4000rpm and that’s it !

[Dci1612]

Hi all ,

What ever gear I’m in if I put the foot down I can get to 3500 and it will kick 2 or 3 times then will sit at 4000 flat out ??

any ideas ??

Regards
David .

 

[bmnelsc]

Hi all ,

What ever gear I’m in if I put the foot down I can get to 3500 and it will kick 2 or 3 times then will sit at 4000 flat out ??

any ideas ??

Regards
David .

Try checking fuel pressure first although consistent RPM is a bit suspicious - I would expect a bit of hunting at the top if it was running out of fuel. Otherwise it must be spark related so you need to run the DME test plan. Its in the shop manual. Apparently there was a "stand alone" booklet for this purpose also but I have not been successful in finding one.

 

[Dci1612]

Hi Bruce ,
Thanks for your reply.


I have replaced the DME relay the TPS
coil leads plugs cap arm battery.

Vac test shows around 15

I have done a fuel pressure test and it’s ok

David .

 

[Dan944t]

hi David ,

have you thought about maybe changing the fuel preasure regulator ?

 

[Dan944t]

also thinking coukd it be a stuck open wastegate valve ? if at all possible maybe check it out?

just sone ideas

sounds to be sone thing that has to be consistant

atb
Daniel

 

[Dci1612]

Hi Daniel ,

Ive tested the wastegate and It’s definitely opening.


I’ve now ordered a fuel pump and the fuel filter/strainer that’s inside the tank !

thanks
David .

 

[Dan944t]

hi David, good that you can rule out the wastegate was wondering if it was maybe stuck open?

i had similar problems when on the dyno live mapping and went through new pump strainer ect ect as the piwer just wasn’t going up over certain rpm and it ended up being my brand new adjustable fuel preasure regulator spring, so i put the uprated 3 bar bosch unit back on and the rest is history ,….still have it on my shelf the best brand too. that killed 2 weeks of searching for a problem all over the place boost leaks you name it. would be great if it was your problem as it’s easy to change. i have my old one knocking about somewhere if i can find it that is?..

 

[Dci1612]

Well I suppose the fuel regulator will be the next change then !


Thanks for your help.

 

[944Turbo]

Is the throttle butterfly opening fully?
Is it the same when the car is in neutral (no load)?
Does the car have any modifications?
Tony

 

[Dci1612]

Hi Tony ,

yes the butterfly is opening.
The car will Rev fine out of gear and when driving if you just creep up with out loading/boosting .


I think it’s had remapping work in the past , it’s got a duel port wastegate

Thanks

 

[944Turbo]

So sounds boost related are you getting black smoke too at 4000rpm? is the dump valve stuck open? Any other major boost leaks - the couplings to the inter cooler can split and open up as the engine rocks under load.

I think that around 4000 rpm is the point where the Airflow meter is fully open and the car switches to look up tables for fuel / ignition so I wonder if the 'fully open' signal is not getting through correctly - if it is telling the ecu it is closed at fully open instead of wide open?
there is a guide here on testing the AFM
https://clarks-garage.com/shop-manual/elect-22.htm

unusual fault, good luck!

Tony

 

[Dci1612]

Thanks for the link Tony !


I will have ago at this on Saturday and hopefully we can get somewhere !


Ive got the rattling heat shield too ??

 

[Dci1612]

Hello all ,

just an update !


I have changed the Airflow meter and all is working again ??

Thanks for all the replies

David .

 

[Dan944t]

nice one david ! glad to hear you found the culprit mate ????

daniel