Hi to all.
Please help me to build spark coil driver.
Original spark coil driver fail often. I need to add external driver. Need help to determinate R1 and R" value. Zener value. I choose TE2486 because this kind of n-mos is very strong and I never found it broken in this context. Any other (better) solutions is welcome.

 

Certainly the voltage rating for the mosfet will be important, as well as the current rating. It may be that you will need to add a series diode to protect from a reverse current thru the mosfet.

 

mosfet is already usen on other ecu. It never fail.

 

The TE2486 seems to be associated only with "scammy" types of websites,
I would not use it for any purpose.
Possibly it is a very old Part-Number.

FETs must be specifically chosen for a particular, exact, application,
with all surrounding Components and values taken into account.

Transistors normally fail from a large variety of careless-misuses or misapplications,
NOT because they have a magical, "Never-Fails" Part-Number.

All Transistors can be caused to fail if You don't read and understand the Specification-Sheet.

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Please describe, IN DETAIL, what You are attempting to achieve by adding a Current-Boosting-FET.

Why does your factory-Installed ECU have failing Coil-Driver(s) ?
Is this a well-known, common-failure for this model of Engine or ECU ?

How many ECUs have You replaced so far ?

What have You changed on Your Engine,
including ANY Electrical changes, and/or, Mechanical-parts-changes ?

Does your Engine have a Distributor and a Single-Ignition-Coil ?, or ........
does your Engine have a "Coil-On-Plug" Ignition-System ?

The "fix" that You are proposing will be more complex than what You are imagining.

What is the Brand-Name, and Year of your Car ?

If your Car has a Lucas-brand-Electrical-System,
throw-away the entire Car, and buy a different Brand of Car.
Lucas has been inferior for almost ~100-years, and it's still unreliable junk,
sorry but it's a fact, ask any Ferrari-Mechanic.
.
.
.

 

The TE2486 seems to be associated only with "scammy" types of websites,
I would not use it for any purpose.
Possibly it is a very old Part-Number.

Answer - it's marked Motorola. The ecu is used in 1990 cars


FETs must be specifically chosen for a particular, exact, application,
with all surrounding Components and values taken into account.

Answer - It's used as coil driver. Fiat still use same coil but different driver.

Transistors normally fail from a large variety of careless-misuses or misapplications,
NOT because they have a magical, "Never-Fails" Part-Number.

Answer - my own fail because vibration, heat or undersizet. The reason is one or all of them.

All Transistors can be caused to fail if You don't read and understand the Specification-Sheet.

Answer - OEM ecu supplyer know well the specifications but they "think" like consumerism.

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Please describe, IN DETAIL, what You are attempting to achieve by adding a Current-Boosting-FET.

Answer - I want to extend ecu life so I need to add extenal driver.


Why does your factory-Installed ECU have failing Coil-Driver(s) ?
Is this a well-known, common-failure for this model of Engine or ECU ?

Answer -the ecu is IAW59f and is very famous for this type of failing.

How many ECUs have You replaced so far ?
Answer -Any shop here in Italy change at last 2 ecu every month. It's very common problem.

What have You changed on Your Engine,
including ANY Electrical changes, and/or, Mechanical-parts-changes ?

Answer -nothing.

Does your Engine have a Distributor and a Single-Ignition-Coil ?, or ........
does your Engine have a "Coil-On-Plug" Ignition-System ?

Answer -This is the coil CE20058-12B1


The "fix" that You are proposing will be more complex than what You are imagining.

What is the Brand-Name, and Year of your Car ?
Answer -fiat punto 188 1.2 8v

If your Car has a Lucas-brand-Electrical-System,
throw-away the entire Car, and buy a different Brand of Car.
Lucas has been inferior for almost ~100-years, and it's still unreliable junk,
sorry but it's a fact, ask any Ferrari-Mechanic.
.
.

Answer - It's not Lucas problem.
I have to say that our entire economy is based on the hope that things will break again. More than 47 years ago we produced a "device" called Voyager1 that continues to work very well without any maintenance. Anyone who does not live on "youtube shorts" asks himself: How did we create something eternal (almost) in 1977 and in 2025 we cannot build a car or other device that can work at least 1 year without maintenance?

I apologize for the off topic but I really don't like consumerism.





I opened one old ecu and this is the wiring. Do you think it's complete or I need to look better.

 

This may be slightly off the topic, but I heard it while on a service trip to the UK back in 1984:
The question was "why do the Englishmen drink warm beer??"
The answer given was: "Because they have Lucas refrigerators!!"

 

"Consumerism" is not the problem, or the solution.
Government protection of "Corporatism" is the problem, this is basically soft "Fascism",
in the USA we still have too much of it,
but it is changing rapidly. Do Not Give-Up, or become Jaded.
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I see by your Coil-Part-Number that You probably have 2-Ignition-Coils,
because You probably have a 4-Cylinder-Engine,
and both Coils operate in a "Wasted-Spark" configuration.

What You are proposing is just adding more potential-Problems to go wrong.

How many Electronics-Projects have You successfully completed ?
( answer honestly, because You are the one who will be stranded far from Home if it Fails )

I recommend a Commercial Product from DIY-Auto-Tune called "Quad-Spark".
It costs roughly ~110.oo USD, and it's Bullet-Proof,
shipping may be extra, I haven't looked into Shipping-Costs in a long time, they might be crazy-high now.

It's made in the USA and uses modern IGBT-Transistors specifically designed for driving Ignition-Coils,
and is completely "Self-Protecting" against Voltage-Spikes.
And, since it is only available with 4-Independent-Channels, ( hence the name "Quad-Spark" ),
You will always have 2-Back-Up-Channels for a "just in-case" odd-failure.

There are a few other parts that will be required for your circumstances,
Two ~2-Watt, 20-Ohm-Resistors, and
Two 5-Volt, 5-Watt-Zener-Diodes, and
Two "FET Gate-Drivers" to invert the original Coil-Ground-Signal from the ECU.
These parts are extremely over-rated because You are very-likely
to install all of this stuff under the Hood, with the Engine,
which is the worst possible place for it,
where all of the parts will be subjected to ~100C Hot-Air at all times when the Engine is running.

Always mount any Under-Hood-Electronics in the coolest area You can find,
preferably in front of the Radiator, with an Aluminum-Shield to keep-out Direct-Rain-Water-Spray.

Electronics are always safer, and last longer, inside the Car,
but High-Current-Ignition-Wiring may cause Noise in your Radio if it is brought inside the Car.
But the Wiring can be run inside of Flexible-Aluminum-Conduit eliminating the Electrical-Noise problem.

All Ground connections should be bolted directly to the
Engine-Cylinder-Head or Engine-Block, and, at the same single-Bolt.
You may have to replace the original-Bolt with a
longer-Bolt to accommodate the additional "Ring-Connectors" that are stacking-up too thick.
A long "Threaded-Rod" and multiple Nuts will also work.
Also use "Serrated-Lock-Washers" to prevent lose-Electrical-Connections.
.
.
.

 

Sorry @LowQCab original car wiring will remain the same. If "new" external coil driver fail I just use original coil driver from car ecu. Furthermore I have THOUSAND of TE2486. And, as I says, for my experience it never ever fail in this context.