When it is cold my 1987 900 8V starts but I cannot rev the engine without it cutting out. It will not idle unless I keep my foot on the throttle to keep the revs up. When the engine has been warmed up its fine!! I would welcome any advice?

Thanks

Could be the fuel cold start valve or the fuel enrichment but I'd start with the idle control valve or auxillary air valve - this opens an orifice to control idle speed until engine is warm (this is all assuming Bosch K-jetronic).
To check remove valve but keep electrical conection, look through where air passes should be a v. small opening. Remove fuel pump relay, jump terminals 30 and 87 in the fuel pump relay holder, the aperture in the valve should open if it dosnt then this is the problem. Check must be carried out on cold engine. If you are not sure what you are doing get someone who is to do it - dont jump terminals for longer than needed

Adrian, the aperture CLOSES when shorting 30 to 87; the auxiliary air valve is supposed to close as the engine warms up and the extra air-supply for idle function is no longer needed...!!

I'dalso suggest aux.air valve malfunction as the cause of your idle problems.

Mike M

Mike
Are you thinking about the AIC valve on the LH fuel system? The info I posted about the K-jetronic auxillary air valve is from the Saab factory manual so I'd expect it to be right!
The apeture will close as the engine warms but on a cold engine the apeture will be fully open but only when power supplied i.e. by shorting fuel pump relay. I did it this way and it worked fine.