Calling on the expertise of members of this: CEL followed by SDL

Half way through a spirited drive, last weekend, the Check Engine Light (CEL) came on followed moments later with a blinking Slow Down Light (SDL). I was around five miles away from home, so, I drove her back, parked her and started researching the cause using this wonderful site.

It is worth mentioning at this point that the car had its engine out major service done June `09 by Competizione. The headers and the Y-bypass exhaust were replaced with Fabspeed’s equivalent, the cats were replaced with Hyperflows and the exhaust bypass valve with Capristo.

While researching found out that only the left and right Cat ECUs can cause a blinking SDL and that the center ECU can only cause a CEL, hmmm. Checked my ECUs and found that the center and right ones were replaced with ones having the green baking (newer ECUs) but the left one still had the black backing (older), more hmmm.

Where to start, during the drive the exhaust bypass valve sounded like it was open all the time, so, I started checking for vacuum in the line leading to the Capristo bypass valve while the engine was on and found that it had slight suction in it. I did notice that when disconnecting the line from the valve, the valve clicked once as if something dropped inside of it, which gave me the impression that it might be working fine.

I ordered a new ECU from Ricambi and when it got here this morning I disconnected the battery, replaced the left ECU, connected the battery again, started the engine, waited 20 minutes (15 minutes should have been enough) but both lights persisted. I then took her on a 15-minute drive to no avail. Another thing that I noticed was that the engine never went into Limp Mode, triple hmmm.

I have no idea where to go from here except take her back to Competizione. I am open, however, to any ideas you may have. I was planning on a nice one hour drive with some friends today; do you guys think I should continue driving the car?

Thanks in advance
1997 F355 Spyder

 

Thanks for the advice. I did end up going on my hour ride with some friends, which ended up more like an hour and a half. 10 minutes into the ride the blinking SDL goes away and a sudden jolt of happiness overcomes me; but as we approach our midway point to stop for a bite to eat stopping at a few traffic lights along the way, the SDL comes back on, bummer.

On the way back, the SDL disappears again 10 minuets or so into the trip and remains gone all the way home. Don't know if I should be happy about this as I don't trust that thing anymore. I will try your suggestions and keep posted, thanks again.