Re: the caviler will starts and run but then it loses...
Could be a number of things. but first check to make sure the voltage is around 13.4 volts.......
if the voltage is off in any way that could be the bugger. because most electric fuel pumps have a kill switch in them that will cut it off to try to save it from shorting out. mainly from running out of gas. since running really low and out of gas can shock the pump and cause it to burn up
unless youve had the fuel pump replaced before........ its most likely a bad connection.
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Lets start at the beginning. The engine computer grounds the pump relay. The relay gets power from the EFI relay when the key switch is on and from the starter fuse when the key switch is in the start position. Do you know if the pump relay is getting power from both sources and a ground from the computer ? Can you run a hot wire to the blue black wire going to the pump and keep it running ?
can you spray it with brake cleaner or caarb cleaner in the intake breather hose to see if it will run might not b the fuel pump.could be spark or we call fire .if you spray it and it runs ,yes its a fuel problem if not spark or compression
I would check the EEC relay and the fuel pump relay for power and ground signals first. Both circuits are controlled by the ignition key switch. The fuel pump should be powered for 3 seconds when you turn the key on.
DON"T USE STARTING FLUID ! It sounds like you have spark but no fuel as it runs on starting fluid maybe your alarm system is wired to cut out the injectors it could be the concern.If it cranks over i would say the key is ok!
There is a fuel pump "roll over" valve in the floorboard on the passenger side. It stops the fuel pump from running incase you roll the vehicle to prevent a fire. Check that the switch didn't trip from someone possibly kicking it or something. Then check any fuses or relays (swap relays if you have a spare or switch with the same on in a different slot). If everything checks out ok, then you probably need a fuel pump
There is a fuel cutoff switch on the passengerside floorboard, towards the right kick pannel, there will be a little red button on top of it, check to see if that is tripped, also when you turn the key to the on position listen to see if you hear the fuel pump prime up, just a short buzzing noise from the underside of the cab, if you dont hear it, that is a good indicator that your fuel pump maybe bad, i would also check the pressure at the fuel rail, chrome or black colored bar located near the fuel injectors.
definitely could be something smaller. Like a relay....even a filter.
Few things to try:
Just turn the key to on, not start and see if you listening to the fuel tank if you can hear the pump going. If not, its either the pump or the relay.
Most of these trucks have another switch that kicks in after the enigine is started and runs the pump so you may be able to spray starting fluid in it while cranking it and get it to start. Then the other switch may kick in and run it. that will let you know if its the relay or what. Let me know what you find. I just replaced a relay on a 93 and it was only $8.....worth a try. Also, there will be a fuel pump fuse, probably close to the relay, could be that!
Need to check for fuel pressure and volume. If you turn the key on and you have pressure, then you should be able to start and run. If your fuel pressure gauge has a releif hose on it, then while running, dump fuel into a jug and the engine should stay running. If the vehicle will not start but cranks over, then turn the key off and on a few times. the fuel pump will only stay on for a few seconds and cycle off. Sounds like you are losing your fuel prime from the pump to the engine. Only fix is to replace the fuel pump if you are losing your prime.
If it is fuel injected it will get enough fuel to start but not stay running. I had the same problem with my S10. Turns out the hose that went on to the end of the fuel pump was roted. pull the sending unit and check the hose connections to the pump and the sending unit. If problem presists replace filter first the pump.