ok i am frustrated and have swapped many parts and still this plagues me. 1991 volvo 740 the first issue was a wiriring issue that kept "blowing" the fuel relays 3 in a month so i stightwired the thing to the fuse box and we are fine for a week and even not turn the switch and i hear the pump turn on. ok so i turn the key and no start at times crank but no start. sometimes it will crank right up drive and die in the widdle of the street no dump no curve no high speed, just 10 mph or 40 mph dead.
i have swaped radio suppressor and cooling fan and wire bypassed no start
i have swapped coil regina type with junk yard warranty part no start
i have swapped rpm sensor with junkyard white stripe part new looking no start
i have new plugs wires dizzy cap and rotor from part store
i have swapped the computer bottom right passanger foot area junk yard warranty no start
i have no clue whats left?????????


help ign switich?
i was thinking to bybass and hot wire coil BUT how on a regina type where do you run the hot from the battery to bypass the ingition switch??

Peace and love Ron

 

throwing parts at a problem without doing tests and diagnostics is like trying to hit a deer with your eyes closed.

how about testing the coil voltage with a volt meter before you hack the wiring harness up and introduce MORE problems?

 

tell me how and i will

 

meter set for DC volts. black - probe to ground, red + probe to the power input pin, with the ignition on you should see 12V or so there.

I've never seen a regina/rex system (they didn't sell them in California), but on the schematics, it looks like the 3 pin connector on the left side of the coil module, the black wire to pin "B" (middle pin) is ground, the blue wire to pin A (right pin, next to 2 pin center connector) is opwer when ignition is on. the red-white wire on the leftmost pin C is the signal to the tachometer. the power comes off the ignition switch pin 15R (on in II [run] and III [start]), is connected at the fuse panel (but doesn't go through a fuse), goes through block connector "B" pin 28 (at the left A post on the firewall) then a splice where it goes to the coil, the diagnostic socket, and the Rex ICU. The ground comes from the intake manifold rail and goes through a 10 pin connector "F" pin 7 near the left wheel housing.

 

ok before this i was just out there playing with it testing and i know there is compression so i checked and there is spark i placed a spark plug on the intake and had my daughter spin it over and it sparked but no crank ( i did this test yesterday and the thing decided to start and run on 3 cylinders go figure )
I have the fuel pump wired stright to the battery to test for fuel and the fuel pump wherrs and still no start.

I just do not know back to ign switch?

 

thank you for the help on the coil if i am getting spark on a oiler car i would say the coil is good but these new fi cars??? can i still say that?

 

if you have spark, then the ignition system is probably fine.

on the onboard diagnostic box, if you read the code in jumper position 2, do you get 1-1-1 blink ? that indicates the fuel injection computer (ECU) is alive and not totally dead. also, on Bosch cars, there is a 'DTM #3' test you can do with the diag box, this cycles all the engine actuators (fuel injectors, idle air valve, electric fan if you have one, etc), and if those all click-click-click, you can usually presume they are good. I don't know if Regina has the same thing or not, as I said I've never seen a Regina car.

these tests are described here, Engine and OBD Diagnostic Codes you don't need any code reader, there's a test button and LED under the hood already.


this FAQ for 7xx/9xx is chock full of useful info on troubleshooting these cars.
Volvo Maintenance Hints for 700 900 S90 V90 Models

 

oh, you said you jumpered the fuel pump relay. that relay has two separate relays in it, one for the ECU power, and the other for the fuel pumps. if you unplugged the relay, and jumpered the fuel pumps, that would leave the ECU unpowered.

 

i have the relay plugged in but the main power to the fuel pump wired to a switched 12v so it does not go thru the relay any more since something was causeing it to go thru relays or i kept getting bad ones (2nd possible) so to eleminate guessing i made sure the pump had power. I tested yesterday and it still does but maybe not enough? could be a pressure thing?