What injection timing are you running?

[vtin]

I know there are various factory specs for the 4M40 injection timing advance. For my Pajero the spec is 12deg ATDC with 1mm plunger lift. I believe that this is the spec for the mechanically injected 4M40 with EGR. Just curious what kinds of advance have you set and what results you've had. I just set the timing to factory and while the engine is quiet, it is also sluggish. Not super happy with this setting, I will try to experiment with a bit more advance in the coming weeks.

[vtin]

Going to advance the timing a degree this weekend. With the stock timing the cold starts have too cold a combustion resulting in light blue smoke/fuel out the exhaust. There is a constant light blue haze at load from the exhaust. Going to advance timing in 1 degree increments until I'm happy with a balance between power, economy and smooth running.

Also my glow/egr ecu is fried. The glow/egr ecu also controls a solenoid on the injector pump which is called "overflow restriction valve". According to some wiring diagrams that i've been looking at this solenoid is also controlled by the glow/egr ecu. The valve is responsible for controlling internal pump pressure (and conversely hydraulic timing advance) as well as recirculating fuel back to the tank (maybe for cooling). I'm interested in it's ability to raise internal pump pressure and thereby advance injection timing.

I think the solenoid advances timing during off boost/egr operation (idle-2000 rpm). Can anyone confirm or disprove this hypothesis? Currently I'm experiencing retarded timing like symptoms while in this rpm range.

I have wired this solenoid to a switch in the cab so I can control it manually to experiment how it effects running. So far I am able to nearly remove the symptoms of retardation during the idle-2000 rpm range. If I advance injection timing further, by setting plunger lift at 1mm at say 11deg ATDC or earlier the retardation in off boost can be totally removed.

I think I will try to wire up a vacuum switch to control the solenoid, turning it off off boost. Or maybe I can use the boost signal.... Has anyone done this, does vacuum rise proportionately to rpm?

Thanks for reading my drivel!

[vtin]

Activating this solenoid also helps a lot at cold start and running. Advanced timing via internal pressure.

I was also debating to braze the second relief hole shut on the solenoid, thereby always keeping it in closed position.

Here is a photo of ze valve in question (green cap):

[Big-Bird]

you should attend the Mitsu tech nite at my place this Saturday afternoon. April 25th.

I am working to have the TV out in the garae if there is another Flames/Canucks game to watch.

We have 6 different JDM's making an appearance. Mostly Mitsu's but a few Toyota VX 4x4's as well.

Your engine tunine info could be a good subject.

PM me for the address

[vtin]

Wast able to make the tech session, but if there is another one I would love to take part. Please let me know.

Instead I spent the time tuning in the garage. I couldn't drive with the stock timing, it was much too retarded to get good power/consumption. As I mentioned before I set the timing to the stock (underhood) spec of 12*ATDC, the result was poor starts, low power, lower economy and generally incomplete/cool combustion. Not sure why the stock timing would give this... my hypothesis is it's due to my removing the EGR system as well as the 1,100 m elevation in Calgary. Looking at the various factory specs of 4M40 timing the non-EGR modles all have timing 9* ATDC and earlier.

I advanced the timing to 9 degrees ATDC. So now I have 1mm plugner lift at 9*ATDC. Running is noticeably noisier, but combustion is nice and clean and power is good, less lugging at 2000RPM/boost threshold and really solid top end power. I don't mind the noise as its not that intense and since the timing is "not as advanced" as some run on their diesels of similar size and class, I am not worried about high EGTs. (I haven't installed a probe yet)

Also I ended up leaving that overflow restriction solenoid as it was, because the misfires totally stopped with the 9* timing. Just have that manual switch for it to raise internal pressure at cold start. I don't see a reason to mess with it now.

Does anyone know if the VE pumps have a port off which we can measure internal pressure. I'd like to install a gauge to measure this to make sure that the pressure curve is within spec through the RPM range.