740 mystery

tina pangborn · Post by **tina pangborn** » 04 Oct 2009, 16:26

My 1988 740 turbo wagon is a mystery. It will start run and drive but after I shut it off it will not start again. Sometimes I have waited 2 weeks and tried to start it and it started theirs the mystery? When it started acting up it would die out and It would restart about 1/2 hour later. I replaced rotor rotor cap ignition modular spark plugs and fuel pump. I was going to sell but I just love the way the car drives when it does run. Is there anyone that might know this mystery? thanks for your respones

DeRail · Post by **DeRail** » 04 Oct 2009, 17:02

Almost sounds like a wonky fuel pump relay because of the fact that you need to wait 30 minutes for the car to start working again. Short of replacing the relay, there's not much you can do other than try to give the a hard flick when the car acts up. If you're able to restart the car afterward, then I'd say the relay is a part of the problem, but bear in mind that the relay can still be too far gone if it doesn't respond to the flick method.

Report back your findings
Darrell

tina pangborn · Post by **tina pangborn** » 04 Oct 2009, 19:14

DeRail wrote:Almost sounds like a wonky fuel pump relay because of the fact that you need to wait 30 minutes for the car to start working again. Short of replacing the relay, there's not much you can do other than try to give the a hard flick when the car acts up. If you're able to restart the car afterward, then I'd say the relay is a part of the problem, but bear in mind that the relay can still be too far gone if it doesn't respond to the flick method.

Report back your findings
Darrell

tina pangborn · Post by **tina pangborn** » 05 Oct 2009, 14:08

How easy is it to get to the fuel pump relay on my 1988 740 turbo wagon?

Post by **billofdurham** » 05 Oct 2009, 15:35

Very easy. It sits behind the ashtray in the fuse/relay board. Remove the ashtray and its retainer and you will see it. It is possible to pull the whole relay panel out. Remove the plastic box (which also contains the accessory socket) above it to make it easier. There is a clip that you bend slightly to release the tray. Lift upward slightly, then the tray slides rearward and out. It doesn't need to be turned or twisted. The wiring is long enough to allow the panel to be pulled out a fair distance.

The relays are shown in the attached:

740 fuse_relay board.pdf: (335.29 KiB) Downloaded 93 times

Put your finger on the top of the FI relay and switch on the ignition. You should feel a click if the relay is working. If you don't feel the click, switch off and give the relay a hard flick with your finger and try again. Unfortunately, the only way to test the relay is by replacing it with a known good one. None of the other relays are suitable.

Bill.