S2 test drive - severe juddering

[Chris D]

I very recently test drove a 1994 S2 avant, which had covered 170K miles with full history. The car had been stood for a couple of months but fired up with no problems. The engine had been running for around 10 mins before taking the vehicle out for a run. At low revs the car drove as I expected it to, but when the throttle was opened up, in any gear, the engine lost all power and caused the whole car to judder violently until the throttle was relieved back to less than 3000 RPM. We pulled the car over to the side of the road and whilst stationary increased the revs through the range without any fault or misfire. This must indicate a problem only whilst the engine is under load - does anyone have any ideas?

[horvathg]

I very recently test drove a 1994 S2 avant, which had covered 170K miles with full history. The car had been stood for a couple of months but fired up with no problems. The engine had been running for around 10 mins before taking the vehicle out for a run. At low revs the car drove as I expected it to, but when the throttle was opened up, in any gear, the engine lost all power and caused the whole car to judder violently until the throttle was relieved back to less than 3000 RPM. We pulled the car over to the side of the road and whilst stationary increased the revs through the range without any fault or misfire. This must indicate a problem only whilst the engine is under load - does anyone have any ideas?

Chris,

I had a similar episode. As it came out, the faulty lambda sensor had to be replaced. You can prove the lambda fault if you disconnect the single black wire coming from the lambda to the ECU, this connector is in front of the windshield, right under the stabilisator bar. If disconnected it goes fluently, its most likely the lambda. Also watch out for the VGF switch, cos it may cause almost identical symptoms, at least I had it, too.

cheers

[Dr H]

Sounds like overboost protection to me!

Usually indicates a big air leak somewhere. If it is just an air leak then it is nothing too much to worry about it just needs tracking down and fixing. Needn't cost that much (famous last words)

Lots of candidates like the intercooler O-ring, any of the main hoses, vacuum tubing etc. etc. CAn you get the owner/garage to get it looked at?

[audiman]

Boost leak(or leak as described above)!!!!!!! That sounds like the problem. As Leigh said, main suspect is IC o ring followed by the other main hoses. Other common one is turbo to intercooler spliting at the t-piece. Check the ECU for fault codes.

HTH

[Crawford_S2]

Defo sounds like overboost protection routine, most S2s have the decency to let you part with your hard earned before doing this, but they all do it. As above, look for leaks on the inlet side and the smaller tubing.

[Chris M]

I had a very simalar problem with mine, as soon as i floored it over 3500rpm it seemed to kangaroo. I replaced the WGFV (waste gate frequency valve) and it cured it. Good look with the problem.

Cheers

Chris

[Beetie]

Defo big boost leak, nearly as big as the one on mine at billing eh Tom!

[Chris D]

Sounds like overboost protection to me!

Usually indicates a big air leak somewhere. If it is just an air leak then it is nothing too much to worry about it just needs tracking down and fixing. Needn't cost that much (famous last words)

Lots of candidates like the intercooler O-ring, any of the main hoses, vacuum tubing etc. etc. CAn you get the owner/garage to get it looked at?

Everyone seems to be pointing to airleaks.
Not easy to get checked out as it's in Spain - I have to make a decision based what people are telling me it could be and chance taking those spare parts with me if I decide to buy it. Someone who's very experienced has said it's the 'Michelin Man' piping!
I own a 20v ur so I'm thinking of donor parts at the minute.
Cheers.

[Chris D]

Boost leak(or leak as described above)!!!!!!! That sounds like the problem. As Leigh said, main suspect is IC o ring followed by the other main hoses. Other common one is turbo to intercooler spliting at the t-piece. Check the ECU for fault codes.

HTH

Cheers for advice.
I've been looking recently on e-bay at some diagnostic testers that connect to a laptop and run with Ross-Tech, free software. These are selling for approx £30 - £45 and are mainly for post '96 cars, but certain pins can be used for older cars.

I know some people make their own and use the blink codes - but I wouldn't know where to start!
Any top tips for buying/making a diagnostic tester?

By the way, as you can see I'm new to the S2 forum, but have to say it's a fantastic way to source some excellent info from other people sharing their knowledge and experience!

Cheers.

[audiman]

check out Paul Nugents website.

https://www.s2central.net

some great little helpers such as pulling faults codes and loads of information.

One other thing, you say its 1994, this means that it is an ABY car, these DONT have the mich. man hoses. Only the older 3B's have this, first thing to check would be the O ring that seals the Intercooler onto the cross member.

[Chris D]

check out Paul Nugents website.

https://www.s2central.net

some great little helpers such as pulling faults codes and loads of information.

One other thing, you say its 1994, this means that it is an ABY car, these DONT have the mich. man hoses. Only the older 3B's have this, first thing to check would be the O ring that seals the Intercooler onto the cross member.

Thanks
Yes it is an ABY car. Is this O ring easily accessible?

[audiman]

Remove front bumper and take off the intercooler, the o ring sits in the IC. Dont bother fitting a new one, check the BTDT areas, there is a thread about a mod to replace the o ring.

[Lee]

I had similar symptoms when my coil leads broke down (the short stiff rubber HT leads between the coil packs and the plugs on the ABY). Just take them out and have a quick look at their condition. I they have a light covering of oil or look particularly discoloured and brittle this could be the cause of your problem. Should take you less than 20 minutes to assess their condition. Mine would missfire when under load or higher revs causing the car to shake quite volently at times when it was down to only 2 cylinders working, backing off it would run normally on part throttle. My plug boots were destroyed by the oild weeping through the rocker cover gasket. Rubbish (remains of rubber and congealed oil) in the bottom of the plug recesses also caused the spark plugs to start unwinding even if torqued properly exacerbating the problem.

Lee

[audiman]

exacerbating

Oh big words! LOL

[Chris D]

I had a very simalar problem with mine, as soon as i floored it over 3500rpm it seemed to kangaroo. I replaced the WGFV (waste gate frequency valve) and it cured it. Good look with the problem.

Cheers

Chris

Thanks - did you replace it yourself?
What was the rectification cost?
Don't suppose you might have the part No?
My problem is that I have to commit myself soon to going over to Spain and bringing the car back to England. I either have to take over enough tools and bits to try and repair car or just drive as it is the 650 miles to the ferry, in Santander, driving at less than 3000 RPM - which could prove a real pain!
I'm trying to cover all the options of what could be wrong by taking in all the different suggestions thrown at me from the forum - and a bit of luck it's nothing too serious.

Thanks for all your input.

If it makes over here I look forward to bringing it to a future S2 congregation.
I'm in High Wycombe, Bucks, at the minute.

Cheers,Chris