VW Corrado Loss of Power
Discussion
2.0 16 Valve 9 A Engine.
This issue has been going on for weeks now and I'm running out of ideas?
Mainly appears after about 20mins to an hour of running, although I've noticed it's particularly bad in damp conditions.
It's never stopped completely or left me at the side of the road, and it does tend to clear after more running - for instances I've just done a round trip of 200 miles motorway running. Very bad on the way down (wet conditions) not as bad on the return - dry..
The engine response is down on power as if restrained, but it does not seem a fuel or electrical issue. The power delivery hesitant, but if you floor the accelerator after initial hesitation you get full power. But the throttle response is not smooth at all. Strangely turning the ignition off/on clears the fault for a few minutes, but the fault returns.
I've replaced cap/rotor/leads as a matter of course, and the throttle position sensor as I'd had advice this could be the issue.
I've also had advice that it could be the Lambda sensor, or Catalytic Converter (it is on its last legs CAT rattling) someone said it could be the honeycomb breaking up and restricting flow. I was going to go ahead and replace them next, but some very rough running in damp conditions this afternoon has made be question that logic..
Any advice would be welcome
This issue has been going on for weeks now and I'm running out of ideas?
Mainly appears after about 20mins to an hour of running, although I've noticed it's particularly bad in damp conditions.
It's never stopped completely or left me at the side of the road, and it does tend to clear after more running - for instances I've just done a round trip of 200 miles motorway running. Very bad on the way down (wet conditions) not as bad on the return - dry..
The engine response is down on power as if restrained, but it does not seem a fuel or electrical issue. The power delivery hesitant, but if you floor the accelerator after initial hesitation you get full power. But the throttle response is not smooth at all. Strangely turning the ignition off/on clears the fault for a few minutes, but the fault returns.
I've replaced cap/rotor/leads as a matter of course, and the throttle position sensor as I'd had advice this could be the issue.
I've also had advice that it could be the Lambda sensor, or Catalytic Converter (it is on its last legs CAT rattling) someone said it could be the honeycomb breaking up and restricting flow. I was going to go ahead and replace them next, but some very rough running in damp conditions this afternoon has made be question that logic..
Any advice would be welcome
It's a Dinosaur 1994, I'm led to believe the engine management is fairly rudimentary and does not give good feedback on codes (I've had it in a garage)... And when it was in the garage it was running perfectly (at the time)
No I've not changed the plugs, as I'd only realistically expect failure on one maybe? And the issue is nothing like running on 3 pots.. I suppose it's a cheap try at least and something to rule out..
No I've not changed the plugs, as I'd only realistically expect failure on one maybe? And the issue is nothing like running on 3 pots.. I suppose it's a cheap try at least and something to rule out..
It has a diagnostic socket under the gear shift gator, but I'm told it's a 3 pin type and the info given is not that reliable.. The garage that informed me of this have a good reputation and for honesty and specialise in VW.. It's rare I take any of my vehicles to a garage as I normally try to repair myself - but I was at loss this time and hoped they'd be able to go right to the fault rather than me faff about..
I'll give the plugs a change, but I'm not that sure it explains the symptoms between dry and damp running.. I'd expect a duff plug or more to give bad performance from cold start and all of the time - rather than after a duration of time.
I'll give the plugs a change, but I'm not that sure it explains the symptoms between dry and damp running.. I'd expect a duff plug or more to give bad performance from cold start and all of the time - rather than after a duration of time.
Single coil.intresting question though??
When the problem first appeared I spoke to the prop at the aforementioned garage, he suggested it sounded like the coil breaking down. This is my second Corrado, my first was written off but I kept some spares. I fitted the old coil of that and the problem settled down for a couple of weeks - it's still fitted.. It's obviously a now very old item and that too is now failing after being sat for a long time. I guess that would also be a reasonably cheaper item to replace new and rule out..
When the problem first appeared I spoke to the prop at the aforementioned garage, he suggested it sounded like the coil breaking down. This is my second Corrado, my first was written off but I kept some spares. I fitted the old coil of that and the problem settled down for a couple of weeks - it's still fitted.. It's obviously a now very old item and that too is now failing after being sat for a long time. I guess that would also be a reasonably cheaper item to replace new and rule out..
Thanks for all your help and advice chaps..
Got to admit I'm fairly embarrassed it's taken so long to narrow down! I've been running Corrado's for 20 years, this is my second, the reason being they are fairly bullet proof and very reliable.. This has been my first major issue in all that time.. They rarely go wrong!
Got to admit I'm fairly embarrassed it's taken so long to narrow down! I've been running Corrado's for 20 years, this is my second, the reason being they are fairly bullet proof and very reliable.. This has been my first major issue in all that time.. They rarely go wrong!
Salut Mignon!
It looks like you were right on the money a few posts down. It appears that item on the air box is what measures the rise and fall of the air flow plate via some sort of potentiometer which is now worn. There is no seperate MAF.The whole metering plate is NLA .. There is just one on e bay but very pricy! However there is a replacement potentiometer arrangement also on the bay (from China?!)
It looks a bit of a faff but doable.. Has anyone attempted a repair like this?
It looks like you were right on the money a few posts down. It appears that item on the air box is what measures the rise and fall of the air flow plate via some sort of potentiometer which is now worn. There is no seperate MAF.The whole metering plate is NLA .. There is just one on e bay but very pricy! However there is a replacement potentiometer arrangement also on the bay (from China?!)
It looks a bit of a faff but doable.. Has anyone attempted a repair like this?
Yup! This ye olde chestnut again!
I purchased the part from China an received within 5 days!
Perfect quality and replica to original Bosch part.
When fitting I realised after a bit of thinking - and poor results...
The Spring contacts that make contact with the circuit board were not making contact! Weakened with age. Gently bent them to make contact, and it runs ok - except it won't tick-over.
It will at idle, but as soon as you load up the drive train, it dies, it re - starts ok, but as soon as you go for a run and dip the clutch. It stalls..
I opened up the throttle butterfly's on their 'stop' adjustment. And it fixes when the engine is warm..
When cold - NO..
Any ideas ?
I purchased the part from China an received within 5 days!
Perfect quality and replica to original Bosch part.
When fitting I realised after a bit of thinking - and poor results...
The Spring contacts that make contact with the circuit board were not making contact! Weakened with age. Gently bent them to make contact, and it runs ok - except it won't tick-over.
It will at idle, but as soon as you load up the drive train, it dies, it re - starts ok, but as soon as you go for a run and dip the clutch. It stalls..
I opened up the throttle butterfly's on their 'stop' adjustment. And it fixes when the engine is warm..
When cold - NO..
Any ideas ?
Many many thanks Mignon.
Without your advice I think I'd be chasing this issue for a long time!
It did need adjustment, I read the link you'd previously provided (I'd forgotten you'd placed it)
It's not running perfectly, but it's a huge improvement - and I'm in the ball park now!..
I owe you a few Beers sometime - cheers fella!
Without your advice I think I'd be chasing this issue for a long time!
It did need adjustment, I read the link you'd previously provided (I'd forgotten you'd placed it)
It's not running perfectly, but it's a huge improvement - and I'm in the ball park now!..
I owe you a few Beers sometime - cheers fella!
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