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[Paul Lewis]

Hi everyone. Anyone who has been on this discussion list recently will probably know that I have been having some intermittant running problems with my M reg 16 valve (with CAT) and I have still not managed to solve the problem. A couple of guys..Nicko and Tom have also been on this discussion list as 'guests' and mentioned that they have had the same problem and that several other 33 owners have also had the fault.

Basically the car runs really poorly as if there is fuel starvation or a weak mixture until it has warmed up and then runs fine. This is the case everytime with my car and it makes pulling away from stationary with a cold engine a tricky business. I have spoken to many Alfa specialists..well Clovertech, Automeo and Alfaaid to name a few and none of them can pinpoint the problem. I was told that it was probably the engine temperature sender that screws into the left hand throttle body but I have swapped that with a s/h one from a P4 16 valve engine. When my P4 was on the road, it never had that problem so surely the s/h sensor is okay?

I think it would be really helpful to me and those other guys if anyone could shed any further light on this annoying problem. Is there a simple not too technical test to see if the AFM is working correctly? Could it be a problem with the air temperature sensor in the AFM?

I really would appreciate any advice because otherwise I'll be forced to sell my car on e-bay for a pound!!!!!!!!!!!!!!!!

Cheers Paul.

p.s I have recently swapped the ecu's over, putting the one from my old P4 into the M reg and that didn't cure the problem but the car seems a lot quicker. Could the chip in the P4 ecu be an aftermarket one or is it just that the P4 ecu's have remapped chips to cope with the extra drag from the 4 wheel drive and extra weight??

[tvatavuk]

Hi Paul,
I don't know how to check AFM and I guess that you sold yours from P4, since you don't have it available for swap?
About P.S. If you take cat P4 and cat 16v, there is no notcable difference in ECUs (if you switch cars), so i would assume that yours is tuned, or at least it was done in factory for P4 non cat.
Strange clicking? sound you heard when you swaped ECUs came from injectors which were opening/closing with somewhat different timming then before, that is normal once ECU learns most of things it can learn and injectors get in shape with new timming, it disspears.
If I were you I would probably ultrasonicly cleaned injectors or can you swap one from P4? If you can, do it with cold engine because some fuel allways squirts on engine. First to replace would surely be one where you hear tappets clicking.
Have you checked cyl compression on cold engine?
_________________
Tino Vatavuk
Little black dress which replaced Alfa Romeo 33 S 16v Permanent 4 GMo

[Guest]

Have you checked the Lambda sensor?
If it's not working, like mine wasn't, then you'll get very rough fuel distribution especially from cold!

[Paul (not logged in)]

Hi There. I had a new lambda and new cat fitted only a few months ago.

Cheers Paul.

[tvatavuk]

Hi Paul,

many people had similar problems after changing their lambdas.
There was some story about bosch lambda with same number as one on FIAT/AR original part, at the end it turned out that car would run ok only with FIAT/AR original replacement part made by BOSCH
Do you have a way of replacing that lambda, with some from 16v that runs well?
_________________
Tino Vatavuk
Little black dress which replaced Alfa Romeo 33 S 16v Permanent 4 GMo

[Paul Lewis]

Hi Tino, thanks for the advice about the lambda sensor, but I am sure that it is a proper Alfa one as it was fitted by a specialist Fiat/Lancia/Alfa garage and cost around £80. Also my car has had this fault for as long as I can remember, even when it had an old knackered lambda and cat on it.

One other thing I should mention is that when the car has warmed up is does run okay but not perfectly. It is still quite jerky on the throttle especially just above 2000RPM. I don't know if that is significant. There is plenty of power but it seems a little nervous on the throttle. Is this how 16 valvers are? My P4 was never as jerky or nervous as the cat 16 valve. Is it the cat that makes them a bit crap to drive?

Another thing is that when I had the distributor swapped over, one garage re-set the position of the replacement. Could it be that this has affected the timing? I was under the impression that it was controlled solely by the ecu and that it didn't matter what position the distributor is in?

Also I don't have a spare AFM, which is the only thing I haven't changed!!!

Any advice?? Paul.
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Currently own a late 33 16 Valve (M reg) in Silver, with P4 alloys and superspint back box.
I live out in the sticks with not an Alfa specialist for miles around!!

[tvatavuk]

Hi Paul,
2-2200 rpm are resonant revs of 16v boxer, you never want to be there for too much time. Some older rpm meters had this area yellowed, other did not.
If there is a slightly inbalanace (worn cams, tappets or even gasket leaks or head cracks) anywhere in engine, you will feal it as shaking.
16v were allways more responsive then P4.
Cat for sure kills them a bit because you lose some hp, and as if that is not enough, it is not uncommon that pieces from cat ceramic arrray fall off and clog rear box.

Position of distributor, well that could be the reason, it is true that ecu controls spark but this does not mean that we can rotate distributor cap as we like. Is it distributor (along with arm) or was only distriputor cap that was repositioned?
If you can, have it checked at some other alfa specialist.

If that does not help if you want it, thing I can do is to send you tuned chip for ECU. It is without fuel cut off, and with remaped fuel settings, limit is same as before. It is anything but not jerky.
Just send me address on tino.vatavuk@st.htnet.hr
Do you have access to EPROM reader/writer? If you have I could send you only binary file. EPROM chip you need is standard M27256, and empty one should not cost more then costs 3-4 pounds.
If it helps, i would be intrested in copy of yours factory non cat P4 chip.
I plan to put bin file of mine factory cat P4 chip on web, and non cat version would be also interesting. (In case there is difference)
_________________
Tino Vatavuk
Little black dress which replaced Alfa Romeo 33 S 16v Permanent 4 GMo