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91 Celsior/LS400 No fuel


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HI guys.


New here. I just snagged a celsior for the motor and interior but after getting it home I realise its a !Removed! beautiful vehicle and have decided to get it on the road.


Day one, no power. Previous owner had removed an aftermarket sound and lighting setup and did NOT bother to put it back together. I sorted it out and now it cranks fine. However the keyfob is pretty well screwed and messes with the immobilizer. 

Now I have it cranking and all interior electrics are working, including the massage seats which I thought would have been out of action by now.

The issue I have now is there is no fuel. No fuel pump prime that I can hear. I am new to these cars but I have searched forums and can only find forums that are left open ended as the op's nearly never post the resolutions they find if any at all. 


I located the fuel pump relay in the front right ( a lone yellow relay under its own cover ( 4 parallel pins)). It was coroded so I cleaned it with contact cleaner. No go.. Used a multimeter and battery tester to check the relay socket, no power to be found.

ANy tips would be greatly appreciated. 

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Pulled the ecu. Can not spot any bad caps or dead solder anywhere. No power to fuel relay socket...Hooked battery + and - to fuel pump panel behind seat, noise from Fuel pump relay area but no pump sound. 

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Hi Moarpower,

Did you check for fuel pressure? There are a few steps you can take to determine if there is a problem with the wiring, relays, or the fuel pump itself.

See this if you don't know how to check for fuel pressure:



1. Verify the battery voltage is above 12 volts.
2. Disconnect negative (-) terminal cable from the battery.
CAUTION: Work must be started after 90 seconds from the time the ignition switch is turned to the LOCK position and the negative (-) terminal cable is disconnected from the battery.

3. Remove the union bolt holding the left hand delivery pipe to the rear fuel pipe. Remove the 2 gaskets.
CAUTION: Put a shop towel under the delivery pipe. Slowly loosen the union bolt.

4. Install the rear fuel pipe and pressure gauge to the left hand delivery pipe with 3 new gaskets and the union bolt. (SST 09268-45012)

Here are some useful videos for you:




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Okay. If there is no fuel pressure measured, go ahead and check the electronic fuel injection (EFI) fuse and relay in the engine bay fuse box:


Here is a diagram of the fuse and relay locations in that box. Note that this diagram is also on the underside of the fuse box cover, which can be removed by unscrewing the two screws that hold it in.


If these are good, go ahead and check the wiring that leads to the fuel pump. Here is an electrical diagram for the fuel pump system:

See ChrisFix's video that I posted for reference on how to do these troubleshooting procedures if you are not sure.. There are also plenty of resources online for relay, fuse, and wiring testing.

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Thanks Celsi0r

Ok . So another day done. New fuel pump and filter installed as the old one literally looked 25 years old..Replaced the circuit open relay and viola. She sprang to life. SOunds good, runs good..A little fumey but thats to be expected for something that has sat for so long.

This celsior only has 95000 kms on the clock. 

I let it idle for a while and she began to hunt ever so slightly. So there are still some issues here. I will clean the iacv and throttle body/ Ill see whats up soon enough. 

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Excellent. Glad to hear you found the culprit.

That's very low miles for a Celsior - good find. Keep us posted on your progress.

Edited by CELSI0R
Circuit opening relay detail corrected by Moarpower
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In this car the circuit opening relay is mounted next the ecu behind the glove box. Opened it up and realised it was not engaging. I engaged it manually and finally got power to the FP relay.

Now to solve the hunting idle.

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