Mondial t cold starts and idle rough

Hi Lino.

If it is the cold start sensor or valve or switch or whatever its called, its the blue plug that goes into the right side at the top of the plenum.

This can easily be unplugged. Try this and then start the car and see if it makes a difference. Its no harm driving with it removed. When i had my service last year the specialist Ferrari garage actually disconnected it and secured.

I had similar problems at the time with stalling, rough running and no start but cranked strongly. The problems were all solved and now runs very strong.

First thing i did was to check that there is spark to each cylinder by attaching a timing gun to each spark lead for a consistent strobe. I had 5 cylinders running only. To solve the problem was a combination of items. Firstly i changed the 2 coil modules that sit above the coils in the left side of the engine compartment. This is a common problem and is easy to do yourself. 2 screws each module and some conductive paste. This fixed the backfiring i had and some stalling but still had lots of run running and no starts.

Then i changed the 2 leads that go from each of the coil modules to the center of the distributors. Then i changed all 8 spark plug leads and all 8 spark plug extenders.

This basically was a new electrical route from the coil to the engine and made such a remarkable difference it totally transformed the car.

I still had some non start issues whether the engine was cold or hot. This was a separate problem which was the white vertical connector plug in the fusebox which melted at the fuel pump and a/c connection points. Have a look and you may see the white vertical connector brown and burnt. I replaced the connector and bought some new connector pins that the wires go into to slide in. Rather than just crimp the wires on the connector pins i also soldered them.

Since then all issues have gone and pulls like a train. Simple stuff, not too expensive and can be done at home.

Hope that helps, let us know how you get along.

I did write threads here about the connector.

http://www.ferrarichat.com/forum/mondial/397125-starting-problems-dreaded-melted-fuel-pump-connection.html

 

Replacing a relay that was located at the back of the car, passenger side and it fixed the problem.
There was a thread that outlined this that I created a year ago. Steve Magnussen walked me through it.
I remember he ran me through the diagnosis process, unplugging stuff, checking for voltage etc.....
You might want to search for it. I'd forward it to you if I could..... It might be very helpful.

 

I don't think the T has a frequency valve protection relay like the 3.2 (US version) if thats what you meant.
Sorry Lino, I dont know much about the T engine setup to help. maybe also check the 348 boards as well.
This is a good resource for 3.4 engines: http://www.my348.com/

Here's something very simple you can try for cold/hot start problems, check your grounds, especially battery off/on knob and engine cam covers will have two grounding straps, make sure you have good contacts.
Some other ideas to check - could be your fuel pressure regulators, crank sensors, spark related issues.

best

 

Hi Lino,

Ron above was referring to the frequency valve which is not in my 3.2 euro spec but appears in the US spec cars. But as Mike mentioned also, i am not sure if the 3.4t has one of these at all.

The engine is very different in design between the 3.2 and the 3.4. If you know where the cold start valve is then do try removing it first and starting the car to see if any difference is obvious.

But as mentioned, check that you have spark to all 8 cylinders.

I know there are numerous threads on the 348 forum about ecu problems that affect the running of the car. From what i gather in a 348 there are 2 ecus,1 for each bank of cylinders which may be the same for the 3.4t.

Cheers.

Peter

 

Hi Lino, not sure if #46 is your problem but this is what you were asking for.

Ferrari Mondial t Parts : Table 28 - WATER PUMP
#46 125769 2 Water temperature sensor $ 21.05
Image Unavailable, Please Login

 

I had exactly the same problem on my Mondial t and after putting up with it for months I finally found that an air hose had come off under the plenum chamber, allowing secondary air into the intake on the right bank fuel system.

Looking at the engine from the back (standing at the rear of the car) the hose was under the air intake plenum on the right side, about half way down. the actual hose connection that had come off was in the V of the engine and very difficult to get at.

In the end my friend's 12 year old daughter managed to refit the pipe by lying on the boot/trunk and putting her arm down the front of the engine.

It might not be that on your car, but the symptoms were exactly the same. So worth a look...the hose is very hard to see so could easily be missed (as it was on mine, even by the dealer, they had messed with the mixture screw on the RHS MAF unit to try and stabilize the fuel mixture!

 

I had that same problem too on my T. You have to be very careful when washing your car not to poor any water over the engine bay, these engines are very sensitive to humidity and cold mornings starts. Since I paper sands all ground connections that connects to those red valve covers my problem disappeared, and my idle is silky smooth.

 

Check for corrosion at the water temp sensor connector first. It is rare these sensors fail.

Corrosion or a poor connection will do this. You can also test the resistance to see if the sensor is within spec. The fact that it was sudden indicates to me it just got to the point where the connection became too crappy... <grin>

As pointed out, there is no warmup regulator or frequency valve control relay on the 3.4L cars.

 

Hey Lino,
Here is a thread from 2009 by 3forty8 on changing the coolant sensors without removing the plenum. He does not describe a cold start problem that led him to change them but rather error codes.

The thread then morphs into Dave Helm's research on electrical connectors and hoses (Two kits that I plan to purchase with our major service)

http://www.ferrarichat.com/forum/348-355/229830-replacing-coolant-temp-sensors.html

Dave

 

Excellent plan. However, if it was me, I would get the car running smoothly first. Even if it means painstakingly cleaning the connector plugs and possibly adjusting the prongs/receptacles so that they are tight. My thought is, you want to go from a good running car to a fantastic running car. If you do the kit yourself and the problem still exists, you'll wonder if it was something else all along or if you made a mistake with the kit. At the very least you risk missing that satisfaction of a job well done when the car fires up perfectly. On the other hand the kit might solve everything but you won't know until you install it.

Probably best to call Dave Helms.

Dave

 

Not yet. with the warm summer air, the car is ready to go in only about a minute. It's on my list though.

Dave