Cold starting issue/lack of power when cold - diesel

Cold starting issue/lack of power when cold - diesel

Author
Discussion

mikeyr

Original Poster:

3,118 posts

194 months

Monday 13th November 2017
quotequote all
Any thoughts on whether two symptoms are related? And is my optimistic cheap fix likely to be a cure (before I give in and take car to a garage) - should state that I'm not mechanically minded; as you'll see from my post; but I've been having fun trying!

Car - Pug 2002 2.0 turbo diesel (90hp!) with primer bulb. 120k on clock. Recent purchase, not really used much yet, could have been sat at dealers for a bit. Annoying not OBDII compliant so can't do any simple fault reads.

Starting symptoms:

  • Will start first time, straight away if the temperature is above (roughly) 8 degrees
  • If less than that takes much longer for starter motor to turn over engine (10 seconds) but will then idles perfectly
  • Never any smoke on start up
  • Have seen air in fuel lines on occasion when first running
Driving symptoms:

  • Need more throttle to pull away until engine warms up
  • Car is sluggish for first couple of minutes then seems to transition to driving well (at one point I was able to put my foot down flat in 2nd with no acceleration)
  • Engine temperature is slow to reach operating temp but then this could be normal for a diesel; first one I've had
Things I've changed:
  • Air filter
  • Fuel filter assembly - car feels very sprightly now (for a 90hp monster) once warm!
  • MAF sensor
  • Run some EGR cleaner in it (before changing MAF)
My naive thoughts:

If I continue to see air in fuel is it possible that this is cause of slow running and I have a leak which disappears once everything is warm and pipes/connectors have expanded?

I have a vacuum leak which again resolves itself once pipes are warm.

I have a glow plug issue in conjunction with the above. Seems strange that there is such a night and day difference between a couple of degrees air temperature which is why I've ruled out battery.

Injector leak?

My optimistic hope:

Could it be a temp sensor on the blink? Would that have any impact on the amount of fuel supplied to the engine?

Any hope for the last option?!?








E-bmw

9,242 posts

153 months

Monday 13th November 2017
quotequote all
Firstly, I am not the most experienced of diesel engines but the basics are there.

1. Does the glow plug light come on when starting & are you waiting until it goes out before cranking?

2. Have you checked/had the glow plugs checked?

3. Have you checked/had the injectors checked?

mikeyr

Original Poster:

3,118 posts

194 months

Monday 13th November 2017
quotequote all
1. Yes (comes on for few seconds), wait for it to go on before turning.

2 and 3 are both 'not yet', everything I've done so far was basic maintenance for car that doesn't have any real history with it.

Could, of course, be anything but interested in thoughts as to possible causes.

finlo

3,768 posts

204 months

Monday 13th November 2017
quotequote all
I'd say it's definitely glowplugs, and it only takes one dud one to seriously impair cold starting/running.

mikeyr

Original Poster:

3,118 posts

194 months

Monday 13th November 2017
quotequote all
Are glowplugs used once car is running though? I thought they were purely for starting purposes.

stevieturbo

17,273 posts

248 months

Monday 13th November 2017
quotequote all
mikeyr said:
Are glowplugs used once car is running though? I thought they were purely for starting purposes.
On modern engines yes they can be used after starting at various times to assist clean combustion until the engine is warmed up.

bungz

1,960 posts

121 months

Tuesday 14th November 2017
quotequote all
Only takes a slight dip in temps for a diesel to be happy to start on the button to being a bit reluctant if the glow plugs have had it.

Set in my car need refreshing, couple of degrees is enough to go from starting on the button to spluttering a bit at first start.

mikeyr

Original Poster:

3,118 posts

194 months

Tuesday 14th November 2017
quotequote all
Interesting - don't get any smoke, etc either way.

My google-fu isn't working great so haven't been able to find any evidence that the plugs are required for running, certainly not for several minutes. Weird that once warm the engine is very happy.

mikeyr

Original Poster:

3,118 posts

194 months

Friday 1st December 2017
quotequote all
Update - new battery helped situation (e.g. got car to actually start) but the cold weather means that I have to turn starter for up to ten seconds and pump throttle to get car to start.

Mechanic has had a look and apparently glow plugs are fine but are only going on when engine is cranking. No preheating (I had noticed glow plug light goes on and back out within a second), they've swapped a relay from another car and issue remains.

Suspicion is that the coolant temp sensor might be sending incorrect temp data so going to try switching that. Will update further after this.

littleredrooster

5,539 posts

197 months

Friday 1st December 2017
quotequote all
A couple of things to note - (I had a 2.0HDi-engined Xantia which was reluctant when cold)

You could try priming the fuel system before trying to start to see if air is the cause; to do this, turn the ignition on to the 'Run' position (this opens the fuel valves in the system) and pump the rubber bulb until it goes firm. This should purge any air out of the top-end of the system.

Although the glow-plug lamp only triggers for a second or so, the glow-plugs can remain energised for much longer after this by a second relay; this may or may not be at a reduced current, I'm not sure. If any of the plugs are goosed, this will have a detrimental effect on starting. TBH, for the cost of a set (£40-ish?) I would stick a new set in anyway after that mileage.

As you've already mentioned, battery voltage is important; if the HDi engine doesn't crank quickly enough, it takes ages to start when it has a few miles on the clock. Mine had ~160k miles on and the battery turned out to be the cause of poor starting; it would crank for a long time, but just not quickly enough to start it.

mikeyr

Original Poster:

3,118 posts

194 months

Friday 1st December 2017
quotequote all
littleredrooster said:
You could try priming the fuel system before trying to start to see if air is the cause; to do this, turn the ignition on to the 'Run' position (this opens the fuel valves in the system) and pump the rubber bulb until it goes firm. This should purge any air out of the top-end of the system.
Have done this previously when changed fuel filter, didn't think about turning ignition key at all but it seemed to happily fill the new filter with diesel. Should this normally be performed with key turned?

littleredrooster said:
As you've already mentioned, battery voltage is important; if the HDi engine doesn't crank quickly enough, it takes ages to start when it has a few miles on the clock. Mine had ~160k miles on and the battery turned out to be the cause of poor starting; it would crank for a long time, but just not quickly enough to start it.
Fitted a new battery for that very reason with increased CCA which helped.

cptsideways

13,553 posts

253 months

Friday 1st December 2017
quotequote all
Is this an XUD lump? if so it will probably have the POS Lucas smoke bomb generator pump.


My bet is the cold start advance is up the duff, this will give your exact symptoms. Thankfully its all clockwork.

There is a thermostat with a cable attatched, it pulls a lever when cold that is connected to the pump, this advances the timing. My guess is the stat is seized, the cable is rusty & or the lever mech is out of adjustment. All relatively simple fixes.

First check to see advance cable actuates - I bet it does not

Quick check would be wedge a screwdriver the advance lever mech & see what happens


Here is a handy guide
https://www.306oc.co.uk/forum/printthread.php?tid=...

mikeyr

Original Poster:

3,118 posts

194 months

Friday 1st December 2017
quotequote all
Not an XUD, it's from the DW10 group. Similar set up?

Not had any smoke at all though...

mikeyr

Original Poster:

3,118 posts

194 months

Friday 8th December 2017
quotequote all
Update - post fuel filter and battery car doesn't seem to have any more hesitation issues. It's running nicely.

Mechanic checked live data and temperature data seems to be correct (some further investigation shows that they don't use glow plugs pre-cranking unless very cold outside). Car will start at lower temperatures now but only after some attempts so new battery has helped. Suspicion has switched to the starter motor which appears to be a known weak spot.

This is being swapped next week so hopefully that'll be the issue resolved.

mikeyr

Original Poster:

3,118 posts

194 months

Monday 18th December 2017
quotequote all
Last update in case it proves to be useful for others...

Car had been getting better with more use which suggests the battery wasn't fully charged when first used. However, was still cranking for several seconds before spluttering into life. New starter motor has got it starting straight away even when cold.

I also bought a new primer bulb (and associated pipe) direct from Peugeot which has stopped the air in the fuel line. Amazed at the difference between the stiffness of the new bulb (oo-er!) and mine.

End result, no starting issues, no lack of power. Happy days! Hope this thread might prove to be useful if others have same issue.


E-bmw

9,242 posts

153 months

Monday 18th December 2017
quotequote all
Well done & thanks for finishing the story to possibly help others.