1995 Ferrari 348 - cold start issues

did he clean the fuel injectors?

 

Crank sensor comes to mind. Check before just replacing.

 

By "fuel check valves" do you mean the fuel pressure regulators (tav 9, item 63)? Have you checked to see if there is raw fuel leaking into the vacuum tubes (tav 9, item 74)? It sounds like it's possible that the injection system is bleeding off pressure while the car is sitting. That certainly shouldn't happen if the regulators are new or recent.

Is there any chance that the clamps for the intake sleeves are loose or crooked, so the sleeves aren't seated properly?

Any chance that there is a problem with an alarm/immobilizer system?

 

JEFF!!!

Long time no see bro! Good to see you posting again!

 

Things I would check:

1) Throttle position sensors
The ECUs use the resistance measurements of the TPS recorded from the first initial warm up parameters stored in the memory after power has been disconnected/reconnected. If you have disconnected the battery and have not let the ECU relearn the TPS resistance readings and set the initial start up parameters it can cause running issues. After you have confirmed that the TPS are reading the correct resistance, try doing a hard rest of the ECUs. Disconnect the battery for 15-ish seconds to wipe the memory, reconnect it then start the car (if it will start and stay on) and let it idle until the radiator fans kick on. Make sure to do it on a cold engine. After it has warmed up take it for a 30 minute drive around town.

2) All vacuum lines
Check to make sure they are ALL connected properly, and in good condition.

3) Fuel injector barrel connectors
Check the condition of the wiring and pins on the barrel connectors (there are 2 of them, 1 for each bank), for the fuel injectors, located up under the rear of the intake plenum. The male and female pins should be clean, free of corrosion, and making firm contact to each other. The wires should also be in good condition.

4) Fuel pressure regulators
As has been stated, check to make sure they are not losing pressure over night. You may need to attach a fuel pressure gage to each rail and then see what it reads in the morning as compared to the night before.

5) Idle air control valves
Check to make sure they are clean and working properly. They can get gummed up from fuel vapor varnish over time and get sticky.

6) Throttle bodies
Make sure that they are clean, balanced from see to side, that the air bypass screws are adjusted properly, both opening and closing at the same time, and that the throttle stops are adjusted properly.

 

Yes, the info is in this thread.

https://www.ferrarichat.com/forum/threads/348-throttle-position-sensor-adjustment.453969/

 

When it hard starts, does doing anything like blipping the throttle help? (yes, I know it's an FI car), but it could help steer toward throttle bodies or other places.

sjd

 

I'm still betting on problems with the fuel pressure regulators, since you haven't mentioned checking them or replacing them. See my post #4 and Ernie's post #7 above. The regulators should maintain 3 bars of pressure (approx 42psi) in the fuel system for an extended period of time while the engine is shut off. No fuel pressure, no start.

 

For awhile, there were inventory problems with these pressure regulators (i.e. NLA). However, both are in stock now.

https://www.rockauto.com/en/parts/standard+motor+products,PR298,fuel+injection+pressure+regulator,6124
https://www.rockauto.com/en/parts/standard+motor+products,PR161,fuel+injection+pressure+regulator,6124


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https://www.ferrarichat.com/forum/threads/348-fuel-regulator.553432/

 

What are your coolant temp sensors reading when the engine is cold. You may need to send the car to a shop who can read the data from the ecu's with an SD or Leonardo. Stop throwing parts at it.

 

Just reviving this thread as my experience may help someone else on here, I am over in the UK. I have a 1992 348TS with 35000 miles, When purchased it had just had a major £17.000 service as it had not been used so cambelts new fuel pumps, Catalytic converters and the list goes on, I use it every week weather permitting, I had a slight radiator leak which I got fixed and while I was in there replaced various sensors and coolant thermostat, After a while the cold starting got very poor it would fire up on one bank the after about 25 seconds the second bank would kick in then the car would be fine all day, Then same issues from cold again so I naturally thought Fuel pressure on the right hand bank. Anyhow last week I decided to tidy up and paint the air plenium so I stripped and removed it and while I had better access to the top of the engine noticed that the R/H temp sensor conector had a broken spring clip, I purchased a replacement and cut the old one off then soldered the new one in and as I push fitted it back on to the sensor I noticed that there was movement in the connector, I have now fitted a new temp sensor put everything back together turned the key and the car started perfectly and has done everytime since, The old temp sensor had parted company from the brass fitting so I guess it had lost its connection, It was a £25.00 fix. If you are experiencing the same problem check your temp sensors.

 

Excellent information thanks for posting. I'm actually chasing a hot start issue but I'm going to check my sensor and wiring just on principle you never know.