440 Bad Idle

[innit]

Hi

I have a 1994 440Si (1.8) The idle on the car has been getting progressively worse over the last 18months or so...it doesnt stall or anything it is just really lumpy and almost 'phutt phutting' out the exhaust.

I know that the units fitted to these cars are not the smoothest around but it definitely did not idle like this when I got the car. It had its 90K service a couple of months ago and the dealer could not find anything obvious. It had new plugs and leads, dizzy cap and rotor arm. I have checked all the vacuum hoses I can find.

What am I missing? It does not seem to affect the econmy (an average of 34.5 mpg since I got the car)I am just worried that it could get to the point where the air pulses damage the catalyst.

Thanks in advance


Adrian

[mikeholroyd]

Adrian
I had problems with my 1.8 being rough at 2000-2500 rpm, and tried all the things you have done. Nothing seemed to cure it, so I tried a replacement ECU from the scrappers. £20. it worked. Situated behind the drivers kick panel, dead easy to get in & out. The problem with mine was a leaky sunroof letting water run into the pillars onto the ECU box. You don't say whether or not your car has a factory sunroof, but if it has, check it isn't leaking. If it is, about £15 for new roof panel from salvage, and then change the ECU. Worth a thought anyway. Also check all the tiny little rubber hoses at the back of the engine, at the base of the singlepoint injection unit. These do perish because of the heat, and it may be worth replacing them as a matter of course. The only other suggestions are 1. check gasket between injection unit & the manifold. Use instant gasket to reseal if necessary.
2. check manifold to engine block gasket, as you may have a slight air leak.
Good luck in your detective work. Hope this helps.
Regards
Mike
1992J 440GLI 1.8

[Cougar 27]

I normally clean the throttle assembly inlet and drop some fuel injector cleaner into the petrol tank which does the trick.

[Cougar 27]

Forgot to say try running it on 97 Ron Super unleaded, just filled mine up today with it, and its cured the rough idle !.