Intermittent starting problem

[mightywolf]

My '98 S70R has got a funny little habit. It only happens occasionally (maybe once twice a week at most). I'll get in, turn the key and it turns the starter motor but won't fire. If I turn the ignition back off and on it usually fires up straight away (I sometimes have to turn it off and on 2 or 3 times). I've started to notice it happens more if I've parked on a hill. It happens regardless of the amount of fuel in the tank. The rest of the time it fires up first turn straight away.
I've also noticed it occasionally does it sat in traffic. It'll idle normally and suddenly the revs will drop like its about to stall and then return to normal (it never stalls) Its an auto an it does this regardless of the gear and happens in neutral or park so I don't think its a gearbox thing.
Any ideas before I have to go down the route of changing all the plugs, leads etc etc?
cheers guys.

[polak t5r]

hi mighty wolf i had the same problem on a 850 t5 few years back every time the car was on a hill it wouldnt start changed everything it turned out to be maff sensor proberly not the same thing but if you try everything else might be worth a look

[Phuturephantasy]

First thing I would try would be cleaning the Idle air control valve and the MAF sensor - a search should bring up any how to's

[mightywolf]

cheers guys

[Blackdog]

Had a similar starting problem with our 99 V70 2.5D.

Would crank until the cows come home but would not fire up.

When it happens again try taking the key out, turning it over and then starting.

If it fires up I would suggest that it is the ignition ring antenna.
This is the bit around the place where the key goes in with White marks on.

I am told it reads the key an turns off the imobiliser.

Regards

Steve

[Dacvolvo]

I also had a similar experience. Turned out it was the fuel filter under the car - a stone had managed to pierce it and if I left the car parked up for more than 2 hours, I would have to turn the key twice before she would start...

The first turn of the key and the starter motor would just turn but the engine wouldn't start. I would wait 3 seconds and then turn the key again and the engine would roar into life.

Parking on a hill facing down the way would cause the problem to be more frequent. Also, there was a very (and I mean very) faint smell of petrol.

It cost £10 to have a new fuel filter installed from the local Volvo garage.

[mightywolf]

I've only just replaced the fuel filter, so its not that. It does fire up if I turn off the ignition and turn it on again. Sometimes have to do it 3 or 4 times but it usually fires on the 2nd turn. I'm gonna clean the maf and the idle air valve first

[Jamest5r]

Crank and cam sensors would also give you problem mate, get the codes read if you can saves a lot of messing around.

[mightywolf]

had the codes read and it hasn't got any coming up. i've cleaned the m.a.f but that hasn't made any difference. so where exactly is the idle air control valve?

[Blackdog]

Mightywolf,

I still go back to the Ignition Ring Antenna.

As I said same symptoms. Would crank, not fire but would eventually start on some time second, sometimes third, and sometimes even more. Would even start first time some of the time LOL!

Fortunatally the V70 came with more history than the Victoria & Albert museum.

This showed that the problem was not new to the car and had indeed been back to Volvo for diagnostics which were inconclusive. She left the dealer not cured but with a note of suspected faulty Ingition Ring Antenna.

We changed the part (circa 40 quid) and the car has started first time, every time ever since.

Best of luck tracing the problem.

Steve

[mightywolf]

cheers blackdog, but i don't think its that. it stutters sometimes while sat at the lights or when you put your foot down (only for a second and then it acts like nothings wrong)
the idle air control valve looks fine but i'm gonna give it a quick clean anyway. think it might be plugs or leads.

[mightywolf]

ok quick bump. still have the problem. I've changed the plugs, leads, dizzy cap and rotor arm. Cleaned the maf sensor and the idle air control valve. its not throwing up any fault codes either.
It seems to be fine for a while then it comes back. for a couple of days it'll do the not wanting to start thing and then it won't come back for a week! But it does the rev drop thing nearly every day. Sat in trafic and it just occasionally gets a slight drop in revs like its gonna stall and then picks up again. Also noticable is when your stood and you set off again I get a blip like it hesitates and then clears and is fine. It only does this at very low revs (i.e when setting off from lights or pulling out of a junction which is a bit annoying).
I am still thinking it could possibly be the idle air control valve just sticking? I did give it a real good clean though and it seemed fine. Any more ideas?

[mightywolf]

anyone?

[JelT5]

Wish I could offer some advice that might be useful, it looks like you've pretty much covered everything though.
Could it possibly be a vac leak on the BOV?

[mightywolf]

Wish I could offer some advice that might be useful, it looks like you've pretty much covered everything though.
Could it possibly be a vac leak on the BOV?

its funny you should mention that. I did suspect my bov may be leaking at the diaphram. Could that cause it? its a bailey dv26.

[JelT5]

its funny you should mention that. I did suspect my bov may be leaking at the diaphram. Could that cause it? its a bailey dv26.

It's a possibility- BOVs can cause some problems on T5s. My Forge one didn't, I took it out because I wanted to hear the turbo chatter lol.
For the sake of a few minutes work- why not remove the DV, block the hole up and try it? You never know.

[mightywolf]

It's a possibility- BOVs can cause some problems on T5s. My Forge one didn't, I took it out because I wanted to hear the turbo chatter lol.
For the sake of a few minutes work- why not remove the DV, block the hole up and try it? You never know.

it won't do any damage will it? obviously the re-circ is blanked off, but won't it do any harm if it can't dump the excess gas?

[JelT5]

No it won't mate- we don't run enough psi/bar of boost to cause damage to the turbo.

[mightywolf]

cool i'll try that. cheers.

[eddielam]

try the fuel pump relay, mine does the same, a friends was cured by it, i will change mine tomorrow and write back. cheers