[charlescrown]

This problem started 2 days ago. I have checked the fuel pressure with my scantool and when the engine is running it's spot on target but drops quiet quickly to zero when you turn the engine off. Is this normal or is there a fuel leak from the regulator or injector. I intend to test the glow plugs in 2 days time along with a service.

[mickd]

Hi,
No power should equal no pressure.
Could you please add,  year, kms, battery age, etc, cheers

[charlescrown]

Sorry left out a few specs. Its a 2008 with 170,00kms and battery is abt 6 months old. I figure if the pressure is dropping off it explains the long crank time to start but haven't overlooked the glow plugs. I will do a full service on Thursday and check it all out. Also I will read the fuel pressures tomorrow morning before I go to work when the car is in that predicable state. I know that unless the fuel pressure is up to a set point the injectors won't turn on but after seeing smoke after starting I am quiet confident it's not that but in the glow plug area.

[Misha]

Grab a multi-meter and check the battery (or take it to supercheap even better for battery health check, i think they check it for free).

Check the glow plugs;
Take connector off that's connecting to the glow plugs, then take the metal long plate off (behind the engine, its awkward to get to, but very dooable) then check with a multi-meter on OHMS each glow plug. Red to glow plug, and black to a ground on your car. They should all read well under 1-2 OHMS or somewhere in the area. If one or more are reading in the 10's, 100's or 1000's than that might be it.

Metal long plate:

[charlescrown]

Thanks. That's for tomorrow. I went out at 6.30 am and put my scantool on and watched the fuel pressure build up and it started as it normally does. This afternoon I tried again and it took quiet a bit on cranking to fire up which makes me think the glow plugs are ok but the power switching side of the circuit (relay) might be the culprit. Does anyone know how these engines start without glow plugs in Australian climate?

[tw2005]

Thanks. That's for tomorrow. I went out at 6.30 am and put my scantool on and watched the fuel pressure build up and it started as it normally does. This afternoon I tried again and it took quiet a bit on cranking to fire up which makes me think the glow plugs are ok but the power switching side of the circuit (relay) might be the culprit. Does anyone know how these engines start without glow plugs in Australian climate?

I hear they have no issues in the UK.  It's all about compression and the heat that generates. Never tried a start with no glows, easily could try but would be smoky for a bit. Easily monitor the voltage at the harness feeding the glow plugs for level and duration. I believe 30secs past the glow lamp extinguishing it can still have power there

[charlescrown]

OK all 4 glow plugs were open circuit. Quiet easy to replace so we'll find out tomorrow morning.

[mickd]

OK all 4 glow plugs were open circuit. Quiet easy to replace so we'll find out tomorrow morning.

4 out of 4, not doing things by halves then, eh ?   

[charlescrown]

Car started fine this morning. I am a little concerned that with all 4 plugs burnt out  that the timer is not working as it should which is ECU controlled . The genuine manual is pathetic and should have a simple chart of time/temp but no. All checks out OK with a current clamp, scantool and multimeter. Time will tell.

[nzenigma]

Car started fine this morning. I am a little concerned that with all 4 plugs burnt out  that the timer is not working as it should which is ECU controlled . The genuine manual is pathetic and should have a simple chart of time/temp but no. All checks out OK with a current clamp, scantool and multimeter. Time will tell.

Reason is in the unanswered question.

Does anyone know how these engines start without glow plugs in Australian climate?

Without glow plugs they will start fairly easily in QLD. No doubt, a bit slower in colder states.

What you are not addressing is that your car was still starting ok with progressively less functional plugs. They did not all die at once.

[charlescrown]

Well sorry to advise you as you are technical expert but it did happen quickly. My concern is the timing of the glow plugs which may have been the factor burning out the plugs. Sorry I only have 39 years experience and my initial question was relating to the fuel pressure decay period which I am sure you can answer.

[mickd]

Well sorry to advise you as you are technical expert but it did happen quickly. My concern is the timing of the glow plugs which may have been the factor burning out the plugs. Sorry I only have 39 years experience and my initial question was relating to the fuel pressure decay period which I am sure you can answer.

Sorry, but I'm lost :
Reply#5
tw says power to glows can be on for 30 seconds past lamp light going off, and how to test and tevord time.
How long are yours on for?

Your 3rd post:
You've checked pressure in morning and is spot on , but then  you had problem in arvo - what was pressure then ?

Now:
If you think it's eaten the plugs by cooking them,  then - How long are they on for?

[tw2005]

Well sorry to advise you as you are technical expert but it did happen quickly. My concern is the timing of the glow plugs which may have been the factor burning out the plugs. Sorry I only have 39 years experience and my initial question was relating to the fuel pressure decay period which I am sure you can answer.

Sorry, but I'm lost :
Reply#5
tw says power to glows can be on for 30 seconds past lamp light going off, and how to test and tevord time.
How long are yours on for?

Your 3rd post:
You've checked pressure in morning and is spot on , but then  you had problem in arvo - what was pressure then ?

Now:
If you think it's eaten the plugs by cooking them,  then - How long are they on for?

Pretty sure Charles is a qualified tech but he quoted this from the manual.  "I got a bit worried by how long the continued to operate for but the book says under 20deg around 36 seconds"

I don't know how long they would have to run to burn out  but I think the timer is the ecu . maybe the relay contacts could weld and stay latched? dunno, had no issue with mine yet apart from expected replacement. Not something you could have a hard and fast rule for life either, I'd expect cycles would come in to it

[charlescrown]

I'll clarify. The starting problem started a few days ago. Prior to that there was no indication that any of the plugs had gone and yes they usually do go one by one but you get a short lumpy idle for a few seconds after a cold start. The fuel pressure test was done at multiple times in the day hot and cold. The car has always started after a little cranking. This time it took ages and blew a big white puff of smoke a clear indicator of unburnt fuel. Hard to remember just what it was like new. Monitoring the target and actual fuel pressure there is the target figure and nothing till you started cranking which builds up to target and the car starts. There is a pressure switch on the fuel rail that prevents injection unless the pressure reaches a set point. I want to find out if the pressure decay is a normal thing or I have a fuel leak. I'll have the opportunity to scan another one tomorrow and will post back the results which may help anyone else. I'll also compare the glow plug on times.
Hyundai make good cars but write pathetic manuals. A time/temp graph would put it all to rest.

[Dazzler]

I'll clarify. The starting problem started a few days ago. Prior to that there was no indication that any of the plugs had gone and yes they usually do go one by one but you get a short lumpy idle for a few seconds after a cold start. The fuel pressure test was done at multiple times in the day hot and cold. The car has always started after a little cranking. This time it took ages and blew a big white puff of smoke a clear indicator of unburnt fuel. Hard to remember just what it was like new. Monitoring the target and actual fuel pressure there is the target figure and nothing till you started cranking which builds up to target and the car starts. There is a pressure switch on the fuel rail that prevents injection unless the pressure reaches a set point. I want to find out if the pressure decay is a normal thing or I have a fuel leak. I'll have the opportunity to scan another one tomorrow and will post back the results which may help anyone else. I'll also compare the glow plug on times.
Hyundai make good cars but write pathetic manuals. A time/temp graph would put it all to rest.

Cheers for that summary Charles, the current world situation is a classic illustration of how what is normal isn't always set in stone.

OK all 4 glow plugs were open circuit. Quiet easy to replace so we'll find out tomorrow morning.

I meant to comment on this earlier. They can be a nightmare to remove if you are unlucky. We have a couple of tales of whoa on here about such instances and one was from @Asterix who was a VW service manager in a past life. 

[nzenigma]

Well sorry to advise you as you are technical expert but it did happen quickly. My concern is the timing of the glow plugs which may have been the factor burning out the plugs. Sorry I only have 39 years experience and my initial question was relating to the fuel pressure decay period which I am sure you can answer.

Thanks for the reply 

Using your 39 years of experience, you may have checked the primary pump in the fuel tank...and found that the Australian diesel i30 does not have a pump. Therefore, unlike the petrol model there cannot be any pre-priming !!!
If there is fuel in the line to the HP pump , that pump is designed to do all the work ( when cranking)  and apply pressure to the rail immediately.

You assert that all the glow plugs burnt out at the same time. How do you know?  Do you check daily ?
During your vast time in the trade you will have noticed that a properly functioning glow plug has low resistance (1-6 ohms); that is almost a short circuit.
Therefore, testing all the plugs while they are strapped together will give a similar reading.  How do you know if you have 4 good plugs or 2 good and 2 duds, etc?
Guess you already know all that.

[mickd]

I'll clarify. The starting problem started a few days ago. Prior to that there was no indication that any of the plugs had gone and yes they usually do go one by one but you get a short lumpy idle for a few seconds after a cold start. The fuel pressure test was done at multiple times in the day hot and cold. The car has always started after a little cranking. This time it took ages and blew a big white puff of smoke a clear indicator of unburnt fuel. Hard to remember just what it was like new. Monitoring the target and actual fuel pressure there is the target figure and nothing till you started cranking which builds up to target and the car starts. There is a pressure switch on the fuel rail that prevents injection unless the pressure reaches a set point. I want to find out if the pressure decay is a normal thing or I have a fuel leak. I'll have the opportunity to scan another one tomorrow and will post back the results which may help anyone else. I'll also compare the glow plug on times.
Hyundai make good cars but write pathetic manuals. A time/temp graph would put it all to rest.

Okay Dokay.
So,
If plugs are all good and not blowing white smoke,
 but still cranking a long time, 
could the time it takes to teach injection pressure be taking too long ?,
 due to pressure sensor faulty?,   or sus pump ?

 

[nzenigma]

There is a pressure switch on the fuel rail that prevents injection unless the pressure reaches a set point.

Wrong. At the end of the rail is a screw in pressure SENSOR. It does not prevent anything. It sends rail pressure information to the ECU . The ECU then controls the suction valve on the HP pump.

[charlescrown]

Did a little bit of testing this morning of the glow plug on times. What I found was they continued to work up to 75 deg.  I'll have the opportunity to test another car tomorrow and compare the data. Oh by the way I30 glow plus have a resistance of 1/4 ohm cold not 1-6 sorry that the test temp is not specified.

[charlescrown]

At the end of the rail is a screw in pressure SENSOR. It does not prevent anything

Sorry if the sensor is out of range the ECM shuts down and sets a DTC. I don't have a DTC but my initial question is the decay time for the fuel pressure after the engine stops because of this it takes a little bit of cranking to reach it's target and start but obviously the program is designed to accept this as a tolerance when cranking having an allowable period to build up the rail pressure.  My question still remains unanswered about the fuel pressure decay. Is it meant to hold pressure after the engine stops?

[mickd]

Hi,
Reply#1
No one has corrected me if I'm wrong.
Know for certain that my motorcycles " do not have fuel pressure stored in the system " once power off.
You would need another device to activate after power off but keep pump on until activation of device to lock in system pressure and then deactivate once power on and pump back on. More trouble than worth.

[charlescrown]

Petrol EFI holds the fuel pressure for a long time but Diesel I don't know. Anyway as I mention I'm all setup to carry out the tests on another I30 and will post back. My concern at the moment is the long time the glow plugs operate for. I know from experience on older diesels that didn't have a timer circuit on the glow plugs you could easily burn them all out by excessive on time. I need to find out by comparison testing if that's normal to put my mind at rest. Being ECU controlled the only influencing component is the temp sensor but it looks pretty much what I would expect. I would think if it was causing the glow plugs for so long it would show extremely low temps but that's not the case.

[nzenigma]

Did a little bit of testing this morning of the glow plug on times. What I found was they continued to work up to 75 deg. 

 You cite engine temperature not "On times" (seconds) . As per tw2005 above, initial start is 30 secs, also 40 secs reported. Engine temperature irrelevant. In cold climates glow plugs and EGR are reactivated by low ambient temperature.

Oh by the way I30 glow plus have a resistance of 1/4 ohm  .........

......... and that has remained a near short cct. since I was in school. Did "you have 4 good plugs or 2 good and 2 duds, etc?" ???? Move on.

At the end of the rail is a screw in pressure SENSOR. It does not prevent anything

  My question still remains unanswered about the fuel pressure decay. Is it meant to hold pressure after the engine stops?

I assume you are talking about rail pressure. On a low Kms engine the rail will retain pressure for days. Obviously as injectors , pump and pump return valves age the pressure will decline, but not to 0. The engine still operates normally.

If you have white smoke and loss of pressure look for a leaking injector.

[charlescrown]

Oh hum

[nzenigma]

Oh hum

 

Ah... ..... now we understand your arrogance and your irritation at being questioned about basic electronic procedure 

@charlescrown  wrote in 2016:
 "I have been involved with ECU programming for the last 12 years with Holden Delco systems and have ventured outside the square with the Bosch EDC16 so occasionally one needs to seek the input and opinions  from other learned people like yourself."

I wondered, irrespective of all the bluff and posturing , why you did not understand basic diesel crdi principle.

Irrespective, as an electronics tech. since 1968  and self employed Hyundai mechanic for the last 5 years; my advice was valid. 

[Dazzler]

There is no award on the i30 owners club for getting the last word or bragging rights.. I hope we don't lose a member or two over this thread. 

[charlescrown]

Nah I have thick skin not like some others. I'll post back tonight with the comparison results.

[Dazzler]

  Sounds like a plan.

[charlescrown]

OK the tests are complete. My car with 170000kms and another with only 66kms. What I found was if the key is turned on and engine not running the glow plugs work for around 30 seconds. Once the car is started @15 degrees they operated for 2 minutes 15 seconds which drops down to nothing after 75 degrees. Both cars produced similar results with a variation I put down to ambient temps and the fact that there would have been some variation in my timing and temp accuracy but the differences were minimal. The main thing was the graph plotting temp against time for both cars was very close. This tells me that yes my glow plugs did not burn out suddenly from excess on time but was obviously over a period of time. The strange thing was I never noted a change in crank time or excessive smoke. So my conclusion is that all is well and I have no concerns. I also disconnected the fuel rail pressure switch and the engine cut out immediately as it said it would do in the manual and logged a high pressure code. The rail pressure on both cars had a similar decay rate that ended up at 220kPa after a short period of time this tells me the fuel system is in good condition.
 I would like to thanks all those for their valued input and suggestions.

[mickd]

Okay , so glow plugs it was . Excellent. 
The fuel pressure blah blah wasn't the culprit .Excellent.
Now have a time & temperature reference re glow plugs. Excellent.
Also have pressure reference.  Excellent.

May you have many, many, many more trouble free kms of motoring.