Vans cutting power after about 1.5 hours driving

[Combat squirrel]

As title, my Renault master 2013 LWB 2.3 diesel van has randomly started loosing power for a couple of seconds at random times, speeds and hills, it always drives perfectly fine for approx 1.5 hours then the power loss kicks in.

The engine doesn’t cut out, as in stop, but its like....the throttle stops working and the vans engine doesn’t want to make power, i can put my foot to the floor and it wont accelerate, then if i lift it off or drop down a gear it carries on just fine.

I had the fuel filter replaced thinking some rubbish from the filter was blocking it or something but thats not stopped it happening.

It did it today 8-10 times (after approx a 1.5 hours of driving around) for a fraction of a second each time, just powers ‘gone’, drop gear or lift off for at least say....2 seconds then it picks up and works fine again.

When its actually running the engine sounds perfect, runs great, just started doing this and I’m worried it will totally break down or something, I cant have that, I need 100% reliability,

Any ideas?

 

[Dis86]

Could be a cooling issue.

 

[Bat]

Intermittent sensor fault of some sort would be my guess. Get it hooked up to a diagnostic machine or app.

 

[Rroff]

Intermittent sensor fault of some sort would be my guess. Get it hooked up to a diagnostic machine or app.

Yeah was gonna say first thing would be to see if there was anything on OBD.

 

[ShiWarrior]

is it a hybrid ?
go plug it in, see if that helps ?

(joking !)

 

[Combat squirrel]

Yeh been running obd doctor pro from a WiFi obd plug sending data and exporting as csv spreadsheet, recording all data possible and nothing obvious appears in the data.

Only error message it gets is 'glow plug circuit A problem' but I doubt a glow plug would do that? It runs perfectly well otherwise?

 

[Rroff]

I could be wrong but almost always with our vans when problems like that start creeping up even when it doesn't give an EGR code initially it has been EGR related problems often the sensor or valve getting gunked up. (Though usually once the power loss starts kicking in and/or over-revving the engine management light comes on and generally the vehicle goes into limp mode for awhile).

Another suspect for power loss can be suction control valve related (that is usually fairly rare in my experience but I'm no expert).

Glow plugs should not cause an issue once the vehicle is running.

 

[jpaul]

I was going to say high pressure fuel rail issue - google (echo chamber) showed me this thread
https://www.rac.co.uk/discuss/forum...ons/12633-renault-master-fuel-pressure-issues
so failing pressure relief valve ... but, the idea of putting some fuel cleaner or better quality fuel in for a while might help, as it suggests.

 

[dale1uk]

It sounds similar to what I had happen with my previous Trafic work van. It didn't happen as often though, and would only last for a second or so. With mine it was a fault with the accelerator pedal. I can't remember what Renault did to fix it as it was under warranty and all sorted through my work.

 

[Combat squirrel]

Thanks for the input guys, appreciate it, it could be an array of things then

This may sound crazy but I get properly anxious when my vans not working correctly so I'm trying my best to track the issue down.

The only other thing I can think of, the only garage able to do much with the van previously (in that case remove the speed limitation as it used to be a commercial van) was the Renault garage in the wirrel, all the other Renault garages between Stoke and North Wales didn't have the gear to do that.....so I'm thinking maybe they'll be the only garage with the equipment to access ALL sensors on the van?? (Not just the general obd 2 ones I can see)

Unless anyone knows anyone around Stoke with ALL the gear and is a diesel specialist?

 

[Orionaut]

I could be wrong but almost always with our vans when problems like that start creeping up even when it doesn't give an EGR code initially it has been EGR related problems often the sensor or valve getting gunked up. (Though usually once the power loss starts kicking in and/or over-revving the engine management light comes on and generally the vehicle goes into limp mode for awhile).

I would be inclined to guess something like this too at first look.

And do not forget that Not all faults put the MIL on either. and many faults, even in the engine management, can only be read by a manufacturer specific scan tool.

(There is a reason the (Illegal) modification of EGR systems by removing and/or blanking them off is such a popular procedure. )

 

[Combat squirrel]

Well, fuel filter changed, and now the crank shaft sensor - its failing even faster now - power cutting after 20-25 mins, made it home ok, but getting dangerous on the road now, I guess I need a specialist ? I wonder how expensive :/

 

[Scythe]

Well, fuel filter changed, and now the crank shaft sensor - its failing even faster now - power cutting after 20-25 mins, made it home ok, but getting dangerous on the road now, I guess I need a specialist ? I wonder how expensive :/

I heard of a similar issue like this on a Transit two weeks, and it too was the pressure relief valve on the end of the fuel rail - a simple and cheap fix so I hope this is the case for you.

Not a diesel specialist, but I recommend ABP motorsport in Hough near Crewe (less than 5 mins from M6 Jct 16/A500). They work on anything and everything, and have always done me a good job with diagnosing and fixing.

 

[stickyjamfinger]

Hi, I've encountered this type of fault a number of times, most occasions it turned out to be the Bosch CP3 hp fuel pump failing on one or more of the heads, most times I've fitted exchange pumps as they are cheap enough, I have overhauled them also but due to time constraints it was far quicker to buy in mostly new Bosch exchange units.

 

[Combat squirrel]

Only thing the advanced Renault computer man could find wrong was a dodgy break pedal 'switch' sending erroneous signals to the ecu making the van think it was breaking when it wasn't, thus cutting the power to the engine. Replaced that switch now and so far so good....it's driven well past the point of it cutting out before

 

[Scania]

Only thing the advanced Renault computer man could find wrong was a dodgy break pedal 'switch' sending erroneous signals to the ecu making the van think it was breaking when it wasn't, thus cutting the power to the engine. Replaced that switch now and so far so good....it's driven well past the point of it cutting out before

Was just about to suggest this, I’ve had it happen in quite a few commercials over the years.

 

[Combat squirrel]

Was just about to suggest this, I’ve had it happen in quite a few commercials over the years.

Thanks! But Yeh driven it all over this evening and fingers crossed working perfect so far

 

[jpaul]

was a dodgy break pedal 'switch' sending erroneous signals to the ecu making the van think it was breaking when it wasn't, thus cutting the power to the engine.

I don't understand the logic .. yes reduce the power/fuel , & coast if you take your foot off the accelerator, which is what happens when you brake, but, an additional mechanism on the brake pedal. ?

 

[nicRob]

I don't understand the logic .. yes reduce the power/fuel , & coast if you take your foot off the accelerator, which is what happens when you brake, but, an additional mechanism on the brake pedal. ?

Quite a few modern vehicles will cut power if the brake is pressed when you're pressing the accelerator too, may be a safety thing I guess

 

[MatteH Oxford]

I don't understand the logic .. yes reduce the power/fuel , & coast if you take your foot off the accelerator, which is what happens when you brake, but, an additional mechanism on the brake pedal. ?

The ECU will deactivate things like cruise control/AC if the brake is pressed, so will perhaps throttle input is overridden if it's receiving a (false) signal from the brake.