Fuel injectors

Where do we start on this one men?!

Tim..

"Tim (remove obvious)" wrote in message news:dqth63$7oi$ snipped-for-privacy@nwrdmz02.dmz.ncs.ea.ibs-infra.bt.com...

I didn't even know there were 1997 Volvo 940 turbos!!! Did they sell these in Canada?

How do you know the injectors won't "open"?

If that is established, then;

if you have fuel, and you have spark, and you have turn-over, then;

Test the harness leads at each plug for signal, either with a tester or that nifty expensive Bosch kit.

Is there fuel in the rail?

Can you hear the fuel pump working?

Check fuses. Pull #1 and 11 while the car is running to reset the fuel pump.

that's a start.

RS

"Tim (remove obvious)" wrote in message news:dqth63$7oi$ snipped-for-privacy@nwrdmz02.dmz.ncs.ea.ibs-infra.bt.com...

Look at the tach when you crank the engine - it should kick about once a second... more or less. If it doesn't kick the ECU isn't getting impulses from the crank position sender (which means the spark is also missing).

If the tach is kicking or you know you have spark, I believe the injectors are opening but you have no fuel pressure. Unless your fuel rail is a lot different then the one in my '85 760T there is no place to readily hook up a pressure guage. I had to improvise. But you can check for *some* pressure by unfastening the nut that connects the fuel line to the back of the fuel rail after trying to start the engine. Fuel should try to squirt out well before the nut comes loose, and if you unfasten the fitting completely it should release about an ounce of fuel altogether. If it hisses when you loosen it the main pump is running but picking up air from the tank, while if it gives little sign of life the main pump isn't running.

Something to check, fairly rare but it happened to me and a couple of others, is that the wiring at the battery positive post hasn't corroded in two. In my 760, the 10 ga wire that provides power to the ECU and therefore the fuel pump had corroded completely and fell aprat when I moved it.

Mike

The injectors are fed from a resistor block. The power comes from battery plus via relay contact of the Radio Interference Suppression relay. The Grey wire at pin 2 of the resistor assembly feeds current via four resistors (one for each injector). The injectors are ground switched via the ECU pin 18. The RIS relay contact also feeds the coil (Blue wire on the 15 terminal of the coil). The coil drive signal and the Tachometer pulse feed come from the Ignition Amplifier pin 1, the Amplifier being switched by the ICU pin 16, on pin 5. On turbo equipped cars the RIS relay should be permanently "on" but on non-turbo cars it is switched by the ECU pin 21. Pin 21 switches the Fuel Pump relay on turbo cars. On 1995 onwards cars there appears to be only one fuel pump even with LH2.4 system.

All the best, Peter.

"Tim (remove obvious)" wrote in message news:dqth63$7oi$ snipped-for-privacy@nwrdmz02.dmz.ncs.ea.ibs-infra.bt.com...

Should be fixed at side of one of the strut towers (right hand tower on UK models).

All the best, Peter.