I own a 1986 740.

The problem:
When starting the car, it takes a second time at turning the key (spinning the engine) to start it. This grows into trying 3-5 times, then 7-10 times. After which, the car usually starts up, idles radically for about 10 seconds, then runs fine. As the car takes longer and longer to start, it eventually refuses to start, to which i have to tow it to my house. I let it sit for a day and try to start it again and presto, it starts right up!

I guess my question is, what would take the car longer and longer to start eventually preventing it to start altogether, only to have it start up the very next day?

Food for thought:
Engine turns over, just doesn't start. It isn't an overheating issue. This problem has been going on for a few years now. I changed the brain and the power stage, but there is the possibility of it went bad again. I hot-wired the relay responsible for the fuel pump to run all the time to test if that was the problem, it wasn't.

Thanks in advance.

 

I'd look at the Fuel Injection relay, Temperature Sensor, and Hall Sensor in the distributor. Also, your car may have wiring problems, so eliminate that, too. (1986 is known for flaky insulation), so look at the wires.

 

Alrighty, ill try that. Thanks.

 

If I remember correctly, there was a TSB for the 740s relating to this problem. I'm not an expert but if my memory serves me well, the problem was due to the cold start injector was dumping too much fuel. The TSB was to re-wire the cold start injector so that it was only activated while the starter was engaged.

Search the forum here for this. You might want to look over at Brickboard at their 700/900 FAQ that may address this issue.