Hi,

 

Had my Octy for almost 5 years, and it's never missed a beat, until last 6 months. Under acceleration/load the car judders or hesitates.

 

This tends to happen at the lower revs, and then once it gets through those judders, accelerates as normal.

 

Car has had full service including all filters, sparks etc...coil packs changed under recall from Skoda.

 

Car has been scanned for faults and nothing is showing up.

 

A couple of garages have looked at it, plugged in laptops etc, and apparently all curves look fine.

 

The only thing showing up was that the lambda was running a little lean. Although it's had a new lambda and it's still doing it.

 

Am running out of ideas, and just wondered if anyone else had any ideas. Have done a search but the most common fixes tend to be coil or maf related. Maf has been changed too.

 

Car has a stage 1 map (REVO) and one garage suggested to check the map. This was done about 4 years ago, but have never read or found nothing on faulty Revo maps?

 

Doesn't make any difference with regards to which fuel is put in, or whether the weather is hot or cold

 

Thanks in advance Dan

Edited 22 March, 201511 yr by dandy1

Could it be a fueling issue? Pump/ injectors? Did all filters include fuel? What plugs are in and what's the gap?

Sounds like coil packs, but you say it had the recall ones....still not impossible that it's one or more of those, would be unlucky but...

Bit of a bugger when it doesn't throw a code. I had coil packs going in my Toledo and didn't get a code. But this could also mean it's fuel related.

Have you cleaned the throttle body and had it realigned lately?

Was it a genuine MAF by the way?

Mucky throttle body?

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Mucky throttle body?

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Definitely the easiest cheapest check and potential fix.

Mucky throttle body?

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This was the issue with my juddery acceleration.

Just make sure you have it aligned with VCDS afterwards

If you don't unplug it when you clean it you may get away with not realigning, but alignment could be part of the issue. If you don't own or have easy access to vcds then just try the clean first but be prepared to have it realigned.

If the lambda is running lean have you checked for split vacuum pipes under the inlet manifold and the rest of the breather pipe system. Also worth checking the plastic pipe that goes from inlet manifold to the brake servo. Easiest way to check them is to spray them with carb cleaner with the engine running. If there split, you'll know

Ah yeah lean could be a leak after turbo, forgot about that. TB and pipework be good places to start then.

Thanks for the replies fellas..

 

yeah it was a genuine maf, and i agree it seems like a fueling issue. Feels like it's not getting enough fuel so cutting out? maybe?

 

Although will definitely check the throttle body, thanks for the suggestion. 

 

Interesting about the hoses, but I think i've had most breather pipes changed. There were a few split ones, along with some dodgy injector seals which was all picked up on the last service I had. I had hoped that these all accumulated to the cause of the issue, but after having the work done, there was still no change.

Ok...small update. Finally had the throttle body cleaned today. Small improvement on throttle response on the lower revs, but hesitation/judder is still there.

 

All pipework / breather pipes checked and still no issues there.

 

The garage that did the work think it's a map problem. I've done a search but can't find any issues regarding Revo maps! 

 

Can maps go wrong? The map has been on the car for almost 5 years, with no issues.

 

One more note, over the past week and a bit, the hesitation / judder has definitely got worse...more violent. 

 

Does anyone else have any more ideas?

 

I think next option is to maybe take the car back to where it was mapped, take the map off and see if the problem is still there....

Have you explored the fueling? Try get a used fuel pump, would then be a fairly inexpensive check and a job you could do yourself. Failing pump would either overfuel or lean out the mixture, possibly fluctuate between the 2 which would play havoc with the running. Not swearing it is that but seems to be one of few avenues left to explore.

Could be worth a diagnostics session on a set of rollers if that doesn't work. If the map has been on for 5 years it's highly unlikely that's the issue, running as standard could be worth a check but you're better off finding out why it's not running right as it is.

Just my contribution, for what it's worth...

 

Sometimes these days, what with all the complicated engine management and diagnostics, we tend to rely on computers to help us find faults. Which for the most part, they do. However, that can often lead to complacency in not checking the basic mechanicals, as we might have done 10 or 20 years ago...

 

So...have you done a compression check? That can illustrate many problems, from dead rings to sticky valve lifters. Don't forget these cars have hydraulic valves - if one is duff, you're gonna get compression issues on that cylinder, which could cause the fault you describe.

 

Valve timing? It is not beyond the realms of possibilty that the timing belt has jumped a tooth at some point. That would also cause poor running.

 

 

Finally - don't know if this helps or not, but I had a Revo remap done on my '51 plate Vrs when I bought her nearly 5 years ago. She still runs incredibly well - almost better than ever these days, so MY map hasn't done anything strange or changed at all. I would think that this scenario is very unlikely...

 

 

Good luck though, and keep us updated.

Ah yeah lean could be a leak after turbo, forgot about that. TB and pipework be good places to start then.

Leak after the turbo would probably cause rich-running, as the boost would escape but the extra fuel would still be injected, however a leak between MAF sensor and turbo intake would cause lean-running, because extra air would be going into the turbo without registering at the MAF.

 

Also, check the Coolant Temp sensor is functioning properly; if the ECU cannot determine the engine temperature correctly it won't be able to fuel properly.

Leak after the turbo would probably cause rich-running, as the boost would escape but the extra fuel would still be injected, however a leak between MAF sensor and turbo intake would cause lean-running, because extra air would be going into the turbo without registering at the MAF.

 

Also, check the Coolant Temp sensor is functioning properly; if the ECU cannot determine the engine temperature correctly it won't be able to fuel properly.

Ah yeah apologies for the mix up

Next thrilling installment!

 

Mine started to misfire a bit at low revs/throttle again, this time with an oily smell. Turns out the engine breather pipe at the top of the engine where two breathers converge was split, right before it goes into the turbo inlet pipe AFTER THE MAF SENSOR! 

 

Was buggering up the fuelling a treat!

 

Dead easy to check; its literally just under the engine top cover, on your right as you look into the engine bay. mine was all perished and rotted and split.

 

New jobber from TPS, 10 minutes to fit, pair of new jubilee clips as the old clips have to be cut off and voila, happy-happy turbo time!

Next thrilling installment!

 

Mine started to misfire a bit at low revs/throttle again, this time with an oily smell. Turns out the engine breather pipe at the top of the engine where two breathers converge was split, right before it goes into the turbo inlet pipe AFTER THE MAF SENSOR! 

 

Was buggering up the fuelling a treat!

 

Dead easy to check; its literally just under the engine top cover, on your right as you look into the engine bay. mine was all perished and rotted and split.

 

New jobber from TPS, 10 minutes to fit, pair of new jubilee clips as the old clips have to be cut off and voila, happy-happy turbo time!

Bit of a favourite area for splits that one, fitted my oil catch can other day and the lower breather had split almost right round where it meets the crankcase breather Y pipe. Not sure how long it had been like that, probably shortly after I swapped stock Y for a silicone one, wasn't until disassembly I really noticed, would account for the light covering of oil on the cold side of the engine though!