Alfa 75 ts breaking down at 4000rpm

[simmi1983]

Hi guys,
I've posted on the topic before.
I have a 75TS race car which im due to take to morgan park on Friday and its breaking down at 4, 000rpm.
Ive had trouble with it ever since ive tracked it but previously was only playing up when the car gets warn after doing 5 or so laps-doesnt play up when cold,  however on my last run it got worse and wouldn't rev over 3000.
Now its idling eratically 500-1000 up n down and when you free rev it wont get past 4000rpm. Its not the tacho because its a new auto meter.
When I was tracking it last year I just had to short change at 5k but all it felt like was a rev limiter.
Ive got a spare TS so ive been swapping stuff across to try n diagnose .
So far ive changed -
Ecu ,AFM , crank angle sensor, fuel pump ( full in boot fuel cell with lift pump and bosch 044 fuel pump, coils, coolant temp sensor, tone wheel on the crank is not loose or damaged.
Im gonna go crazy testing fue pressure etc tomorrrow and swap more bits across but was just hoping someone has experienced the same thing and could save me some stuffing around.

Thanks in advance,

Luke

[Citroënbender]

Is it possible there's a gasket leak between two adjacent cylinders?

Also, what's your battery and charging arrangement? Are the wires and terminals all A1?

[bazzbazz]

It seems someone else has already suffered what seems to be a similar experience to you, check this out, it may help -

http://www.alfaclubvic.org.au/forum/index.php?topic=14577.0

Baz

[simmi1983]

I don't think it's a compression issue -it really feels electrical to me.
I have rewired the while car bar the ecu harness.  Ive made it really simple with a battery post in the engine bay wirh a battery in the car. Im using a 6 pole battery isolator with a field cut to the alternator.
Ill test compression and alterbator charge tomorrow but my voltage gauge says 14v which is fine.

[simmi1983]

Baz, thanks for the link for that other thread.
Did he get an answer to that or did he assume it was the balancer?

[simmi1983]

Turns out I had 2 problems.  The one that has always been there is low fuel pressure-only has 9.5v at fuel pump, so am running new wiring and relays to keep good voltage up the back tomorrow.
My main and most recently problem is a dud CAS- I replaced it last year thinking it would fix my original problem but instead it just caused another. Lol.
All good,  all sorted and hopefully will have it ready for the track tomorrow.
Thanks for the advice.
Luke

[Citroënbender]

Did you initially replace the CAS with a used or new part?

I'm assuming the fuel pressure was reading low under max load?

[bazzbazz]

Now I would have suggested CAS as a possible culprit, but in your initial post you mention it had already been replaced. Silly me assumed it was with a new part.    

[simmi1983]

Fuel pressure drops down below 2.5bar which isnt right. It should slightly increase or remain the same. Thats the thing Baz it was a new part! Thats why I didnt look coz I was complacent... cost me close to $200 too. Now the original sensor from the 80's is doing a better job
I have to keep remembering-just coz its new don't make it right!

[Divano Veloce]

I had a similar problem with mine at broadford last year.... i did a bunch of stuff that didnt fix it... eventually i replaced both distributor rotors (vw golf mk3/4 are the same) and this fixed it. Theyre glued on....

[simmi1983]

Now has fuel pressure and runs like a dream.. until the cat converter snagged on my car trailer and broke the headers lol  lucky ive got a spare car to pilfer from.
Race in 2 days-hope nothing else goes wrong!!