Volvo S70/V70 (1996 - 2000) - 98 V70 T5 erratic idle and stall fault a mystery

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Sun 24 Feb 2008 12:23
98 V70 T5 erratic idle and stall fault a mystery - Reddevil
I really need some advice or help here. The car is an S-Reg Volvo V70 T5 and when the engine is switched on it idles at between 2,000 rpm and 3,500 rpm. It is consistently revving up and down between the rpm I just mentioned. When I put my foot on the accelerator so as to drive it, it just stalls. This means I have to start the engine again but the same thing happens. Its been in dry-dock for 3 weeks now and no one seems to have a clue. The first theory was the fuel pump...that appears to be fine. The next theory was the engine management system but that has been tested and it is fine. Does anyone else have any other theories?

Edited by Pugugly. on 24/02/2008 at 12:36

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Sun 24 Feb 2008 13:10
98 V70 T5 erratic idle and stall fault a mystery - injection doc
There's no mystery, it sound like it has a huge air leak or throttle position sensor fault.
Live data info should reveal all if diagnostic kit is used properly.
The reason it idles up & down is because the engine is getting too much air & not via the AFM. the IAC is trying to stabilize the idle causing it to be erratic & the reason it stalls when you touch the throttle is that the air leak is making it run too weak causing it to stall. Need to check manifold gaskets & all hoses & brake servo etc.
Inj Doc

Edited by Dynamic Dave on 24/02/2008 at 15:16

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Sun 9 Mar 2008 12:40
98 V70 T5 erratic idle and stall fault a mystery - keep the heap going
excellent advice that...to find the leak you could spray some WD-40 around the inlet and when the revs rise, then the leak should be in that area..
SNIPQUOTE!

Edited by Dynamic Dave on 09/03/2008 at 13:38

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Sun 9 Mar 2008 17:01
98 V70 T5 erratic idle and stall fault a mystery - injection doc
Do NOT USE apray's containing silicon as this will cause permanent damage to the oxeygen sensor's. That includes using engine bay enhancement sprays to make evrything look bright & shiney!
Make sure a propellant you are using does not contain any silicon lubricant.
IJ
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Mon 10 Mar 2008 14:58
98 V70 T5 erratic idle and stall fault a mystery - keep the heap going
Do NOT USE apray's containing silicon as this will cause permanent damage to the oxeygen
sensor's. That includes using engine bay enhancement sprays to make evrything look bright & shiney!
Make sure a propellant you are using does not contain any silicon lubricant.
IJ

Take your point on that, but I thought WD-40 was just an oil blend. It certainly does not as much lubrication behind as some of the teflon type sprays. I did use ether (in quickstart) to get going in desperation once, but I wouldn't recommend that one a warm/hot engine.
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