944 Motronic repair



Introduction

944, 2.5L model '85 - '89 and 944 Turbo, 2.5L model '86-'91 have all a Motronic Fuel Injection system. This motronic system is also called a pulsed injection system. That means the system only sprays fuel into the intake manifold when it is required in the combustion cycle. When you use this method, it results in more accurate control of fuel levels and delivery but also maintain ideal stoichiometric air/fuel ratio.

Failures

In general the Motronic Fuel Injection is very reliable. Problems arise when the connected sensors are not functioning properly. But sometimes the Motronic computer is the trouble maker. Bosch is not producing these Motronics anymore, so new ones are virtually impossible to get or you have to pay a lot of money. Sometimes the relay of the system fails. That is the reason why most 944 drivers have a spare relay in the car. The relay (position close to motronic beneath driver seat) is in fact a double relay: one to control the Motronic and one to control the fuel pump. Anyhow if the user checked the relay and sensors and the car has still problems: We can effectively repair the defective controller for you and restore it to specs !


Common symptoms of a failing Motronic 944 are:

  • Engine will not run at all (no start).
  • Bad idle running (fluctuating or > 1000 rpm).
  • Fuel consumption too high.
  • Burning smell in your car (overvoltage).




  • Motronic 944 Turbo.



    Motronic 944 Turbo 35 pins connector.

    The Porsche part numbers are on the top cover of the unit. The above unit is a unit with Porsche number 951 618 121 10 and a Bosch part number of 0261 200 088. The Porsche part numbers for the Motronic and corresponding Bosch part numbers are listed up in the table below.

    944 models Porsche part number Bosch part number
    944 2.5L '85-'87 944 618 121 03 / 13 0261 200 076
    944 2.5L '87-'88 944 618 121 05 0261 200 086
    944 2.7L '88-'89 944 618 121 06 0261 200 089
    944 Turbo 2.5L '86-'88 951 618 121 02 / 08 0261 200 075
    944 Turbo 2.5L '87-'91 951 618 121 09 / 10 0261 200 088


    Repair-service

    928-ecu-repair offers you a repair of the Motronic for a reasonable price. Due to the large number of variants of the basic unit, it is often not possible to offer an exchange unit from stock. Your faulty unit can usually be turned around by our workshop in 3 working days.

    Once you disconnect the faulty Motronic from your car, send the unit to 928-ecu-repair. When we receive the Motronic, the first thing we do is connect the unit on a Motronic-testbench. This PC controlled testbench acts like a 944 car and with a logic analyser we measure the signals of your faulty Motronic. Next step is replacing of broken parts and retest again.

    Warrant and prices

    We offer a 2 year warranty on replaced parts and labor. Any obvious abuse of the unit will render the warranty invalid. Modifications to the car's systems are beyond our control, and are at owners' risk. Please email us for a quotation for your Motronic repair. Our preferred payment method is bank transfer (or Paypal for our international clients).


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