Dear all, Do you know how the clean the idle valves of my 348 ? Maybe I can replace the parts but I don’t know what is the part number. If it is not available anymore, do you know an equivalent ? Thank you so much
Does the 2.5 engine have idle valves? The idle appears to be controlled by adjustments on the intake. There is a procedure described in the manual. Items 3 & 4 are adjusted. Image Unavailable, Please Login There are other devices called "extra air valves". These allow extra air to the intake manifold when the engine is cold. I haven't been able to find them in the parts manual. Experts?
If you mean "Additional Air Valve" (provides additional air during warm-up), the part number is 124802 (see the attached extract from the parts catalogue). I saw one on Ebay - https://www.ebay.com/itm/Ferrari-348-TB-348-TS-Mondial-3-4-t-Additional-Air-Valve-Air-Injection-/122165387409?_trksid=p2349526.m4383.l4275.c1#viTabs_0 but also check with the Ferrari parts suppliers. Similar valve was used on BMWs of the 80's and some Volvos of 80's and early 90's. These valves all look the same on the mentioned cars/engines (probably on some other engines as well) but they probably have some differences in the size of the opening and the rate of closing as the engine warms-up.
Yes, I mean this Additional air valve... is it possible to clean it and to check it before I buy a new one?
It looks like some of the components may need cleaning, but also lubricating if there is metal to metal contact. Image Unavailable, Please Login Is there 12 volt power going to the valves during engine operation on your car? Can you compare the resistance of the coils on the valves? Power for the valves comes from fuses 9 and 20 (the same fuses as the cat O2 sensor heaters). The fuel pump relays provide power to the fuses.
These are rather crude warm-up idle regulators. When cold, they are open and, when you start the engine, they are internally heated up by the 12V supply which causes them to slowly close over a few minutes. This rate of closure is supposed to follow the engine's decreasing demand for extra air (transition from richer to normal mixture) during the warm-up but it is just approximate so it does not control the idle speed as precisely as the later stepper motor control. I have played with a couple of these in the past on one of my BMW's. I had a bad one in which the "guillotine" had detached itself from the shaft and was moving freely as I shook the valve. The guillotine is rather thin and it appears to be made of some hard black plastic. I don't think they get sticky but spraying some cleaner from both sides may help. Before that, I would bench test them when cold: 1. Look through one of the ports and note the size of the opening; if you don't see any opening, the valve is bad 2. If you see the openings, verify that they are about the same size on both valves 3. Connect 12v power supply and watch how the opening is closing; the guillotine moves very slowly so it will take some 5-6 minutes for the opening to fully close; if it does not move at all, the valve is bad These valves have a small adjuster/calibration stud (with a locking nut) which sets the cold size of the opening. When the locking nut is released, the stud can be moved somewhat sideways thus pre-setting the opening and it can also be used to move the guillotine slightly towards the closed position if it does not fully close with the power supply connected for, say, 10 minutes or so. This DIY re-adjustment may work on engines with a single valve but, in the case of two valves on the 348, the additional problem would be synchronising them. If one or both valves are bad, one can take a chance and by a BMW or a Volvo valve and see how it performs. If the idle speed from cold is too high (as on BMWs the valve is calibrated to 2.0, 2.5 or 2.8 lit engine, vs. 1.7 lit of the 348's bank) the guillotine can be moved to slightly reduce the cold opening. However, the BMW valves are also becoming obsolete and can cost as high as $500 new if found. There are relatively cheap BMW ones (not by Bosch) currently on Ebay - https://www.ebay.com/itm/Fuel-Injection-Idle-Air-Control-Valve-Standard-AC358/324063484744?fits=Make%3ABMW&epid=1123032481&hash=item4b73b05b48:g:9MsAAOSwlnFdppfl
Marc, I just found my used valve which I kept as spare for my ex Volvo 240 (K-Jetronic). The part number on it is BOSCH 0 280 140 114. What is the Bosch number on your valves? The valve I have (0 280 140 114) is for the following engines: VOLVO 240 Saloon (P242, P244) (Year of Construction 08.1974 - 12.1993, 121 - 155 PS, Petrol) VOLVO 240 Estate (P245) (Year of Construction 08.1974 - 07.1993, 109 - 155 PS, Petrol) VOLVO 260 Coupe (Year of Construction 09.1979 - 12.1981, 155 PS, Petrol) VOLVO 260 Estate (P265) (Year of Construction 07.1975 - 07.1982, 140 - 155 PS, Petrol) VOLVO 260 Saloon (P262, P264) (Year of Construction 08.1974 - 07.1982, 140 - 155 PS, Petrol) VOLVO 740 Saloon (744) (Year of Construction 08.1983 - 08.1988, 117 - 150 PS, Petrol) VOLVO 740 Estate (745) (Year of Construction 01.1987 - 08.1988, 117 PS, Petrol) VOLVO 760 Saloon (704, 764) (Year of Construction 08.1981 - 07.1988, 156 PS, Petrol) VOLVO 940 I Saloon (944) (Year of Construction 09.1990 - 09.1993, 121 PS, Petrol) BMW 3 Saloon (E21) (Year of Construction 11.1979 - 08.1982, 105 PS, Petrol) BMW 5 Saloon (E12) (Year of Construction 06.1979 - 06.1981, 102 PS, Petrol) OPEL Kadett C Coupe (Year of Construction 09.1975 - 07.1977, 105 PS, Petrol) OPEL Manta B Saloon (Year of Construction 09.1975 - 08.1977, 105 PS, Petrol) If you cannot locally find a cheap used BMW or Volvo valve for experimenting, I can send you the one I have which is in a working condition.
Thank you so much for your comment.... The car is not in my garage now, I shall check the number on it ASAP.
Regarding the link to Ebay for Standard AC358 I provided above - this valve is for 3.5 Lit BMW engines and will certainly not be a feasible alternative for the 348. Here's the summary of idle valves that may be suitable alternatives by Standard and Bosch ($110 to $160) as they are for 2.0 to 2.3 Lit engines: Image Unavailable, Please Login
