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Trafic 1.9dci poor cold starting **fixed**

57K views 21 replies 15 participants last post by  JNallyNation 
#1 · (Edited)
HAD A PROBLEM WITH MY 06 1.9DCI TRAFIC VAN DONE 70K.

SYMPTOMS

First start of the day was a challenge to say the least, I could crank it for 20 to 30 seconds constant, possibly 3 or 5 times maybe more it was flat mostly and occasionally gave a slight indication that it was firing.
When it did start it was instant no lumpyness but there was plenty of smoke of the unburned fuel type.
Once running it would start all day (though not instantly maybe 10 to 15 revolutions) and ran great on the road.

live data showed rail pressure while cranking to be circa 120 bar.(dropping to 0 bar instantly when cranking stopped)

cranking speed 250ish, ambient temp, fuel temp, coolant temp within 3 degrees of each other.
battery voltage was +12v before cranking dropping to around 9.6v at worst.battery was very good could crank for +5 mins if required

These figures led me to think faulty high pressure fuel pump or leaky injector, air leak somewhere.

No swarf was evident in fuel filter,injector leakoff test showed all within 10%
no air in system and hand primer solid after 2 or 3 pumps :confused:(head scratch time):confused:


CAUSE OF FAULT


On the end of the fuel rail there is a pressure relief valve that has a constant bleed to return via a connection to the injector return pipe.
(I assume this is a safety feature to bleed the fuel rail of its high pressure to prevent injury to fiddling fingers if a pipe is loosened)

I removed the connection to this valve and plugged the pipe then attached a lenght of plastic clear pipe to the fuel rail. disconnected the electrics to all the injectors (to prevent engine start)
on canking I got 120 bar fp and a good flow of fuel up the pipe from the fuel rail.

With nowt to loose I removed the pressure valve from the rail (it was tight )gave it a clean and a blow off, cleaned the seat best I could in the rail.
refitted it connected pipe and injector electrics then cranked her up.

let her run for a couple o mins to ensure system fully air free then installed the clear tube on rail again as before with injector electrics disconnected.

on cranking this time :d 280 bar fp on the rail :d and only a small seep up the clear pipe.

RAIL PRESSURE DROPPED TO AROUND 40 BAR WHEN ENGINE WAS STOPPED THEN BLED AWAY EVENTUALLY TO 0 BAR SO BE WARNED THERE MAY BE PRESSURE IN THE SYSTEM FOR A WHILE AFTER ENGINE STOP.

reinstated all parts, engine started almost instantly on key turn
an took her for a 10 min spin.

on return performed the above test again but we were back to original results.

a quick call and visit to the local breakers yard and only £30 lighter in me pocket I had a replacement rail from an unstripped engine with no swarf in the filter, removed it an checked this myself.

Its been fitted 2 weeks now and the difference is :d, from cold key straight in and turn now starts as expected even when not waiting for preheat, 2 or 3 turns only.

this fault was intermittent to start with, gradually over the last year getting worse but latterly with the colder weather to the point that it was a pain daily.

I haven't found any mention of this fault / fix anywhere on this forum so thought it may help a few others with a starting problem, its easy to check and costs nowt to do.

IS IT SOMETHING THAT IS OVERLOOKED GENERALLY ?


IF YOU READ THIS AND IT RESOLVES YOUR PROBLEM PLEASE LET US KNOW HERE TO ASSESS IF ITS A FAIRLY COMMON FAULT.
 
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#2 ·
Good post and if I may request, could the mods put it in the stickies.
It's another piece in the DCi fuel system jigsaw :cool:

Any chance of some photos so others can identify parts ?

I seem to recall, a post somewhere on cleaning and re-seating these sort of relief valves but can't remember where, whether DCi or timed injection units no idea but would be good if we can tie it together ??
May not even have been on this forum.
 
#4 ·
Good post and if I may request, could the mods put it in the stickies.
It's another piece in the DCi fuel system jigsaw :cool:

Any chance of some photos so others can identify parts ?

I seem to recall, a post somewhere on cleaning and re-seating these sort of relief valves but can't remember where, whether DCi or timed injection units no idea but would be good if we can tie it together ??
May not even have been on this forum.[/QUOTE

I've added the photo from my previous post a few weeks ago that only got a reply from yourself Dancingdad.hope this is sufficient.

I'm not that familiar with the setup of the 1.5 dci engine but wonder if it has a similar valve somewhere that may need checked as there are a lot on here with similar symptoms to mine , Miss m springs to mind for one
 
#9 ·
hi zeddytd im having similar probs with my 1.9 dci laguna i felt at 1st it was glow plugs (heater light not staying on more a couple of seconds) changed them .better start but not what it should be ..frosty this morning turned over sounded like it wanted to start ended up with flat battery tried to jump it to no avail ended up towing it started evetually ran perfecty all day ,glow plugs heating light on dash is not lighting up at all now is this similar to your problem ? ta smoky
 
#10 ·
smokey

if you have a leak in the high pressure side of the fuel system cranking the engine over by towing may overcome the pressure loss simply by turning the engine over faster therefore supplying more fuel and towing will aid starting by putting some heat into the engine through turning it faster.

internally you could loose high fuel pressure through pump wear, injector not seating properly or as in my case through the bypass valve on the rail.

have you checked the fuel filter for swarf indicating a fuel pump problem?

has it started ok since the first non start?

first things i would do would be an injector leakoff test (test kits on good ol ebay for around £20)


and check the bypass valve on the rail as described in my original post, position on the fuel rail may be slightly different as I.m not familiar with Laguna set up though.

let me know how you get on

wouldnt worry much about glow plugs atmo in present ambient temps they shouldn't prevent a good system from starting.
 
#11 ·
Hi all, have spent the month trying to resolve what appears to be a very common problem, ie, stalling when using low revs, eg coming out of roundabouts etc, combined with this I had problems starting irrespective of hot or cold engine etc. Linked to snap on diagnosis machine and found an error code for fuel pressure rail. Did numerous tests and did have pressure upto 22000psi and 5000psi on tickover so suspected wiring fault, many hours later, this was not the case. Lots of advice sought but with no joy, many suggestions such as fuel injector pump faulty, fuel line from tank, dirt in filter and many more. I eliminated all these options but realised there was air in the clear pipe near the primer bulb at the fuel filter. This led me to believe there was air returning via the 'Pressure Relief Valve' in end of high pressure rail, didnt appear possible because of pressure readings but thought try as only £120 and cheap in the grand scheme of things. THIS FIXED THE PROBLEM COMPLETELY AND IS STILL GOING STRONG

On all the sites and forums this was never mentioned and Renault 'appear' to not know this. They would rather sell you many other irrevelant parts.

To Summarise, if your Van STALLS, DIFFICULTY STARTING please try this 1st!!

This is a very common part which is fitted to many vehicles and can be obtained relatively cheap thru online auction sites, just make sure the vehicle was running before being removed. Hope this helps you guys and keeps some costs down!
 
#12 ·
I had this on my van, it wouldn't start after th MOT , when they do the emissions test they rev the b*lls out of it, this gives max fuel volume but no corresponding load. I also bought a non runner with same fault, owner had a garage replace pump, injectors, sensors and more, still couldnt fix it. Problem is you can't see the fuel leaking back so its over looked. Oh btw no fuel should pass , if its constantly passing it u/s .
 
#13 ·
Thanks zeddytd, fantastic work and article, it has been a huge help. My traffic would not start properly for a whole year; it was worse when it was very cold (minus temperatures to about 7 degrees Celsius) however it was still slow to start even when warm.

After reading this and changing the pressure relief valve it worked perfectly! Well chuffed; it even starts up perfectly in minus 4. I spent a year going down different avenues before I found this article. Renualt wanted 1200 quid for a new engine wiring loom - very happy I told them where to go and then found this article.

Thanks again.
 
#14 ·
Likewise, thank you all for taking the time to document this, we are unable to get our trafic running at all now, and have gone over the whole glowplug area to no avail, so will look at the fuel pressure relief valve next. I also had a 1200£ quote for a new wiring loom, there were certainly area's that were in terrible shape after rubbing through by the airbox above so I cut all of the bad sections out and resoldered new sections back in. The van was running much better after that but would still try and stall coming off roundabouts in 2nd gear, or over speed bumps etc. Occasionally it would stall when pulling up to a junction after dipping the clutch. Restarts fine and continues no problem for a while.. So now we suspect fuelling, and this valve. Priming the fuel filter shows that there is pressure there, all good, so it must be from there to the injectors that is not fully operational. Tried a snap on scanner on it which so far has only given a 1826 glow plug circuit fault, but need to re check this again. Will keep you posted on progress..
 
#15 ·
The pressure relief valve on these only opens when the fuel rail pressure rises above maximum allowed pressure & certainly does not open at any other time. The vast number of vechicles now use the electro-mechanical valve 2 wire terminal plug.whereas on the traffic it's just the mechanical. Just very curious
 
#16 ·
Thanks Mickey, A Renault tech has diagnosed low fuel pressure, barely achieving 100 bar on cranking, then drops to zero within 2 seconds of ending cranking. Thoughts are either injectors or this valve so it's a leak off check to be done next.. Has anyone any idea of approximate cost of a worst case scenario of 4 injectors needing replacing?

Thanks,
Paul.
 
#18 ·
Great thread this,priceless info I too have ordered new bypass valve , As my dci trafic seems to have too much fuel pressure , leaning towards valve being stuck closed , The amount of Fuel it turns to vapour out exhaust , It stinks of diesel ,Have to run it at night on drive otherwise smoke the street out!!!
Anyways will update my findings soon as valve arrives and is fitted.

Sent from my SM-A320FL using Tapatalk
 
#19 ·
This thread may be just the answer I have been looking for. I have a 2003 1.9 with old style fuel rail. Mine tries to start but can't manage it without a bit of easy start. I have disconnect the pressure valve from the leak off pipe and when it cranks it drips slowly from the valve and drips quickly for a second when I stop cranking. Am I right to understand that when cranking there should be zero discharge from the valve?

My readings are 200 to 250 rpm when cranking and reporting 300 to 350 bar in the rail. It is trying so the injectors are firing.

When started it idles at 820 rpm and reports 380 bar. 2000 rpm gets 500 bar and 2400 rpm gets 590 bar.

Thanks for the help....
 
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