So here is what i have done.
Removed Number 1 fuse and check for voltage lower pin...good 12V.
Reinstall number 1 fuse , removed number 11 fuse and check for voltage lower pin while cranking...no good.
Reinstalled number 11 fuse.
In trunk separated fuel pump harness and checked resistance of fuel pump..got 2.4 ohms ( should be between 1-2 ohms).
With harness still disconnected in trunk checked voltage across pin 1 and 4 ( voltage to fuel pump wires) while cranking...no good.
Ran hot wires to fuel pump..I hear it working.
Tried starting at the same time it is hot wired...no start.

When I tried starting normally(?) I do not hear the 2 sec whirring of the pump.
Fuses were checked for continuity..all good.
Both cooling fan and radio suppression relays are relatively new, connections appear good there
Could it be the crank position sensor that is bad?
Even if the CPS is bad should I not get the initial 2 sec whirring of the fuel pump?

Solved!!!
Couple days attempting a no start fix I could not get 12v while cranking at the lower terminal fuse 11 and also at the fuel pump end in the trunk ( wires 1 and 4 ) . I did not have sparks at the plugs either. The first attempted fix was to install a new aftermarket Crank position sensor (CPS). Still no start . Relays were swapped , installed a new ICM and spare coil that I had , even an inexpensive CPU from ebay..still no start. I disconnected all wire couplings in the engine bay . cleaned and reinstalled. The fuse and relay block inside the car the seemed intact...no burnt areas or disconnected wires.... THEN I had an idea ..this from one of you guys , Blindboy , I believe.The old CPS had lost its outer black protective sheathing so I wrapped it with aluminum foil and taped it up with electrical tape. I reinstalled the old CPS and the car started! So the new aftermarket CPS did not work for me and all along after its installment I was swapping things around when in fact the new one was bad. So assuming there wasn't any thing wrong with the old cps , which component was bad? I proceeded to disconnect and reconnect each component that I had installed and it came down to be a bad coil. Yes a bad coil! So now I have a spare ICM and cpu at hand. All is good for now . Thanks all for your input.

Bendix makes some good stuff then. Bendix makes the Regina injection ECU / Rex ignition ECU.

If you've not yet swapped ECU or disconnect the battery since the no-star happened, you check codes and inspect for things like the faulty CPS or fuel injection relay and so forth:

https://www.brickboard.com/FAQ/700-900/EngineOBDCodes.htm

You also have that fuse an relay board or box or platform behind the ashtray. This item at the age of your 1991 Bendix Rex ignition / Regina injection, or any any 900 series, should be inspected for heat related damage from excess current draw and faulty connection corrosion that creates heat.

I'm unsure, yet the Bendix Regina fuel pump relay, different from the white Bosch LH-Jetronic fuel pump relay, may suffer from issues like broken solder welds. Easy to open these Regina fuel pump relays, and, with magnification, just like the 700 / 900 FAQ Bosch white fuel pump relay, may have solder weld cracks you can reflow.

As for the CPS, if the insulation sheath is failing, replace the CPS.
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Kittys are fuzzy and sometimes fluffy! Spokane, WA RULES!

Thank you kitty. Used cpu on the way as well as a relay. CPS is new. Parts will arrive this weekend and will update!

Didja check the OBD for fault codes, however?

OBD fault code is one way to begin root cause analysis as to fault cause.

I'm interested in knowing whether you have fault codes in socket 2 (Regina fuel) and socket 6 (Rex ignition).

Not had my ham-handed hands inside a Bendix Rex / Regina 700/900 engine bay. Bendix Rex / Regina sort of remind of Bosch D-Jetronic. Yet still want to own a 700/900 with Bendix Rex / Regina and M47 II or a 164 with M410.

Mr. Complains all the Time.
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Kittys are fuzzy and sometimes fluffy! Spokane, WA RULES!

I keep a sparkplug in the car so that I can check for spark without tools.

I actually keep old ignition parts and other things like old wiper blades in case something breaks - think of how easy it is for someone to steal your new wiper blades.

Guys , thanks for your input thus far.
Allekat...I have not checked sparks as yet ...will do shortly
Amarin....Thanks for the info regarding the FPR fuse 1 to fuse 11 connection...more on that below
Blindboy...I installed a new CPS , still no start ( kinda expected so , nevertheless lets call this a preemptive move)
Chris M...yes the problem is intermittent. So while attempting to fix the no start , I did get it to start on occasions and I notice while messing the connector behind the carpet in trunk area the car would shut down at times so I went ahead and put two connectors back there . One for the fuel quantity and one for the fuel pump quantity. This is a regina sys..so only one fuel pump. Mere coincidence while other areas were failing?

nyalex.....so I had some spare FPR and
had partial success with one . Finally I would get the pump to prime initially. I could hear the pump whirring.
If I am not mistaken , one of the relays ( cooling fan or radio suppression) contols the injectors? I checked those too as far as good connections and swapping out.


So this is where I am at. The pump now primes initially. While cranking I am NOT getting 12 volts back in the trunk connection ( pins 1 and 4 ) for the fuel pump. Nor am I getting 12 volts at the lower connection fuse 11. I do get the initial 12 when the pump initially primes though.
What is the pathway of the voltage to the fuel pump while cranking?



As always , thanks in advance fellas
Paul

If I might add, that I am not getting any spark at the plugs also.
So what would prevent not having 12V at the bottom of fuse 11 while cranking? I suppose this is the feed to the fuel pump and the reason I am not getting 12V while cranking between pins 1 and 4 .
I was able to get the fuse block out and inspected the connections on the underside. It looks rather clean under there and I could not see any evidence of burnt or overheated areas . All connections seem intact.
Also , the tach does not jump while cranking and my CPS is new. There is an 8 pin connector near the passenger strut. A few months ago I cleaned things up there. I think I will bypass that connector and others , in time , by hardwiring , solder and heat shield.
I do believe once I can get 12V while cranking at lower end fuse 11 the car should start.
Could the ECU be faulty?

Check your distributor rotor Ohms. if your car has one. Usually around 1K. It will have continuity or it won't
..

I will check the distributor but first I have to get 12 volts at the pump while cranking.
I have since learnt that the tach in a regina system will not jump while cranking. I will wrap the old cps in aluminum foil to see if the car will start.

Last time my 89 745t stalled out, it was the main relay. It power both the Pump and the ECU. I keep a spare fuel pump and radio suppressor relay along with a spark amplifier in a parts box in the car. Check all your electrical plug-in harness and dab some electrical grease on all the connection. Check and clean the multiple ground wires under the engine hood. I keep an old main pump relay that I internally rewired to simulate using jumper wires when relay is removed. Relay can work intermittently while starting to fail..

So, a used ecu and a new relay. is on the way. I have a spare coil and ignition control module. At present I'm cleaning up all wire contact areas.
Will report back soon. Thanks

Hi Everyone , thanks for posting. I will dig in some more in the week and post back. Appreciate it

Behind the fuses is the fuel pump relay. Its on the left side and is white. Take out the cigarette lighter/storage tray (2 screws behind the cigarette lighter cover) and you can pull that relay out. Take the case off it and look for cracked solder joints. You should 100% hear the pump prime when you first turn the key to run.

I don't bother checking for cracked joints anymore - often the cracks are so small at room temperature that they are not visible. I just reflow or replace the solder on every relay I come across.

Did the no-start just suddenly happen or has it been intermittent?
Are the plugs wet or dry?
Is the cam turning, as in possible broken timing belt? (I know the symptoms don’t exactly point to this but hey, it’s easy to check.)

Fuse 1 provides power to fuse 11 via the fuel pump relay
The relay must be in good condition otherwise insert a known good spare
All wire connections from fuse 1 to relay to fuse 11 must be sound

You might have to take out the entire fuse panel, turn it over and check all connections below it
Some connection could be burnt from overheating
Overheating could melt the surrounding plastic holding the fuse causing loose fitting fuse
Loose fitting fuse causes more overheating
Its vicious cycle over the years
It could not be repaired as the plastic has become brittle with heat
Like you said its could be something long overdue

You might have to look for spare fuse panel just in case

Regards,
Amarin.

CPS goes bad on these all the time,,I took aluminum tape that I got at Home Depot,,wrapped it around the wires until[ I could get another\
car started right up..

I don't see where you checked for spark.
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