Volvo: Fuel Injectors, inline fuel pump, volvo 740gle

Question
Hello Ray ,
I hate to bother you with a long story , but let me start off by giving you just a bit of history on the car first . It's an 88 Volvo 740GLE with the 2.3...only 145k miles .
The car had ran great till bout six months ago when the inline fuel pump went out . I was down with cancer at the time and waiting on surgery and had a young mechanic replace both pumps and the filter as well . For some odd reason he ripped out the fuel pump wiring's and replaced it all to where now you have to use a toggle switch to turn on the pumps ......OK , it irked me a good bit , but it worked .
A few months after this , maybe four months ,the injectors quit opening . So the ECU was replaced with a remanufactured one. The car been running fine up till the other day .
I get a friend to pull the car back home for the wife and I take a look at it...and guess what I find ? The fuel injectors are not opening yet again . OK , so I've had my surgery and feel just a might better and I decide that I can  fix it this time...and the young mechanic is no longer to be found ,   lol . So the first thing I think is the ECU is still under warranty and the parts store does replace it . Takes me ten minutes to put it in the car and still no injectors are opening . Any suggestions ? I'm now on a very limited budget , so any inexpensive ones will be appreciated .
Btw , Fuel is coming up to the fuel rail and the injectors.

Thanks ,
Earl

Answer
Earl,
Look at the shock tower area both sides. There should be two identical relays. One is for the injectors and the other for the electric cooling fan. Turn on the key jump the wires at the t/stat in the radiator, the fan should run. Figure out what relay supplies that power. Swap it with the other relay and see if that will power the injectors. Many older cars also might have wire harness problems. Look at the harness to see if the insulation is coming off. Last three numbers of that relay 592.