V70R 'surging' under full acceleration

[jongs]

Hi guys,

I have a 1999 phase 2 V70R AWD auto which is showing an odd problem....

It is most noticible on the motorway lets say when you have been following a truck at 60 mph and then want to get back up to speed quickly. If I kick it down and keep my foot on the floor by the time I get to around 90mph the car feels as though it is almost trying to cut out or there is fuel starvation - it basically stops accelerating and surges - out of curiousity I lifted a bit and then accelerated again and it crept up to about 130 but I think that this took longer than it should have done in a 270 bhp car (late at night on a wide motorway) But it does this almost everytime I accelerate hard up to 90ish from say 60- 70. Has anyone else had this? It is fine accelerating in kick down from say 20mph to 70mph continuously....

The car has just been fully serviced with cambelt and has done 100k miles. Apparently the previous owner's son works for Volvo in Sweden and they went over there and it was chipped by Volvo to around 270bhp and given a strut brace too.

Thanks for any help,

Jon

[Conehead]

I have similar at the mo with Kickdown and it flies then all of a sudden feels like the rev limiter kicks in. If I use 90 % throttle it keeps going without cutting out.

I have a Maf fault code up so I'm putting it down to that, except every now and then the Etm fault appears if I keep pushing.

Going to SW for a couple of things on wednesday so I will let you know if they find the definite cause

[mharriso]

Have you replaced the fuel filter lately??? if you have dropped performance at high fuel demand this is often 1st check, then fuel rail pressure, then fuel pressure regulator.....

also as mentined would look at cleaning the MAP sensors, checking all vac lines for leaks, and cleaning out the PCV system...

Best of luck,,,

[Jod T5]

generally the explanation for the car running in this manor is due to a vacuum hose leak....
very basically...
because of the exhaust sensor (lambda), the ecu can read the air/fuel mixture being burnt at all positions on the fueling map apart from at wide open throttle (WOT)..it can therefore detect any overfueling and react accordingly, therefore nulifying the lack of boost allowing the car to pull well, if not at optimum ability...
at WOT when the ecu is not answerable to the sensor it copes the best it can but will run rich due to loss of boost at this time....

i would check your vacuum hoses and also ensure that the rotor arm has been changed..ever?
cheers
jod

[don kalmar union]

Good evening Jon,

It is not possible to get Volvo to change software in their cars in Sweden as they offer no such service. There are however some Volvo staff in Gothenburg who can do this sort of work 'on the side' if they are in the right department with access to all the right tools.....possibly the previous owner's son had such a contact.....but a job done by such an individual would give no problems whatsoever.

The best way would be for you to get the car checked by a local dealer who can diagnose any faults with the car that may be causing the problem and also tell if there is any 'foreign' software present.

I have that kit myself and if you are ever in north London I can check it for free at a convenient time.

Regards, Don.Norchi.

[jongs]

Hi Don,


Thank you and the others for your advice - I have a friend with a garage who has a decent scanner so I will start with him reading any fault codes present and take it from there!

Jon

[FlyingWardrobe]

Hi
I'm new on the forum as I joined trying to find an answer to this exact same problem. I have an 850 R auto with the same fault, I had the main seal between the gearbox and engine replaced at a volvo dealer and ever since I have had this problem. Under hard acceleration I get 'popping' from the exhaust but ease off a bit and it is fine, the strange thing is this doesn't happen in the first 10 minutes when the engine is cold! Only when it has warmed up.

It has been back to Volvo about 4 times, initially they thought it was the MAF but on trying a new one this did not fix the issue, they have now replaced the fuel relay and this appears to have reduced the problem but it still does occur every so often. It's due back in where they are keeping it a few days to try and figure it out once and for all.

I'll post a reply if they fix it

regards
Dave

[jongs]

Hi Dave,

Thanks for the comments - I replaced the spark plugs recently (genuine volvo ones) and I think that the problem may have started after that - I get a popping from the exhaust at idle now when the engine is warm which it did not do before. I am going to try taking them out and check gapping etc......

I cannot find any vacuum leaks and no fault codes stored so hopefully I got a dodgy plug!

Jon

[jamrussell]

does the surging only happen as you are reaching the rev limiter?? if so it could be the fuel cut out (dont hold me to it though). i owned a nissan 200 running around 350bhp and that was the problem. got the ecu re-mapped and the problem went away.

hope this helps

james

[Jod T5]

Originally Posted by jongs

I cannot find any vacuum leaks and no fault codes stored so hopefully I got a dodgy plug!

Jon

sorry but a high majority of the issues you descibe are down to vacuum leaks..have you checked here...http://volvospeed.com/Repair/vacuum_lines.php
cheers
jod