F355 rich on start up

My 95 F355 on cold start has a rich exhaust smell, Do you think my secondary air pump is not working? Car runs great otherwise

 

The secondary air pump is noisy and very obvious, so you will know.

I think your cats are deteriorating, but you may have years to go. Also,

maybe your garage windows are not open all the time as in summer?
spring fuel reformulation in California?

 

I have Hyperflow cats so I don't think it is the problem. I don't hear anything coming from the air pump though.

 

Upon cold start, you should hear a whistle from the air pump...it will shut down after 2 to 3 minutes. If it does not start (coolant must be below 59 degrees F), you will need to investigate whether it is receiving power, and if the pump has failed. Failures don't seem to be uncommon. They are damn expensive, but there are threads here of other pumps that can be retrofitted, I think even the 360 pump, which is less expensive than the 355.

I would think if the air pump failed the "check engine" light would trip, but am not certain.

 

I'm no mechanic, but the whole point of the air pump seems silly. It appears to simply "dilute" the rich, cold idle exhaust stream with large quantities of air, so it is sort of "cheating" the emission test at cold idle, and until the cats heat up and start operating optimally.

 

It pumps extra air and therefore oxygen into the (necessarily rich) warmup exhaust mixture to help the catalytic converters "kick" and light up faster and start their required chemical reactions.

When the cats can sustain the reactions on their own, the airpump turns off.

 

The air pump is a really loud, annoying whistle. It makes me really happy when it stops.

 

The fuse for the air pump blow all the time. Open up your fuse panel in the passanger side footwell. If the pump is not working I put money that the fuse is blown. Worth checking and if needed replacing. If it is blown it drew too many amps and then the question is why? If you take it apart you will see the way it is manufactured that the pump srapes easily and is a really poor design.

Regarding the CEL, nope it may not trigger the light. Mine didn't.

 

The factory fix for the current draw is to install a fuse 5 amps higher. Apparently Ferrari set it up too close to max. I think the original fuse was 15amp, and was replaced with a 20 amp.

 

Yep, tried that still blew.Took the pump apart and it was scraping. The crartmanship on that one is a real POS. First found out it was scraping by pulling the pump and bench testing it. The sound on those things are atrocious.

 

I don't know how common that is, but definitely sounds like a defect to me...

 

Pretty common actually. There were several threads on the old board regarding a dismantle and overhaul.


#16 06-25-2005, 01:52 PM
pino
Karting
Silver Subscribed Join Date: Nov 2003
Location: South Central PA
Posts: 168

I took my noisy airpump apart thinking there was something inside that could be rubbing or needing lubricated. What I found was a plastic impellar that was totally disintegrated and cracked. Needless to say, I reassembled sans the impellar and it is quiet as a mouse. Not very effective, but quiet.

 

Another


[thread]157114[/thread]

 

I had a blown fuse. Replaced with a 20amp fuse works great and very little noise except a small whine.
Thanks everybody for your help!

 

No problem, glad it worked out.