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Santa Fe non starter

CpLuAg

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Hi all, struggling with a Hyundai Santa Fe non starter. OY11 ZTW KMHSH81XNBU727692
Wondering if anyone has any ideas as I’m not brilliant at diagnostic but I’ll always have a go.
Vehicles a 2011 2.2 TCI Diesel. Unfortunately through a combination of myself and other garages, so far it’s had a second hand high pressure fuel pump, new fuel metering valve and regulator, rail pressure sensor, engine ECU and a fuel filter.
With a little brake cleaner it starts and runs all day, fuel pressure normal 29.00MPa 19% duty at rail regulator at idle but in limp mode due to fault code intermittently in ECU after starting on brake cleaner, fuel rail pressure too high P0088. As soon as vehicle is shut off it will crank until battery dies.
I’ve checked wiring between injectors, fuel pressure sensor, metering valve and regulator back to ECU, no faults found. During crank the injectors are not being activated but as soon as it picks up on the brake cleaner and fires up, the injectors start working, it’s a site vehicle so I’m on and off it as and when we get a gap inbetween jobs.
Fuel temperature reading is normal, I’ve checked the new Bosch rail pressure sensor against Bosch specified readings and it’s within spec at idle, cranking and rest. However when cranking PID data shows cranking at high pressure, measured a while back so don’t have the exact figure, I think around 55.00MPa..
I’m not sure how the ECU is seeing high pressure during cranking as what I measure at the rail pressure sensor is within spec so i thought that was the cause of it not firing the injectors. I spoke to ECU testing and they had 4 other cases where this same fault had been reported with failed ECU’s shutting off injectors on cranking but they were unable to repair the ECU’s.
It’s probably going to be something silly I’ve overlooked but obviously this vehicle is becoming a bit of a money pit, thankfully not at the customers expense, this vehicle was sold to us as the previous owner had given up trying to get this fixed elsewhere.
thanks In advance.
 
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ChrisEarls

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I know you have fuel pressure fault but Hyundai always cut out with fuel faults and restart after key out for 10seconds. Have you looked at any crankshaft sensor readings? I have come across this before
 

CpLuAg

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Hi, thanks for your reply. This vehicle once started on brake cleaner doesn’t cut out it will run for aslong as you leave it on but once shut off it won’t start hot or cold even if I take the key out for 10 seconds and retry.
I've been working through diagnostic steps with a technical helpline and we thought we’d found it with the ecu not firing the injectors during crank when the rail pressure sensor was in spec but ecu was seeing high pressure so I haven’t looked at the crank sensor readings yet. I will hopefully check it tomorrow and get back to you. Cheers
 

CpLuAg

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Hi, didn’t get a chance to have a look last weekend and I’m off all this week. Boss was on about cutting his losses and selling it when I finished last week but it’s a great car to learn on so hopefully it’ll still be when I’m back in. Will keep you posted.
cheers
 

CpLuAg

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Update, vehicle still on site. Had half hour free so i checked the low side fuel pressure after filter, battery flat and booster not enough to turn over so just with ignition on I get 4 bar of pressure. Will update on cranking pressure when I get time to work on it again, thanks
 

ChrisEarls

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Update, vehicle still on site. Had half hour free so i checked the low side fuel pressure after filter, battery flat and booster not enough to turn over so just with ignition on I get 4 bar of pressure. Will update on cranking pressure when I get time to work on it again, thanks
Did you get a reading yet for your crank sensor? The 2.2 gave very little trouble with hp fuel side few pumps and injectors but generally when their gone they will start but once the engine comes under small load it will cut out flag fuel pressure fault and start again once the key comes out of the ignition for ten seconds. You’re low pressure is fine, so what is your scan tool telling you about your high pressure. The crankshaft sensor will give you the same symthoms on these as it’s not seeing high enough engine speed until you give it a dart of brake cleaner. If you’ve no way of scoping the crank sensor I’d just throw one into it because if it’s not the problem now it’ll be a problem at some stage on it they always are.
 

CpLuAg

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Did you get a reading yet for your crank sensor? The 2.2 gave very little trouble with hp fuel side few pumps and injectors but generally when their gone they will start but once the engine comes under small load it will cut out flag fuel pressure fault and start again once the key comes out of the ignition for ten seconds. You’re low pressure is fine, so what is your scan tool telling you about your high pressure. The crankshaft sensor will give you the same symthoms on these as it’s not seeing high enough engine speed until you give it a dart of brake cleaner. If you’ve no way of scoping the crank sensor I’d just throw one into it because if it’s not the problem now it’ll be a problem at some stage on it they always are.
Hiya, thanks. Yeah it’s a site vehicle so it’s as and when work goes quiet, I asked my boss for a low side fuel pressure tester but he got a high pressure petrol injection pump test kit from eBay for £25, I managed to make something fit but it gives you some idea of why things take so long.
i haven’t scoped the crank sensor the boss seems to think we’ve fitted one already but I don’t remember doing so. The high pressure reading is erratic peaks and troughs. I can read cranking speed and it gets up to around the 250 rpm if I remember, I will get a picture next time I crank it but it’s not a steady rise on the fuel pressure anyway it’s all over the place. I dip in and out of this so my memory gets abit muddled about what has been tested now but once running fuel pressure is bang on specified and regulator valve duty cycle is bang on. Ill take your advice and take a punt and order a crank sensor, if it has been done I’ll send it back, there’s no customer involved so it’s on me, are aftermarket sensors usually ok on these or has it got to be genuine?
 

CpLuAg

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Got an hour on it today. I’ve checked cranking fuel pressure on the low side, 3.2 bar so I’m happy with that.
Back probed the cam and crank and the zoom function is utter rubbish on the snap on as I’ve said before so I’ve done the best I could to keep the quality.
The crank sensor is hidden behind the starter motor and I couldn’t get one today. I’ve attached a picture or three of readings for viewing.
 

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CpLuAg

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is it cranking fast enough to trigger the injectors ?
Hi, no it doesn't trigger the injectors. I've had a booster pack and just a fully charged battery on it before and its spins over quickly but wont fire up, a few sprays of brake cleaner and it will pick up on it causing it to spin over faster and faster then fire into life and runs until switched off. thanks
 

Jodiephillips

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Hi, no it doesn't trigger the injectors. I've had a booster pack and just a fully charged battery on it before and its spins over quickly but wont fire up, a few sprays of brake cleaner and it will pick up on it causing it to spin over faster and faster then fire into life and runs until switched off. thanks
from the crank capture i think its only cranking at about 180rpm which maybe to slow
60000ms / 325ms =184 rpm
 

Mark-C SDN

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What is the data telling you whilst its cranking?
 

CpLuAg

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from the crank capture i think its only cranking at about 180rpm which maybe to slow
60000ms / 325ms =184 rpm
hi, yeah at this point the battery was dying again, i just wanted to capture a waveform before i finished for the day to check for any anomalies in the signal itself, i've not long been using a scope so i'm not too familiar with how to tell exactly when they are bad, i see alot of zooming in using a pico scope to see bad waveforms on videos i watch but believe me this thing wont zoom at any decent quality or freezes up.. and what voltages should the signal be reaching while cranking, whether that even makes a difference.. i will be getting a Pico scope eventually and i have afew courses booked too now they are running again so with all this i hope to finally fix this car or at least understand how to test it better, doesn't help i may have an hour a month on it haha. Yeah the data pid shows cranking at about 250 rpm normally. thanks
 

Ian d

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Hi i have similar fault symptom before on a mondeo, RC test showed starter motor interference/ major spikes replaced starter motor and all ok. A quick RC test may be key
 

CpLuAg

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Hi, no haven’t tried towing, brakes are sticking on due to it being parked up for so long, it’s a job to even push it and we don’t really have anything on site suitable to tow this vehicle at the moment but I’ll keep it in mind if we do.
Haven’t tried an RC test, I will try add that to the test list for when I get it back in again, many thanks
 

Grant Watkins

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Sounds like you are not achieving specified fuel pressure, the engine Ecu will not start firing the injectors unless specified fuel pressure is reached. With a bit of brake cleaned added the engine will crank faster and start to run on the brake cleaner which will get the pump to achieving the specified fuel pressure. You either have poor supply on your low pressure side or a leak on the high pressure side. Hyundai line the fuel tanks with a material that can come away and block the fuel tank filter, have had several Santa Fe do it. All the ones I have done you could get to sender unit under the back seats.
 

CpLuAg

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Sounds like you are not achieving specified fuel pressure, the engine Ecu will not start firing the injectors unless specified fuel pressure is reached. With a bit of brake cleaned added the engine will crank faster and start to run on the brake cleaner which will get the pump to achieving the specified fuel pressure. You either have poor supply on your low pressure side or a leak on the high pressure side. Hyundai line the fuel tanks with a material that can come away and block the fuel tank filter, have had several Santa Fe do it. All the ones I have done you could get to sender unit under the back seats.
Hi, that's my thinking, the ecu is not seeing the information it needs to trigger the injectors i'm just struggling to find out what its not seeing. i have checked the low pressure side and am getting 4 bar ignition on and 3.2 when cranking, once started the car runs and revs ok, would a blocked pick up pump not cause running problems/cutting out? The high pressure pump has been replaced with a second hand unit, high pressure fuel is erratic/unsteady when graphed at cranking speed but once running will run at the specified idle pressure and regulator duty cycle is bang on spec by manufacturer.
I'll get the fuel pressure gauge back on and run it just to make sure the low side is ok, i don't have a high pressure tester but during crank the rail pressure sensor is reading within spec as stated by bosch and is a new bosch sensor. thanks
 

Mark-C SDN

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>>> high pressure fuel is erratic/unsteady when graphed at cranking speed <<<

Thats possibly your issue right there.

Give me a call if you want a sounding board.
 
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