I have an 87 740 turbo that sometimes won't start. I have read through the postings and tried to find the radio relay and cannot find such item. I have also change the fuel injection relay with no help. The fuel pump is also new. What am I missing?

Read through this.

http://www.brickboard.com/FAQ/700-900/EnginePerformanceSymptoms.htm

Radio suppression relay should be under engine hood near the expansion coolant tank. Plugs, wires, cap, rotor. General tune up stuff.
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My 740 doesn't seem to have a radio suppression relay. There are no relays on the passenger side shock tower or the radiator overflow tank. Could an old battery be the problem?

I would be very surprised if it does not have a radio suppression relay. It would be on the drivers side shock tower. It is similiar in size to the fuel injection relay only it is black and has a silicone sealant around the cap and base.

Remove the relay and insert a short piece of insulated wire between the two sockets that are connected to the two heaviest wires. If it does not start but then does once you insert the jumper wire as described you have found your problem.

These relays respond well to being resoldered and then resealed.

Randy

I found a relay on the drivers side shock tower which is similer to a fuel injection relay. Then I tried jumping it with a wire and all I got was a noticeable click at the intake manifold but no starting. It doesn't have any sealant at all. it is totally solid.

Is it black?

Did you remove it and in its place insert a short section of wire so that it would connect the two heavier wires (there should be four wires on the female connector)?

With that wire in place you attempted to start the car but once again you found that it would crank over but would not start?

If the answer to all of the questions is "yes" then you have eliminated the radio suppression relay as the cause of your not start situation.

Randy

Yes. It may show 12volts static, but trying to start voltage drops. Have you tried to jump it when it won't start? And turbos really, really, really, hate any type of air leak. There is also a turbo section in the FAQs.
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I just replaced the radio supression relay but still the problem exists, what is next?