29-07-2024, 08:01 AM
Hi mate. Sorry for the slow reply. I don't check in here very often now.
A few questions for you.
> How fresh is the fuel in the tank?
> I assume you had pressure at the rail when you had the pump running?
> Also, how long did you take cranking it over with the pump running? After I'd replaced the pump one time on mine it took a long time to catch afterwards - may have been an air lock somewhere I guess.
You're right that power for the pump is via the duel fuel relay, but is also dependent on the fuel cut-off switch not having been tripped (although unlikely without a collision). Certainly worth a try replacing the relay as they can still be sourced very cheaply, although don't get an unbranded one (which are only about £10). Assuming you have the 16v XSi then part number is 454935. The Nagares ones are fine Fits MAHLE MR 7 Multifunctional Relay OE REPLACEMENT | eBay. Either that or second hand genuine Omron one.
The relay is powered from the ECU, and then goes on to provide power for more that just the fuel pump - also the injectors & the ignition coil. As you said it will start with fuel in the intake then you have spark, which means the relay is at least partially working. If a new relay doesn't fix the issue then post back here. I'd have to dig out a wiring diagram to check if the coil & injectors are powered off different sides of the relay. (It has two separate controls).
A few questions for you.
> How fresh is the fuel in the tank?
> I assume you had pressure at the rail when you had the pump running?
> Also, how long did you take cranking it over with the pump running? After I'd replaced the pump one time on mine it took a long time to catch afterwards - may have been an air lock somewhere I guess.
You're right that power for the pump is via the duel fuel relay, but is also dependent on the fuel cut-off switch not having been tripped (although unlikely without a collision). Certainly worth a try replacing the relay as they can still be sourced very cheaply, although don't get an unbranded one (which are only about £10). Assuming you have the 16v XSi then part number is 454935. The Nagares ones are fine Fits MAHLE MR 7 Multifunctional Relay OE REPLACEMENT | eBay. Either that or second hand genuine Omron one.
The relay is powered from the ECU, and then goes on to provide power for more that just the fuel pump - also the injectors & the ignition coil. As you said it will start with fuel in the intake then you have spark, which means the relay is at least partially working. If a new relay doesn't fix the issue then post back here. I'd have to dig out a wiring diagram to check if the coil & injectors are powered off different sides of the relay. (It has two separate controls).