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Renault Traic 1.9Dci 2005
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Discussion Starter #1
hi,
I have a Renault Trafic 1.9dci 2005
Non runner, turns over but no start, before it stopped running it was struggling to idle, running rough and accelerator peddle had a mind of its own.
Had a mechanic come look, and found that there are volts on the neutral cable running from ecu to fuel pump regulator... Traced neutral/ground wire cable back to ecu, no damage on cable, I now have disconnected the ECU opened it up, but it all looks good inside, no water egress or burn marks,
So I am have opened up the loom to check the cables, checking and cleaning plugs to see if any correction, pulling fuses and cleaning connections, making sure all earths are good (battery and body)
I am hoping someone might be able to advise my next course of action, or diagnose the root of the problem, as I have well past my ability lever, and slowly losing the will to live,
thanks for reading.
 

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Super fantastic Mod Technical Supremo Nice Guy
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Confused

How many volts.
Sure its not a passive volt and not a fault
Glow plugs show a voltage, but battery never goes flat ( Passive volts )
Where is the fuel pump regulator on this ???????
 

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Super Moderator Technical Supremo Platinum Member
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If it is the fuel pump regulator I am thinking of, in the back of the pump, getting a spurious signal is no surprise to me.
About all you can do without an oscilloscope is check if you have 12v between the feed wires.
It regulates via a pulsed signal at high frequency, a normal meter simply gets confused.
And if I recall correctly it is switched earth, ie the ECU controls the pulse by switching the earth electronically.
Often leakage when that happens, easy to measure a volt or so difference between a switched and a solid earth.

Personally I would be checking the common causes of poor idle and hard starting....
Fuel feed, EGR, Injectors leaking are common items, have all been checked.
 

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Discussion Starter #4
Confused

How many volts.
Sure its not a passive volt and not a fault
Glow plugs show a voltage, but battery never goes flat ( Passive volts )
Where is the fuel pump regulator on this ???????
3.5v coming from the ecu going to fuel pump regulator, situated on the right-hand side of the high pressure pump, its a 2 wire sensor
 

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Discussion Starter #5
If it is the fuel pump regulator I am thinking of, in the back of the pump, getting a spurious signal is no surprise to me.
About all you can do without an oscilloscope is check if you have 12v between the feed wires.
It regulates via a pulsed signal at high frequency, a normal meter simply gets confused.
And if I recall correctly it is switched earth, ie the ECU controls the pulse by switching the earth electronically.
Often leakage when that happens, easy to measure a volt or so difference between a switched and a solid earth.

Personally I would be checking the common causes of poor idle and hard starting....
Fuel feed, EGR, Injectors leaking are common items, have all been checked.
thanks, and yes Fuel feed, EGR, Injectors leaking all checked, split the cable to see which side was giving volts (ecu side)in morning going to check the relays & got a plug&play ecu for £45 will stick that on, been looking all over for a wiring diagram for other components/sensors sharing the circuit but cant find one and the Haynes Manual has not got it (or it has and i can't find it)
Anyway will update the thread when it eventually gets sorted.
 

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Discussion Starter #6 (Edited)
All relays tested, all Good.
Fuse/relay box clean, no corrosion
NOTE: I am updating this thread as I go to hopefully help eliminate possible issues for other members in the future if they suffer the same "crank no-start" with similar symptoms as myself.
187426
 

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Super Moderator Technical Supremo Platinum Member
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Before you swap the ECU, what fuel pressure are you getting on crank?
 

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Discussion Starter #8
Before you swap the ECU, what fuel pressure are you getting on crank?
Personally never checked, (my crap scantool would not show live data but the mechanics snap-on did) I cranked it whilst he was checking the data and codes, when I asked him, he said it was "fine".. I am starting to wish I had been more forthcoming in my request for knowing what data he was seeing, I think that when he back probed the connector he got the volts on the fuel pressure regulator neutral ,he got it in his head that it had to be a 1. short in the loom, but then when he put a trace on the cable it was clear back to the ECU he decided 2. it was the ECU.. I was sceptical, but he was so sure, when we opened up the ecu and it was bone dry and no burn smell or marks he still was confident that it was the problem.
So I found a plug&play ecu for £45 ...going to leave it till the ECU gets here on Thursday... But I am becoming more sceptical by the hour that the problem is elsewhere.. But time will tell.
 

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Uhmmmm
I got this problem, whenever someone blames the ECU I get this reflex thought...why?
The answer is that it is often the bit they don't understand so they will blame that instead of checking other items.

Not always true but it is often enough for me to question an ECU replacement.
 

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Discussion Starter #11
Uhmmmm
I got this problem, whenever someone blames the ECU I get this reflex thought...why?
The answer is that it is often the bit they don't understand, so they will blame that instead of checking other items.

Not always true but it is often enough for me to question an ECU replacement.
I am starting to agree, by him sticking with its the ECU, I feel stuck until I can prove otherwise. If it turns out not to be the ECU (which i am starting to suspect is the case) it will confirm my suspicion that he did not really understand and/or able to find the root of the problem, so used the ECU as a get out of jail free card;)
But on the plus side...
All the wires got a few days out of the wiring loom to get a sun tan:p
& I found a socket I dropped the back of the engine last year(y)
 

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What do you mean by accelerator pedal had a mind of its own??

Not responding or revs running away or what?

I assume that things like TDC (crank) sensor have been checked?

Were there any warning lights on dash or any stored faults in diagnostics?
 

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Discussion Starter #14
What do you mean by accelerator pedal had a mind of its own??

Not responding or revs running away or what?

I assume that things like TDC (crank) sensor have been checked?

Were there any warning lights on dash or any stored faults in diagnostics?
What do you mean by accelerator pedal had a mind of its own??
Before it was a non-starter, the van would have a delay in revving, & sometime not rev when depressing accelerator pedal and also revs running away after accelerator pedal was released, This all came on over the space of a hour, before that it was all running fine.

I assume that things like TDC (crank) sensor have been checked?
Yes, i replaced the crank and cam sensor before I called the mechanic, I also replaced the glow plugs, checked fuses and relays

Were there any warning lights on the dash or any stored faults in diagnostics?

no engine management light,
glow plug light comes on and goes off after a few seconds but the glow plug light comes back on after a few seconds
immobilized light works as it should
the only fault codes I got on my crap code reader were for the seatbelt tensioners, as I had removed/swapped seat and not plugged them back in agos ago...

I know now, i should have not just left him to it, and should have got the codes he got with his scan tool, but I thought I would be able to trust him as he was so confident he knew what the problem was..
in hindsight, I was being very naive
 

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Discussion Starter #15
Here is what the "machanic" report looks like

Importance:CRITICAL
Description:Tech found fuel pressure regulator valve buzzing, tested electrics and found no wiring fault, tech has found that the fuel regulator senor has 2x powers instead of 1x. It should be 1x power and 1x earth, pin 1 showing battery voltage which is good and pin 2 showing 3.6v which should be earth. Traced wire going to ecu from the regulator and the ecu is pushing 3.6v through to earth at the component. Tech strongly advised to get ecu tested.
Trouble code(s):Ecu needs sending of to be tested
 

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Super fantastic Mod Technical Supremo Nice Guy
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post your oval plate, lets get the wiring diagram up and have a look..
THIS was all WITH the key out , not on position 1
AND this fault kept draining your battery
 

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That's better information though still doesn't jangle any solid thoughts towards what the problem may be.
Give your oval plate info for Ourkid pls and bear with me rambling here in the hope it generates something useful.

Reading your mechanics report I am less cynical, if only because he recommended testing the ECU not replacing.
Less happy as the indications are a fuel regulation fault yet he said fuel pressure levels were "fine"
And not sure if the volts on the earth wire were with the regulator connected or not ??

The fuel regulator is the "throttle" that drives the revs, faults with that can give all the faults you describe.
Please confirm sudden onset not dragged on for weeks?

The indication that the fuel regulator is doing what it should comes from the fuel pressure sensor.
The ECU says let's have X pressure and send the signal to the regulator.
The regulator changes pressure to suit
The sensor reads what the pressure is and hopefully all is well.
If it isn't, the ECu signals a error and indicates this on the dashboard by lighting the Glow Plug Light.
If the light was on the mechanic should have seen an error message re fuel pressure.
Probably wouldn't unless the light was on as these can be lost when ignition off.
But there is no way that a data read out of the fuel pressure would look right "fine" if the regulator is playing up...would be low or all over the place or jagged if in graphical form.
So far so good, things are making more sense to me now even if not solved the problem.

Pressure regulators normally fail mechanically.... they are no more then a solenoid operated cone that opens and closes a hole to let more or less fuel through and thus control the pressure...the cone jams, dirt, wear so it doesn't close completely...mechanical.
Second is electrical.... it is Pulse Width Modified voltage...basically a high frequency pulse system and the ratio between pulse at 12v and pulse at 0 gives the amount the solenoid opens.... buzzing would indicate an electrical issue.
But at the moment not sure whether that is the valve or the ECU or if the valve failed and that has taken the output in the ECU or what.
If the 3v on ground is with the valve connected, it could be the valve shorted, if it is disconnected, it can be a spurious voltage that is confusing the test meter or simply a floating ground...those often show a voltage.
And could be the ECU duff.

I don't like playing parts darts but if I was going to spend on a guess I would be swapping the regulator....
Or sending the ECU for testing
I would not be buying a virgin ECU at that price cos I simply don't trust it and because even if it is pukka, you would need CanClip to set it up.
And if it turned out to be a regulator fault that has taken the ECU, plugging a new ECU in would only bu55er that one as well.
 

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Discussion Starter #18
post your oval plate, lets get the wiring diagram up and have a look..
THIS was all WITH the key out , not on position 1
AND this fault kept draining your battery
no, it was with key on, and no the fault is not draining the battery,
 

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Discussion Starter #19
That's better information though still doesn't jangle any solid thoughts towards what the problem may be.
Give your oval plate info for Ourkid pls and bear with me rambling here in the hope it generates something useful.

Reading your mechanics report I am less cynical, if only because he recommended testing the ECU not replacing.
Less happy as the indications are a fuel regulation fault yet he said fuel pressure levels were "fine"
And not sure if the volts on the earth wire were with the regulator connected or not ??

The fuel regulator is the "throttle" that drives the revs, faults with that can give all the faults you describe.
Please confirm sudden onset not dragged on for weeks?

The indication that the fuel regulator is doing what it should comes from the fuel pressure sensor.
The ECU says let's have X pressure and send the signal to the regulator.
The regulator changes pressure to suit
The sensor reads what the pressure is and hopefully all is well.
If it isn't, the ECu signals a error and indicates this on the dashboard by lighting the Glow Plug Light.
If the light was on the mechanic should have seen an error message re fuel pressure.
Probably wouldn't unless the light was on as these can be lost when ignition off.
But there is no way that a data read out of the fuel pressure would look right "fine" if the regulator is playing up...would be low or all over the place or jagged if in graphical form.
So far so good, things are making more sense to me now even if not solved the problem.

Pressure regulators normally fail mechanically.... they are no more then a solenoid operated cone that opens and closes a hole to let more or less fuel through and thus control the pressure...the cone jams, dirt, wear so it doesn't close completely...mechanical.
Second is electrical.... it is Pulse Width Modified voltage...basically a high frequency pulse system and the ratio between pulse at 12v and pulse at 0 gives the amount the solenoid opens.... buzzing would indicate an electrical issue.
But at the moment not sure whether that is the valve or the ECU or if the valve failed and that has taken the output in the ECU or what.
If the 3v on ground is with the valve connected, it could be the valve shorted, if it is disconnected, it can be a spurious voltage that is confusing the test meter or simply a floating ground...those often show a voltage.
And could be the ECU duff.

I don't like playing parts darts but if I was going to spend on a guess I would be swapping the regulator....
Or sending the ECU for testing
I would not be buying a virgin ECU at that price cos I simply don't trust it and because even if it is pukka, you would need CanClip to set it up.
And if it turned out to be a regulator fault that has taken the ECU, plugging a new ECU in would only bu55er that one as well.
Thanks for your info,

And not sure if the volts on the earth wire were with the regulator connected or not ??
Both connected & disconnected... even cut the cable when disconnected to make sure the volts came from the ecu sfeed side

The fuel regulator is the "throttle" that drives the revs, faults with that can give all the faults you describe.
Please confirm sudden onset not dragged on for weeks?
All came on very quickly, from running rough, to sporadic throttle, cutting out all came on over the course of 1-2 hours then ultimately , non-starter

I don't like playing parts darts but if I was going to spend on a guess I would be swapping the regulator....
Or sending the ECU for testing
Yes, just buying a new fuel pressure regulator, (already replaced fuel rail pressure sensor) and going to stick a new pressure release valve at this stage a bit of parts darts seems to be my best option, and will fit the new parts and refit original ecu before trying the replacement ,

Parts Should be with me by Friday,
 

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Discussion Starter #20 (Edited by Moderator)
post your oval plate, lets get the wiring diagram up and have a look..
THIS was all WITH the key out , not on position 1
AND this fault kept draining your battery
VF1FLACA66V26****
Renault Trafic II 2005 Diesel Van 1.9 dCi 100 FWD -- FL 1870cc 74KW 101HP F9Q 760

I've edited the VIN number to protect you. DD
 
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