Hunting or pulsing when cold.

[wright_t5]

Hi, everyone, someone.

New to the site, just registered, not sure how everything works..

Questions about 850-T5, When it is cold the engine feels like it is hunting, ie: it seems to want to speed up then slow down, not really bad but you can feel the "hunting" feeling.

ANy ideas how I can get my beast into the 14's at Santa-Pod, have manged 15.1, but I want it quicker..

any clues?

Wright_T5

[Mrsmopp]

Hiya! Welcome to the forum!

First off to find out whether you can reach the glory 14's what mods have you done?

The 14's aren't easy but they can certainly be achieved!

Regarding your "hunting" issue I know this is a stupid question but do you have your aircon on permanent?

x

[wright_t5]

Air-Con, not on all the time only when needed.

Mods, K & N Panel filter,

Anyone out there tried a full induction kit? any noticable difference?

Chipped, although have boost problems now!!!

Next mod, SpeedSprint exhaust

Once I work out how to use forum, will post pictures...

[Mrsmopp]

What chip have you used? Any idea what kind of horses you are pushing now? When does boost come in and when does it drop off?

x

[Wobbly Dave]

Have you checked the plugs? 0.8mm gap - should be using NGK platinum - BKR7EVX (could be a few letters out). NGK only make one plug for the T5

[wright_t5]

Chip, it's an upsolute one, not sure of anything else.

Horses, well it's claimed to produce 277, but have not done anything to prove this.

As for the boost, well, if you nail the throttle, it gets up and goes, the boost climbs as you would expect, it holds boost for a bit, then drops off almost to the centre position on the gauge, then after a few seconds boosts again, depending on the load, incline of the road, and how long you can keep accelerating!!! it can do this 3 or 4 times....

Having spoken to a few other people (Non-Volvo) people, they have said it could be, fuelling, weak actuator, ECU just cutting power etc, so I am confused and bewildered by all the possibilities, I would like to know why it's doing it, but how do I find out what's happening??? if you drive it "normally" it is ok, but it's when you really want the power... it back off just at the wrong moment...

[wright_t5]

Not sure about the plugs, have changed them, I presumed for the correct ones listed, used my local supplier, not Volvo... (Too expensive!!)

[Wobbly Dave]

Set of the proper NGK will set you back about £30 for 5. Volvo always overcharge - especially for bits of plastic

[Wobbly Dave]

BTW I had a similar problem with mine - under full load she would hunt. Turns out wrong plugs - which had broken down. For £30 it is worth doing anyway.

[wright_t5]

Umm, although the hunting happens at low speed when cold, so I am not sure it would be plugs, as it runs so well otherwise..

[Mrsmopp]

It doesn't sound like the plugs tbh. Did you have any problems before the chip was fitted? If not it sounds to me like your ecu is overriding the chip as its not consistant. I could be wrong tho (it does happen more often than not lol)

Where abouts are you we may know a good specialist in your area that may be able to help with diagnosis.

Is it just when the engine is cold or does it happen when she's warm too?

x

[wright_t5]

Hi,

I am not sure whether it did it before I fitted the chip or not, I have since noticed it, if you turn the radio on and drive normally you don't notice it, it's when you are doing about 20-30 MPH (Doesn't often happen!!!) if you keep the throttle constant she feels like shes surging slightly, not a lot just a little.. but it seems noticable, well to me anyway.

I work in Surrey and Live in Cambridge

Thanks....

[wright_t5]

Hi, Me again, just following up on this thread, and hopefully the last follow up.

Thanks again to Justin, who found the "broken" elbow on the inlet manifold tucked away down low... I would have never had known..

Anyway, part was very cheap even at Volvo, the bi*&h was fitting it, fairly easy to get the old one off, more like James Herriot to fit the new one, eventually acheived a result.. all appears to be ok now, hunting is not evident now.

Perhaps there should be a "technical" thread, for all those useful tips and hints...

Cheers again....

See yah all soon..

[Mrsmopp]

Glad you managed to sort the problem.

We are looking at changing the venue for the next 1/4 mile meet so may be able to get some quicker trap speeds!

x

[wright_t5]

Ok, Tell me more!!! Where too next?

[Mrsmopp]

We are trying to arrange something for Avon Park http://www.avonparkraceway.com/events/ which is Warwickshire.

We have all been to Santa Pod on many occasions and think that a new track could face us with new challenges and perhaps improved times!!!

x