A4 1.9 tdi no power when up to temp.

This is my 1st post on here so hello to everyone.appologees if this gets a bit long winded.
Recently i bought a 2003 a4 avant as a project car.now when i bought it it was acting up qith the power issue.the owner was honest and told me she put unleaded in the tank(roughly 3 ltrs of petrol when the fuel light had just come on so prob 1/8 of a tank).i have changed the under bonnet fuel pump for a known good one and also changed the filter.the problem is that at a cold start up the car runs sweet with plenty of power.then as it hits optimum running temp it takes ages to build up reves.now its not yhat it cant rev just that it really labours after 2k.there are no lights on the dash and the pump in the tank is working.any ideas?i dont have any software i can connect to the car with so really shooting in the dark.many thanks for taking the time to read this and thank you in advance for any help you can give.

It will be difficult to fix without VCDS, but I would start by replacing the coolant temperature sensor.

Thanks for your reply nero morg.well at least its a cheep swap so what have i got to lose.my doupts lie in the fact that the problem only started after the misfuel episode.also i dont have any smoke from the exhuast which would usually be a symptom but admittedly not always.can i just ask another question as i dont have much knowledge of tdi engines.if my injectors were damaged in the misfueling would they work ok when cold and only hang up when hot?just clutching at straws i suppose.will try the temp sensor and get back with results.thanks again.

It depends on how long it was driven for. Sometimes you'll be OK, sometimes you'll have to replace the injectors.

Mmmm.its a real bummer not been able to communicate with the ecu.any injectors ive ever seen go bad were bad all the time.i suppose if the temp sensor doesnt do it i will have to get connected some how.would injectors throw a light on the dash do ye think?cheers

Injectors won't cause a check engine light unless it was misfiring. Most you will get is low power all the time and smoke. If it clears out and drives fine, drive on.

Injectors can act a bit funky in some failure modes, but it's usually more that they struggle cold than hot. Usually, mind.
So in neutral, will the engine rev up past 2k fine hot? I ask because if with no load it will go fine but struggles with load I may question at least in part the turbo- the vanes may be heavily sticking when hot.

Also....
You say you replaced the under hood/bonnet pump...
Which engine do you have? I see it is an A4 Avant, 2003... is it a 1.9L? Pumpe Deuse? I'm a tag ignorant on the overseas units.
Gas can hurt the newer injection systems a lot quicker than the old Injection Pump style, but it isn't good for any of them.

Nero Morg said:

Injectors won't cause a check engine light unless it was misfiring. Most you will get is low power all the time and smoke. If it clears out and drives fine, drive on.

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Ye i think the drive it on approach was taken by the prev owner alright.theres no smoke attall.also meant to say that the odd time it could be driving in its underpowered state then all of a sudden the power returns for a moment then gone again.its really strange.im no newby to working on petrols and i understand the principals of diesel engines bit this has me whacked. Thanks m8

Typrus said:

Injectors can act a bit funky in some failure modes, but it's usually more that they struggle cold than hot. Usually, mind.
So in neutral, will the engine rev up past 2k fine hot? I ask because if with no load it will go fine but struggles with load I may question at least in part the turbo- the vanes may be heavily sticking when hot.

Also....
You say you replaced the under hood/bonnet pump...
Which engine do you have? I see it is an A4 Avant, 2003... is it a 1.9L? Pumpe Deuse? I'm a tag ignorant on the overseas units.
Gas can hurt the newer injection systems a lot quicker than the old Injection Pump style, but it isn't good for any of them.

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Its the avb engine code.1.9 tdi.yep 2 pumps.no lift pump.yes if in nuetral it will rev all the way up if i wish.i can here the turbo spoolling up just fine which is why i havent mentioned it yet.......yet lol.im just thrown by the misfuel i guess.coincidence?thanks

Coincidence maybe, still a data point. Your problem is a bit unique. I would first check the various temperature sensors. Check them at ambient temperature, then again at operating temperature. You'll see goofy numbers for a bad sensor.
I'm not at all familiar with that engine, brief search, fueling;
timing belt-driven Bosch VP37 (VerteilerPumpe) electronic distributor injection pump, direct injection (DI) with five-hole nozzles, Bosch EDC 15V+ electronic engine control unit

Not sure what component could have been damaged by gasoline.
Other causes of those symptoms may point to internals, maybe do a compression test cold and hot.

Thanks bobnoh.the fuel pump is actually driven of the camshaft.it really doesnt feel like a compression issue as there doesnt seem to be any misfire.it cranks level and even ie no dead cylinders at any temp.i have to wait till prob monday for a temp sensor so i suppose i will give that a whirl and go from there.just another strange thing while i think of it is the car seems to me anyway to be getting really good mpg.i have this habbit of putting 20 euro in the tank.now the 1.9 tdi i just sold would do about 120 miles mixed driving.this seems to be getting 135 ish to the same amount of fuel.price has only changed by around a cent or 2 per litre.unique......oh yes.

So i fitted the new coolant temp sensor and no change attall im afraid.i have noticed that if i disconnect the battery for a while when i reconnect it and drive,the momentary spurts of full power happen alot more before dissapearing again.this leads me to beleive it is a ecu issue as a damaged part would stay damaged whever the battery was doing.does this make any sense to you guys?

That's just the ECU doing it's job. Once certain conditions are seen repeatably, it defaults to a safe mode or limp.

Without a diagnostic tool (s/a VCDS mentioned above) it would be an expensive guessing game.

If you have a laptop you would only need to buy a OBD2 adapter that is compatible with VCDS lite.
The lite version is free to use, most needed features work.

wonneber said:

Without a diagnostic tool (s/a VCDS mentioned above) it would be an expensive guessing game.

If you have a laptop you would only need to buy a OBD2 adapter that is compatible with VCDS lite.
The lite version is free to use, most needed features work.

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Ah ok.i didnt know that thanks.and thank you to everyone for your advice and comments.they have been very helpfull to me.i will keep you posted.cheers

Hi y'all
All I want to know right now is Whats the correct oil pressure
for my 2004 VW "1.9" TDI wagen ?

Thanks in advance !
(I've been searching for hours...sorry if I am in the wrong place !)

Ok guys i got a loan of a scanner that managed to pull acode out of my car.it was for the map sensor(open circut).now i have to say i wasnt convinced but thought hey give it a clean and see what happens.so after cleaning the code arased which it wouldnt before the clean.i took it for a drive and for about 2km it was as if it was fixed.just as i thought yippee the old girl went back to her old ways.at least now i had a direction to go so i just made sure it wasnt coincidence by giving it another clean and same story.anyways i picked up a new map and now she is as happy as the day she left the factory.thanks again to all of you.i prob would have taken the wrong route without your guidence.hope this helps someone else.i will list the symptoms below for clarity.

Low power after car reaches full temp
No light on dash
No smoke from exhaust
Started first tip of the key always
Idled perfect
Fuel economy actually got better from what i can tell.def didnt get any worse
When first started in the morning it ran like a champ then just lost the power.

Thats all i can think of right now.cheers again lads.

Thanks for the report! Helpful. Do you know what the code number was?

BobnOH said:

Thanks for the report! Helpful. Do you know what the code number was?

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Yep.sorry should have included it.it was 17564.i could only get the generic code from my freinds diag tool.wound up being good enough.

From https://www.ross-tech.com/Search-Results.html?q=17564

17563/P1155/004437 - Manifold Abs.Pressure Sensor (G71): Circ. Short to B+. Possible Symptoms. Limp mode. Possible Causes. Connection(s) to/from …

Sounds like a power wire shorted.

Yep thats the one.and to think i was chasing the misfuel issue.i very nearly ordered a complete set of injectors at massive expence.i think it may have had a part to play in the map sensor crapping itself but not sure how it could.the old map was fairly well coated in oil which must have come up the turbo tube from the inter cooler which also had some oil in it.or it could have just been a plain old coincidence.

Bluepants said:

Yep thats the one.and to think i was chasing the misfuel issue.i very nearly ordered a complete set of injectors at massive expence.i think it may have had a part to play in the map sensor crapping itself but not sure how it could.the old map was fairly well coated in oil which must have come up the turbo tube from the inter cooler which also had some oil in it.or it could have just been a plain old coincidence.

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Mine was soaked with oil many years ago.
I think that was affecting the ECU to think the air temp was hotter.