SAAB 93 Juddering

[Jason 93]

Hi,

I am new to the site and forum but can anyone give me some advice on the following:

I have recently purchased a SAAB 93 1.9 (120bhp) TiD Linear Saloon on a 06 plate with 43k on the clock. I have now noticed it juddering in most gears before your about to shift up a gear. If you hold the pedal at the point of it juddering it will slightly increase before the judder stops. I would'nt say it is a large judder but certainly noticable to anyone in the car.

The car is still under warranty from the dealers garage and is going back next monday. Ihave heard that SAAB has modified leads and valves to over come this problem.

Is this correct? and any advice I would greatly appreciate.

[HDi fun]

Does it judder under light load, say cruising at 80mph in 5th/6th gear?

You mention leads. Which leads is it to which you/Saab refer? If anyones mentioned HT leads then there's none of these with a diesel engine.

The engine your car has is a Fiat/Alfa derived JTD unit. These use electronically controlled injection but if the high current wires to these were suspect it probably wouldn't start at all.

This juddering sounds to me, initially, at least, to be a problem with the dual mass flywheel.

Give us some more detail and let's see if we can come up with a coherent answer. It might make it a little easier if you find yourself challenged by the supplying Saab dealer.

[Jason 93]

Hi,

I cant say that I have noticed it juddering under light loads in a higher gear at 80mph. It is more noticeable from 2nd to 3rd and 3rd to 4th with a light load ie the driver.

The SAAB dealer garage mentioned innjection leads into the engine which he said may have a poor contact. (Well at least thats what I think he said) He had a look under the bonnet and went straight to the rear of the engine and checked what he called the ECR/ECG? Valve. But he said that it looked like a new one and this would not be the course which is when he then said that it could bethe leads.

[HDi fun]

The injectors on common rail diesels need loads of current to crack open the injectors against the high fuel pressures involved.

Unless this is very Fiat diesel specific it sounds as if the mechanic is not really too sure how diesel engines work.

Poor ignition leads can give such misfiring and juddering problems with petrol cars. I've never been aware of a comon rail diesel suffering from poor injection quality as a result of poor electrical connections to the injectors.

If the car starts cleanly then I'm really not convinced it's an injection related problem.

If you dip the clutch before changing up and keep it held down does the juddering diminish as the engine revs drop to idle?

I'm still thinking about the flywheel at this point

[turbo]

I have to agree. Clutch, flywheel area I think. I`d be surprised if it was to do with the injection side of things

[HDi fun]

If it was fuel-delivery related I think you'd have warning lights a-plenty, and chapter and verse on the information display. You'd also have sod all power. THe other place to look is the other end of the engine. Frequently there are dual mass crank pulleys used to dampen the usual 4 cyl diesel rotational vibrations. These are cheap to replace, about forty quid to buy and about 1/2 hour's labour charge.

There's one other very simple thing to check, and that's the tightness of the front wheel bolts. It's unliely this is the cause but a friend of mine had a problem 20 years ago with a FWD Astra where oen one front wheel was ever such a tiny bit loose.