Hello, I have been working with my 91 940 turbo. I was able to get to the point where she would start and run with starting fluid, but would later cut off and need starting fluid to restart. I changed the crank position sensor and she would start without starting fluid. About two hours later she was back to needing fluid. Today, I replaced the Radion Suppression relay or sensor by the tower. She once again started without fluid. She ran at an idle for about one hour. She cut off and now she will quickly fire when the starting fluid is added, but will not continue running like she once did. :

-Two new fuel pumps (no fuel pressure at the time)
-New Crank Position Sensor
-New Ignition Amp
-Tested Radio Suppression Relay
-new fuel pump
-all new fuel lines
-Fuel pressure regulator
-new plugs
-new wires
-new plugs
-new air mass sensor
-cleaned idle control valve
-all new vacuum hoses

As you can see, I have invested quite a bit of time and efforta nd am now at a loss. Any help would be greatly appreciated.


Thanks.
Mike in Ocklawaha FL

I didn't read anything about installing a new fuel pump relay. You can pull the cap off of yours and look for cracked solder joints. Re-solder the joints if necessary, or replace.

Make sure the cam is turning and in time with the crankshaft. Check for spark by installing a spark plug in spark plug lead you have pulled off of an installed plug.

You said you installed new fuel pumps. Make sure the polarity is correct. They will run backward.

Check for any fuel pressure by loosening the high pressure hose where it connects to the fuel rail. Your car probably has a Schrader valve on the fuel rail where you can using a tire pressure gauge to get an approximate idea of the fuel pressure. About 42 psi.

If the spark plugs have been drowned in fuel for a long time, you might need new ones again. Ask me how I know.
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john

Mike,

There is a high boost pressure switch on the coolant tank mount that controls the ground for the fuel pumps. If you remove the wires to the switch and ground them to the chassis, the fuel pumps should run with the key on. Jumper the RSR socket across the two larger wires (I think red and red/green) and see if the car will fire up. With intermediate failures to start, I am always leary of the wiring harness connections especially the connector bodies. Make certain that the grounds are tight and the connectors pulled apart and cleaned with electrical solvent and pipe cleaners. My 88 765T did the same thing for months until I finally rewired the car on the suggestion of a girl mechanic in Canada(Sorry guys!). I make it a point to rewire every car that comes in now. Hope you find it.

Regards,
--
Will Dallas, www.willdallas.us, www.willdallas.org, www.willdallas.com, www.dallasprecision.com 86 245 DL 222K miles, 93 940 260K miles, 88 765 GLE 152K miles, 88 780 246K miles, 93 Buick LaSabre 119,000 miles

Wow Mike, you have thrown a lot of parts at this problem.

I think you will be best served by telling us a bit more.

How did the problem start? Did it die while running? Did it just not want to start one morning?

Have you checked the compression?

Have you checked for leaks at the intake manifold gasket and injector seals?

How old is the gasoline in the tank?

Why did you replace the fuel pumps and lines? Did you replace the fuel filter? Why do you suspect the fuel system? Have you checked for fuel pressure and injector pulses?

Do you currently have a good strong spark?

Let's start there. Others will chime in soon I am sure.

--
Mr. Shannon DeWolfe -- I've taken to using mister because my name misleads folks on the WWW. I am a 52 year old fat man. ;-)

This started when I went to start the car warm and she would not kick over. Towed it home and found no fuel making it to the injectors or rail. Replaced all fuel pump components and even clened the tank. I have made sure the gas in the tank stays fresh ( I only had to make this mistake once). I was able to get good fuel pressure after this and she still would not start(@#%&). I then changed the plugs, wires distributor cap, rotor and she fired up. I drove her for two days till she went to the stage of not restarting w/o starting fluid. She would run OK after that, but if she cut off, she would need a spray. I installed the Crank Sensor and she would start w/o starting fluid, then she died while running and I was back to ground zero. I went to the salvage yard today and purchased the Radio Suppression Sensor and she fired up after installation. She ran good while I let her idle in the driveway. After an hour, she once again died and now will not start even with the ether. I have used this as an opportunity to go through and make sure all the simple components which fail at around 125,000 have been replaced, but I am now having my shade tree mechanics skill insulted....Mike in Ocala Florida

Check the voltage at the ignition coil +15 terminal when the car does not start. If is in not within 0.5 volts of battery voltage, you have a bad suppressor relay or connections to it. It is not unlikely that you either: got a bad used relay, or replaced the fan relay instead. Injectors, AMM and ignition coil get powered from this one circuit.

Thanks all of you guys, Maple leaf nailed it. I get to still keep my dignity with your help.....Mike in Ocklawaha Florida

OK, so what was that actual answer? Did you get a bad used relay - or did you install the replacement relay in the wrong circuit (cooling fan instead of injection)? ...or was it a bad connection to the relay?