F355 Air Injection Pump

Sounds like it will work ....... just be careful not to leave it open 'all the time' especially at lower rpms, as that will surely cause a CEL ...........

The 355 bypass sadly ...... 'opens with vacuum' ........... otherwise if it were like the 360 where 'vacuum keeps it closed' ....... then one would just hook it straight to the intake manifold (under the TBs of course)......

 

A Capristo exhaust valve would be the trick!

Details on the Capristo valve operation:
http://www.ferrarichat.com/forum/showthread.php?t=201300&highlight=capristo+valve

But you WILL get a "check engine" light if the valve is always open on a 5.2 car. With the Capristo valve, you could simply disconnect the vacuum line and the valve will revert to "always open" operation. Then you simply reconnect the vacuum line to restore normal operation. I have never tried it, but might sometime. I wonder if I should plug the line while it is detached with a golf tee or something?

 

+1 ............. true .......

 

Nice fix!

Do you suppose that the impellor was getting stuck, and that opening the case freed it?

 

It is possible that one or more of the poles of the armature in the motor is dead. I'm not sure how many this particular motor has, but in some cases, bad windings can cause the motor not to self-start if it is in a specific position, but still work fine in others. If this is the case, then it will be random chance on when the motor will start and when it will not start. The more poles on the armature, the greater the chance of it working each time you try it. Eventually, your luck will run out again though and you will have to spin the motor manually to get it to start.

 

Yup. And that's why magneto shops were invented...to repair that specific problem (among others).

 

Congratulations !! It sometimes pays dividends to check the the simple things first !!!

 

Good evening ladies and gentlemen,

after having quite some trouble with my new F355 on the vacuum system (burned fuse of air pump), I quickly want to give you my opinion on this topic/air pump issues.

Some of you have realized that the 328, 348, F360, F430 and F458 and many more do NOT have ITB's (individual throttle bodies), while the F355 has them. Their pro is a better throttle response, but the con is that such intakes are not suitable as vacuum sources (to keep the thread short, I do not explain here why). However, with the F355, Ferrari decided to still use it as a vacuum source.

This setup leads to an vacuum of appr. -0.2barg (-6 inHg) when engine is on idle and -0.5barg (-15 inHg) when revving the engine high and instantly closing the throttle).

On the F355, the "secondary air injection shut off valve" starts opening at around -0.3barg (-9 inHg) and is completely open with -0.4barg (-12 inHg). Pressure which the tank does not have during the first 2min of cold engine start, when the "secondary air injection system" is on and my engine is only idling to warm up the oil.

My conclusion: with the original setup, the "air pump" runs against a closed "shut off valve", with no air flow, heating itself up, and sooner or later welding its fan solid with the casing. Not to mention the (minor) negative consequences for the exhaust systems and environment when this system is not working.

My recommendation:
changing the spring of the "shut off valve" with a softer one. On my car, the valve now starts opening with -0.1barg (-3 inHg) and is fully open with -0.17barg (-5.5 inHg). Since I did this change, the air pump fuse stays happily in now for more than 7 months and 4000km. The softer spring and less closing force of the valve should not matter, since further downstream there are anyway check valves. By the way: the diaphragm type valve/actuator can easily be opened with almost no tools just by opening the snap fit.

Another conclusion: Ferrari did not care much about a proper vacuum system, since on the F355 it's not used for the power brakes as on most other cars of this era. Tuners that go from "Common throttle body" to ITB's usually install an extra air pump to overcome this problem.

Best regards from Switzerland

 

Great review, thank you.

My connector melted before the fuse blew which I fixed but I suppose the next weak link will go again.

 

based on my input from 1h ago, can somebody once measure the vacuum tank pressure on their F355 (on idle after startup without trottle), too? In all the inputs I saw up to know, nobody seemed to have measured it.

My F355 is just on around -0.2barg (6 inHg), which would be a very bad value on a single-throttle-body-car, but I reckon perfectly fine on a ITB-car with interconnected vacuum lines.

Best regards for your inputs.


To drbob101: the next weak link will show up soon, for sure. It's amazing how many little "imperfections" they built in: vacuum system, exhaust header, Cat temp sensor, bypass valve exhaust, airbag ECU, valve guides,.... guess all of them could have easily found and fixed with a proper test campaign....

 

no it does not

 

So you replied to a 6 year old thread....AND your answer is incorrect.

 

yes i responded to a 6 month old post in hopes it would help someone. You are incorrect if you think your secondary air pump opens up your exhaust bypass valve. You may believe what you like but if you ask the your Ferrari tech he will explain to you more in depth as it was explained to many others as well as myself.

 

cool someone else who understands it is only for emissions at a cold start and has nothing to do with the exhaust bypass valve

 

I do believe Mr. 6 posts is mostly correct (no offence) Engine vacuum is used for bypass solenoid valve operation. The vacuum is stored in the "bean can" reservoir. The secondary air pump provides positive pressure.

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The two systems are related by vacuum. Vacuum is used to operate the secondary air valve.

 

i

If you unplug your secondary air pump or pull the fuse you will find that your exhaust bypass valve will still work perfectly fine without it. The bean can does hold the vacuum pressure, you are correct however the engine has vacuum pressure, as any automotive engine, when the car is running although very little because of the multiple throttle bodies but enough to be collected in the can. It is pulled from the can when needed. I'll stop responding after this one only because this has been explained many times before because when someone feels they are right they simple wont go any further to learn more about how the entire system works. You can remove the pump from the car, cap all the lines and that exhaust valve will still work. My pump was bad when my car was purchased and my valve worked fine and the Ferrari tech. explained to me why and how it still was working.

 

Six year old post. ...and splitting hairs here.

 

Yeah, and what about the 100 other posts on the F355 forum describing the correct operation. Just because Google found the wrong one is not our problem.

 

This thread was started by "conscom", aka Gary Yee. Gary passed away a few years ago at a track event in his BMW. He had only just prior, sold his F355 and purchased a F430 Spider. May Gary rest in peace.

 

Oh Wow.