Hyundai i800 injector fault......maybe !

Evening all, I'm relatively new to scoping & could use some advice....... does this look like a good pattern for cam, crank & cylinder number 1 injector ??? It looks to me as though the injection point is too late ??? Thanks for any input

stevo739 wrote:Evening all, I'm relatively new to scoping & could use some advice....... does this look like a good pattern for cam, crank & cylinder number 1 injector ??? It looks to me as though the injection point is too late ??? Thanks for any input

From that image alone it is impossible to tell. Almost. I would guesstimate that injection finishes in that image just before TDC ,<5* (Don't quote or rely on that - slightly more than a educated guess).

But there is nothing from a Cam or Crank signal alone that shows TDC. The missing tooth is not on TDC.

Does this engine have a problem?

It is always better to put up the psdata file along with the image.

Cheers
FF

Please send us the psdata file then this may help. Have you looked on the waveform library.
Thanks Phil R

Thanks for your reply chaps, Yes it does have a running fault. It originally came in with an injector stuck open in cly 3 so was losing rail pressure through that cylinder. New injectors fitted & coded & it now runs really rough & is wetting/not correctly firing the cylinders 2 & 4 ? I was hoping to check the fuel delivery timing as accurately as possible using my scope. I will try to upload the psdata files later on (I couldn't fathom it out the other night).

Thanks again, Andy

stevo739 wrote:Thanks for your reply chaps, Yes it does have a running fault. It originally came in with an injector stuck open in cly 3 so was losing rail pressure through that cylinder. New injectors fitted & coded & it now runs really rough & is wetting/not correctly firing the cylinders 2 & 4 ? I was hoping to check the fuel delivery timing as accurately as possible using my scope. I will try to upload the psdata files later on (I couldn't fathom it out the other night).

Thanks again, Andy

That image does look pretty damn ugly. But without the psdata file I'd be putting my neck on the block saying anything.

So putting my neck on the block (again a slightly educated guesstimate and not something I'd go on) I'd say cyl 4 is the worse offender. But the psdata file will confirm if that is correct or not.

I think it has been brought up before about checking the delivery with the scope but there are so many variables like fuel temp to take into consideration. I could be wrong. Diesels are not my area.

Cheers
FF

psdata files of all 4 cylinder relative compression Vs injector triggers ?

psdata file of Cam Vs Crank Vs Injectors

That image does look pretty damn ugly. But without the psdata file

I agree with FF, absolutely not enough information within that capture. The engine speed prior to Injector 1 firing to the Left of the capture is much slower than the subsequent firing of said injector. One wonders if that is because it has just started or is "Mid Stream" so to speak"

Working with capture provided it is evident that, assuming 1342, that Cylinder 3 is contributing most. By default that condemns 1,4 & 2 - We don't want to be there unless it is really is a fact

I would like to see a PSD file from Ignition on > Crank > Idle > 1500 > 2500 > WOT > Back To Idle with a little more time across the screen.

New injectors fitted & coded

Please clarify, how many and purchased from ???


Some history may help, age ? mileage ? service history ?

Has it been misfuelled ? perhaps take a fuel sample, stir it up and take a HC reading then compare to "known good" diesel sample.

& is wetting/not correctly firing the cylinders 2 & 4

Multiple Injector failure. Not Nice. Is that Just Bad Luck ?? or a Man Made Error / Consequence of ??

You make now mention of fuel filter - any swarf in it ?

I would love to be able to give you a psdata file for ignition>crank>idle>1500>2500>WOT ....... only problem being it doesn't run (well, not well enough to raise the RPM anyway).

4 new injectors purchased from Hyundai direct & also coded by them with a new fuel filter fitted at the same time.

I have next to no history on this vehicle as my customer has only just bought it himself (only covered 900 miles in it), although the vehicle has done 126,000 miles used as a taxi !!!

Hi Andy

Some good waveforms there, I have picked out one that paints a picture of the fault and symptoms.


As you can see Cylinder 1 is the only one making any worthwhile contribution towards rotating that engine. The effort of Compression in 3, 4 & 2 are nothing but a burden to it with little in return.

I guessing that this was Mis fueled which introduced swarf into the fuel system. That most likely caused the original offending injector to jam open.

Would be nice to know why the Dealer threw 4 at it ??

If my guess is good then the Fuel tank, Fuel lines, Lift Pump, Fuel Filter, Fuel Rail, Pressure Sensor, Fuel Regulators, Metering Valves, Fuel Coolers / Heaters ............ should have been either replaced or thoroughly cleaned before fitting Injectors.

I do appreciate that may not be economically viable.

That same swarf has now ruined the new Injectors. That includes Number 1, we have no evidence that it good, fact is that it is better than the other 3 , Period !

I suspect you are flogging a dead horse here. If you do wish to continue then start with tests rather than expensive parts.

Drain the fuel, empty the filter and look for contamination, Relative Compression Tests Hot and Cold. Inspect the inside of the tank for anything nasty.

(only covered 900 miles in it),

If the swarf theory is good then it has done well

although the vehicle has done 126,000 miles used as a taxi !!!

Even Taxi Drivers wont buy an ex Taxi - The Irony !!!

I would take that mileage with a pinch of salt too, perhaps pull the cluster out and look for evidence of it having been dismantled.

Of course I may have this all wrong, if this was presented to me I would be looking for pre payment at each step just in case the client walked in and tucked the Signed Registration Document up my shirt.