Volvo 480 Turbo Auto J reg 1991

[Paul.C]

Hi , I have a 480 Turbo Auto. Purchased from a specialist with full history last Aug. I have had no end of electrical faults & leaks all but one of which have been rectified by the dealer at no cost to me. The one final niggle I have now is that approx every 1000K the tickover becomes rough & jumps from normal down to about 300 then the engine nearly dies then leaps to about 1600 then drops to normal then the circle begins again. Also when it gets like this, on kickdown the car is as rough as a dog as does not 'go' like a turbo should. To rectify this all that is needed is to clean the rotar and distributor cap terminals which become blackened for some reason.My dealer has 'repaired' this twice and I have done it once myself. Can anyone explain why this occurs & how to rectify it once and for all please.

[Ben H]

The funny idle could be due to the throttle potentionometer or idle speed control valve. You can just give the ISCV a quick clean and it should be OK. The TP usually has to be adjusted using specialist equipment though.

[Paul.C]

Thanks for the reply , would either of these cause the rotor & dizzy terminals to go black every thousand mile or so & would cleaning them cause the ISVC and /or TP to function perfectly for the 1000k or so that it does?

[Joe440Andrew460]

Hi Paul,

have been reading about your problems with your 480 and I was hoping you could even help me out with my query. I have a 1991 H Reg 460GLEi Auto that, similar to yours won't go very well when you kick down. What happens when you do go for kickdown? Mines not a Turbo model but it gets as far as 3K revs and quite frankly will refuse to rev smoothly or past 3K revs thereafter! I'm stuck at 65mph! Is this similar to your auto? It played up after we serviced it last year and replaced the rotor arm and cap with new even though they had just been done but that hadn't fixed it but we are gonna try it again just to make sure!

Let us know your info

Andrew & Joe

[Paul.C]

Hi , I am in the process of having mine repaired as I type. As it is still under warranty till Sept I am letting my dealer sort it!
On mine the rotar & dizzy cap terminals become totally blackened after about 1000k from cleaning this is when the problems occur. Also I found that the plugs were also totally black. In my case that has to be the problem (I hope). It would appear to be a case of it running to rich. My dealer is going to check & correct the settings (FOC). He also suggested an ATF change. If you look at one of my other replies (from Tim) it will advise how to check if the throttle stop is correctly set. Mine was perfect but if it is out it can cause kickdown probs. On kickdown at the moment mine activates but the car just judders and kangaroos while the speed remains as it is. Once I get it back and know what the prob was I shall post it on the forums for other to see.
Thanks.

[Paul.C]

Hi again.
Just realised that Tim E-mailed me direct.So you won't find his info as I thought. He suggested new dizzy cap & rotar. I would suggest genuine Volvo parts - more expensive but worthwhile as they will last.
Also he said Idle control valve problems are very common on fuel injection 400's - clean with cotton buds & meths every 6 months or so.
Another to check is the throttle valve basic idle setting. Turn throttle by hand and it should make a slight click just before it closes against the stop screw. If it does not try slackening it.When the throttle is at rest it should not be under tension - it should have plenty of slack. For the kickdown he suggested to check kickdown cable adjustments (via Haynes manual) & also to have auto transmission fluid changed if overdue - thinks 30K intervals - mine is pushing 50K but is being done today!
Thanks

[Joe440Andrew460]

HI Paul
I had changed the rotar arm and Dist Cap before the problem started and I have already changed them once for genuine Volvo parts and its still doing it as that was suggessted.
Could the ATF really be at fault, I went to an autobox specialist and they seem to think it would have nothing to do at all with the gearbox as it changes gear ok through all the gears, it just wont go over 3K revs!
Thanks anyway, I might just have another go as you never know!

Andrew

[Paul.C]

Hi Andrew.
My troubles appear to be solved! It was the MASS AIR FLOW SENSOR after all my trials! It now runs fine - just hope it stays so. I have changed my ATF and it has certainly smoothed things out. If you do not know when yours was last changed it may be worth doing - it won't do any harm. If it is really old it can make the changes harsh & sluggish.
Good Luck.