K2500 won't start

Have a 97 454 Vortec 4x4, the other day it started as normal and I got about half a mile away and it lost all power and died. I managed to tow it back home and have now had a look.
It has a spark at the plugs when cranking, good oil pressure even on cranking, at first I thought the fuel pump had burnt the wires again so I dropped the tank and all was ok, I also tested the pump whilst out just to be sure and again it runs fine.
After putting it all back together I tried it again and still not firing.
I then put a live feed direct from the battery to the pump and had it running constantly but still the thing won't fire up.
The fuel relay should be a five pin unit but at the moment it only has a four pin one fitted (the other one broke months back and I never got to fitting another one as yet). When the ignition is turned to the on position, if I remove and replace the 20 amp fuse that does the fuel there is a distinct buzz/whiring noise from a unit on the top of the engine for a few seconds and then it stops, I believe it is posered by the fuel relay as this clicks on and off at the same time.
I don't have a code reader and the service engine light has been on since I bought the vehicle some five years ago.
The only unusual thing to start happening over the past few months is the use of coolant, I am loosing somewhere around two to three pints over a couple of hundred miles but doesn't use more if I do more miles so am assuming it is a leak to a particular level, having said that the temperature is fine all the time.
Help really appreciated as no dealers over here know these engines.

Have a 97 454 Vortec 4x4, the other day it started as normal and I got about half a mile away and it lost all power and died. I managed to tow it back home and have now had a look.
It has a spark at the plugs when cranking, good oil pressure even on cranking, at first I thought the fuel pump had burnt the wires again so I dropped the tank and all was ok, I also tested the pump whilst out just to be sure and again it runs fine.
After putting it all back together I tried it again and still not firing.
I then put a live feed direct from the battery to the pump and had it running constantly but still the thing won't fire up.
The fuel relay should be a five pin unit but at the moment it only has a four pin one fitted (the other one broke months back and I never got to fitting another one as yet). When the ignition is turned to the on position, if I remove and replace the 20 amp fuse that does the fuel there is a distinct buzz/whiring noise from a unit on the top of the engine for a few seconds and then it stops, I believe it is posered by the fuel relay as this clicks on and off at the same time.
I don't have a code reader and the service engine light has been on since I bought the vehicle some five years ago.
The only unusual thing to start happening over the past few months is the use of coolant, I am loosing somewhere around two to three pints over a couple of hundred miles but doesn't use more if I do more miles so am assuming it is a leak to a particular level, having said that the temperature is fine all the time.
Help really appreciated as no dealers over here know these engines.

where to start ??? are you sure this is worth it ?///

Its a 454, its gotta be worth it!!!

Does the pump run when you turn key on?

Have you checked for spark at all your plugs?

May be a good idea to do a compression check before going too far.

Yes it's worth it to me even if gas costs just over 8 dollars a gallon and I only get 10 miles to the gallon. Apart from the fuel pump wiring burning out a few years ago this motor has been great for my family as a bus and hauling building materials around plus pulling trailers.


I will do a compression check and check all plugs for a spark.
I don't think that the fuel pump is working correctly on the key but will give that a look into as well, however when I put a constant live to the pump it certainly whirred away but the motor still wouldn't fire up, could there be a pressure issue or a fuel solenoid that is not opening as it should?

Any useful help appreciated. Cheers.

Fuel pressure is a definite issue in your case. MT2500 has posted the pressure tests on this forum and should be easy to search for.

When key is turned on (engine off) the pump should run for 2-3 seconds and shut off. This is normal. Replace the relay with the proper one. (I don't think that's an issue but it needs to be done).

Since the SEL has been on for the 5 years that you've had the vehicle and you haven't checked it out for DTC's you really need to get that done and post back any and all DTC's (Active and History).

If you don't have the tools and/or knowledge on how to do this then you need to find, and probably pay, someone to do it.

Today's engines have so many electronics and sensors that they can only be diagnosed with high end, and costly, tools.

Good luck and let us know.

I finally had time and a willing companion to check some things out.
The pump does infact run for 2-3 seconds when the key is turned on.
All the spark plugs had a spark BUT not a very bright one.
It was when I was testing them out that I heard what sounded like a large spark/arc near the distributor. I took the coil lead off and re-attached and the vehicle fired up.
I can only assume that the main HT lead was not fitted correctly and that eventually the distance the spark had to overcome was too great for the spark to give enough to fire the motor up. I'm still at a loss on this as I have never replaced the leads or the cap, infact I have never even repaced the plugs in the time we have had it.
I now have another question, how the hell do you get to the distributor cap with all the hoses and wiring loom in the way?
I want to replace the plugs, leads and possibly the distributor cap mainly because I have been too lazy in the past but found without the truck getting around was a nightmare so maybe I should do some maintenance on it. I will also get the correct relay for the pump while I'm at it. As for the water leak I remember seeing somewhere on here that the inlet manifold is a slit manifold and the lower gasket could be leaking so will get the system pressure tested to see if I can confirm this before getting too far into head gasket changes.
I will also look out for a code reader at some time, as you say cars are now so complicated with sensors everywhere that at least it would be a good place to start when trying to find faults.
Thank you for your help (the chevy dealers over here only know the small daewoo things and I have to go to specialist importers for parts, which can be very expensive especially if I order the wrong bit).