The OP indicated the car is a 2.5 ECU model. They do not have CEL lights as per manual.
It's possible that both 2.5 and 2.7 Euro cars were fitted with wiring for the CEL lights. As Bertil says, the only requirement for a fully functioning test system will be bulbs and a shorting pin. Both 2.5 and 2.7 USA cars have test buttons (according to the parts manuals), so the wiring may be present on both types. The only problem I see is that the Euro car may not have all the anti-pollution equipment that US cars have (and the CEL light may illuminate during normal operation, not just during test). The bulbs may have to be removed after the test after the codes have been interpreted.
My UK spec 2.7 348 (1991) had everything except the test-buttons with their pigtails incl. connectors (which I found on Ebay). The CEL-s do not come "on" without a reason. And the "CEL" system works - I had the left CEL come on when the left fuel pump started dropping pressure.
Looking at the wiring diagrams, it looks like you short out the black (earth) wire to the grey/red (HR) wire. Not sure if the wire colours are visible on these older cars. Image Unavailable, Please Login The grey/red wire goes to pin 13 of the ECU.
I was expecting a simple waterproof 3 way connector hardwired to the switch, but from your description and looking at images of the switch, there must be a short harness from the 3-way (?) connector to the 2 pin plug on the switch. Image Unavailable, Please Login
Yes, a short harness 3-2. This is what I got from Ebay: Image Unavailable, Please Login Image Unavailable, Please Login There is one currently for sale on Ebay (https://www.ebay.com/itm/234164124256) having an interesting description.
Hi No, you don't have to remove the bulbs after testing on the euro cars. I have had the cel bulbs in place for 8 years and no Illumination at all. Bertil
One other item on the 2.5, there is no socket on the either ECU plug in which you can plug the pig tail shown above. I was sure of that but just checked to make doubly sure. While there is the open slot in the binnacle for the light, I have never checked to see if there is any wiring to the socket. I guess you could place a jumper wire at the ECU plug but if there is no wiring to the light it still would not function. It is unusual that Ferrari didn't provide a way to check possible codes because US cars started using that blinking method in the mid '80s. I did find $.30 under the seat so my checking wasn't for nothing.
Here are the fuel pumps. I installed two new pumps with all new parts... Image Unavailable, Please Login
I just rebuilt the pump on my 355. It wasn't nearly that bad, but the damage had certainly begun. An item of note that when I was taking it apart one of the wires nutted onto the pump was finger tight to the point of I thought I had the wrong size socket on my driver because without paying too much attention it felt like it just spun as if it was too large. Also I'm a believer that tossing a pressure guage is an easy and often overlooked step when troubleshooting. Stick to the basics first.
First Ferrari trip today, same problem... New fuel pumps, new Temps seniors. I don’t know the direction i must search. All your ideas are welcome.
MAF is my bet, could be O2 sensors. You can go component by component measuring resistance and volts to determine which components are out of whack the details are in the workshop manual, you can get to the various pins through the ECU harness. Either that or start removing and replacing parts till you find the one. As I said for me it was the MAF. Sent using FerrariChat.com mobile app
Your problem could be due to a faulty Idle Air Control (IAC) valve (one or both). Check what type of IAC-s your car has. Being a 2.5, it should have two IAC's inside the "vee", mounted on top of the coolant cross pipe, as shown on this diagram and picture: Image Unavailable, Please Login Image Unavailable, Please Login However, some have reported having the IAC valves like on this picture: Image Unavailable, Please Login
That was my first thought, too, but would the behaviour change with temperature? Would there be much radiant heat in that area?
Yes, I noticed your suggestion re IAC but there was no response. If the IAC-s are the type as shown on the first two pictures in my post above, these actually control the bypass air purely based on temperature. When cold, they are supposed to be open to let more air for cold starting. When the engine starts, the power (12V) supplied to them slowly heats up the internal by-metallic element which gradually closes the bypass air orifice via a rotating disc. The valve heater and the by-metallic element are designed to completely close the valve by (approximately) the time the engine is fully warmed-up. Rather crude method of idle control and, of course, they do not respond to engine load like the IAC-s on the 2.7. When the engine is at the operating temperature, the engine heat is transferred to the valves which also helps keep them closed. I had a few cases of this type of idle valves malfunction (due to age) on the BMW-s of the 80's I owned before. Some had burned-up internal heater, some were not responding to heat and on one the internal rotating disc that controls the air opening had completely detached itself from its shaft.
Sorry for the late answer guys, but it was the night here in Europe. There is a small difference when i start the engine when it is hot... it is a little bit harder to restart, correct me if i'm worng. When you start the engine (cold or hot), you don't have to touch the gas pedal at all. Image Unavailable, Please Login mine is this one: do you have any ref for this part ?
I couldn't find any numbers for it. Maybe you could try cleaning it first. Are you saying it's harder to restart when hot but runs fine afterwards? In what way is it harder to restart? I would have thought if it ran better it would have been easier to start.
The car is not at home, i can check the part ref. tomorrow. If someone knows the ref, i shall order the parts today. There are old, so maybe a good idea the change Cold: - when i start the engine without touching the gas pedal, RPM are very low and a lot of vibrations. - When i start the engine when i push the gas pedal (a very few), it starts perfectly. Hot: - when i start the engine without touching the gas pedal, it tries to start but do not. - When i start the engine when i push the gas pedal , it starts after a few seconds.
Search the forum, there was quite a bit of writing on this type of IAC a couple of years ago. Possibly somebody provided the part number for it. It is strange that it is not shown in the parts catalogue at all.
Volvo used this type of idle control valve back in the 1980/90s. Some other marques too if I remember correctly. They were quite problematical. I replaced quite a few. The slide would get gummed up stick. You could clean them out with carb cleaner with some success.. Always the first port of call before replacing..They are electronically controlled but very basic.. 0280140106.html
When the IAC's go sideways it usually affects idle, it surges or hunts, it typically does not affect start only though?
