Injection engines
The position of individual elements of the fuel injection system and the ignition system in the engine compartment of a car with an SR20DE engine
1 - adsorber; 2 - additional air valve; 3 - injection valves; 4 - fuel pressure regulator; 5 - throttle position sensor; 6 - fuel filter; 7 - switching valve, idle adjustment; 8 - coolant temperature sensor; 9 - air regulator; 10 - resistor; 11 - transistor; 12 - ignition coil; 13 - crankshaft angle sensor; 14 - air flow meter
Before checking and adjusting, certain conditions must be met in order to obtain accurate results, i.e. those mentioned in Chapter Ongoing care and maintenance parts or systems must be checked and adjusted accordingly. The idle speed must correspond to the required value.
After warming up the engine and connecting the tachometer and stroboscope, do the following:
1. With the engine off, locate the throttle position sensor (see illustration) and unplug. Start the engine.
2. Increase the speed two or three times to 2000 - 3000 rpm and then let it idle for 2 minutes.
3. Take tachometer readings. The engine must be running at 800 rpm.
4. Take readings of the ignition timing in the strobe beam on the crankshaft belt pulley. If the ignition timing lies outside the limits of 15±2°before TDC, adjustment is necessary. To do this, loosen the distributor mounting bolts (see illustration) and rotate the distributor until the correct ignition timing is obtained. When re-adjusting, always aim for an exact value of 15°. Tighten the bolts again and check the ignition timing.
5. Finally, reconnect the plug.
Note. On vehicles without a catalytic converter, the ignition timing is adjusted in the same way. The crankshaft pulley has a notch on the lip to show the ignition timing adjustment from the outside. An adjusting plate is placed on the camshaft drive cover and each division corresponds to 5°. On illustrations ignition timing marks are shown.
Carbureted engine
On cars with carbureted engines, the work differs depending on whether a catalyst is installed or not.
With catalyst
Before it will be possible to check up the moment of ignition given in the Chapter Ongoing care and maintenance conditions.
1. Warm up the engine, i.e. the needle of the remote thermometer should be in the middle position. When adjusting, the engine must maintain operating temperature, i.e. during pauses, the engine may need to be started in order to warm it up again. The engine must be running at less than 1000 rpm.
2. Connect the tachometer and stroboscope according to the instructions.
3. Accelerate the engine two or three times to 2000-3000 rpm and then let it idle for a minute.
4. Take readings of the idle speed on the tachometer.
5. The engine should run at 750±50 rpm. If the value does not match the required value, the idle speed should be pre-adjusted. Necessary work is described in Chapter Ongoing care and maintenance.
6. Take readings of the ignition timing in the beam of the strobe lamp on the crankshaft belt pulley. If the ignition timing is outside the limits specified in Specifications at the beginning of the Chapter, an adjustment must be made. The illustration below shows where you can read the ignition timing in the strobe lamp beam.
View of the ignition timing marks on the crankshaft pulley. Label "0" marked in yellow.
7. When adjusting the ignition timing, it should be adjusted to different values. In the place shown in the illustration, you can see the installed sensor for boost pressure (on the right side of the car, standing in front of the engine compartment, near the shock absorber suspension). This device monitors the vacuum in the intake manifold and sends an electrical signal to the electronic control unit. Since this affects the ignition timing, it must be switched off. To do this, remove the vacuum hose and insert a bolt of suitable diameter into its end.
Boost pressure sensor position (1).
8. Loosen the distributor mounting bolts and rotate the distributor until the marks "0" And "5" will not stand approximately opposite the pointer if illuminated by a strobe lamp. Tighten the bolts again.
9. Put on the hose and check the ignition. This time the value from Specifications at the beginning of the chapter. The data given must be thoroughly studied, since there may be two different ignition distributors and adjustments are slightly different from each other.
Note. The ignition timing on vehicles without a catalyst is carried out in a similar way.
Without catalyst
On an engine without a catalytic converter, the adjustment is somewhat more difficult, since, depending on the distributor installed, the vacuum hose must either be disconnected from the carburetor and closed, or remain connected. To plug the hose, insert a bolt of suitable diameter into its end. More detailed instructions are given in Specifications at the beginning of the chapter. According to them, the moment of ignition has different values. Otherwise, the adjustment is carried out in the manner described for catalyst models.