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Discussion Starter #1
Hi all. After replacing the headgasket on my 2004 terracan 2.9 crdi, it no longer starts. After some investigation, it turns out that the injectors arn't opening/pulsing. Can you think of any suggestions that may be the issue? I have triple checked that everything is connected as it should be.
 

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Driver display and OBD2 codes. Have you checked for fuel pressure, the lack of which and the ECM will not send a pulse to the injectors.
 

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Discussion Starter #6 (Edited)
Ok... so I have been working hard at getting it started to no avail. I have tried replacing the cam sensor and also I have had a mess around with my fuel pump as someone has put multiple marks on the timing wheel, therefore I wasn't 100% sure which marks to use ( after trying the other marks it still wouldn't start). Unfortunately, I don't have a tester to test fuel pressure, so I'm a little stuck there. I did notice that the manual fuel primer doesn't seem to get hard no matter how long I pump it - out of interest, how hard should it be to start after having the fuel lines off as I know different engines vary?.
The are no fault codes and the display doesn't show any fault lights but the immobilizer light seems to stay on for a long time before going off with the ignition (I haven't had the 4x4 long so I can't remember if that is normal or not).
Any other ideas?
I'm thinking about getting out a mobile mechanic if I can't think of anything else.
 

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AUTOSPARK might chime in with a suggestion...he works on a large variety of Hyundai's! I have a limited knowledge of diesels.
 

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Unfortuineatly I don't have a tester to test fuel pressure, so I'm a little stuck there.
You don't own a voltmeter? That's generally all you need to check that there is enough pressure in the rail to get the engine started.
A decent scan tool will be able to display fuel pressure too.

Gazel said:
I did notice that the manual fuel primer doesn't seem to get hard no matter how long I pump it - out of interest, how hard should it be to start after having the fuel lines off as I know different engines vary?
The primer shouldn't get hard on a CRDi engine because it's not a sealed fuel system. It will get firm but not really hard like the primer on an engine with carburettor would.

Gazel said:
the immobilizer light seems to stay on for a long time before going off with the ignition
That's normal, but when the immob light switches off you should turn the ignition off then back on again to bring the light back on. The engine wont fire if the immob warning light isn't on. The light should switch off during crank.

Gazel said:
How would I go about that?
Seal any leaks.
The low pressure fuel system on the Delphi CRDi system works on negative pressure. On this system there is a vacuum pump on the engine that sucks the fuel out of the tank. When there is a leak fuel doesn't escape, making the leak more difficult to detect. Fuel doesn't leak out through the leak because air is being drawn in.
 

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Discussion Starter #11
Thank you for your reply Autospark this info is really helpful to me. May I ask how I use a voltmeter to check for pressure in the rail?
 

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May I ask how I use a voltmeter to check for pressure in the rail?
You measure the rail pressure sensor signal voltage, which is proportional to rail pressure. It doesn't tell you what the actual pressure is (unless you know the mathematic formula to calculate it, which is what the PCM does) but it at least lets you know that pressure is building in the rail.

The PCM on a CRDi engine wont start to inject fuel into the cylinders until a specific minimum rail pressure has been achieved. That pressure equates to a sensor signal of 1V (on a Bosch system at least). If the sensor signal doesn't rise as high as that during crank no fuel is injected and the engine will never fire.

To measure the sensor voltage you need to back probe the signal terminal on the connector and connect your voltmeter to it. On the Bosch fuel systems that I'm more familiar with the signal terminal is always the center one on the connector. I'm not 100% sure that is the case on your Delphi system. No matter, it's easy to ID each terminal just by back probing each one with the ignition switched on. One terminal will have 5V (power supply), one will have 0V (earth/ground), and one will have 0.5V (that's the signal terminal). Connect your voltmeter to the 0.5V terminal then monitor the voltage during crank. See how high it gets.

Back Probing Sensor Signal Terminal (notice thin pin not the meter probe)
 

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Discussion Starter #13 (Edited)
I think I'm getting 5v constant (with ignition on and regardless of cranking) on the power supply and signal wire. This of course.. is presuming I'm doing it correctly as I'm not the best with electronics. I am using my black wire to go to earth on my multimeter and the red to probe the voltage. It seems that the middle terminal is earth (as I get 0v) and the 2 outer are power and signal. This is the same result as using my black proble on the middle terminal (i.e what I believe to be earth).
Hope this makes sense.
 

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Yes, it sounds like your doing it correctly but the signal voltage isn't right. These voltages are being measured with the sensor connected to the harness...right?
 

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Discussion Starter #15 (Edited)
Unfortunately.. I couldn't back probe as you suggested as there was no exposed wire/terminal from the rear of the harness connector (it seems to be all sealed). Instead I bridged the connector and sensor with some wire that had the insulation cut in the middle and took the reading from there.
 

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Discussion Starter #16
Ok so.... It seems I was testing it incorrectly. I managed to expose to back probe the sensor/connector correctly (as you suggested) and the signal wire isn't going above 0.5v when cranking (maybe 0.53v ish)
 

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Unfortunately.. I couldn't back probe as you suggested as there was no exposed wire/terminal from the rear of the harness connector (it seems to be all sealed). Instead I bridged the connector and sensor with some wire that had the insulation cut in the middle and took the reading from there.
Use a tap....Use sewing needles to pierce the insulation.
 

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Ok so.... It seems I was testing it incorrectly. I managed to expose to back probe the sensor/connector correctly (as you suggested) and the signal wire isn't going above 0.5v when cranking (maybe 0.53v ish)
You don't need to expose any of the wire to back probe the connector. Just slip a pin down the side of the wire and it will pass through the seal and make contact with the terminal inside the connector.

Your voltage measurement confirms that there is no pressure in the rail. You probably need to bleed the fuel system but that is often a major PITA on a Delphi system. See the video at the link below. It's made by the guy that I did my CRD training with and it'll give you an idea of what's involved. Admittedly his method is a little bit OTT.

Priming Delphi CRDi Fuel Systems
 

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Discussion Starter #19 (Edited)
I don't really have the tools to bleed the air, so I may have to call a mechanic out or try and source some hardware to do the job (out of interest, is the primer that is on the Terracan not sufficient to do the job?). Do you think that it's more likely to be air in the system as oppose to the pressure sensor being faulty?
 

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Hello,

not so long ago, I had a Ford Mondeo diesel which has no lift pump at all and is therefore very difficult to bleed.
I bought myself a vaccuum pump for really very little money and it was a really worthwhile investment.

Connected to the return pipe on the return side of the pump, a vaccuum pump will pull the fuel
all the way from the tank, through the filter and the high pressure pump to the return pipe and will therefore also
pull all the air out of the system at the same time.

Clear plastic pipes let you see when there is no more air and then the car would start.
If you cannot get bubble free fuel flowing through the pipe, then there could be a leak somewhere that needs investigating.

The same pump can be used in one person brake bleeding and also to remove excess oil from an overfilled engine
using the dipstick tube.
I have done both of these, having replaced the front to rear and cross axle Terracan brake pipes and also slightly
overfilled the engine at oil change time.
So much easier than accessing the sump plug and trying to let just a bit out without getting covered in oil.

I bought this one and at that price it could be seen as almost disposable.
It has become one of the most useful tools that I have.

If it still won't start, I would assume that cracking the injector feed pipes would remove the rest of the air once
the pump is fully primed but I would think that in the absence of other faults, it will start, just like the Mondeo in the video.
 
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