Before any troubleshooting starts, a complete engine inspection should be carried out on an engine with D-Jetronic.

  • Adjusting valves
  • Check cam lifting
  • Check compression
  • Check plugs, contacts, air filter, ignition cable, capacitor, distributor cap and finger and replace with new parts where necessary.
  • Check ignition setting
  • Never drive unleaded without lead additive (the engine would have to be rebuilt for this)

Look out!

  • There is a very nasty bug that can be installed by “hobbyists”. The nipple on the intake manifold (the one the hose from the oil filler neck goes to) must have an exactly calibrated hole.
  • for B20 it is 2 mm, for B30 2,5 mm
  • If the nipple for the brake booster connection (BKV) is fitted, the D Jetronic will go crazy due to incorrect air
  • Often the nipples of BKV and crankcase breather are mixed up
  • gives additional poor braking performance due to vacuum reduction

In my experience, I have found 80% of the errors in the D-Jetronic at VOLVO are due to incorrect engine settings or component defects.

Engine starts cold only on one valve group (runs only on 2 or 3 cylinders), after 2 to 3 minutes of idling the phenomenon is gone.

The cause is oily trigger contacts at the bottom of the distributor teeth, the only thing that helps is to replace them. If they are no longer available, a suitable 1-2-3 distributor can be installed, it has an electronic release of the valve groups.

Other symptoms and their causes:

High fuel consumption

System pressure too high

Pressure sensor defective

Leakage around the introduction manifold  ore the brake bouster valve

Brake booster, hose on pressure sensor, crankcase ventilation system check for leaks

Water temperature sensor has sub-book

Jerking at constant speed

Constant speed jerking is normally due to the throttle position switch (TPS). Replace the old version with screwed cover with the clipped version. It can also occur with the newer version (cover only clipped). In this case the contact paths are worn by the rotor and by play in the throttle shaft. Therefore, before replacing the throttle switch, the bushes and possibly the throttle shaft must be replaced.

VOLVO-GRUK.CH has a solution for you to replace the circuit board in the DKS. Have a look at the information in the topic throttle switch.

Poor engine performance

Too little fuel, or mixture too lean

System pressure too low; measure

Check flow rate

Replace fuel filter

Check the injection nozzles. Run through ultrasonic cleaning or nozzle cleaner (do not immerse valves, only hook them in)

Pay attention! If the mixture is too lean, there is a risk of engine damage. Gives holes in the piston

Exhaust manifold glows during operation in the lower speed range

Engine runs too lean at idle, set CO value to 2%.

For the first version without ECU CO-Poti increase fuel pressure to 2.2 bar if possible

Temporary dropouts (B30E and B30F)

If the clamp of the wiring harness behind the holder of the throttle linkage is missing, the wiring harness can cut itself at the sharp holder. At this point always a valve group gets mass and injects uncontrolled.

Pull off the hose and leave the nipple at the distributor open. Close the hose connection at the intake manifold. The engine has a better thermal performance (runs cooler due to more early ignition) and has a lower consumption.

As there have been problems with nozzles lately due to residues from the unleaded fuel (emaciation or bad spray pattern of the nozzles), either the use of nozzle cleaner (Liqui Moly) or ultrasonic cleaning of the nozzles is recommended.

Caution! For the high density electric motors (compression 10,25:1) it is absolutely important to use the correct heat value of the plugs. Only W 5 BC (225 of the old BOSCH standard) or compatible candles may be used. If the heat value is too low, there is a risk of piston burners.

Be careful with NGK, these are multi-range heat value candles which tend to be on the hot side. Bosch 225 corresponds to about 215 NGK.

Octane Rating

For B20E and B30E it is essential to fill up with 98 octane Super Plus.

For B20F and B30F 95 octane Super Lead Free is sufficient.

  • Under no circumstances drive with unleaded petrol without lead additive (the engine would have to be converted for this)

Look out! Absolutely important!
When replacing parts, pay attention to the identical Bosch numbers, see the information in the Bosch equipment lists for VOLVO.

In case of problems occurring after the purchase of a vehicle, check all components of the D-Jetronic for correct part numbers. Often the previous owner has installed wrong, apparently identical looking parts from an Opel or Mercedes

Repair and maintenance of components
  • Bosch, Kohler and Schwemmer (control units etc.)
  • Reinhard Koch Bruchwiesenstrasse 2-4 D-66111 Saarbrücken www.innoteco2.de (injection valves)
  • Auxiliary air slide (ZLS) Hermann Ebner h.ebner@spitzenberger.at (+43 699 12248844)
  • Injection wiring harness at Buttkereit Duisburg. www.buttkereit-onlineshop.de
  • Throttle Position Switch (TPS) 0 280 120 039 Replacement of the printed circuit board at VOLVO-GRUK