high idle when hot

POE · Post by **POE** » Sun Jun 29, 2008 6:57 pm

hi, when start from cold, it idles about 1000 then after a few minutes drops down to about 800 but after been driving for about 5mins or so goes up to 1200 revs a doesnt get any lower and stays like this ,89 turbo, any ideas on yet another idle post.thanks

NATHANWALLER THE 480 NUTT · Post by **NATHANWALLER THE 480 NUTT** » Mon Jul 14, 2008 8:53 pm

I have the same sort of problem. Idles fine when first started but after a very short period (30sec - 2mins) the idle climbs to 1200rpm and holds there rock solid.

I also have another problem when I accelerate hard, it works fine until it gets to about 3000-4000 revs and then it starts stuttering and holding back in a big way.

Drives fine apart from the high idle and it never misfires until you try to boot it!

Any help would be very gratefully received as I have a brother who has his own garage and worked for volvo main dealer here in Southampton for over 15 years before he went out on his own but he is not much help as to say he does not like them is a under statement so when I ask for advice he gives it the get rid , loads of common faults but I can still use his workshop which is very handy to say the least. Especially when you have to do the clutch on it!!

BTW Its a 91 turbo and the emissions were fine last time I checked but cant remember if it was idling high then? I don't think it was......

Ps Its my 3rd 480 and me and the wife love them

SteveR · Post by **SteveR** » Mon Jul 14, 2008 9:37 pm

Almost identical to mine - 93 turbo. I have not started troubleshooting yet apart from eyeball for obvious air leaks. Mind you the cutting out/stuttering seems so sharp it leads me to think it is an HT issue.

NATHANWALLER THE 480 NUTT · Post by **NATHANWALLER THE 480 NUTT** » Mon Jul 14, 2008 10:12 pm

My brother did check the ht leads with a fine mist of water from a spray bottle and he did say that there was some arcing from the leads but it runs sweet up until the stuttering kicks in so I am not that hopeful that it will cure it but they are on my to get list but at the mo there is no overtime at work so I am skint to say the least.

NATHANWALLER THE 480 NUTT · Post by **NATHANWALLER THE 480 NUTT** » Thu Jul 17, 2008 9:26 pm

Changed the ht leads tonight and the stttering has gone

Not sure about the idle but one less thing to worrie about

What a pain in the ass it is to change the leads, they are on a mount with a breather hose over them that's pined by the inlet manifold. Another 480 five minute job!!!!

sr480t · Post by **sr480t** » Fri Jul 18, 2008 6:52 pm

I have exactly the same proplem too, its so annoying becoz sometimes when i race it happens and end up loosing and know if it was running properly it would win. I changed the HT leads to the high performance Magnicore leads but it still happens, the sparks plugs are good for a good few thousand miles yet and changed the rotor arm. I did have it rolling roaded and did have a big problem of over fuelling becoz i did not have a Lambda sensor. Once i got a new sorted it ran great apart from this little problem.

Paul240480 · Post by **Paul240480** » Tue Jul 22, 2008 8:15 am

Hi All. Mines a 91' Turbo Auto. All of the symptoms mentioned in this thread have shown in mine over time.

I've changed, HTs & plugs (now on NGKs).
Replaced Turbo intake rubber pipe, mine had split.
Replaced Coil & the multi-plug terminal next to it (Turbo's only I think).
Cleaned the Idle Control Valve following the brill' 'how to' thread on here.

These seemed to solve the problem, but only temporarily. After time, the erratic idle/performance returned & the plugs sooted up.

Now I've read another thread on the VOC forums.................

To the rear of the throttle body is a braided pipe of about 2". It connects to a brass nipple on the body & goes to a very thin plastic pipe at the other end. Held on by two small clamps. CHECK THIS PIPE. Very commonly they are badly perished. Mine 'fell apart' when I touched it.

I got a replacement yesterday (the place did'nt even charge me

). Fitted it (5 Mins) Result, tick over smoother than a smooth thing. Performance restored

NATHANWALLER THE 480 NUTT · Post by **NATHANWALLER THE 480 NUTT** » Thu Jul 24, 2008 11:01 pm

I don't think I have a leak as the vacuum/boost gauge stays pinned but I could well be wrong.
Its so stable and low 800 when its cold but flies up when its warm.

As the revs come ddown when I take the foot of the throttle I get a slight blip at 1600revs, Is this possibly related?

rgreenhalf · Post by **rgreenhalf** » Fri Jul 25, 2008 6:38 am

Checked Crankcase Ventilation?

NATHANWALLER THE 480 NUTT · Post by **NATHANWALLER THE 480 NUTT** » Fri Jul 25, 2008 9:04 pm

No I haven't . I have searched on here but cant find anything, could you please point me in the right direction otherwise I have to ask my bro and he is so anti 480 its hard to get a answer because I don't think he wants the car to run smooth other wise he will have no ammo left to slag it off with....

Paul240480 · Post by **Paul240480** » Sat Jul 26, 2008 7:55 am

Still take a look at that little pipe I mentioned in my earlier post. The braid can look okay but rubber insides can still be knackered.

As for PCV, I think if you look at the engine, just to rear & to one side of the idle control valve you will see a cannister type thing with some black foam around it & a few pipes coming from it. I THINK this is all to do with PCV - Can someone confirm?

I replaced the cannister a few months back as when I removed mine it had a hole twice the size that it should have been where it fits on

Cost about 80Ã¢â€šÂ¬ at the mainstealer.
Cheers.

Volvo 480 Club Europe

high idle when hot

high idle when hot

Idle Snags................ another thing to check.