Hello all. Hope you are well and cv-19 free. I have been having a no start/start with my 740. Fortunately I have another car that I have been using and I am taking some time from my other projects to address the issue. I have a flow sheet that I downloaded a few years ago for troubleshooting and I started by checking the condition of fuse 1 and 11 which are fine . The voltage at lower pin of fuse 1 shows battery voltage (12v+).
I could not get 12v at the lower pin of fuse 11 while cranking ( as directed by the downloaded trouble shooting guide) Interestingly though while cranking to check for this voltage the car started and ran! Let's back up . A few years ago I had a similar situation and found that there was corrosion at the connector behind the carpeting above the left wheel well . The large pink wire ( 12v to pump during run mode ?) was the culprit so I bypassed the connector totally for that wire alone . In addition I also ran another wire from a 12v source on the fuse box straight to the pump via a switch that I installed as a back up.
Now to the present. While the car is running I reinserted fuse number 11 and it continued to run. ( so what is connected to this fuse?) I then proceeded to shake the entire fuse block assembly and the car shuts off. Now I am thinking that I need to remove the fuse box assembly for closer inspection and so that will be the next challenge . Hope there is something in the faqs for that. Will update then.
Cheers
Paul

Twice, when I had problems with our 90 744 TI, the pfoblem was the crank position sensor.

As for wiring, on out 88 745, I found a wire to one of my headlights passed 12 volts, but not enough current to light the bulb.

Give any suspect wires and connections a good pull to see if the wire strands are corroded away.

Also, check for corrosion in the small wires connected to your positive battery post - I had one that corroded away.

So, as I mentioned , I had wired another 12v source to the fuel pump, bypassing all the connectors along the way. While fiddling with the fuse box assembly I noticed that the shrink tape that I used for a spade connection was very hot and so I took the tape off and realized that the connection had become undone and created a connection/no connection condition. Long story short , I reconnected everything back to the way it should be and all is well now. i do get 12v while cranking at fuse 11. This issue made me do a few things which were overdue. I cleaned up and secured connections to both the radio suppression relay and fan relay . Also under the suspension brace , passenger side, I did the same thing with the two large connectors and one four prong connector as well. I removed and cleaned all fuses in the fuse box, now my horn works!
What is still a mystery to me though is that the car started and ran for years with the fuel pump wiring modification that I did but will not do so now. Anyways eliminating the mod and reverting to the way it is supposed to be is working so I consider the start/no start issue fixed. Time will tell and thanks for the suggestions gents.

So..I am having a no start condition again and I made a separate thread regarding this. Now I am not getting 12v at lower end fuse 11. I don't even hear the 2 second fuel pump ( regina system) priming.

I was able to get the car started.It was a bad coil

Ill bet there is a bare wire somewhwere?

Thats what I am thinking. Something is loose under there.

replace your fuel pump relay.....Check your distributor rotor for 1k ohms.

Ill bet there is a bare wire somewhwere?