I am posting this with a hope that someone can help a fellow Zed owner who doesnt have access to this place

 

He has a JSpec Auto TT with low mileage in good all round nick.

 

When he accelerates hard it pulls strong upto, say, 5-6000 rpm and cuts dead. Not a rev limiter as it has only developed this fault recently.

 

Could a faulty PTU cause these symptoms?

 

Having not been in his car I cannot say much more than this, he is a mechanic himself but [not a zed one ] cant sort it.

 

If it was a fuelling problem would it not stutter? - this is as though the engine is ceasing ALL activity until he lifts off, then he can resume acceleration.

 

If anyone can help me [him, us whatever] Ill be greatly grateful.

 

Thanks,

Glen

Has he carried out an ECU diag'?

 

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MAYBEE A COIL CUTTING OUT I HAD THIS ON A BIKE ONCE. DEFO SOUNDS ELECTRICAL

mine does that ,but only in the wet(hks filter) only when i floor it in the heavy spray on the motorway,i lose acceleration completlt until i back off the pedal,

 

 

get him to check that the air flow meter has no crap building up on the sensor

i might be wrong it's just a thought

2p

 

philly

 

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Thanks folks,

 

Going to get his car over to my place and swap my PTU onto his and see if that clears up the problem.

 

If not will look into it further..

Will check the Air Box meter hasnt got clucked up with the funk of 40000 crap dirty roads.

 

Thanks again.

 

Glen

mine a normally aspirated Z, but when I used to run Saab turbos you could get what's being described if the wastegate was stuck closed. A boost pressure switch would cut the ignition, then switch it back on again once the pressure was down. If you reduced the rate of acceleration ie boost then you could rev past the previous problem point. WD40 used to sort it. On earlier models I used to bolt shut the wastegate, and mount a boost guage on the dash and drive it with one eye on the guage. You get better acceleration further up the boost levels.

...good fun.

Yeah sounds electrical to me! Check the CAS, PTU, coilpacks and injector connetors for the green shite

 

CheerZ,

 

Andy

Does it happen in every gear?

Its an Auto and will not get to high enough revs to do it in first.

 

It does it at around 6000rpm in second - the strange thing is it cuts power (seems to disengage gearbox) and reduces the revs to around 5000rpm with no drive.

 

If the gas pedal is let off quickly and then floored the power returns upto almost redline and then _something_ kills the power??

 

We tried my PTU today and exactly the same so not PTU.

 

We are starting to think that it could be something to do with his speedo conversion (JSpec to mph).

 

It is most strange but if doesn't seem to be a fuel prob (new filter fitted) but more as though the ECU or something is saying "no more power/cut revs back to 5000rpm/no drive to the wheels thru gearbox - (its one of those strange auto thingies )"

 

Anyone shed any light on this - seems very odd

 

Thanks,

Glen

Glen, is it an import??? If so it sounds like the speed convertor is screwing up the speed signal to the gearbox controller.... Try removing the convertor and try the car then...

 

CheerZ,

 

Andy

Choz for the suggestion Andy!

 

I am thinking along those lines too,

will try your suggestion and see what happens.

 

Thanks chapZ,

Glen

hi m8 also have a look at the cam shaft positioning sensor.....nissan consult test gave that on mine....i'n since swaped mine cause i hadn't had it long....good luck..

OK update - we have tried my PTU and the guy (andy) has bypassed the Speed converter.. still the same.

 

I guess next we will try my known good CAS and TPS on his car to see...

 

Is it poss that the speed converstion could have damaged the ECU at all..

 

And can I try my (Jpsec Manual TT) ECU in his car ??(JSpec Auto TT) ...

 

Thanks for all your help chaps, and hey - what goes around comes around in Zed world, this guy Andy - top bloke - has just got me a set of 18" SO3 rears for under £400 fitted.

 

Kudos indeed

 

Glen

Glen,

Don't think a manual ECU will work in an auto car. T'other way around maybe ....

Manual ecu won't work in an auto Also check the connections to the MAF sensor. Just a thought.

 

CheerZ,

 

Andy