Rough as a bag of spanners

[Freddie]

I have just had minor accident damage repaired on my 850 2.5 20v and on collecting the vehicle noticed it took several attempts to start the vehicle and when running was misfiring, sluggish and generally not very well. Fortunately it has been converted to LPG on which it runs as sweet as anything and the above symptoms apply only to running on petrol. I am informed the body repairer has had the vehicle in the oven and also spot welded a small lug on the body to assit pulling out the dent. I also know the battery was not disconnected. The symptoms seem like fuel starvation but could it be the ecu? Anyone any ideas?

[markas]

Hi ya,

If the battery is disconnected from ECU from long period this will clear fault codes etc. I remember the last time i actaully had a service a long time now and mine was just like yours with the rev counter swinging more than and election swingometer! It eventually stabilised as the ECU learn my driving style.

I would if you can put your battery on change for starters or at least check is voltage whilst off and with the engine ticking over and if the LPG is OK i would think that is ok too, but worth checking.

As they dont cover the inlet for the Airbox dust from the shop which as happened to me gets in the filter. Check this too and if you have a Volvo paper type treat yourself to a new one.

Next it may be worth swapping you old fuel filter if its been in a while as the LPG being on a different circuit so to speak for fuel flow.

Another one that used to cause this on my 460 was a bad rotor cap. Ours being of a good quality copper Bosch/Volvo can last the paste be i do read that between 30 and 50k is a good type to swap out, how long have you had yours presently on ? I made the bad mistake of buying a Europarts one and this you have i suffered too, as the cap didn't use copper but a mild metal.

After this if you still have problems you may have a fuel pressure problem, come back to us if you have, just to get you looking.

Mark

Hi Freddie,

I'm no expert, but I've always been under the impression that it's a really good idea to disconnect the battery and alternator when you do any welding on a vehicle.

With all the electronics our Volvos have on board, it wouldn't surprise me at all to find that the welding has affected the ECU or other control circuits in some way.

I've found my local Volvo dealership very helpful if you just phone for advice, so it might be worth just asking what welding with the battery connected might have done.

Like I say, I'm no expert. Maybe someone else can fill in the gaps?

All the best,

Andy

I'm no expert I would guess that if they used a mig / tig welder (and lets face it they are not going to be using gas welders in this day and age in a repair shop - I'd think) then the current you put through the metal to get it to melt could damage electric circuits.... I know that when building pcs etc that amount of current would cause chips to fry.

Stu