow plugs more if you start driving while the engine's cold. The ECU also controls Exhaust Gas Recirculation, which needs to know the throttle opening.

Normal L300s don't have cold start timing advance, and the rest of the timing is still all done mechanically. On the L200 pump the solenoid is only capable of retarding the timing, to advance the timing for cold start there's still the usual electromechanical gubbins hanging off the underside of the pump. (On a regular pump that area is covered by a blanking plate).
Nothing says "poor workmanship" more than wrinkles in the duct tape.

weelsey
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injection Timing control solenoid purpose

Postby weelsey » Tue Nov 14, 2017 2:24 pm

Thanks! Clearly not one of these: https://www.youtube.com/watch?v=pEBJNv1dYwI
Growlerbearnz wrote:
weelsey wrote:What do you suppose this solenoid does?
Weelll... that section of workshop manual is from an L200, and not entirely applicable to our vans. You shouldn't have one of those- and I want photos if you do! On an L200 that solenoid changes the pump's internal pressure, which changes the injection timing. It's used to retard the timing under high-load situations to allow more boost and power. It was an attempt to get more control and power out of an old pump without having to spend the money on an electronically-controlled unit (and all the wiring and ECUs).

Not your pump:
VE-Fancy.JPG

Ah, yes, I see there is in this image the advance mechanism on the pump, something not on our delicas. nor the return solenoid thingy from the in-between times of pump evolution. I missed that. Yet there is this electrical plug on the engine side (not on the fuel return) also wired up to something. (Pictured below)

weelsey wrote:...concerned something may have changed after I had the pump cover off to replace the top seal, judging by the exhausted fuel under load.
As in, black smoke out the exhaust? You probably put the control lever back on one spline out. Did you have to change your idle speed screw a lot to get it to idle at 750rpm again? (and did you change any other setting screws?)

Oh, you think? I had re-position it thrice, and on the third it started, idled, and performed rather normally without any other adjustments.

weelsey wrote:The purpose of the throttle position sensor is a mystery yet on my manual trans 1990, and I'm wondering if both this solenoid and the TPS are there simply to replace the cold starting timing advance done mechanically on previous models and other VE type pumps. And not to time the injection, which is done mechanically with governor. Any thoughts?


The TPS connects to the glow plug ECU, and cycles your glow plugs more if you start driving while the engine's cold. The ECU also controls Exhaust Gas Recirculation, which needs to know the throttle opening.

Oh, my! There is a steep learning curve for me to perhaps ascend. It has blanking plates. may be more mods. may be adjustments I am not aware of like washers under the actuator, other pump things. I am used to NA perkins diesel rangers; and electronic VWs, and nothing in between!

Normal L300s don't have cold start timing advance, and the rest of the timing is still all done mechanically. On the L200 pump the solenoid is only capable of retarding the timing, to advance the timing for cold start there's still the usual electromechanical gubbins hanging off the underside of the pump. (On a regular pump that area is covered by a blanking plate).


Yeah, and we don't have that on this rig. but there is that electrical thing ....
IMG_1251.JPG
IMG_1251.JPG (699.38 KiB) Viewed 80 times

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injection Timing control solenoid purpose

Postby Growlerbearnz » Tue Nov 14, 2017 4:45 pm

weelsey wrote:Ah, yes, I see there is in this image the advance mechanism on the pump, something not on our delicas. nor the return solenoid thingy from the in-between times of pump evolution. I missed that. Yet there is this electrical plug on the engine side (not on the fuel return) also wired up to something.


What you have there is the rev counter engine speed pickup. It's a hall effect sensor that watches the teeth on the injection pump governor drive gear.

weelsey wrote:Oh, you think? I had re-position it thrice, and on the third it started, idled, and performed rather normally without any other adjustments.


Hmm. If it eventually idled normally without having to mess with the idle speed screw, then the arm is in the right place. I also see your full-load adjustment screw still has the anti-tamper cover, so that's good. From memory the springy linkage under the top cover is a bit tricky to reassemble, is it possible it's catching on something?

The spring under the boost compensator diaphragm will also give you black smoke if it's too weak or the adjustment is wound down too far.
Nothing says "poor workmanship" more than wrinkles in the duct tape.

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injection Timing control solenoid purpose

Postby weelsey » Tue Nov 14, 2017 8:00 pm

Thank-you, thank-you, Growlerbeans! I'm relaxing some knowing now what the wires do.

Perhaps it is catching on something and I need to revisit that pump work. It is very tricky to replace the cap especially if you are like me and forget all about needing to pull the adjusting lever forward to clear the full load screw. the governor spring/idle spring assembly came off of it's lever a time or two, even though the pump on the bench (I used for practice) seemed difficult to dislodge. There is some kind of retainer there that was not retaining as well on the vehicle's pump, I speculated. And proceeded to reassemble.

I don't really think it's possible it could have gone back together incorrectly configured and still have operated. Do you think the compensation business of it could have changed from below as a result of the governor cap fiddling? It's hard to know I guess. May be I stretched the governor springs.

I didn't even get the leaks in the process. The main shaft seal and the throttle shaft seals have made up much of the drying effect of rplacing the cap seal. I'm going to need to have another look soon. Again, thanks for what you do, Growlerbeans!

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injection Timing control solenoid purpose

Postby Growlerbearnz » Tue Nov 14, 2017 9:21 pm

weelsey wrote:I don't really think it's possible it could have gone back together incorrectly configured and still have operated.

It seems like a long shot to me too. It's a fairly complicated mechanism and really only goes together one way. (picture found on teh internets. I recall our pumps being a bit more complex in there)
91.jpg
91.jpg (8.16 KiB) Viewed 57 times


weelsey wrote:Do you think the compensation business of it could have changed from below as a result of the governor cap fiddling?


Not from below, but I did notice in your photo the cap was off. If the diaphragm is rotated it changes the fuelling, and the same with the spring seat (the serrated wheel thing under the spring). All of that can be checked without pulling the whole pump though:

Remove the compensator cover, then remove the diaphragm and control rod. While looking down the control rod hole, move the throttle lever. A small pin should poke out into the control rod bore. The small pin should move freely. You'll need to push the pin back in before you can reinstall the control rod. That pin can get sticky, and can jam the compensator in "full boost" mode and allow more fuel than needed.

The control rod under the diaphragm has an offset cone at the end- you can adjust how much fuel is added under boost by rotating the diaphragm to move the cone towards (less fuel) or away (more fuel) from the pin. The cone will have a wear mark on it where it's been pushing on the pin- reinstall the diaphragm so the wear mark faces the pin.

The spring seat is a bit trickier, and I don't have an unmolested one to measure. If you didn't move it it's likely fine. If you did change it, then wind it up a bit at a time until the smoke goes away (or you find an acceptable balance between power and smoke)

Good luck!
Nothing says "poor workmanship" more than wrinkles in the duct tape.

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injection Timing control solenoid purpose

Postby weelsey » Wed Nov 15, 2017 8:17 am

Here is a picture of our pump cover underside:
IMG_1254.JPG
IMG_1254.JPG (635.27 KiB) Viewed 44 times


I agree it would be hard to put it together incorrectly. but perhaps a part could be missing, or dropped in the pump. egad! I realize now I don't remember seeing a washer on the throttle shaft of the van's pump, shown on the open pump on the bench.
IMG_1255.JPG
IMG_1255.JPG (690.8 KiB) Viewed 44 times
hmmm. This is not making me relax.

I did not have the compensator cap off of the pump in the van. I appreciate you sharing your knowledge on the compensator adjustments. The one on the bench appears unmolested, and it appears a good option may be to put energy into the spare pump send it to my pump guy and replace the original.

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injection Timing control solenoid purpose

Postby weelsey » Wed Nov 15, 2017 12:43 pm

I put the governor spring from the spare, less worn looking pump in. Found I needed to adjust idle as no lever tooth did the trick. In hindsight, i could have also replaced the governor cap, compensator settings and all with it. The spare looks less used, perhaps not even tinkered with. I'm going for a test drive now to see what if anything the different spring assembly does. Having to turn up the idle would perhaps also mean there would be less fuel in other throttle position ??

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injection Timing control solenoid purpose

Postby Growlerbearnz » Wed Nov 15, 2017 1:41 pm

weelsey wrote:I did not have the compensator cap off of the pump in the van.

Ah, that's the spare injection pump in the photo. Excellent.

weelsey wrote:Having to turn up the idle would perhaps also mean there would be less fuel in other throttle position ??

Absolutely. Less travel of the throttle arm means less fuel at full throttle and high revs. If it doesn't move far enough you can end up reducing your maximum engine speed, but there's an adjustable full-throttle stopper to fix that.

The other thing that occurs to me is that the pump timing might be out, though I expect you reinstalled the pump at the same angle as it came out. Massively retarded pump timing could create more smoke, but it would also make the engine really sluggish and I suspect you would have noticed that.
Nothing says "poor workmanship" more than wrinkles in the duct tape.

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injection Timing control solenoid purpose

Postby weelsey » Thu Nov 16, 2017 8:02 am

yahoo! I need to be on the pedal at highway speeds now, but it appears the over-fuelling has reduced. it's not lacking power and it may even start better. And it feels smoother somehow with less gushing hiss from the exhaust. tho perhaps I have simply cut the full throttle short, and I may want to adjust the full speed.

Growlerbearnz wrote:Less travel of the throttle arm means less fuel at full throttle and high revs.

If it was a tooth backward and I put down the idle, it would be giving more fuel I suppose. The linkages in the governor spring assembly I replaced were much less sloppy then the one removed, which is why I imagine there was not a perfect position.

I'll give it a go like this for a while. This is perhaps a temporary sort of fix but if it gets me near 10l/100km it'll be swell.

Growlerbearnz wrote:it would also make the engine really sluggish and I suspect you would have noticed that.

It didn't have trouble with getting up to speed. I haven't removed the pump and so the timing should not have changed from previously, which I hope is decent.

So on to other things, like trying to mount my spare tire on the back, somehow, in preparation for a big test of my soldered rad and pump tinkering.


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