Volvo Repair: 1990volvo740turbo, rf interference, noise suppression

Question
QUESTION: no pulse at injectors

ANSWER:    Bob, not much to go on here. What have you checked? A very common problem is the radio noise suppression relays go bad. It's just a shot in the dark, but you haven't given me much to go on? The injector pulses are directed through this so they do not case RF interference. Give me more info. and I will try to help more.

Mark

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QUESTION: cant find that part in alldata the car has a leak in the sun roof and got the fuelinjection comp wet so i got a replacement but i still have no pulse i can start the car on starting fluid till it runs outp

Answer
  Bob, Great, you have Alldata. The first thing you need to do is look at all the fuses and be sure you havn't blown one. Then look at the FI schematic and see what pins on the ECU control injector firing. I thought it was 18 and 21? 5 volts go out to the injectors full time key on, cranking. This voltage goes through the noise suppression relay. The injectors are fired by grounding the other wire in the ECU for a specified time (pulse width). Take your test light or DVOM and see if you have five volts on one of the injector wires at the injector when cranking. If not, thats the side of the circuit you need to trace. Start back at the ECU itself and see if you have the five volts there. Let me know your results and I will try to help more.
  You should beable to locate the supression relay by using Alldata's Electrical component locater. I thought it was on the top of the inner left fender? There or on the left strut tower. If you find it, just give it a couple of raps with a screwdriver handle while cranking and see if she fires up for a second or so. If it does, you've found your problem.

Mark