1990 SC won't start.

EveryDayBird

Registered User
I have a 90 SC Manuel bird, the car has sat for about 5 months. I was going to move it in the shop to do some work on it, but the car did not start. the Fuel pump did not prime. So guessed that the pump went out, dropped the tank and replaced with a new pump. But still no pump priming when the key is first turned, and does not come on anytime after. Did some checking on the fuses and relays but they were all fine, then also find out that there was no spark. I am in the dark when it comes to these cars. I work with the Turbo Coupes and Sport Coupe T-Birds more then anything. I really need help.
 
I have a 90 SC Manuel bird, the car has sat for about 5 months. I was going to move it in the shop to do some work on it, but the car did not start. the Fuel pump did not prime. So guessed that the pump went out, dropped the tank and replaced with a new pump. But still no pump priming when the key is first turned, and does not come on anytime after. Did some checking on the fuses and relays but they were all fine, then also find out that there was no spark. I am in the dark when it comes to these cars. I work with the Turbo Coupes and Sport Coupe T-Birds more then anything. I really need help.


I would focus purely on fuel delivery at first and forget about spark for now.

Have you checked to make sure the ignition switch in the column is good? Those things are VERY prone to failure with age. I think I've replaced one on almost every bird I've owned all the way back to '81. Personally I would start there. Try turning the key back and forth slightly while in the ON position to see if the fuel pump kicks in or not. Is everything else working in the car when the key is in the ON position?

If you're certain the fuel pump isn't priming and you're certain that power IS flowing from the ignition/key switch, you need to verify that the pump is getting power to eliminate the possibility of a bad new pump off the shelf, or a bad connector, or a bad relay. If you still have access to the pump harness plug near the tank (without dropping it again), check for power going to the pump on the appropriate wire. If there isn't any power there, you should check the relay in the trunk. Start with verifying power from the key all the way to the pump and go from there. Do you have access to a code reader? If not, GET ONE. Best money you'll spend....then do the KOEO test. That might help identify problems with the IRCM.

These engines are not that complicated once you understand all the components involved. However, there are SO many connections in a given power circuit that you MUST verify each circuit from end to end and not skip over anything. Don't over think it. If the pump isn't working, make sure it's getting power first.

Kevin

p.s. Did you change the fuel filter when you changed the pump? If not, do it regardless of whether the pump is priming or not. I've had no-start conditions where the filter was so clogged with ethanol deposits after sitting that the car wouldn't run.
 
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Could the EEC relay have failed or being going bad, I checked the PCM and it is not getting the proper voltage. If I am not mistaken the relay is in the IRCM?
 
Could the EEC relay have failed or being going bad, I checked the PCM and it is not getting the proper voltage. If I am not mistaken the relay is in the IRCM?

Could be - could be grounds too. Have you run the codes?

And yes, part of the power path for the EEC goes thru the IRCM, downstream the Power Dist. Box/EEC 30A fuse, behind the battery.

How much voltage is it getting? How did you check? Any chance you measured the keep-live circuit? Was the center bolt/ground in place during that check? How many volts at the battery?

By the way, wiring is a big part of any SC, and a factory manual/EVTM can be invaluable. Check eBay.
 
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I checked the yellow wire on the plug with a volt meter, was getting about 8 volts. The test was with the IRCM plugged in and voltage at the battery was 12.62.
 
Put a volt meter probe into the EEC fuse in the PDB, over to ground, and see what you get.

Might need to lift the power dist. box and inspect the connections from below - there have been cases where corrosion and/or melted connections were found hiding down there.
 
Just a question, but what controls the priming of the fuel pump/running of the fuel pump and ignition. This may help to, but when the fuel pump went out, so did the windows and the sunroof.
 
Just a question, but what controls the priming of the fuel pump/running of the fuel pump and ignition.

EEC, in concert with PDB, IRCM, Inertia Switch/Fuel Pump Relay etc.
Diagram:
fuel_relay01_diag.jpg
This may help to, but when the fuel pump went out, so did the windows and the sunroof.

Another reason to yank and inspect the PDB's belly. Note the IRCM has nothing to do with windows/moonroof ;)

Any welding done on the car recently?
 
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Got the car to start, I have spark now, but still not fuel pump. No spark was caused by loose ground, and the 5th wire on the CKP. But still no fuel pump.
 
Fixed the power to the pump, it was the pink/black power wire that runs inside the car under the back seat. It was corroded, so replaced it with the same colour coded wire all the way to the pump plug. But now there is no injector pulse, Cam sensor?
 
I checked volts at the battery and was getting 11.73(I know a little weak) but I was getting 11.72 at the red(hot) wire on the injector, and the tan(EEC) I was getting 0.73 of a volt. I am getting a pulse at the plug using a NOID light. I also plugged in a well know good testing injector, and it was clicking. So with my luck the injectors are clogged, and need to be replaced or cleaned. I sprayed starter fluid and the car started and ran as long as it was getting fed. Not to long so not to burn the rings. Going to pull a plug just rule those out as well.
 
Sorry if I missed it - do you have (pressurized) fuel in the schrader valve on the rail?

So with my luck the injectors are clogged, and need to be replaced or cleaned.

How old were the injectors before it was parked? Might be worth going for it regardless.

Does the moonroof work again yet?
 
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I checked volts at the battery and was getting 11.73(I know a little weak) but I was getting 11.72 at the red(hot) wire on the injector, and the tan(EEC) I was getting 0.73 of a volt. I am getting a pulse at the plug using a NOID light. I also plugged in a well know good testing injector, and it was clicking. So with my luck the injectors are clogged, and need to be replaced or cleaned. I sprayed starter fluid and the car started and ran as long as it was getting fed. Not to long so not to burn the rings. Going to pull a plug just rule those out as well.

When I was having a similar problem last month and the car ran on starter fluid, the injectors were clogged. Removed, cleaned, and replaced the injectors and all is now good.

If you have pressure at the schraeder valve on the fuel rail (30-40psi roughly) and it runs on starter fluid, it's almost a certainty that the injectors are clogged. ~~~~~~ ethanol in our fuel is a horrible horrible thing.
 
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