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diesel engine knocking juddering tick over leak off test

14K views 53 replies 7 participants last post by  Nessmuk  
#1 ·
As title says engine vibrating and diesel knock also revs counter seems to fluctuate on tick over , did a leak off test let it run for 2 mins ( picture attached ) do you think I should just get all 4 injectors tested and reconed ? would dodgy injectors create the above faults ?
The first time I start the engine after leak off test it does seem a lot better but soon the knocking and vibrating reappears.

If injector test would be advisable does any body know a reliable place around the north west who will test and if needed recon them at a reasonable price ?
 

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#3 ·
How big are those bottles?

When I did my leak off test I had two bad ones. One leaked over 300ml, the other over 250ml, the good ones leaked almost nothing by comparison.

Didn't you have injector problems a few weeks ago and discovered that you had a mix of 501 and 504 injectors? Are they all the right type now and coded correctly in the ECU?

Simon
 
#5 ·
How big are those bottles?

When I did my leak off test I had two bad ones. One leaked over 300ml, the other over 250ml, the good ones leaked almost nothing by comparison.

Didn't you have injector problems a few weeks ago and discovered that you had a mix of 501 and 504 injectors? Are they all the right type now and coded correctly in the ECU?
Simon
Different car, yes all the right type and coded in correct using mongoose.

Bottle are 500ml each
Let engine tick over for about 2 mins but am I right in thinking the volume that is leaked off should in the same region ?
Below are the results.
INJECTOR 1 X 170ML
INJECTOR 2 X 150ML
INJECTOR 3 X 58ML
INJECTOR 4 X 92ML
 
#4 ·
I have just been speaking to an independent local to me and he says that it is now best to buy them direct from Jaguar at approx ÂŁ120 each, the recent batch are (apparently) much better than they were and definitely better than recon ones.

He quoted ÂŁ600 + vat to replace all 4.
 
#6 ·
I have just been speaking to an independent local to me and he says that it is now best to buy them direct from Jaguar at approx ÂŁ120 each, the recent batch are (apparently) much better than they were and definitely better than recon ones.

He quoted ÂŁ600 + vat to replace all 4.
Thanks for that worth giving main dealers a ring.
 
#7 ·
I think the readings are excessive on all 4 but was thinking is it worth getting them reconditioned ? or not ?
My main question is would bad injectors like these explain the issues I am having on tick over.
Engine vibrating, knocking, rev counter fluctuate.
Don't want to replace injectors to find I have another problem.
No codes using mongoose or warning lights.
 
#11 ·
No mine as no codes, no flashing coil light no engine management.
Mine is on tick over engine vibrating, knocking, rev counter fluctuate.

Not sure what you mean by.
If you can keep it from ticking over the problem goes away... sort of.
What do you mean rough running ? do you mean rough when ticking over ?

Like I say what I really want to know is would my faults occur with injectors that are not up to scratch.
 
#12 ·
Keeping the revs above tickover when stopped in traffic usually stops the flashing coil light coming on, the codes in mine were totally wrong, but setting them correctly made little difference.

Yes, if the injectors are worn out or have the wrong codes in the ECM, they could, your leak off test results don't look great (mine were about 20-30ml each for 2 mins @1800rpm), so I suppose they are a strong candidate. A good indy or Delphi agent might be your next port of call.

But there are other causes as well, for example I think the EGR can also cause this if it is stuck open just a little bit, a bit more and it will stifle the engine totally AFAIK. How is your EGR ? also check for air leaks generally.
 
#15 ·
Alto, there is a specific way of doing the leakoff test to ensure consistant results. That said your 1 and 2 don't look too healthy.

From Goudy's post

Now ready to perform test.

I did it like this with a stop watch on my phone to count off the times. It was a continuous test, so one part flows into the next without stopping the engine:
Idle for 2 minutes
3000 rpm for 30 seconds
Idle for 30 seconds
3000 rpm for 30 seconds
Idle for 30 seconds
3000 rpm for 30 seconds
Turn off engine.

I then removed the clips and pipes and let them drain into the containers before refitting the car's return pipes.

Results and what to look for.
I believe this test should show a good injector is returning around 25ml, but it should be fairly obvious if one or more are duff by the amount variation.
 
#17 ·
Hello yes I know but the 2 mins at idle gave me 170ml 150ml 58ml 92ml which is well over the 25ml ? I think if I had done the idle 30 sec and the 3000rpm 30 secs and so on the readings would have only increased or am I missing something ?
 
#16 ·
Ye like I say think with the readings the injectors will need changing.
Just looking for opinions before splashing the cash if you know what I mean.
I would hate to spend all that money and still have problems I would be sad
 
#18 ·
Apologies Alto, you're absolutely right, with the full test you would have needed bigger bottles :)
 
#19 ·
Just can not understand why I am not getting any fault codes with the leak off readings like they are ?
But like I say hope it is the injectors that are causing my problems.
Is it normal for car to still run with out fault codes with leak off readings like this ?
Engine vibration, smoke, knocking, and rev counter fluctuating ?
 
#20 ·
My understanding is that excessive leakage will result in over-fuelling as the ECM can't control the firing process properly, so yes.

My leak-off test results looked really good, but I am willing to bet that replacing them all (they are nearly 90K old) will be the only thing that cures my ongoing P0325 code.
 
#21 ·
I think the fuel pressure has to drop below a certain value to put the MIL on. From what I recall the pressure usually drops when under load and giving it some welly. Tickover and just pottering about wouldn't unless they were really goosed.

Have you been able to drive it yet?
 
#22 · (Edited)
I have drove it but like you say not give it any stick, just ticking over and pottering around.
But not been up hills or any thing with it .
Again that is what is bothering me with the leak results I would say they are really goosed ? why are fault codes not showing ?
 
#23 ·
I only started getting problems on mine when towing my caravan, solo it was fine. Towing was when I started getting the flashing coil light and eventually P0251 with the MIL on.

I didn't think mine wasn't that rough running with the old injectors but it's a whole lot smoother now I've changed two of them and cleaned up the inlet tract.

Simon.
 
#24 ·
You wouldn't get any codes because the system up to the injector is working as it should, all the pressures, fuel rail etc will be spot on. The car doesn't monitor the leak off values, it just goes back to the filter.

If it helps. The first time I met this, just one injector was goosed, it was leaking practically all the derv being fed to the injector, no fault codes, the car simply stopped running in mid journey. Because there were no fault codes, it took quite a bit of faffing to figure out what was wrong. This was back in 2003 on a Mondeo with the same motor. I didn't have access to the fountain of knowledge on here at the time.
 
#26 ·
I'm no expert but IMHO I'd say yes, all four are cream crackered.

Diesel specialists I spoke to offered to test injectors and refund that test cost if you got them refurbed. Must be someone near you offering that service. I used a company from the Delphi website as I wanted the reassurance of them being done properly. Make sure whoever you use gives new codes with the refurbed injectors.

Simon.
 
#27 ·
Don't know weather to go with new ones instead ÂŁ455 for 4.
Company near me charge ÂŁ10 each injector to test ( they always come back needing to be refurbed )
Then they want ÂŁ100 to refurb, which ever way you look at it the cost is ÂŁ400 and a lot of people say refurbing is only a short term solution.
 
#29 ·
It's a no-brainer.
 
#28 ·
ÂŁ445 for 4 news ones sounds very good
 
#32 ·
Then buy them!