My 95 US 456GT has become a bear with hot starting (or lack there-of) I run John's MSW COP kit for ignition with real Denso coils and sparkplugs mailed with the kit. Car starts up cold instantly. After 2 different 50+ mile drives recently if failed to want to re-start for awhile. I had also been noticing slightly longer crank times leading up to the two most recent no starts. The car pulls strong, idles and drives beautifly. After shutdown, with a fuel pressure gage on the rail it holds over 50psi on each side, so I don't suspect FPR. Nor was there any signs of fuel in either vacuum line. I have checked and cleaned connections on the COP harness, have checked and cleaned the external ignitor connection on the side of the airboxes. Have pulled and cleaned but not replaced the Crank sensors. Have an updated Guido Fuseboard. Have not opened up the panel again yet. I can hear pressure building up in the EVAP system when I remove the fuel cap, but has always done that. I have R&R the fuel pump supports with Fabios PTFE parts as well as new filters so no bad rubber in the system Have been in contact with John, but no useful suggestions yet. I'm spitballing or fail to fully understand what the crank and Cam sensors do, but could faulty parts be to cause hot starting? Inspecting the fuse board and reseating the ECU plugs would be next. But hoping to find a real culprit
Injectors were serviced in 2019, prior to my ownership. The intake manifold has not been off since i have owned the car.
I would check the coolant temp sensor. Can you check the corresponding voltage cold and hot on the ECU plug?
'95 is 5.2? If so.... Image Unavailable, Please Login Image Unavailable, Please Login I'm just concerned that it will take you so long to access the plug and set up your test gear, the car will have cooled down. Best to have the battery off as there are live battery connections on the ECU.
What about heat-soak affecting the 30 year old + starter itself (if it is ?) This is an issue with us modified big cube (434+) modern Corvette guys. My C5 shop always wraps them in that gold foil.
According to Wiki, the 5.2 engine was introduced in 1996, the M in 1998. Anyway, I don't have data for the 2.7.
Ian- 5.2 in the US was introduced in Spring 2006 in the model year 97 456 for V12s. The F355 had 5.2 for MY 96. There were no US MY 96 456s. Wiki is a really poor Ferrari source.
Now I'm really lost, Terry. 2006? Did you mean 1996? I don't understand why MY97 covers Spring 1996? Thankfully, anyone can amend Wiki. I corrected some information on the 348. Maybe you could do this for us with the 456?
Ian- Yup, spring 1996, brain fart. At least I got the model years right. And yup, the spring 1996 5.2 456s came out as MY 97s.
Nick, to rule out the new fuse board, put the old one in if you still have that (and if it is still working)...
Haven't touched anything this week. I still have the old fuseboard, but there was 1 broken relay connector when it was removed, from relay S, WSM 'key operated services'. Image Unavailable, Please Login I will check or swap both relays for Fuel injection and fuel pumps as well as each Motronic fuses and plug. Clearly the fuses are intact. I still feel this isn't the path to resolve this. Car never exhibited any delayed starting on the OEM ignition system, so I can always return it to that configuration, but really hoping to leave the COP system in place now.
