Testarossa Cold /idle ok but car stutters when engine is hot

Coil packs?


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first change from left to right side and otherwise to see if it is the coil issue. if so then it would be ok only to change the faulty one.

 

Good advice
The coil pack usually starts breaking down first when hot because either the fluid (that acts to cool) breaks down or the electronic module breaks down

 

only new coil or also the electronic for the coil?

 

Vacuum lines tested ?

Sparkplug connectors ...

 

I would do the following:
1. Borrow an oscilloscope and check the ignition on each bank (you can do it by putting the scope inductive probe first on the left-hand coil-to-distributor wire, then on the right-hand side). This will tell you if it is ignition-related
2. if you still have the O2 sensors, back-probe a voltmeter into them to read the voltage. Best to use 2 (right-hand, left-hand) so you can observe voltage as it warms up. This will tell you if it is fuel-related

 

both or only one side?

I told you already change from left to right side and then you see

nice that it was not more

but I wonder: your mechanic tested a new coils and the failure still has been there? and now you write you changed the coil and all is ok - what now???

 

Assuming these coils are similar to those on the mondial, these can get hot and break down after say 4 miles.
With the car cold, start it up and drive until the engine starts to play up, then jump out and put your hands on both coil bodies. If you notice a temp difference then the warmer one is the one breaking down. Mine stated to misfire after about 4 miles and the temperature difference was easy to find. When the coils are cold you can test them and they will be electrically good

 

good idea
but before you touch the coils you may shut off the enigne

 

Thanks, Mike, this is a very interesting observation! My car has had these symptoms since I took it out for an hour or so at highway speeds for the first time since my full major service. And it has been fairly easy to reproduce again. The last I checked with my mechanic, he didn't know what was wrong, but said the car would drive very, very nicely and then <boom>, start sputtering and went to ****. With what you're saying, he could test my coils from today until the end of the world when they're cold and they'll check out (or could check out) OK. But only start to disintegrate and misfire or not fire when heated.

Unfortunately, *I* got fired since I last talk to my mechanic, so I've really been focusing on other priorities for the time being, but I will definitely go down and talk to him tomorrow and see if we can do this "heat test" on the ignition coils when the engine starts sputtering.

 

Went down and talk to my mechanic this morning. He says he actually figured out what the problem was - the fuse panel overheating - and was just waiting for the part. I asked him, about the part currently in the car, "it isn't a stock fuse panel, is it?". He replied that yes, it was a stock fuse panel. So that's another thing lyin' Artie screwed me on.

Could I test his idea by driving around with the fuse panel cover open and maybe have a couple of small computer fans blowing in on the fuse box?

 

picture from the fuse box would be fine

there are several options:
I prefer a cheap one: take 5 relais ( 2 for the fuel pumps, 2 for the water radiator fans and 1 for the AC fan ) outside the fusebox and connect the wires directly to those and you have no more problem

you may search here - a lot of information you will find about the fuse box

 

Mine started farting and banging as the coil warmed up, in effect it was running ok on 1 bank as its coil was fine, but the other was causing the problems.
The ends of the plug wires can go hard over time, be sure you get the correct wires as it will not work correctly with aftermarket ones unless a straight replacement, its very fussy on these

 

Thanks Romano and Mike for your responses. I called my mechanic to try and get it back and do a little testing on my own, but he says a lot of things are unplugged and it's not drivable in its current state. He says the new fuse panel should be in very soon. I'll provide an update then.

 

I talked to my mechanic about a week and a half ago and he said the problem ended up *not* being the fuse panel. Turned out to be ignition coil, driver's side. Replaced it with the model for the 512, and says it hasn't had any problems. I test drove it around town for 20 - 30 minutes this afternoon and didn't have any problems. Will drive it some more later in the week to verify the problem is truly fixed.

 

Out of curiosity how much do the coil go for?


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I got effed. I really need to talk to my mechanic and let him know if there's an identical non-Ferrari-branded part, I'd rather use that. Little over $700.

 

Seems okay to me! Coil pack on my cl65 are about 2k and need to be replaced often!!


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Did you check the cross reference sticky thread at the top of this forum? Lesson for next time then.


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