Hi Rona,

You have folks way smarter and well practiced with Bendix Rex ignition / Regina injection to support your root cause fault finding so you can effect repair.

This site contains Mitchell wiring diagrams in PDF files that may help you as well as other information.

http://www.v8volvo.se/mekartips/volvo/

Download Volvo 740 1991 Mitchell.pdf

PDF page 23 of 28.

Wire color is your primary guide as relay pin #'s are not highlighted.

The RSR is in the 12 VDC power path provided to the injector. The ECU closes connection to ground for the injector pulse duration.

An issue with 700-900 series is the fuse panel and relay board hidden behind the ashtray at the bottom center console. After 30+ years and less, corrosion forms at high current connections such as fuse sockets (the spade terminals locked into the plastic of the board) and relay sockets. Sometimes you can see heat malformation of the plastic and, worse, black charring around these sockets on the board. The fuel pump relay socket can show in time heat malformed plastic.

In the 700-900 FAQ, a user identifies the fuse/ relay board as a serviceable items. Maybe early in life one could use a DeoxIT-D spray or grease, remove fuse and relays, spray, and reconnect.

I'll guess the Regina fuel pump relay through age and use may form cracked solder welds internally as with the Bosch fuel pump relays.

Though your discovery of a disconnected Radio Suppression Relay wire harness connector socket may indicate prior owner modding to get your 740 running by hacking it.

How many miles? Any fuel pump will fail in time and miles (hours?) of use. Don't go after market!

The 700-900 FAQ does not support Bendix Rex / Regina the best. I sort of like the Bendix system as it is like Bosch D-Jetronic with the manifold vacuum (or pressure) sensor.

Sorry to go so long.

Hope that helps.

I'm sure you'll figure the thing out. Also, search the RWD forum for others prior posts with Bendix Rex / Regina issues.

Questions?

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