76 series engine knock cold

Hi mark,i have searched and read all the past threads,like i said everyone seems to point to an injector overfueling noise,iam not convinced that toyota have checked properly,it really does knock away cold,you would swear a rod is about to throw.The say it is fine and have to live with it,the question i ask is why out of 90% of the people with this problem have had an injector replaced and mine is normal,cant be right.I just have to cross my fingers that when it runs out of warranty next year that it does cost me a fortune,i can just feel what is going to happen.Should i take it and get a second opinion somewhere?

Cheers

Wayne

Would it by worth getting a second opinion from a diesel injection specialist rather than a the manufacturer that just fobs you off.Just a thought.

Cheers Scoof . :-)

Hi V8G, has the dealer actually heard the noise himself? Just wondering if it would be worth parking it in their yard overnight, and starting it up in their presence the next day and let them hear the noise. If they heard the nosie and persisted in saying it was fine, then I would insist that they put their comments in writing. doc

Thanks guys for your suggestions,yes it has been left overnight at the toyota dealership and they have heard the knocking sound and admit there is one but still persist that it is normal.I think i will take it to a diesel specialist and see what comes out of that.It knocks when cold and as revs get higher so does the knock,it does go away after about 15 minites (approx) when it warms up.Toyota said they have tested all the specs on the injectors and they are all within spec.Look iam just trying to get to the bottom of this before end of warranty next april,i can live with it if the engine goes forever with that typr of knock but everyone else that had a similar problem seems to have had it fixed.
Will let everyone know how i go in the near future.


Cheers

Wayne

Agree with what you say to a point. My undertstanding is that the v8 diesel is a common rail design and the timing and duration of injection is controlled by a solinoid which is an integral part of the injector. The fuel pump on these engines only supplies fuel under pressure to all injectors at a reasonably constant pressure and rate. If one injector has a crook nozzle or solinoid then one cylinder can malfunction.

Cheers ob

Kevin

The comments you have made are not relevent to a Common Rail Diesel as the supply pump only delivers pressurised fuel to the 2 injector rails on the V8 (one for each bank) & the injectors are operated by the electronics depending on the needs of the engine

With common rail toyots's the operation of the injectors can be checked as the engine is operating with the intellegent tester 2 (toyota's diagnostic tool) & if the injectors are in specification in theory everything should be ok

If you are concerned (and if the dealer hasn't actually heard the engine on cold start ) leave it there overnight & let them start it in the morning (with you there) with the IT connected & take a snapshot of the data while it is rattling & if it is out of spec (or if they believe the noise on cold start is abnormal) they can than send the data to toyota (this may have already been done though)

The common rails also have what is called a pilot injection noise when cold & this is normal

Good luck & let us know how you go

Regards Don

Sorry about that, my mistake. I thought you were talking about the 6 cylinder not the V8

With comon rail injection be it diesel or petrol there is too mutch faith in electronic diagnosic equipment & i have used them. They may tell you the injectors are ok but only electronicly or turn of individual injectors to check if cylender mises. This does not tell you if injectors are dribling. They turn out mechanics which rely on diagnostic equipement & have lost basic diagnostic skills.

Thanks don for your thoughts,i might just do that,take it back to toyota after a second opinion and get them to snapshot it and i will get it sent to toyota.I know what will happen if i dont get to the bottom of this.
Will let you know how i go.


Cheers wayne