HDI and different ecu's

[DeeTurbo]

Hi all,

I was thinking about the quality in drive between the earlier HDI's and later ones in 306's.

Basically there is a big difference in the way the 2002 3 plug ecu engines sounds and drives compared to the 1 plug ecu in my 2000 dturbo.

I know some of the differences might be to do with the life the engines have had but I still think there is a big difference just because of the ecu in the cars.

The main things I feel is that the 2002 car feels a lot more refined, a lot quieter on idle, smoother and the revs hang for longer to make for a nicer gear change.

I did have an issue with the ecu in the 2000 car and found a 1999 ecu at the time and when swapping it over I noticed the screen on PP2k was different to how it was on the original ecu.

This made me think, if it would be possible to swap the ecu out for what was in the last 306's. If I got a unlocked three plug ecu and rewired or got an engine loom off a later car would it work?

I'll be getting an electronic fuel heater that comes on the later car to.

What do you guys think?

[Frosty]

Only thing i can think of is the later ones have the flap on the inlet elbow, not 100% sure what that actually does. Someone did tell me but i can't remember.

[DeeTurbo]

That doesn't matter. That's for the the egr system to help exhaust gasses in to the inlet. The car will run fine without it.

[cully]

body-ecu loom on the early hdi with an extra plug near the ecu
on the later 3 plug the ecu is connected to the engine loom

[Piggy]

Revs hanging is a MASSIVE bug bear of mine. Horrid feature of the edc15 mapping... Can't see any benefit

Afaik there are only minor map differences. I would think it's relative to the engine and injectors being healthy, no a map, for what difference you are describing

[Ruan]

There are a huge amount of differences between all versions of the 8v HDis software. The changes are mostly in the pilot start of injection and quantity and the main start of injection and EGR rates and the quantity by air mass (or "Smoke Map") is also changed quite a bit between versions. The later engines are calibrated to pass the Euro3 standard, notably the 3 plug ones (010592), this is why they have the doser valve to force more EGR, they also run nowhere near as much timing at low injection quantities (again, to reduce NOx).

I'm surprised you think that the earlier ones don't hang the revs for as long - for the record, the values which control this are identical between all 306 software revisions. It may be that the clutch switch has failed in the earlier one - the switch does affect how quickly the revs will fall after releasing the pedal.

You can easily change the software around so the earlier ECUs run close to the same values as what would be found on a later 3plug anyway, no need to change out the entire ECU.

[DeeTurbo]

Ah, I was thinking that there would be more processing power in the newer ecu's making them able to better control fuelling .

I've checked the clutch switch via PP2k on both cars and they both work correctly, I also thought it might be that. The other thing I thought it might have been was the throttle cable snagging so I replaced it.

The 2002 car has 072 injectors in and I think the 2000 are 062 or 044. Could it all be down to them for the better running? The injectors in the 2000 car are even on leak off test and the corrections values show even on pp2k.

[Ruan]

Between single/3 plugs there's very little difference other than the connectors on the bottom. The software structure is a bit different, but it's still the same EDC15C2 - all EDC15s use pretty much the same microcontroller and architecture. The main differences as mentioned is the increased EGR control with the doser valve.

The later car probably has less worn solenoids and internal valving - I suspect that the amount of fuel injected is out of calibration, thus injecting more at short durations - this is what causes the fabled injector "rattle", it's not the injectors themselves making the noise, it's due to an uncontrolled pilot/main injection causing the pressure rise to be too great, causing that characteristic rattle you hear.

[DeeTurbo]

I've had some 072 injectors that I need to install for a while.

I'll get them installed and report back.

Before installing used injectors do you ever remove the nozzles, clean them and the needle?

I normally use caustic soda (can of oven cleaner) to clean the carbon and residue off. Most the time I've taken the nozzles off I've noticed some brown discolouration along the needle.

[Ruan]

I've had some 072 injectors that I need to install for a while.

I'll get them installed and report back.

Before installing used injectors do you ever remove the nozzles, clean them and the needle?

I normally use caustic soda (can of oven cleaner) to clean the carbon and residue off. Most the time I've taken the nozzles off I've noticed some brown discolouration along the needle.

Personally wouldn't hit them with anything that caustic, at most I'd disassemble and ultrasonic the parts. Just make sure you don't mix up any of the parts from each injector.

[Uberderv]

I've had some 072 injectors that I need to install for a while.

I'll get them installed and report back.

Before installing used injectors do you ever remove the nozzles, clean them and the needle?

I normally use caustic soda (can of oven cleaner) to clean the carbon and residue off. Most the time I've taken the nozzles off I've noticed some brown discolouration along the needle.

  
I've cleaned them before using BBQ cleaner, it can restore the correct spray pattern but obviously can't do anything about wear.
  
I find the BBQ cleaner is thinner which is better for setting up a little rig to force it through the nozzle.

[Ruan]

In honesty as above, when they're worn, they're worn, no amount of cleaning will fix it. The early CRI1 injectors don't last very well and just because the cylinder correction quantities and leak-back between cylinders are acceptable, doesn't mean they've not got worn internals etc. Remember that the per cylinder correction quantities are only based upon the crank acceleration per cylinder that is increasing the overall engine speed more than the others, i.e. if all injectors were worn evenly and injecting too much - the ECU cannot correct for this because the control logic does not have a calibration of engine speed to injected quantity since this changes hugely depending on temperature and wear etc, it's highly variable, combined with the fact that the pilot quantity is not corrected per cylinder. Only later management systems with Lambda feedback (FMMA) can really compensate for the injectors being out of calibration.

New nozzles and calibration will make them absolutely perfect again, but as is predictable, it's not cheap. You can probably pick up some tested injectors for not a huge amount.

[damiank94]

Hmm. Some time ago I rode a 406 HDi 90 with siemens system. What surprises me most, that engine sounds different than my 307 RHS, namely more like a petrol engine. Does those 076 injectors for Bosch change how the engine sounds?