High. Pressure sensor and Fuel Rail pressure plausibility P1190

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Dreamed

Member
Posts
69
Location
Edinburgh
Hi guys!

I have a Freelander manual, TD4, '53 plate, Facelift.

After reading everything I could about fuel issues with Freelander I decided to ask for help as I'm a bit lost and I don't want to guess and buy things just to discover the issue is still there...

I recently changed the fuel filter (that rusty screw...omg)... after a few breakdowns and limp modes (p1260).

While replacing the filter I discovered the old filter was installed backwards by whoever the mechanic was... It was running like that for about a year.... I don't understand how it was possible. In any case, after changing the filter, car started and everything went back to normal...for a while. I also changed the oil and car was running sweet. And premium fuel is a blast.

Present Issue: P1190 Fuel Rail pressure plausibility

I also discovered a P0190 (FR pressure sensor)
P0191 Rail pressure offset test
P0605 Processor fault

But these last three never came back after deleting them. Only P1190.

The hippo has the EGR blanked, a Vortex breather, a new vent filter, air filter clean and I recently cleaned inlet manifold, but without taking the MAP sensor out. All these have been done this spring - summer.

Symptoms-> Rough idle, immediately after starting. RPM goes up and down. It settles after a minute. I start reving, in fist gear it accelerates slowly and with effort and the engine sounds as if it's abused. Basically low power.. I drive a few good minutes in second and third gear with relatively low power, but not that bad. Then as I stop at a traffic light and I accelerate again, usually in 2nd gear, when RPM reaches 1.9-2k it starts limping and engine rattles. Erratic rattle and limping up until RPM goes over 2.5k. Then it stops limping, but still low power. This symptom is exacerbated especially when I downshift from 3rd to 2nd and start accelerating as I release the clutch. 4th gear lags. It picks up slowly.

I went on bypass today and car doesn't push over 70MPH unless slightly downhill when I reach 80MPH. Problems start occurring when RPMs are around 2k. and below. I can hear the rattle and hesitation whenever RPMs drop to 2k. MIL usually comes when engine is warm already.

Occasionally I see smoke. Once it was blue, another time it was grey. It clears quite fast. Again, smoke appears sometimes when I slow down from higher gear and stop to idle.

Start-up:
Car normally starts with 2-3 seconds delay and hesitation. If its warm, no hesitation. Never really had any starting issues after changing fuel filter.

I inspected all hoses. Everything is fine now. I discovered a cracked turbo hose though. I replaced it, but that wasn't the problem apparently.

I did the injector leak test and they don't leak more than 20g a minute.

I cleaned the Camshaft sensor and I realised the screw that holds it in place doesn't screw completely, just spins endlessly, so I had to use some gaffa tape (for now) to make sure it's fixed. But I don't think that is the problem.

I cleaned the High Rail pressure sensor with contact spray, and inspected the wires visually. I cannot guarantee the connections are fine when plugged.

According to diagnostics. HP is around 26000- 28000 Kpa at idle and goes up to 125k at 65-70mph and 3kRMP. The values don't seem that bad, but I suppose fluctuations are concerning.

LOW pressure pump is about 360- 375 at idle (KPa I guess, diagnostic doesn't specify).
It usually fluctuates between 345 min and 390 max even at higher speeds and RPM.

Fuel pressure regulator current -> 0.7 at idle and increases to over 2.10. (1.21 at 62000 KPa high fuel pressure for example )

Inlet pressure 102.2 at idle.

The inlet temperature is most of the times low, starting from 19 degrees and increasing to max 25 I would say.

And the cherry on top of the cake...if I remove the Green HFR Pressure sensor while engine running, the rattle disappears and the engine sounds smooth immediately. I drove without the sensor connected for some time and P1190 never appeared (probably cause it's dependent on the sensor). There was no limping or rattle, just low power... It seems the loom/harness has been changed already as I see the old wires cut next to the green thingy.

So, could you please tell me what all this means? The car limps with sensor connected and also rattles and as soon as it's disconnected rattle stops and engine becomes silent and decently smooth. Could that indicate something with a high probability? I will inspect continuity on the cable tomorrow...but I cannot guarantee the actual contact to the actual sensor is 100% bulletproof. I tried moving the green plastic with engine at tick-over, but nothing really changes. In any case the problem occur under load not when I rev the engine stationary. I would attempt cleaning the sensor, but I've read once it's taken out, it better be replaced. How can I test if the sensor is 100% broken?

I've been trying to solve this for about two weeks now... Any help would be appreciated. Thanks!
 
a couple of things to check, cleaning the inlet manifold without removing the MAP sensor is not good, so that maybe damage,? I presume you jet washed the inlet out, try changing the vortex filter back to the wool type blue filter, and reinstate the EGR making sure it is clean and working as it should. after that maybe try a different fuel rail sensor, I think I have a couple somewhere, and a spare MAP sensor
 
Hey Arctic, thank you so much for your reply. Yes, I realised too late I didn't take the MAP out. :eek: The car was fine though for over 3 months after cleaning the inlet, which was not jet washed by the way, as I don't have access to such equipment. I just soaked it in degreaser. Also the diagnostics give me a MAP reading, which doesn't seem to be so far from the truth. The only thing I don't understand is why MAP goes from 102.2 to 101 - 100 Kpa when I start reving and only a few seconds later it goes up. I will reinstall EGR and put a wool filter back, but I'm sceptical as most people here seem to have their EGR blanked and cyclone mod installed and are fine. But I'll try anything. As for the spare spares, that sounds amazing :D.
 
The only thing I don't understand is why MAP goes from 102.2 to 101 - 100 Kpa when I start reving and only a few seconds later it goes up

Sounds like the MAP sensor is faulty. The reading should climb above 100Kpa as soon as the engine is revved up. The MAP should give a reading of about 185Kpa at full boots.
If the EDC doesn't see an increase in MAP, then it won't apply more fuel.
 
Thanks for your input! I will check live readings again, but as I said the pressure goes up to 185 eventually, just a small delay, which is normal with live readings, I guess...

You might be right and MAP sensor is at fault, still how come car works without limping when high pressure sensor is disconnected?

I would like to restate the issue. Code P1190 Fuel Rail pressure plausibility. Main symptom, rattles and cuts intermittently at around 2000RPMs. Symptom goes away when HP sensor disconnected, except for lack of power, but that is to be expected I guess.
 
Also, could anybody confirm, with a full working TD4 what are the readings for Low Pressure Pump? I've heard some people saying it should be operating at 4 bars+. Others say 3.5. It's obvious my Low side pump is not new, yet no P1260 code anymore after changing filter.

I see on the description of OEM pumps that they operate at 5 bars. So thats a huge difference... But if anyone confirms their pumps runs 350-390 like mine does, then I'll know that's not the issue.
 
Also, could anybody confirm, with a full working TD4 what are the readings for Low Pressure Pump?

Your low pressure rail is fine, mine runs perfect on 330 to 355Kpa. The EDC will flag low pressure (MIL on) at ~275Kpa and will generally cut injection altogether if it drops below 250Kpa.

Have you checked the HP rail sensor or its harness? There is an overly harness available to replace the poor quality original HP rail harness.
 
Have you checked the HP rail sensor or its harness? There is an overly harness available to replace the poor quality original HP rail harness.

I did, continuity checks with 5v and I believe the harnes was replaced already as I see the old orange one hanging there with cables cut. I have the green harness. What bugs me is that high pressure reads OK @26000+ kpa at idle and up to 130k at 3k revs 5th gear...
I tried fiddling with connection, but nothing happens unless I unplug it completely and engine says: Thank you, I needes this .

As for low pressure pump I am asking because I can hear some weird erratic sounds coming, like a glurg. Maybe it’s from sedimentor. Are we talking about the low pressure pump for TD4 after 2002 right? (when it was upgraded) Not 100% sure 2.5 is the minimum requirement for later models. I wonder why some people say 4+?

Having a diagnostic helps but I wish I knew what the values need to be for a functional facelift td4.

I will clean Map sensor next. Maybe disconnect MAF sensor and reconnect high pressure sensor to check if maf is changing anything.
 
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Are we talking about the low pressure pump for TD4 after 2002 right? (when it was upgraded) Not 100% sure 2.5 is the minimum requirement for later models. I wonder why some people say 4+?

The engine won't run correctly if the low rail is under 250Kpa, as there's a risk of damage to the HP pump. If the low rail drops below 250Kpa, the malfunction lamp comes on and power is limited. If the EDC determines the low rail is too low for the HP pump to remain protected, it inhibits running altogether. An acceptable running pressure on the low rail is anything over 300Kpa, however the EDC will accept anything over 275Kpa as ok.
The low fuel delivery pressure can as high as 400Kpa, but this varies with pump and filter quality. In reality, most low pressure rails run at between 330 and 360Kpa, which is more than enough.
 
The engine won't run correctly if the low rail is under 250Kpa, as there's a risk of damage to the HP pump. If the low rail drops below 250Kpa, the malfunction lamp comes on and power is limited. If the EDC determines the low rail is too low for the HP pump to remain protected, it inhibits running altogether. An acceptable running pressure on the low rail is anything over 300Kpa, however the EDC will accept anything over 275Kpa as ok.
The low fuel delivery pressure can as high as 400Kpa, but this varies with pump and filter quality. In reality, most low pressure rails run at between 330 and 360Kpa, which is more than enough.

Hi John.
Below are a few snap shots of the M47 on a R40 diesel.
 

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Ok thanks for that! Valuable info!

Now I have an update. Don’t know why I didn’t mention it before, but when key is in ignition I can hear a hiss coming from the high pressure pump or around it. More like underneath the engine mount or maybe behind the actual hp pump.

I will upload a video soon. Meanwhile I am curious to know if that hiss is normal. The hiss stops when priming of the LP pump is over. I think that hiss will stay there all the time as long as LP pump spins.
 
Here's the video.


at the end I show the voltage reading for rail sensor return voltage (backprobe)
It could be the fuel being pumped through the HP pump. It could also be the HP regulator beingmodulated by the EDC. If you unplug the HP reg, does the noise stop? If not, then it's likely the fuel flowing through the pump.
 
It could be the fuel being pumped through the HP pump. It could also be the HP regulator beingmodulated by the EDC. If you unplug the HP reg, does the noise stop? If not, then it's likely the fuel flowing through the pump.
By HP regulator you mean HP fuel sensor?
If yes, noise doesn't stop if I disconnect it.
I've read many people hear that hiss and that is normal, but cannot be 100% sure.
 
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