Is this a fueling problem?

[mmacneill123 0]

Hi folks

 

Picture this, you are happily doing the speed limit on the motorway and suddenly you lose power - sometimes throttle has no effect as you tumble possibly all the way down to stationary, splutter and suddenly you are okay again for 20 mins; other times throttle just causes lots of preignition and no power increase.

When the engine is pretty warm and you go into the supermarket for 20 mins, come out again, car will start but die straightaway - takes a few times to splutter, again throttle no effect, suddenly it will run and if you keep it high revs it will keep running. Idle stays low until it has been running again for a good while. Cold idle is initial fine but then lumpy until it is up to temperature.

 

MAF, ISV, plugs, plug-leads, temperature sensors replaced, cleaned up the fuel-pump relay and ECU relay. Only VAG-COM fault code is Lambda out of regulation range - Lambda sensor is due for replacement but have a feeling that will not cure the problem owing to the fact it happens when the sensor value is ignored at speed.

 

I am hearing a tick from the fuel-pump relay when the ignition is in the on-position but not started, which is why I am wondering whether it could be dicky relay or an unhappy fuel-pump.

 

Any genius mechanics out there?? Please persuade me this is fixable or should I opt for my wife's preference for me, a new VW-UP :-(

[dr_mat 0]

Certainly could be, but you would want to see if you can look at the measuring blocks for ignition timings and any error codes while you're driving along. Some codes, such as the crank sensor, will simply be overwritten when you stop the car so they won't show up unless you catch it in progress.

BTW the fuelling map is fixed and does not use the MAF/Lambda sensor if you're on full throttle on the Corrado, so if the engine cleans up and starts responding normally on full throttle that would point to that. Also, do you have any modifications?

 

But I've had similar symptoms with a blown head gasket actually. Sorry. .. check the oil and water for mixing and watch for the colour of the steam out the back.

[Dox 23]

When you say cleaned the relays do you mean there replay plate pins or taken the covers off and cleaned inside and checked for dry solder joints?

 

Do the needles on the dash plummet to there stops when the dault appears shen driving?

[mmacneill123 0]

Certainly could be, but you would want to see if you can look at the measuring blocks for ignition timings and any error codes while you're driving along. Some codes, such as the crank sensor, will simply be overwritten when you stop the car so they won't show up unless you catch it in progress.

BTW the fuelling map is fixed and does not use the MAF/Lambda sensor if you're on full throttle on the Corrado, so if the engine cleans up and starts responding normally on full throttle that would point to that. Also, do you have any modifications?

 

But I've had similar symptoms with a blown head gasket actually. Sorry. .. check the oil and water for mixing and watch for the colour of the steam out the back.

 

Thanks for that - I have had VAG-COM on with the engine running for a good while and the Lambda fault is the only one that pops back up as soon as it is cleared. Hopefully the Lambda will be changed soon and did the MAF just before Xmas. Head gasket pretty sure okay, had that happen already :-)

[mmacneill123 0]

When you say cleaned the relays do you mean there replay plate pins or taken the covers off and cleaned inside and checked for dry solder joints?

 

Do the needles on the dash plummet to there stops when the dault appears shen driving?

 

Just the pins and cleaned the fuse box contacts too - has helped the running generally so thought it a good idea to replace them anyway with some new ones on the way :-) None of the dials plummet so do not think it is a general power fault - just loses all power but sometimes recover if I leave the clutch in for a few seconds and let it roll - especially not good when you are trying to overtake!