2002 d5 cold starting problem

[Peter2ltr]

Hello
Iv got a 2002 v70 d5 with around 170k and iv owned it for quite a few years.
Once the colder weather crept in at the end of last year I noticed on cold start
it sits and hunts for a 30 seconds or so until it heats up a little sometimes the hunting is quite erratic almost cut out then bounce back the 1100rpm
I initially thought ah not a problem new glow plugs required but they made no difference also tested and there getting voltage.
Anyone had anything similar? Or any ideas?

[GrahamBrown1]

I would suspect you will have one or more injectors playing up. Monitoring some of the live data on start up would give you a better indication of what’s going on. How does the car run once warmed up? Any faults or warnings?

[5cilinder]

A leakback test on the injectors and checking engine balance /injector corrections in vida will give some clarity.
It will pinpoint possible bad injectors or bad compression

[Peter2ltr]

Originally Posted by GrahamBrown1

I would suspect you will have one or more injectors playing up. Monitoring some of the live data on start up would give you a better indication of what’s going on. How does the car run once warmed up? Any faults or warnings?

It seems to run fine no faults or warnings messages

[Peter2ltr]

Originally Posted by 5cilinder

A leakback test on the injectors and checking engine balance /injector corrections in vida will give some clarity.
It will pinpoint possible bad injectors or bad compression

After reading up a little I have been thinking along the injector route
And leak back test was the next thing I was going to try see if that produces anything.
Unfortunately I don’t have Vida but may have to invest

[Baffler]

Would do no harm to change the fuel and air filter too...especially the fuel filter, if you have no record of it being replaced, as any moisture in there may have congealed during the cold snap.

[5cilinder]

Originally Posted by Peter2ltr

After reading up a little I have been thinking along the injector route
And leak back test was the next thing I was going to try see if that produces anything.
Unfortunately I don’t have Vida but may have to invest

Try a leakbacktest first if there are 1 or more injector leaking more than 40 ml /minute you can then replace those injectors....

As a sidenote ...is your coolant sensor reading out the right temperature? if that is off your injection timing will be off and also the pre glowing times..do a resistance measurement on the sensor itself and compare it with a ntc table

[Peter2ltr]

Originally Posted by Baffler

Would do no harm to change the fuel and air filter too...especially the fuel filter, if you have no record of it being replaced, as any moisture in there may have congealed during the cold snap.

Iv another genuine fuel filter on order for it. It had all the filters replacement a year ago. And only done 7k maybe

[Peter2ltr]

Originally Posted by 5cilinder

Try a leakbacktest first if there are 1 or more injector leaking more than 40 ml /minute you can then replace those injectors....

As a sidenote ...is your coolant sensor reading out the right temperature? if that is off your injection timing will be off and also the pre glowing times..do a resistance measurement on the sensor itself and compare it with a ntc table

Leak off test is the plan this week along with a fuel filter.

The temperature gauge seems to read correct enough but probably means nothing. Do you know Where is the sensor is there more than one? Interesting you mentioned this because I have wondered what controls the cold start procedure.

[5cilinder]

Originally Posted by Peter2ltr

Leak off test is the plan this week along with a fuel filter.

The temperature gauge seems to read correct enough but probably means nothing. Do you know Where is the sensor is there more than one? Interesting you mentioned this because I have wondered what controls the cold start procedure.

Only one sensor...on top of the thermostat housing left on top engine behind the serpentinebelt
Sensor dial is dampened and below 40 celsius not readable, take a cold engine ( a day not used) take the temperature with a different meter and then resistance measure the sensor. Lookup in the ntc table the resistance with the corresponding temperature and if thats off with the measured temperature with the different meter by more than a few degrees celsius ..replace the sensor