Thermo time and manifold pipe corrosion

JRV,
I looked at your picture of the manifold pipe corrosion issue. The thermo time swith is the black thing Ferrari calls thermistor in the parts book? #104628?

Also the parts book shows the pipe that rots out is a srew in part #106241. have you had an easy or hard time getting the corroded ones out. Since they all have corrosion I wonder if I should replace mine now or wait until it fails due to the likely possibility of having to drill it out and chase threads? It sould like this part could be a bitch...what do you think?

In most cases the pipe comes out by cutting it off and tapping in an easy out. Then the Ferrari updated Stainless fitting screwed back in.

If you have the manifold off for any reason replace the fitting or the first time the engine comes out pull the manifold and renew/clean/inspect everything underneath.

I pull the crossover and replace the forward factory 2 ply hose with silicone HP 3 ply hose also.

The TTS are the 2 blue sensors, 1 for each computer, the black sensor is the Temp Sender...

Isn't there another sensor on the front side of the crossover also?

Sorry JRV,

We are talking on two threads and sometimes you answer my ? from thread 1 in thread 2 :-). Anyway yes you are correct sort of. Looking at the parts book The Blue sensors are collant tmep sensors. Black switch is temp sender I guess and there is one on the front which is called thermometric switch which sounds like thermotime switch. So the question is which regulates start-up CO the thermotime switch or the temperature sensors to tell the computer the engine is cold? Can the thermotime switch also mess things up when the engine is hot?

BB,

quoteing from the WSM:

Starting

as the engine turns the ECU has to recognize engine timing from the sequence of signals that are sent from the revs and timing sensors to sycronize injection & ignition.

During the phase whith aspeed of more than 30rpms, the ECU, in order to fascilitate starting, commands all the injectors simultaneously and and for a time only as a function of coolant temp. This command is only activated if the coolant temp is greater than 0 degrees C. After this first injection, once engine timing is known, the sequential and timed function of the injection begins and the injectors are commanded by the ECU in timed manner.

During the starting phase the ECU applies a temp correction factor to the injection time (pulse width) This enrichment follows the trend in Fig. 20 and is active until coolant reaches 60degrees C.

*As the WSM continues on they reccomend checking and setting CO to .07% +- .02 % by turning the screws on the Air Intake Potentiometers. So I suggest you get some idle CO readings to see if you are in spec, then continue down the temp sender path.

Do you still have your 02 sensors hooked up ?????

Yup, I have both o2 sensors connected. Just tested. One to ground test 5ohms another 16ohms. Ground shoud be about 0.5 ohms to zero so I have a new problem here. I think the 4 wire O2 sensors still need to be grounded and pick the ground up through the exhaust pipes to manifold. So I will wire in smoe grounds to the sensors. Do you know if the O2 sensors need to be grounded? Also the co is perfect as tested on the smog machine when the car is hot and running. I have not tested the cold CO.. I also thought about the 30rpms thing becasue there is no way to tell if you have 30rpms. The tachs do not work unlesss the engine is on. They do not work when cranking. I even rebuilt a starter then did not trust the rebuilder and bought a new OEM starter to make sure I could get 30rpms. I even wired two bateries in parallel! I have even hot wired fuel pumps with an outside batery to make them run then crank the engine to ensure full power to the pumps!

BB,

I'm sure almost any starter will get the 30rpms neccesary for starting & triggering the computers. I get these 348's going on low batteries pretty often.

Too many unknowns at this point. I'd back up at this point and pull both injector rails intact & have a helper crank the engine cold to see if the engine is getting it's full spray cold for enrichment.

**Be VERY CAREFUL with this test as it creates a higly combustable fog bank. Helps to have the injectors spray into a rag to keep the airborne mist to minimum.

A few simple but direct tests are in order imo to answer some basic questions, will it not start because of fuel issues or spark issues.

Regards, JRV

JRV,

Yes this is an issue as you stated. The problem is that is do not get the fuel on cranking but the fuel pressure is there. Spark is happening on every wire. I believe there is an electrical problem that causes the lack of fuel spray at the injector during crank. However, once I use starter fluid to get the car to fire somehow the injector turn on and the car runs great. I've been racing the car this way for some time. So the question is what would cause a failure to release fuel on cranking?

I guess one thing at a time.

Once the engine runs the computers turn on the timed ijection sequence so we know the pick-ups and computers are fine.

No fuel to the injectors (they don't open that is) at the 30rpm - 400rpm range which is the resposibility of the thermal switches to tell the computers to turn on full enrichment and the job of the pick-up sensor to givee computers rpm speed info. The pick-up sensors continue to work upon start-up, however the temp sensors info is over-ridden until a temp rise shuts them off.

Based on the above scenario, I would look at temp sensors and their plugs and spec to manual.

Regards, JRV

Well I have thought this all along. I bought new temp sensors and it did no good. I did not touch the thermo time switch however. Since you are a pro wrench and I'm a part replacer I'll give your suggestion a more complete look. I'll inspect the wiring to the sensors etc. and get a new thermotime switch while I'm at it. Perhaps there is a short somewhere in that immediate wiring.