SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D/A

Under the Securities Exchange Act of 1934

(Amendment No. 4)*

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e), 240.13d-1(f) or 240.13d-l(g), check the following box o.

Note:  Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits.  See §240.13d-7 for other parties to whom copies are to be sent.

*The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

This Amendment No. 4 to Schedule 13D (“Amendment No. 4”) amends and supplements the Schedule 13D initially filed by the Filing Persons on January 12, 2005 (the “Initial Filing”), as amended by Amendment No. 1 to Schedule 13D filed on April 27, 2005 (“Amendment No. 1”), as amended by Amendment No. 2 to Schedule 13D filed on November 10, 2009 (“Amendment No. 2), as amended by Amendment No. 3 to Schedule 13D filed on September 4, 2015 (“Amendment No. 3”).  The Initial Filing and Amendment No. 1 were filed with respect to the common stock of IMPCO Technologies, Inc. (“IMPCO”), the predecessor entity of the Company, and may be located by searching IMPCO’s filings with the Securities and Exchange Commission (File Number: 005-40695).  Amendment No. 2 and Amendment No. 3 were filed with respect to the Common Stock of the Company. Capitalized terms used but not defined herein have the meanings given to such terms in the Initial Filing. The Initial Filing, as amended, is referred to herein as the “Schedule 13D.” 

Prior to this Amendment No. 4, the Schedule 13D was filed as a joint statement by Mariano Costamagna, Bruna Giachino, Pier Antonio Costamagna and Carla Borgogno pursuant to Rule 13d-1(k) promulgated under the Securities Exchange Act of 1934, as amended. Mariano Costamagna and Pier Antonio Costamagna are adult brothers. Bruna Giachino and Carla Borgogno are the respective spouses of Mariano Costamagna and Pier Antonio Costamagna. This Amendment No. 4 is filed by Mariano Costamagna and Bruna Giachino only, for the reasons described below, and is an exit filing for Bruna Giachino.

Item 1.    Security and Issuer.

This Schedule 13D relates to the common stock, par value $0.001 per share (the “Common Stock”), of Fuel Systems Solutions, Inc., a Delaware corporation (the “Company”).  The principal executive offices of the Company are located at 780 Third Avenue, 25th Floor, New York, NY 10017.

Item 2.    Identity and Background.

The information contained in Item 2 of the Schedule 13D is hereby amended and restated in its entirety by the following:

(a) This Schedule 13D is being filed by spouses Mariano Costamagna and Bruna Giachino (the “Filing Persons”).

(b), (c) and (f) – Each of the Filing Persons is an Italian citizen, with a business address of c/o Avv. Marco Di Toro, Corso Stati Uniti 62, 10128, Torino, Italy. Mariano Costamagna is Chief Executive Officer and a member of the board of directors of the Company.

(d) and (e) – During the last five years, neither Filing Person was convicted in a criminal proceeding or was a party to a civil proceeding of a judicial or administrative body of competent jurisdiction as a result of which he or she was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws in the United States or finding any violation with respect to such laws.

Item 5.    Interest in Securities of the Issuer.

The information contained in Item 5 of the Schedule 13D is hereby amended and restated in its entirety by the following:

(a) and (b) Mariano Costamagna is the direct beneficial owner of 1,634,185 shares of Common Stock, or approximately 9.0% of the 18,094,043 shares of Common Stock outstanding as of March 7, 2016. Mariano Costamagna has the sole power to vote and dispose of the 1,634,185 shares that he holds directly.  Bruna Giachino does not beneficially own any shares of Common Stock and disclaims beneficial ownership of the shares of Common Stock held by Mariano Costamagna.

(c) Not applicable.

(d) Not applicable.

(e) Not applicable.

Item 6.   Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer.

The information contained in Item 6 of the Schedule 13D is hereby amended and supplemented by adding the following:

On January 11, 2005, the Filing Persons entered into a Joint Filing Agreement (the “Prior Joint Filing Agreement”) with Pier Antonio Costamagna and Carla Borgogno. On April 1, 2016, in order to terminate the Prior Joint Filing Agreement, the Filing Persons, Pier Antonio Costamagna and Carla Borgogno entered into a Termination of Joint Filing Agreement (the “Termination Agreement”). Following entry into the Termination Agreement, on April 4, 2016, Pier Antonio Costamagna and Carla Borgogno filed a separate Statement of Beneficial Ownership on Schedule 13D.

The description contained herein of the Termination Agreement does not purport to be complete and is qualified in its entirety by reference to the Termination Agreement, which is filed as Exhibit 99.2 to this Amendment No. 4 and incorporated herein by reference.

Item 7.   Material to be Filed as Exhibits.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete, and correct.

DATED: April 4, 2016

Exhibit 99.2

TERMINATION AGREEMENT

This Termination Agreement (this “Agreement”) is made and entered into as of April 1, 2016, by and among Mariano Costamagna, Bruna Giachino, Pier Antonio Costamagna and Carla Borgogno (collectively, the “Reporting Persons”). Reference is hereby made to the Statement of Beneficial Ownership on Schedule 13D filed with the Securities and Exchange Commission (the “SEC”) by the Reporting Persons on January 12, 2005, as amended by Amendment No. 1 to the Statement of Beneficial Ownership on Schedule 13D filed with the SEC by the Reporting Persons on April 20, 2005, as amended by Amendment No. 2 to the Statement of Beneficial Ownership on Schedule 13D filed with the SEC by the Reporting Persons on November 10, 2009, and as amended by Amendment No. 3 to the Statement of Beneficial Ownership on Schedule 13D filed with the SEC by the Reporting Persons on September 4, 2015 (as amended, the “Schedule 13D”).

WHEREAS, the Reporting Persons entered into a Joint Filing Agreement, dated January 11, 2005 (the “Joint Filing Agreement”), pursuant to which the Reporting Persons agreed to prepare jointly and file timely the Schedule 13D and any and all amendments thereto with respect to their respective beneficial ownership of the common stock, par value $0.001 per share (the “Common Stock”), of Fuel Systems Solutions, Inc. (f/k/a IMPCO Technologies, Inc.), a Delaware corporation; and

WHEREAS, the Reporting Persons now mutually desire to terminate the Joint Filing Agreement.

NOW, THEREFORE, the Reporting Persons hereby agree as follows:

1.      Termination of Joint Filing Agreement. The Joint Filing Agreement is hereby terminated effective immediately and no Reporting Person shall have any obligation to file, except on his or her own behalf, as applicable, a Schedule 13D (or any amendment thereto) that may be required, in accordance with the rules and regulations promulgated under the Securities Exchange Act of 1934, as amended, with respect to the Common Stock owned by each respective Reporting Person.

2.      Counterparts. This Agreement may be executed in any number of counterparts, each of which shall be deemed to be an original, but all of which together shall constitute one and the same instrument.

[Signature Page Follows]

IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of the date first set forth above.