Timing and injection pump talk

[CoyoteStarfish]

There are a few things I need advice on, namely de-computerizing the M21 injection pump and calibrating it for non-computerized use. This may turn into a write-up for injection pump service and timing related subjects.

1)Properly timing a M21 with the use of a dial indicator for non-computerized operation
2)Replacement of the sensor-injector
3)Whether or not the injection line to the sensor-injector needs to be modified
4)Are there separate timing solenoids for cold start advance and computerized timing correction?

Other issues:
A)Dial indicators and thread adapters. There are a lot out there, which ones are the right ones?
B)If I were to replace the cam-plate in my IP with a large lift one as discussed here before, would that change the specs?
C)Are any other VE pumps compatible with our motors? A spare to bench-build would be nice..
D)Rebuilding a Bosch VE pump, how difficult is it and what special tools do you need?

More to come..

[Frybrid 524td]

3)Whether or not the injection line to the sensor-injector needs to be modified
4)Are there separate timing solenoids for cold start advance and computerized timing correction?
Other issues:
A)Dial indicators and thread adapters. There are a lot out there, which ones are the right ones?
D)Rebuilding a Bosch VE pump, how difficult is it and what special tools do you need?

3)The sensor injector is taller than the other injectors so you'd need to bend the line to span the gap that will be created if you use a non-sensor injector in #4.
4)I don't believe there is any computerized timing correction. Check the VE manuals in the 524td sticky.
A)I got the one from Samstag. It fits.
D) I've pulled apart my spare IP just to figure it out and it isn't too hard to rebuild. There are some pretty comprehensive step-by-steps out there. I believe the one I used was on the Cummins Forum.

[CoyoteStarfish]

Yeah... there is some sort of computerized timing crap going on with the VE on these motors.


Ever hear that buzzing under the hood just before you start it or if you leave the key in the run position? That is the timing advance solenoid in the IP oscillating due to signals coming from the ECU.

The sensor injector (needle lift sensor I think?), a temp sensor and a crank position sensor.. walk into a bar.

No seriously, those sensors factor into some equation in the ECU which is output in the form of an oscillating frequency.. that output changes the IPs timing slightly to compensate for RPM changes, cold starts. The needle lift sensor triggers at the moment of injection so the ECU can get a real idea of when the injector is firing and how adjust the timing within its range.

If you don't get that 'buzz' under the hood, odds are your sensor or wiring is shot. I think the temp sensor (not temp gauge sensor) going out will do it too.

If it DOES buzz, try unplugging the sensor cable while the motor is running and listen to the change in the motor.

[Frybrid 524td]

Yeah, I get the buzz and the car runs rougher with the injector sensor unplugged.

Out of curiosity, why do you want to delete all traces of engine electronics yet add built-in cabin electronics like navigation as you mentioned in your other thread?

[CoyoteStarfish]

I'm a "3 wire engine" sorta guy, ignition power, oil pressure, coolant temp. 4 wires if you want to count the starter, and 5 if you want to include the glowplug trigger. It's not that I hate technology or anything, I simply dislike being dependent on it. If my in-dash NAV or whatever dies, I can still drive the car. If my ECU fails, at worst it will run a bit rough. In a modern car if anything computer-related goes out you are lucky if you can 'limp' the car to a dealer and pay beaucoup-bucks hooking it up to their special diagnostic machines since OBDII is starting to get a bit useless in this day and age. Don't even think about touching an Audi or VW without a VAGCOM cable and software.

There are many technological "helpers" one could add to a car, but I do not want to be dependent on them. And that is why I want my engine to be full mechanical.