Help 96 TDI no power cant drive

[rogersvw]

Hi everybody I hope someone has the answer its driving me mad.


I have a 96 tdi passat estate with the 1Z engine. Now for the last couple of months theres been heavy smoke on acceleration and the same if left idle for 10 min or so.

So i gave it a service. Bad idea i took out the injectors and they were sooted up. Now have given them a pop test and clean and it says they are ok.

Put them back in and the car is gutless. It starts first time and idles perfect but its got no power at all and very slow throttle responce.

All i have done is take out the injectors and refit them. I have checked the sensors as best i can (waiting for vag to arrive). And every sensor changes note of engine but nothing makes any difference to performance.

If somebody has any idea then please help, i loved this car untill then and i just can't sort it.
many thanks Rogersvw

[greg123]

Scanning it is the first step. It's possible you had an IP Issue which has got worse. Run it with the maf disconnected, run it with the airbox disconnected.

If it's not been done, take off the inlet manifold and fully clean it and the 'throttle body' and back of the valves, it will be crudded up with egr and engine oil carbon. Blank off the egr with a metal gasket and disconnect and plug the valve line. Flush the intake pipes and intercooler. Re-route the breater to the floor (atmosphere) or if you are worried about any drops of oil fit a vapor trap to the end of the pipe. This little lot will stop it getting sooted up in future and makes a big difference.

In case it's a fuel issue run 2 new pies to the IP from a clean gallon can of diesel with a small in line filter in the 'in' line, run engine for 5 mins like that.

Let us know when you have it scanned.

Greg.

[rogersvw]

Cheers Greg. Tried it no difference.

Got a vag com no faults found. Have also cleaned intake manifold and even removed turbo and checked. Blanked off egr but no difference.
I have even taken the injectors to a specalist and they say there fine.

Drove this car home from work 50mph down hill 25-30mph uphill and thats giving it some. Car now sits on driveway as just got a golf but only till i sort this one out. Any ideas.
Robin.

[greg123]

Okay it's back to basics. What is your static pump timing in vag-com? Secondly, what is the requested vs actual boot when you are driving (get someone else to drive it).

Have you rigged a bottle of fuel and 2 pipes to feed/return to the IP and eliminated the fuel feed system (tank/lines/filter/joins) as it could be an air issue.

Have you run it with the MAF disconnected?

I still can't think this way, it must be something more simple, but if it comes to it having the IP tested or swapped (can always sell yours on ebay if it doesn't turn out to be the problem) or the ecu tested could be in order. Still stuff to do first though.

Such as, where does smoke come from? Only so many possibilities.

- bore wear (blue smoke, all the time)
- valve guide wear (blue smoke, mainly after revving the engine up and on startup)
- poor injectors
- wrong pump timing/pump fault
- not enough air

I have found air ingress to also cause smoke, I suspect it gets micro compressed in the injector lines and then makes the diesel explode out of the injector tip in an uncontrolled way and maybe hit the chamber walls - in any case, poor performance and smoke have resulted. Could even be that it's mucking up the fuel pump metering/timing and nothing to do with injection.

LEt me know how you get on,
Greg.

[ini]

Carefully examine the wiring and connector on the 3rd injector (needle lift sensor G80)

If the ECU can not get a signal from injector 3, it will use a default map with reduced fueling.

[rogersvw]

Hi guys. right havent done pump timing yet but have tried two clean pipes into clean fuel, no air but no different. I think your right though it must be a quick fix as it was fine before removing injctors. I wonder if i've damaged the ends when cleaning.
If i can get some readings will post them. Will let you know when i find an answer.

[ini]

Have you checked very basic things, like a badly seated injector seal/washer.

Did you use new copper washers, or anneal the old ones?

Are the injector seals the correct type?

Unplug the connector for injector 3, and see if there is any change.

[tdi till I die]

Hi
Any news on your ecu codes? I have an error code on my golf tdi 'needle sensor' - the injector with the sensor (no 3) which massively cuts the power when its faulty.
Ive been quoted lots to replace this and would be interested to know if this was your issue.

Thanks,

[rogersvw]

Hello to you all again. Still had no luck. To answer both the previous messages. New copper washers fitted. Had the sensor on three checked its ok and there is a difference when unpluged and i am still getting no fault codes. The injector company recon that when i cleaned them i slightly closed the holes up and its stopping the injector from delivering max fuel. But as the nozzles are £240 a set i am going to wait for now. The car still sits in my front garden. (Just to let you know I have stuck with vw am now driving mk3 golf until i find a fix).

[greg123]

What about the potentiometer on the accelerator, how does the engine behave does it start and idle perfectly but only rev up like you are touching the throttle a little? Have you got clear line on the to/from fuel feed to the IP and filter, to check for air bubbles? Maybe it's possible to use vag-com to look at the accelerator % signal, to see if the ecu is getting a 100% accelerator signal when you put your foot down.

Will it happily rev to 4,500rpm on just a bit of throttle while standing?

Greg.

[ini]

It does sound like a 'no boost' issue?

Can you hear your turbo spooling up?

Is the MAF connector ok?

Is the wastegate actuator working, is it full of oil?

Are there any pipes off the N75, is it connected correctly.

Are there any obstructions in the intake (sounds daft, but it does happen)

Is everything sealed down ok (airbox lid, manifold etc)

If your injectors were very sooty, it sounds like no air rather than reduced fuel, hard to say, it could be many things.

Just follow the logical elimination process for low power.

I would start by checking MAF, pressure and temp readings with vagcom, then disconnecting the battery and unplugging and checking every relevant electrical connector that you may have disturbed.

[tdi till I die]

Hi
Thanks for the post - throttle pedal potentiaometer? I havent heard of that one yet. Although when i start the car the engine revs up to about 2k without me touching the pedal. Same thing?

[ini]

I think Greg123 hit the nail on the head.

A high idle speed can indicate a defective 'fly by wire' throttle pot.

This is meant to allow you to get to a garage if it stops working.

[greg123]

Yeah I'm thinking that way. What a saga this one! Let us know - it's important in threads like this that the resolution is posted when it's found, to make sense of future cars with same symptoms.

I don't think the throttle potition sensor is a bank killing price so why don't you give it a go.

Greg.


I think Greg123 hit the nail on the head.

A high idle speed can indicate a defective 'fly by wire' throttle pot.

This is meant to allow you to get to a garage if it stops working.