1990 Caprice fuel system problem
TroublingCar
10-18-2006, 10:40 AM
Hi I have a real problem. I have a 1990 Caprice that won't start. However if you pour fuel in the carb. it will run for a brief moment. We checked the fuse to the fuel pump and it is fine. We changed the fuel filter and before we reconnected it we turned the key to find that there was no fuel being pumped out of the tank. We then ran a hot wire from the battery to the fuel pump and was able to get fuel to flow through the line. However when we reconnected the line and ran the hot wire to the pump while turning the key, it would still not start. Does anyone have any idea what I should try next? I am lost on what to do next.:banghead:
capriceowns
10-18-2006, 11:34 AM
a 1990 doesnt have a carb its TBI which looks like a carb, common mistake.
When you said it runs for a bit when fuel is added, then its definetly a fuel pump issue. One could have gone south on you. the fuel pump could still work but not put out enough PSI to run the injectors, EFI is high pressure. check the fuel pressure and if the manual for the car says that what your getting is to low. R&R the fuel pump asm
When you said it runs for a bit when fuel is added, then its definetly a fuel pump issue. One could have gone south on you. the fuel pump could still work but not put out enough PSI to run the injectors, EFI is high pressure. check the fuel pressure and if the manual for the car says that what your getting is to low. R&R the fuel pump asm
TroublingCar
10-18-2006, 01:21 PM
That is understandable but can you explain any reason why we would not be getting juice to the pump when we turn the key on? The fuse is good and the pump at least makes a noise when we run a hot wire to it.
silicon212
10-18-2006, 03:06 PM
Could be the pump relay, could be wiring associated with it, could be the ECM, could be a plugged fuel filter, could be lots of things. Are you getting a service engine soon light?
HLandin
10-31-2006, 08:28 PM
a 1990 doesnt have a carb its TBI which looks like a carb, common mistake.
Close. All models were TBI in 1990 EXCEPT the station wagon which retained the carb. In 1991, all models were TBI.
Like capriceowns says, TBI (which you vehicle has unless its a wagon) requires higher pressure than carb. While the car might bearly run with a carb, with EFI if the pressure is too low, it won't work. I had the exact same problem you described where it wouldn't start, but would fire when we poured fuel into the TBI. It was a clogged fuel filter which will cause pressure to drop before it gets to the injectors. Replaced filter, end of problem.
I would recommend checking each of the items silicon212 mentioned, starting with the fuel filter since it will probably be the cheapest item to try first.
Close. All models were TBI in 1990 EXCEPT the station wagon which retained the carb. In 1991, all models were TBI.
Like capriceowns says, TBI (which you vehicle has unless its a wagon) requires higher pressure than carb. While the car might bearly run with a carb, with EFI if the pressure is too low, it won't work. I had the exact same problem you described where it wouldn't start, but would fire when we poured fuel into the TBI. It was a clogged fuel filter which will cause pressure to drop before it gets to the injectors. Replaced filter, end of problem.
I would recommend checking each of the items silicon212 mentioned, starting with the fuel filter since it will probably be the cheapest item to try first.
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