Technical Juddering acceleration when wet

[trickydisko]

Hello, I have an old 1990 Tipo 1.4 Formula, which is having problems accelerating after it's been rained on. The engine seems to judder (ie. it'll accelerate for a second, then back off for a couple, and repeat) when the accelerator is depressed, this tends to last for about 15-30 minutes of driving before it returns to normal. The problem seems most apparent at medium revs, at low revs it doesn't stall and at high revs the engine seems normal. When juddering, the acceleration follows the engine note, so I don't think anything's slipping.

Can anyone advise me what might be wrong with it, and how expensive it would be to have repaired (I can do a few very basic repairs, but I'm not confident enough to mess around with the engine itself)? The problem is annoying but the car is still driveable, so I'm not inclined to pay for a costly fix.

The general condition of the car is pretty good, it's been well-serviced up until 2 years ago (only oil/filter and brake pads since) and starting in the wet isn't a problem, although the engine tends to be quite lumpy when first started, and will eventually cough its way to a stall if I don't press the accelerator a little.

Thanks in advance for any advice you can give me!

 

[sumplug]

sounds electrical.change distributor cap,HT leads and plugs.check wires at coil for good contact.give car a good service.all should then be well.

 

[HP]

Apologies for my lack of Tipo knowledge - but if it's fuel injected and has had a replacement lambda sensor, see if the connections have been waterproofed.

I've had to fix a few cars which have had universal lambda sensors crimped onto the existing wiring, if they ain't properly waterproofed they don't work in the wet.

 

[sumplug]

please,please,please do not use universal lambas.they are crap.only use genuine ones.this is a common failure problem on cars.

 

[Hellcat]

sounds electrical.change distributor cap,HT leads and plugs.check wires at coil for good contact.give car a good service.all should then be well.

:yeahthat:

The recent wet weather got my Tipo too - same reason. Changed plugs and leads and its fine now.

 

[trickydisko]

fixitagaintomorrow, my car's not fuel injected, but thanks for the suggestion anyway.

sumplug, thanks for your reply, if it's a problem with the electrical components you suggest, would you expect to see sparking under the bonnet if the engine is wet and it's dark outside? I haven't seen that yet, it's just an idea for diagnosis.

Also, I would not be confident replacing those items myself, have you any rough idea of how much a garage would charge to do the work? If it could be fixed for £100 or so all in it'd be worth it, otherwise I'd be tempted to just live with it - unless the problem was likely to deteriorate.