Injectors misbehaving but trying to understand the numbers

[Rhothgar]

Darren

Just for you:-



It is still uploading and will be about another 10 minutes.

EDIT. Check my old cold start videos and the fuel filter vids. Taken 13 years ago. Just made them public so you can see them.

[darbuck]

Hi Roger I checked all you have suggested the fuel regulator is 38% appx at idle from a previous diagnosis session but I have no idea if it's correct. The only injector data I get is microseconds correction and I am not sure what a good set should look like maybe someone else could give me this data off a similar car to mine or expected values.The only thing really in question at this stage is the injection system itself.so pump regulator fuel rail and injectors and of course the ECU. The injectors were always put in zipper bags when not in the car to try to protect them.
Edit
Fuel pressure moves around a good bit so I am not really concerned with the rail or the pump, I am leaning towards injectors/ECU drivers I have a spare ECU but I don't want to change any more parts until I can definitively say it is failed.

I might start a new thread to see if someone with the same type of car as me can give what a healthy injection system would show on diagbox.

[Rhothgar]

Not sure if my mate’s system will recognise a RoI car reg but feel free to PM me the VIN and when I am next up at my mate’s garage, I’ll try and find the data.

38% sounds too high for me. Your engine cannot be much different to mine but let’s assume for one minute that one of your injectors is stuck fully open? Then it would be draining the fuel rail, reducing pressure and causing the fuel pressure regulator to run overtime to keep the fuel rail pressure up to where it should be.

This is certainly one possibility and coupled with your injector figures may be that’s the next logical step.

Some testing workshops will charge you silly money to test the injectors though.

[darbuck]

Thanks Roger I have sent a pm thanks again

[Rhothgar]

Thanks Roger I have sent a pm thanks again

Got it. It will probably be next weekend when I go up.

Not sure if this would work or is sensible?

Pulling the connector of the injectors with the lower fuel rates. I imagine the OCR might drop slightly and then what would happen if the connector on those with the higher fuel rates were disconnected instead?

I imagine the engine would probably not start with one of those conditions and with the other the readings probably would not change much.

Not sure it would prove much because if some injectors are stuck open then the fuel will still be dispensed whether the electrical connector is connected or not. I suppose it is one way to prove an injector.

[Rhothgar]

General info here but you would think it would throw a fault code if it was injector issues.

Make of this what you will:-

[darbuck]

Thanks Roger, that's perfect. I can deactivate suspicious injectors via diagbox. I'll talk to you next weekend. Thanks again

[Rhothgar]

OK. Darren. So your injector flow correction is measured in time rather than flow but if you look at mine cylinders 1 and 2 are approximately equal but cancel each other out whilst 3 and 4 are also roughly equal but cancel each other out. I would expect your figures to follow the same pattern approx.

Isn't there something called 3rd piston deactivation on your car? There is on mine and I've never truly tried to understand where it does. It is odd that your figures do not cancel each other out.

[darbuck]

Yes that's what I'm getting at my understanding is based on fuel trims not the same I know but realistically if two cylinders are 10 then the other two should be -10 not a great example but I think you know what I mean. Essentially you either have open or closed at a predetermined time in the combustion cycle. 3 of my injectors are continuously showing values in the 140 range these values don't change at all two are negative one is positive and the last one fluctuates constantly between 50 and 70 at idle which is what I would expect all of them to do.it says it has injectors controlled but I think it's trying to compensate for one or two injectors possibly 3 over firing. It'definitely misfires you can hear the exhaust puttering and the fact there's raw diesel going out the exhaust side of the turbo says I have an injection control issue not necessarily injectors possibly controller.

Edit
The fact it's not reporting a fault tells me there is more going on than meets the eye I don't think the ECU thinks there is a problem.This is concerning but I am not 100% sure how to verify it.

From Google as far as I can make out injectors should be around 3 to 5 us but I have factorial increases on this. I think if I can get this I should have some idea of how bad it is.

[Rhothgar]

I take it you don't have a Lexia because presumably if you did it would then show the injector flow correction in the same format.

I had this issue trying to work out mg/cp to g/s for the airflow meter on my Xantia with some complex maths so it would be easier like you said already if someone has the same engine and could provide sample data for their engine.

The one issue I have is if you did have the engine running smoothly at one point why after a turbo change has it all gone to pot?

Worth starting another thread I guess so find out if yours is an RHR20TEDVCEDU or whatever the exact engine code is and ask for someone with the same engine code. I'd have thought between RHR engines and even RHZ engines there will not be much difference because at the end of the day all these cars of the same size with the same capacity RH engine will run largely identical with approximately the same fuel efficiency at idle especially when you consider they will be similar MPG's at 56mph with slightly differing aerodynamics. The point I am getting at is at idle there are no such resistances.

I'll see what I can find. It's a shame I haven't got a Diagbox. I was thinking of getting a replacement Lexia unit ie the latest gold chip one but have been more tempted towards getting a Kingbolen K10.

My mate has several different pieces of diagnostic kit but I'll have a look at his Bosch KTS unit which may well have the right data on. In the meantime, let me know the exact ECU your vehicle has. Is it a Bosch EDC15 or 16 or perhaps a Siemens?

[darbuck]

I have diagbox and this is the format it gives for this engine. I think the turbo was only part of the issue and I think it was the injectors that took out the turbo. As I said it ran better but not perfect as I said it was smoking. I think sitting just set off the injectors I have pulled them and tried different ones and it wouldn't even start so put it back the way it was. It's smoking like a steam train at the manifold end as well so significant injector pressure constantly leaking. Running it like this for any length of time would destroy the engine.

I have started a new thread to try to get traction on this

[MattBLancs]

Lots of good info + discussion here.

I can just clear one question up:

3rd piston deactivation: this isn't the third piston of the engine, but of the (high pressure) piston pump inside the engine driven common rail fuel pump.

Below a certain engine rpm (3200 rpm from memory) the pump can flow more than enough fuel with only two of its little pistons actually pumping fuel / generating pressure.

So PSA / Bosch in their wisdom decided to allow a solenoid valve to open and discharge any pressure built by the third piston until the fuel demand (beyond 3200) needed the extra flow.

Some folks used to unplug the deactivation solenoid connector (so it's wasn't ever deactivated) - I think this was reckoned to cure a rattle some HDi suffered with (a rattle that curred itself at 3200)

I think the deactivation was intended to be an efficiency measure (less pumping fuel just to have it discharged back to the return line by the valve on the common rail that is regulating the rail pressure)

[darbuck]

Thanks for that Matt very interesting. Do you know how the microseconds correlate with fuel flow rate you may have said this before but I cant find it.

[Rhothgar]

Great lesson there. Thanks Matt. Good to know.

[MattBLancs]

Thanks for that Matt very interesting. Do you know how the microseconds correlate with fuel flow rate you may have said this before but I cant find it.

Sorry, no I don't know. If my C5 was in running condition I'd try and get you time DiagBox live data to compare, if I can getting going at the weekend I will do so. (It's the 2.2 so not direct comparison unfortunately)