I have a no-start situation on my '90 740GL with the B230F and Rex/Regina ignition (square coil). The engine cranks, but will not start. Only one of the 5 terminals going into the ignition coil/ignition control module shows 12 volts with key in 2nd position - no power on other 4. With key turned to 3rd position (cranking) voltage drops a bit on that terminal, but no voltage showing on any of the other 4 terminals, and of course no power coming out other side of ignition coil. Therefore no power to distributor/spark plugs. Fuel pump relay is good and main fuel pump runs on start attempt. This problem came on suddenly - drove car a couple hours earlier with no problems. No blown fuses in fuse box behind ashtray. Anybody have any ideas?

HVE YOU CHECKED THE CPS WIRE?/I WRAPPED MINE W ALUM HEAT TAPE & IT WORKED

As I stated before this no start situation came on suddenly. 17 years ago I had a faulty CPS and it was intermittent and usually occurred in a 'hot soak' situation. Once the car cooled off it would start. That's why wrapping it with heat tape can prevent this. This is NOT a 'hot soak' situation. I wish it was. I would know how to solve that! lol

The main relay get old and hot then fails. Try inspecting your relay if you can open it up. Just had my 89 745t do intermediate starting. After market relay failure. I'm starting to carry all the related relays and extra ECU
and related components.

The main relay get old and hot then fails. Try inspecting your relay if you can open it up. Just had my 89 745t do intermediate starting. After market relay failure. I'm starting to carry all the related relays and extra ECU
and related components.

The CPS wire is in excellent condition. I have tested it both in and out of the car and it has continuity and registers 187 ohms of resistance - about what it should. However, when cranking there is only approx. 3.5 volts going into it from the car. Do you know if there should be more? I'm leaning towards a faulty ECU. Any thoughts on that and is there anything else that could cause no power - except for 12 volts on one of the 5 wires which is there when the key is in position II, too - to be going into the IC/ICM while cranking?

i FORGOT what was said,,is there spark at the plugs?/ I would switch out the Fuel relay.on the fender & see if thats the weak link.

It sounds like the fuel pump runs when the key is first turned to Pos II, but does the pump continue to run while the starter is cranking? If yes then I would suspect the crank position sensor is OK and I would turn my attention to taking the coil apart and cleaning the internal contacts or possibly a problem in the distributor.

If the pump doesn't run during starter cranking then I would suspect the crank sensor (which would have "likely" recorded a fault code in the OBD). You may need to check what codes are stored, then clear them out, then try starting iit again and see what fault code(s) is(are) recorded.
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Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (STILL not road worthy!)

Problem sol-ved! As I was beginning to suspect it was the CPS causing the no start condition. When I removed it yesterday for testing I also cleaned the contact point at the flywheel end. That may have been all that it needed because upon installing it in the car this afternoon the car immediately started. I had already ordered a replacement one from Volvo yesterday. When it arrives I will replace this 17 year old aftermarket CPS with the new Volvo one and I should be good for at least another 17 years! Volvo For Life! :)

I have already taken the ignition coil/ignition control module apart and cleaned all the contact points - they were all fine to begin with. I have also tested the crank position sensor both in the car and on the bench. It has a resistance of about 187ohms. It is only receiving 3.5volts from the car when cranking. Should it be receiving more? I have also checked for any codes in the OBD - there are none.
As I stated there is NO power going into the IC/ICM when cranking except for one of the 5 wires carrying approx. 12 volts. There is therefore no power coming out to the distributor. So, the distributor is not suspect. I am now leaning towards the ECU being faulty. Any thoughts on that and is there anything else that could cause the IC/ICM to NOT receive power when cranking? As I said, this problem came on suddenly - one moment the car was running fine, the next it wouldn't start.

Failures of the Bendix brain box are rare but not totally impossible. As I recall there was recently one reported on this BB that had some sort of water intrusion problem. Maybe it's got a dirty/corroded harness connection???

BTW - I'm going to guess that the expected voltage to the CPS is 5.0v, but maybe another respondent can verify/correct.
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Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (STILL not road worthy!)

A few months ago when I removed the ECU to replace the blower motor I inspected the connection and it was all as good as the day it was first connected - no water intrusion/dirty/corroded connection.
I removed and cleaned the CPS yesterday and reinstalled it today and the car fired up immediately. So, I'm now thinking it is a faulty CPS. I have already ordered a new one from Volvo to replace the 17 year old after market one. When it arrives next week I should have definite proof that this one is faulty - or not! lol

A faulty CPS “should” have set a fault code in the OBD. But no guarantee that will happen.
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Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (getting ever closer to road worthiness)

Yes, there are no guarantees in life - or cars. Is there? lol