No matter whether the engine system features a Mono-Jetronic (only injection) or Mono-Motronic (with ignition regulation), some drivers do not recognise serious mistakes in the system while driving. This is all the more note worthier as there are just few sensors in the system to begin with, thus, there is hardly a substitute for a missing signal. If e.g., the lambda oxygen sensor fails, the control unit has to make do with just the engine speed and the position of the throttle valve. Nevertheless, the car still operates, though uphill when the accelerator pedal is hit, with a medium to strongly rich mixture.
Depending on the production year of the vehicle it is possible to pick out errors and measurement values via the K pipe with a scanner or normal computer. Sometimes, the OBD plug may be accessible. If you are interested you may check Ebay, there you may find favourable offers, maybe already for vehicles that were produced before 1995. Even the alteration of standard settings is possible with accordingly free-accessible software.

If a vehicle with throttle body injection breaks down, you should shortly check the ignition and subsequently the fuel supply. If possible, you may bridge the fuel pump relay. Be careful, because if you should accidentally mix up the cables that have to be bridged, the control unit is damaged. If you have a cable that is long enough and a ´flying´ fuse directly at the beginning, it is maybe even easier to put the current directly on the fuel pump, also with inside tank pumps. The inflow at the throttle valves-injection case is easy to loosen. If there is no fuel arriving there, exchanging the pump is probably a better idea than exchanging the filter. If fuel is supplied, it is more difficult. If a separate pump relay exists, it can be exchanged, or perhaps the control unit. However, at least, you may reach, without towing, your home or the workshop. Of course, you should not forget to disconnect this auxiliary construction after you have finished your trip.

A huge number of measurement possibilities and settings are possible. Thus you can solve the problem of an unsteady idle running either by checking the idle-speed unit or possibly unregistered intake air. If you are not sure about the lambda control system, you can connect, like with other older equipments with lambda oxygen sensor, also an analogous multimeter. Clear pendulum movements in the 0 - 1-volt area with warm engine indicate a well- function lambda sensor. The check with the oscilloscope is more expertly of course.