Injectors misbehaving but trying to understand the numbers

[Rhothgar]

It's glow plug on these, I think you might be right. Leave it alone put it back together and see how I get on. If there's a problem then maybe do one I suppose. I have a scope with the amp clamp that you can do a relative compression test with, but I haven't figured out how to do it. I'll have to watch a few more videos on it. It's non invasive. But I smoke tested the engine before and didn't find any leaks from the cylinders so probably just over thinking again.

I'll have to practice the relative test I think just for peace of mind. It measures amps as a function of cylinder pressure essentially.

No need to remove glow plugs to test them if you can graph the amps drawn from each one. I did this on an old Smart Forfour only last week.

I have a Picotech oscilloscope so plugged the amp-clamp meter around each glow plug supply lead in turn and got the missus to switch the ignition up. You can probably buy a cheap meter that measures amps being drawn. Saves you removing glow plugs unnecessarily and potentially snapping them though I recommend dousing in Plus Gas of course liberally before trying to remove any.

The Smart needed ONE glow plug and I knew which one it was without removing ANYTHING!

Generally they will draw around 18A at ignition on quickly dropping to 8A on the Smart (each horizontal line represents 5A). You can see from the graph that on the Smart the glowplugs remain on for 26 seconds despite the light going out almost immediately.

Of course, if one or more of your glow plugs are iffy, or the post heating circuit is not fully functioning then this could lead to smoking. It's not clear from your posts just how long you've left the engine running for.

[darbuck]

Hi Roger, Thanks for giving me direction much appreciated.

no pump in the tank on these it relies on vacuum generated by the high pressure pump and the fuel looks ok in the transparent fuel line no bubbles so I am assuming it is ok.

Checked and rechecked codes none available. Oil is halfway between the min and max so not over oiling.

Crank case ventilation or oil vapour as you put it is at a couple of points on the intake manifold no leaks.

Egr is fully electronically controlled haven't tested it but did have a look when I had the engine apart, it was slightly coked up so gave it a good cleaning.will Have a look online to see how to test it .

Manifold was cleaned fully last year again while I had the engine apart.

I don't think this is a compression issue the cranking is very consistent. Air filter is six months old and never on the road.

5w30 oil primed turbo by filling with oil before fitting and then cranked over with the drain disconnected into a basin to ensure good flow.

Then reattached and cranked over again several times to ensure turbo was well primed.

Fuel pressure sensor condition unknown but I think it is good. Reference value is 230 so pretty close to perfect fuel pressure assuming the sensor is correct. Will learn how to test.

Inlet manifold pressure sensor, I'm not sure but will have a look over the next few days. I think the engine is actually in good nick I'm pretty sure it's ancillary issues causing this.

No evidence of fuel pump failure in the fuel filter when changed i.e no metal particles.

I couldn't drive it the fumes coming into the cabin are too high and would be a healthy and safety risk plus the smoke would be hazardous to other drivers from a visibility point of view if nothing else.

She sounds like she is running on two cylinders and the engine is hopping in its mounts timing has been checked several times but I am thinking on pulling the top of the engine apart to recheck it.

I put new valves and stem seals and rockers in her last year as well and they were lapped in correctly.

[MattBLancs]

With respect to glow plug current tests:

That's really good info, I've done "check voltage arrives" with multi meter and simple continuity / resistance check if glow plugs (about 1 ohm in good health from memory) but your current plots tells more.

(We were talking about doing a compression test at the time)


I know glow plugs are still on for a few moments (minutes or seconds I'm not sure) after engine starts, but not sure if would trigger that much smoke if ineffective??

[darbuck]

Hi Roger I redid the test and there were no leaks when I done it correctly. So I have ruled out the valves themselves but I haven't completely ruled out timing yet.

[darbuck]

I tested the glow plugs and the circuit integrity its all good. So I think I can rule them out. There was a problem with them at one point where the light wouldn't go off but I traced that a failed relay. Now it goes off after a few seconds. She starts on the button but runs rough I definitely have misfires. I doubt the glow plugs would cause the smoke. I'm pretty sure this is an injection system fault. I am thinking on bringing the injectors to a diesel specialist. Im not allowed out to the car today by she who must be obeyed. So I'll sneak out when she is watching TV.

[MattBLancs]

Good luck on the escape plan - hope you don't get caught, the punishment for car playing without "home office approval" = very severe!

Thanks for the glow plug update. Think I'm same mind as you, it'd likely not smoke as severely as described from dead glow plugs alone.

If taking the injectors out to go to a specialist, can you compression test from those points whilst they are out?
As previously I've not compression tested a diesel so is unfamiliar ground to me

[darbuck]

I plan to put on a boring movie she'll fall asleep and I can make my escape . Unfortunately you need to pull glow plugs and they're a pig to get at around the back of the engine so not going there, but as I said in an earlier post I have an oscilloscope so I want to learn how to do a relative compression test. I think it would be the best bet. At least it would give me an idea if there is a cylinder problem.I had considered it but the kit I have only has glow plug fittings suitable for this car injector fitting is more like something out of an old tractor.

In others news I have been offered 500 paving slabs for nothing and the lend of a dyna so I will be busy moving them this week I am going to use them along the back of the house where I don't bring cars.

[Rhothgar]

Hi Roger, no pump in the tank and the fuel looks ok in the transparent fuel line no bubbles so I am assuming it is ok. Checked and rechecked codes none available. Oil is halfway between the min and max so not over oiling. Crank case ventilation or oil vapour as you put it is at a couple of points on the intake manifold no leaks. Egr is fully electronically controlled haven't tested it but did have a look when I had the engine apart, it was slightly coked up so gave it a good cleaning.will Have a look online to see how to test it . Manifold was cleaned fully last year again while I had the engine apart. I don't think this is a compression issue the cranking is very consistent. Air filter is six months old and never on the road. 5w30 oil primed turbo by filling with oil before fitting and then cranked over with the drain disconnected into a basin to ensure good flow. Then reattached and cranked over again several times to ensure turbo was well primed. Fuel pressure sensor condition unknown but I think it is good. Reference value is 230 so pretty close to perfect fuel pressure assuming the sensor is correct. Inlet manifold pressure sensor, I'm not sure but will have a look over the next few days. I think the engine is actually in good nick I'm pretty sure it's ancillary issues causing this. No evidence of fuel pump failure in the fuel filter when changed i.e no metal particles. I couldn't drive it the fumes coming into the cabin are too high and would be a healthy and safety risk plus the smoke would be hazourdous to other drivers from a visibility point of view if nothing else. She sounds like she is running on two cylinders and the engine is hopping in its mounts timing has been checked several times but I am thinking on pulling the top of the engine apart to recheck it. I put new valves and stem seals and rockers in her last year as well and they were lapped in correctly.

Thanks for the comprehensive reply. OK. So if EGR is controlled electronically then unless there is a physical rubber vacuum pipe then you wouldn't be able to test it as I have advised. If there is, great! Get it ruled out.

See my latest post on glow plugs, I've just seen in another post that you said there is a glow plug fault. You don't need to strip the glow plugs. Find out from your wiring diagram where the connect it for the glow plugs. If they are powered separately like they are on the Smart then you can test each one individually from wiring that is accessible as opposed to inaccessible.

I wouldn't go stripping it down again just yet. You've surely had enough punishment for now. Let's try and rule things out before more invasive investigation. I see you made mention of DPF sensor and cannot recall how it got damaged. Didn't you snap the wire to that when removing the engine last year? I have a recollection about commenting on that - maybe on another post?

If you know categorically that the reference value for the fuel pressure sensor is 230 and it's giving you 229 then it's fine. However, in live data, does the pressure change when the car is revved? It obviously should so if not then it might be a set value the car tells itself to get you home (ie limp home mode). Does the car rev about 2500rpm - 3000rpm (whatever limp home mode is for your vehicle)?

I mention the inlet manifold pressure sensor (MAP sensor - not sure it will be in the same location as mine so you'll need to check that) only because I read you though it was overboosting perhaps? You would see this in live data. RHZ is 2000mbar not sure about RHR engine so check that and confirm. However, you will not be able to confirm that unless you actually drive it so you need to sort out the coolant cap. Is that not a standard Schrader valve cap like car tyres or is it bigger?

Please do a video of her running from start up around the back and under the bonnet. A longer video is better than a shorter one in my view.

On the subject of the glow plugs, it depends HOW you confirmed circuit integrity. REMEMBER! It's not just wiring. The ECU tells them to switch on and when to switch off. MBL is unsure whether it could cause this much smoke? I am not sure either but I've not seen a video but it sounds BAD!

Don't sneak out if you're not got a sealed cooling system.

@MattBLancs Noted iro compression test and that is still valid but I was simply picking up on the glow plug side of things. EVERYTHING needs to be properly tested and validated before moving onto next stage. I've not seen a video of the smoke only a description. I do not know for how long the engine has been run. There are many loose ends in the picture because I think a picture (ie video) can definitely paint a thousand words. Darren has spent a good portion of his life on this car. We need to be sure that each and every stone is not left unturned. Incidentally, in the oscilloscope test, and any test for that matter, the glow plugs are grounded by the engine block so no ground is needed. One of the main things my diagnostics mate drills into me is 1) to confirm fault exists, 2) test fault without disconnecting anything (because you could be disturbing a connector or wire where the issue lies especially if it is intermittent) and 3) do a wiggle test on the wiring if it's an intermittent electrical fault we are looking for. This is amongst numerous other nuggets of information.

Voltage is largely irrelevant in my view on testing vehicle electrics. I used to think the same but load is important. You could have one strand of wire in a core of 30 strands with 29 strands corroded and put your multimeter on the one strand that is good and get continuity but as soon as you load the wire, it cannot supply the component. Check out Diagnose Dan and this video in particular (one of the best 26 minutes spent of your life)

How not to use a multimeter!



and ScannerDanner:-

How to effectively use a load tester! Not specific for your issue but easy to understand how to fault find down to a nut.



Hope this helps, guys!

[darbuck]

Hi Roger, likewise thanks for the comprehensive reply, I tested from the relay to the glow plugs and had good ohm readings from the glow plugs I tested each one several times and concluded they were good. The fact that they only come on for 5 or 6 seconds makes it difficult to catch the ECU signal.



So I have to assume they are ok given they go off as expected and the car fires up easily. The fact HDIs do not need glow plugs for combustion especially once they are running tells me the problem is elsewhere. Thanks for the videos I'll watch them today. I had electrical short circuit faults on injectors yesterday but I hadn't pushed the connector in correctly so that has been resolved. Like you I prefer to check things while the car is running and across different ranges of load. I have all the equipment to test I just need to take time to learn how to use it correctly. I can assure you I am not buying any more parts for this car without confirming a fault. I know that is what you are alluding to and I appreciate it.

Edit

I think you are right I need to check what I have done more systematically instead of pulling it apart again. The engine ran lovely before I had to change the turbo so something has changed and I don't think it's the turbo. As far as the coolant cap is concerned yes it is just a valve cap I changed it yesterday and it worked so happy bunny.

[Rhothgar]

Edit

I think you are right I need to check what I have done more systematically instead of pulling it apart again. The engine ran lovely before I had to change the turbo so something has changed and I don't think it's the turbo. As far as the coolant cap is concerned yes it is just a valve cap I changed it yesterday and it worked so happy bunny.

I was unaware that it had ran fine. When was this? Did you actually drive it at the time? If so, can you point me to a posting date where you mention the new symptoms as it all seems to meld into one?

[darbuck]

Sorry Roger it ran fine but it was smoking but nothing like it is now.

[darbuck]

It was really smooth running which is why I have said I don't think it's the engine itself

[darbuck]

I'm trying to edit a video so bare with me

[darbuck]

The video doesn't show the smoke very well but suffice to say I can't stay around it very long because of the smell of unburned diesel.

Please excuse the camera skills

No I never got to drive it since I bought it, it would be funny only it isn't. It has become a running joke in the office, not great for an engineer trying to explain away the problems it has given me.

[Rhothgar]

The video doesn't show the smoke very well but suffice to say I can't stay around it very long because of the smell of unburned diesel.

Please excuse the camera skills

No I never got to drive it since I bought it, it would be funny only it isn't. It has become a running joke in the office, not great for an engineer trying to explain away the problems it has given me.

OK. So you never got to drive it but it seemingly ran well at some point in the last year and then the turbo was replaced and it started running badly again.

So without it actually being driven, we know that the fuel consumption must be excessive because not all of the fuel is combusted.

Maybe a stupid question but you have spent an awful lot of money on this car so far but have you changed the fuel filter? Do we know that is good?

1) Are all the turbo pipes sealed and not allowing pressure to escape? I know you've done a smoke test on the cylinders.
2) Have you checked the MAF airflow sensor? Are the readings within acceptable range?
3) You've not checked the compression yet but did you check the pistons when the engine was stripped? If so, did they seem nice tight with little sideways movement and the bores not look scored?
4) Have you ever removed the injectors and left them lying around in the rain or unprotected? You obviously have to treat them with kid gloves. I know you've done a leak-off test and it was in limits but have the injectors been removed and left in an unprotected state for any length of time since doing that test?

If all of the above has been checked and no assumptions been made whatsoever then the following must be considered:-

a) Damaged injectors
b) Faulty injection timing
c) Damaged crankshaft keyway
d) Damaged timing gear
e) Low cylinder compression
f) Damaged rings or cylinder liners
g) Water mixed in the diesel fuel (cracked head gaskets, cylinder head or block)
h)Damaged fuel lines
i) Low fuel pressure to the fuel pump
j) Damaged or incorrect fuel pump timing

Of course, some of the above can easily be ruled out because you will have already checked certain things but all of the above can cause an excessive white smoke. I am sure others could add to that list.

This whole topic started because of doubts over the injectors and unless someone can confirm with a Lexia whether those injector figures are reasonable then it does seem to be the next logical step.

I've try and find a video I took of mine when it was running reasonably well but before I sorted the electrovalve issue and post up.

Please let me know what your fuel pressure regulator open cycle ratio is at idle. I think should be around 17%.