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superb tdi misfiring

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hi just wondering if any one can help in anyway right i purchased a salvage skoda superb it had been flood damaged i dont think it has been in a bad flood. ive stripped all interior and replaced lots of bad connections and the comfort box and that has sorted all lights windows etc in the interior. But the engine is only firing on 2 cylinders im 99% sure water has not gone in the engine but i just dont know whats wrong with it. also i drove it a short distance and it seems to fire on 3 then but the next day its down two 2 again also it smokes realy bad but its unburnt diesel.

I'd do a compression check and check fault codes and measure block values with diagnostic equipment but it don't sound good.

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a friend did plug a computer in to it but it came up with a code cant exactly rememer it started 18 and said can bus to powertrain?? what does that mean?

a friend did plug a computer in to it but it came up with a code cant exactly rememer it started 18 and said can bus to powertrain?? what does that mean?

Thats electric mate, it's a system to tell all the electronics to talk to the ecu, one cheap solution, take the radio out and clean all the connectors, the wire to the radio has a speed pulse and this will probably be part of the canbus, there's two standards, half and full canbus, hth.

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Thats electric mate, it's a system to tell all the electronics to talk to the ecu, one cheap solution, take the radio out and clean all the connectors, the wire to the radio has a speed pulse and this will probably be part of the canbus, there's two standards, half and full canbus, hth.

so it could be the ecu thats broken and thats why its missing? i take it you mean the radio that plays music? (sorry for being stupid) thanks

so it could be the ecu thats broken and thats why its missing? i take it you mean the radio that plays music? (sorry for being stupid) thanks

Yes, just pull the iso plugs off the back to see they are dry, pulse wire runs in one of these, we use it to run our meters.

How wet did the car get btw? was it a total immersion or just a nose job?

Silly thing to check, have you had the air filter out yet, if this is wet or damp even it will play havoc.

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Yes, just pull the iso plugs off the back to see they are dry, pulse wire runs in one of these, we use it to run our meters.

How wet did the car get btw? was it a total immersion or just a nose job?

Silly thing to check, have you had the air filter out yet, if this is wet or damp even it will play havoc.

ive had a look at them they are bone dry and clean ive stripped all interior out carpet seats center console etc to check everything and clean it all im sure the water has only been low as the plugs on the side kick panels are all dry and clean. Ive renewed the airfilter oil and oil filter n the diesel fuel filter. An ive also drained and replaced the diesel in the tank to make sure. Ijust cant understand why it runs on 2 and when its drove it runs on 3 but when it cools down its back to 2?? also once the turbo kicks in it pulls like a train asif its not missing but when you dip the cluch and let it idle you can hear it missing. Also i dont know if this has anything to do with it but when you turn key and ign lights come and the pump kicks in you hear a noise like its sucking diesel but air aswell might just be me. thanks for helping me.

I agree with Lummox, it's not looking good, a mis-firing diesel is almost a contradiction in terms - and CAN-BUS is a nightmare at the best of times.

Perhaps you can try getting the fault codes and posting them up here?

Good luck though :thumbup:

Thats the pump kicking in, almost like the sound of someone empyting a bucket down the loo, this is normal btw.

Airflow meter and cat sensor if it has one would be my next two suspects before writing off the ecu, sadly though neither will show any sort of damage, it'll just be trial and error replacing them, best action would be if you know someone else with the same engine to ask if you could borrow for a few hours and do changeover testing, although it's very strange for a diesel to misfire unless the fuel isn't being delivered properly, when you did the fuel filter did you fill the new one back up with fresh diesel before cranking it over, and did you use the plastic collar that holds the filter away from the engine, if this has broken the bottom of the filter drain you will be getting air in there, worst case and it is the ECU try getting it repaired before forking out for an rather expensive new one, there are electronic places like Lucas that do recon ecu's,pumps and turbos for 25% cost of new ones.

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Thats the pump kicking in, almost like the sound of someone empyting a bucket down the loo, this is normal btw.

Airflow meter and cat sensor if it has one would be my next two suspects before writing off the ecu, sadly though neither will show any sort of damage, it'll just be trial and error replacing them, best action would be if you know someone else with the same engine to ask if you could borrow for a few hours and do changeover testing, although it's very strange for a diesel to misfire unless the fuel isn't being delivered properly, when you did the fuel filter did you fill the new one back up with fresh diesel before cranking it over, and did you use the plastic collar that holds the filter away from the engine, if this has broken the bottom of the filter drain you will be getting air in there, worst case and it is the ECU try getting it repaired before forking out for an rather expensive new one, there are electronic places like Lucas that do recon ecu's,pumps and turbos for 25% cost of new ones.

ok thats one less thing to worry about by cat sensor do you mean lambda or is this a diffrent thing? If it was the airflow meter wouldent it just be flat? or could it cause a miss by telling ecu wrong data?.I swapped the injectors to diffrent cyclinders and made no diffrence so im assuming they are ok. Also when it was running (but still missing) i pulled plug off airflow meter dident make any diffrence apart from light on dash does that mean anything?

ok thats one less thing to worry about by cat sensor do you mean lambda or is this a diffrent thing? If it was the airflow meter wouldent it just be flat? or could it cause a miss by telling ecu wrong data?.I swapped the injectors to diffrent cyclinders and made no diffrence so im assuming they are ok. Also when it was running (but still missing) i pulled plug off airflow meter dident make any diffrence apart from light on dash does that mean anything?

Yes the lambda sensor, as for the Air meter you are right it would most probably just stop the turbo working properly and be gutless rather than missing. thinking on it the lambda if it's playing up probably wouldn't do anymore than make the tickover hunt a bit.

If it's a canbus related thing it's deffo an electric problem, but whether it's the ecu at fault or something that communicates with it I just couldn't say, if it's not the ecu then unless the fault code can pinpoint it it looks like you've got a needle in a haystack to find, might be an idea to contact whoever owned it last and find out if they had any problems with it, I know you were told it had water damage, but it could have had other problems before hand that the water blame is convenient to hide behind, one last thing I can suggest is in the drivers footwell there is some more electronic units behind the kick panel by the door iirc, check here to make sure there's no water still in there, the fact it runs slightly better when warm suggests there is water trapped somewhere.

Have you checked all the earths?

Also have you given the battery a good charging as I am guessing it will have stood there for a long while.

Sounds electronic to me too. It might be worth cleaning up all the injector and sensor connectors and making sure they are free from rust/damage.

Just a thought check the inter cooler hose at the front OS bottom corner, mine was miss firing last week when the hose blew off, with loads of black smoke

Did you get this from Simpson's salvage by any chance???

Just a thought check the inter cooler hose at the front OS bottom corner, mine was miss firing last week when the hose blew off, with loads of black smoke

Did you get this from Simpson's salvage by any chance???

I thought the intercooler was on the n/s? :confused:

I thought the intercooler was on the n/s? :confused:

It could also be there as well I keep forgetting the engines not transverse:D

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ive had the intercooler conector at top of engine off and bottom os they seem fine as for injector conectors there fine there under the rocker cover. i hvent checked every earth but will do this weekend. Also im told the injectors have a codeding that relates to ecu and they can some times loose there code and not work hence miss any one heard of this and if so how easy do they miss.?

We are all stabbing in the dark here. What we need if we are to help you at all are some facts about the engine etc.

Talk of lambda probes dont help when its a diesel (they dont have them) air mass meters wont cause a specific cylinder missfire.

Need fault codes (if any) and more info on the missfire itself. Was the air filter wet?

Its unlikely canbus fault will cause a missfire so worry about that later.

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