Chrysler grand voyager 2004 2.8 CRD – engine cut-out when ac

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Chrysler grand voyager 2004 2.8 CRD – engine cut-out when ac

Postby PAulC » Fri Aug 11, 2017 1:00 am

I have a 2004 Chrysler grand voyager CRD 2.8 which suffers from a problem where the engine cuts out when accelerating between 2000-3000 RPM (under load) over a period of four to six seconds.

I have installed a clear fuel pipe and can see that there is no air in the fuel as it enters the high pressure fuel pump. After the engine has cut there are no codes reported or pending (using a simple code reader) and the MIL light is off.

I have attached the picoscope A probe to the fuel pressure sensor and recorded the readings for the period the engine is running fine and when it cuts out. The FPS sensor is reading a cycling voltage between 3.0V to 3.4V (~1800hz) and the engine runs fine. If the load is maintained and the engine is running between 2000 and 3000 RPM the reading will drop over a four to six second period to around 2.598V and the engine cuts. The engine will restart no problem and the fault is repeatable.

Please see attached images of the trace.
engine cut -3s (normal).jpg
three seconds before cut

First 400ms above shows the normal FPS level with no engine problems.

engin cut -2s.jpg
two seconds before cut

chart above shows Fuel pressure is dropping

engine cut -1s.jpg
1 second before cut

chart above shows Fuel pressure is dropping to what appears to be a trigger level for ECU to shutdown

engine cut.jpg
Fuel pressure sensor at point of engine cut

chart above shows Fuel pressure is dropping, then the ECU appears to cut the injection pules causing the engine to stop. The fuel pressure rises momentarily and then bleeds away.

The fuel pressure sensor, fuel pressure valve and the pressure relief valve have been swapped with no effect on the traces.

If the engine is run with a wide open throttle at ~4000 RPM the fuel pressure reading stays at the 3.4V level and the engine doesn’t cut out, running at full speed for 30+ seconds.

My current thinking is that the injectors are misbehaving and leaking fuel pressure off the rail when the engine is running at ~2500RPM. At this speed the pump pressure delivered is not sufficient to overcome the losses from the injectors and the rail pressure drops triggering a shutdown. I have performed a leak test at idle and all four injectors leak fuel at the same rate. I had the car checked by the local Bosch specialists and they “tell me” they removed and tested the injectors. However the injectors look uniformly dirty and there are no signs of cleaning or any clean patches on the rocker cover which I would expect if they had been removed.

Any ideas on how to identify the fault system component?

Number two and three in the potential fault list are the high pressure fuel pump itself and the pressure control valve operation. I’ve parked the idea that the high pressure fuel pump is the cause because the engine appears to run fine on full throttle at the higher revs for a sustained period.

Any thought or questions welcome!

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Re: Chrysler grand voyager 2004 2.8 CRD – engine cut-out whe

Postby STC » Fri Aug 11, 2017 9:27 am

From what I can see on a basic diagram is that it
1. does not have an electric fuel pump ?
2. Pressure is controlled only by the SCV / IMV on the back of the pump ?

All you really need to do is establish if the pump is being fed properly, is it capable of producing pressure. If so where is the pressure going, or more accurately which restriction is missing preventing pressure generation.

You will need a gauge or transducer teed into the inlet and be looking for about -150 - 200mB rising to 6 - 650mB when you clamp the pipe off forcing it to suck harder. I have had to monitor flow out on the road to get failure in the past.

Unplug the IMV, injectors to prevent it starting, and you should achieve 1000 + bar in 3-4 seconds. Scope the FRP at the same time looking for a rapid even increase.

One end of the rail will have a relief valve, remove the hose and plug it so it wont leak. Attach a pipe and a bottle to that valve outlet. Then drive it to failure and note what is in the bottle.

As for the injectors you can cap one off at a time and look for improvement in FP.
Last edited by STC on Fri Aug 11, 2017 8:25 pm, edited 1 time in total.
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Re: Chrysler grand voyager 2004 2.8 CRD – engine cut-out whe

Postby PAulC » Fri Aug 11, 2017 2:54 pm

STC, many thanks for your comments,

1. does not have an electric fuel pump ?
2. Pressure is controlled only by the SCV / IMV on the back of the pump ?


Right on both counts. The high pressure pump is a Bosch CP3 which has a two gear low pressure suction pump to pull fuel from the tank into the high pressure pump, controlled by the IMV. (I'm assuming the modulation in the pressure recording is the IMV doing its thing)

The 2004 and earlier CRD GV's have a lift pump at the back near the tank which runs for 15 seconds after turning on the ignition to prime the fuel system.

You will need a gauge or transducer feed into the inlet ...

I have attached a fuel pressure/vacuum gauge to the fuel feed test point and it shows five In Hg when idling. Clamping the fuel pipe cause the vacuum to rise to 30 In Hg and the engine continues to run ok.

I've also run some tests today with the crankshaft sensor monitored. Looks absolutely fine with no abnormalities. I also reran the high RPM test. Revs at ~4200 with wide open throttle engine ran fine for 30+ seconds. the fuel pressure stayed high throughout.

fuel pressure + crankshaft sensor.jpg
Running at ~4200 RPM Fuel pressure stays high


regards
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Re: Chrysler grand voyager 2004 2.8 CRD – engine cut-out whe

Postby STC » Fri Aug 11, 2017 9:30 pm

The fuel pressure sensor, fuel pressure valve and the pressure relief valve have been swapped with no effect on the traces.


Are you of the opinion that if your "Pressure Relief Valve" WAS allowing fuel to leak past it, the replacement "known good" WILL eliminate that as a Cause of your issue ???

That is a heavily loaded question :)
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Re: Chrysler grand voyager 2004 2.8 CRD – engine cut-out whe

Postby PAulC » Sun Aug 13, 2017 10:09 am

Hi STC,

I'll give it a try and see what happens.

I notice there are lots of different Bosch IMV's around. Any idea what the differences are? I have one marked 3.1, the one in the Voyager is marked 2.6 and a spare from a different Voyager is marked 2.5.

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Re: Chrysler grand voyager 2004 2.8 CRD – engine cut-out whe

Postby STC » Mon Aug 14, 2017 10:44 pm

Please Read again.

I have not mentioned replacing the IMV !
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Re: Chrysler grand voyager 2004 2.8 CRD – engine cut-out whe

Postby PAulC » Sat Aug 19, 2017 12:02 am

STC,

It's an additional question. Any idea what the markings indicate?

regards

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Re: Chrysler grand voyager 2004 2.8 CRD – engine cut-out whe

Postby STC » Sat Aug 19, 2017 11:55 am

I think we are both off track here.

Are you of the opinion that if your "Pressure Relief Valve" WAS allowing fuel to leak past it, the replacement "known good" WILL eliminate that as a Cause of your issue ???


Here I refer to the "Pressure Relief Valve" on the rail. That will be the ball bearing effort with a pipe into the return.


I notice there are lots of different Bosch IMV's around. Any idea what the differences are? I have one marked 3.1, the one in the Voyager is marked 2.6 and a spare from a different Voyager is marked 2.5.


No idea, hence cannot tell you if the are interchangeable. If you were to use a PWM emulator with scope on FRP then you could fit and test all 3 to see if there is any difference in them.

My thoughts are that this is not an IMV issue, that said I dont have the car in front of me.

I had a CR VAG this week that once warm on moderate to high load would have a fuel pressure deviaton of some 180 bar for literally milliseconds, you had to graph it to see it and the car ran and pulled well, those millisecnds of deviation unfortunately were long enought to put the EML on. No other issues with it. Only 50,000 miles on the clock.

Leak off test was good, both static and as it faltered using a Pressure transducer and scope. Smooth Running Values were very low (less than 0.5 on all 4) upto 2250 rpm so not much use to me when I needed them
I found that to be Injector 3 by a long process of elllimination. The garage took that Bosch Injector to a Bosch Diesel Service Centre who charged them to test it and confirmed it to be serviceable. New Injector and it is confirmed fixed.

Moral of the story is that I too could not believe a slightly worn injector could cause a near 200 bar deviation but the evidence is that it did. These diesels are not very forgiving, the slightest thing will make them go wonky.
Last edited by STC on Tue Aug 22, 2017 10:27 pm, edited 1 time in total.
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Re: Chrysler grand voyager 2004 2.8 CRD – engine cut-out whe

Postby PAulC » Sun Aug 20, 2017 9:53 pm

STC,

As you say the situation you described shows how sensitive the running of the engine is to the overall pressure in the rail.

I read somewhere that the reason the ECM cuts the engine is because it reads the low rail pressure and and knows that given the injector "fueling rate" it has set, the fuel pressure is out of tolerance (i.e there is insufficient fuel pressure to inject the right amount of fuel under this level of demand) Is this why the ECM shuts the engine down without posting a fault code or just folk law?

On my old 2001 voyager I ran out of fuel a few times and the ECM always posted a low fuel pressure error that eventually disappeared after ten restarts (or so)

Allegedly the Bosch specialists in Luton have removed and tested the fuel injectors (union street autos). Although I'm 50/50 as to whether they actually removed the injectors or not, because the uniform colour of the dust/oil all across the rocker cover would suggest no one had used a puller or touched the engine casing.

I'm wondering if the fuel pump has a seal problem? or if it has been run on petrol/diesel mix. What are the symptoms of a pump that has been run on petrol/diesel?

Regards

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Re: Chrysler grand voyager 2004 2.8 CRD – engine cut-out whe

Postby liviu2004 » Sun Aug 20, 2017 11:00 pm

Which software engineer would prefer, safety wise, to shut an engine down due to low fuel pressure instead of going in emergency mode low power. I tell you, none! Forget about it.
There is one exception to this, when a failure would cause engine to accelerate uncontrolled, that is with stuk open throttle.
It doesn't even stop on low oil pressure, to give you the chance to survive and pull over ...
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