Corsa D Injector Resistance

[LeeHabbers]

Howdy ho.

I've done a resistance test on my fuel injectors with a Multimeter and all 4 were 0.9 ohms which I think is low compare to other people's online. I have tried to find the resistance values for my specific injectors online but can't find anything. So wondering if anyone on here may know. My car is a 2011 Corsa D 1.7 CDTi (Engine No: A17DTS).

Thanks.

[Penelope Stopit]

Must be something wrong with the multimeter

12 volts at 1 ohm would give a current draw of 12 amps

12 amps is massive

Sorry it doesn't answer your question

The thing is, there is little chance of 4 injectors all going faulty and showing the same resistance

Is the meter possibly showing 9 ohms, meter range not set correctly?

[LeeHabbers]

The multimeter is only a week old. I've watched a few videos on it and it said set it to 200 ohms which I did. Most of their results came back around 16.5 ohms. I have just read somewhere that they have to be cold so I'll test them again tomorrow as the car was at operating temp. I'm clueless when it comes to volts, watts, ohms etc. No idea what any of it means. Just following vids and hoping they match. Haha.

Edited by LeeHabbers on Sunday 18th October 19:55

[GreenV8S]

Does that engine use common rail injectors? They run very high current (up to 16A or so) and can have a sub 1 Ohm resistance.

Do you have any particular reason to suspect that any of the injectors are faulty? It seems unlikely that they are all faulty so I would assume that the consistent readings indicate they are all healthy, unless you have evidence to suggest otherwise.

[LeeHabbers]

GreenV8S said:

Does that engine use common rail injectors? They run very high current (up to 16A or so) and can have a sub 1 Ohm resistance.

Yeah it does. Would ask what the resistance and that meant but I probably wouldn't understand it, haha.

Thanks

[stevieturbo]

Penelope Stopit said:

Must be something wrong with the multimeter

12 volts at 1 ohm would give a current draw of 12 amps

12 amps is massive

Sorry it doesn't answer your question

The thing is, there is little chance of 4 injectors all going faulty and showing the same resistance

Is the meter possibly showing 9 ohms, meter range not set correctly?

Modern diesel injectors do not always operate at 12v.

And I'd imagine a simple resistance check would tell feck all.

What exactly is trying to be found out with such a test ?

[LeeHabbers]

Car sometimes has trouble starting and the has just started spouting black smoke on acceleration. Idle seems a tad lumpy every now and then and the rpm bounces from 844 to 959 when it was always constant at 850 maybe 1+/-. When driving it runs perfect and since the black smoke started it runs better than ever so I ruled out injectors but just doing a process of illumination. Gonna check the EGR and do a compression test next. Have a feeling maybe the EGR is fooked, possible constantly closed.

Edited by LeeHabbers on Monday 19th October 07:58

[GreenV8S]

LeeHabbers said:

Idle seems a tad lumpy every now and then and the rpm bounces from 844 to 859

This is a wind-up, yes?

[Penelope Stopit]

Have you considered diagnostics, fault codes?

[LeeHabbers]

GreenV8S said:

LeeHabbers said:

Idle seems a tad lumpy every now and then and the rpm bounces from 844 to 859

This is a wind-up, yes?

I meant 959, that's from the ODB, feels really lumpy, but doesn't happen all the time. Maybe SCV?

Edited by LeeHabbers on Monday 19th October 08:01

[LeeHabbers]

Penelope Stopit said:

Have you considered diagnostics, fault codes?

Doesn't show anything but it I haven't tried a top notch scanner yet. It's happened before where I scanned it and nothing came back, took it to a garage and a code came back. Obviously their scanner is ALOT better than mine.

[Penelope Stopit]

LeeHabbers said:

Penelope Stopit said:

Have you considered diagnostics, fault codes?

Doesn't show anything but it I haven't tried a top notch scanner yet. It's happened before where I scanned it and nothing came back, took it to a garage and a code came back. Obviously their scanner is ALOT better than mine.

Garage?????=Money

Can you phone a friend?

[LeeHabbers]

Nah, know a few people that are mechanics but lost touch over the years. Can't really go and ask a favour. No EML has come on so can't be too bad. I'll do abit more digging around and if I end up at a dead end I'll bite the bullet and take it to a garage.

[LeeHabbers]

Couldn't do the compression test as the new gauge I ordered wouldn't fit into the awkward space. I did notice that cylinder 3 glow plug was badly carbonised, the glow plugs were replaced about a month ago. So something is wrong with cylinder 3, werid as the performance of the car is better than ever other than the black smoke

[GreenV8S]

LeeHabbers said:

Have a feeling maybe the EGR is fooked, possible constantly closed.

How do you think that would relate to any of the symptoms you describe?

If there's a problem, you need to get it diagnosed by somebody who understands how the engine works.

[LeeHabbers]

GreenV8S said:

LeeHabbers said:

Have a feeling maybe the EGR is fooked, possible constantly closed.

How do you think that would relate to any of the symptoms you describe?

If there's a problem, you need to get it diagnosed by somebody who understands how the engine works.

I took the EGR off to clean and I had trouble opening up the valve which was usually easy in the past so it was just as guess. Less crap going back into the intake and straight out the exhaust I'd assume there would be more smoke.

[NMNeil]

Penelope Stopit said:

Must be something wrong with the multimeter

12 volts at 1 ohm would give a current draw of 12 amps

12 amps is massive

Sorry it doesn't answer your question

The thing is, there is little chance of 4 injectors all going faulty and showing the same resistance

Is the meter possibly showing 9 ohms, meter range not set correctly?

I know nothing about diesel injectors but regular petrol injectors are often in the 1 ohm range and use the peak and hold method.
The injector is first sent a high current to get the pintle off it's seat as fast as possible then the current is reduced to a much lower hold open level.

[LeeHabbers]

Here's the compression results:

Compression ratio is 16.5:1

Cylinder 1: 330psi
Cylinder 2: 330psi
Cylinder 3: 240psi
Cylinder 4: 220psi

Cylinder 3 and 4 seem low to me compared to 1 & 2, I know there is a leeway of 10% +/- but 3 and 4 are 33% out. Found out that cylinder 3 is the one that smokes cause when I disconnect the injector it's doesn't smoke when I press the throttle. Performance is perfect so not too worried about the compression, just the smoke is pissing me off.

Edited by LeeHabbers on Friday 23 October 11:02

[Zener]

LeeHabbers said:

Here's the compression results:

Compression ratio is 16.5:1

Cylinder 1: 330psi
Cylinder 2: 330psi
Cylinder 3: 240psi
Cylinder 4: 220psi

Cylinder 3 and 4 seem low to me compared to 1 & 2, I know there is a leeway of 10% +/- but 3 and 4 are 33% out. Found out that cylinder 3 is the one that smokes cause when I disconnect the injector it's doesn't smoke when I press the throttle. Performance is perfect so not too worried about the compression, just the smoke is pissing me off.

Edited by LeeHabbers on Friday 23 October 11:02

Thats over a 40% imbalance that motor needs attention you may and I mean may have a slight breach between cylinders 3 & 4 causing that piss poor result

[LeeHabbers]

[/quote] Thats over a 40% imbalance that motor needs attention you may and I mean may have a slight breach between cylinders 3 & 4 causing that piss poor result

[/quote]

I have read somewhere that the A17DTR engine which is almost exact to my engine (A17DTS) has had a few problems with the top of cylinder 3 melting and bleeding towards cylinder 4 but this has only be seen on a few occasions. So could be that I suppose but surely that will cause performance issues. I didn't realise that the engine needs to be warm when doing a compression test so I'll redo it later on and see if it changes. I've also read somewhere that the the PSI is still OK but doesn't seem right to me as they're lower than the other 2 cylinders. The pressure didn't drop when I left it compressed so surely that rules out a leak past the pistons or valves and as you say could be a leak between cylinders 3 & 4, damaged gasket between cylinders maybe?

Edited by LeeHabbers on Friday 23 October 12:17