starting problems - fuel pump resistor relay
07-23-06, 11:48 PM
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starting problems - fuel pump resistor relay
so, my car ('90 gxl) is having starting problems.
i haven't been able to get it started. i tried unflooding it using several different methods, but still no beans. i have not tried using ATF with brand new spark plugs, however. also, i have yet to recheck the compression. so those two things are still possibilities.
what i did was pull the plugs and EGI fuse, and cranked it 3 times for a good 10-15 seconds each time. then put a little regular 20w-50 oil in the lower plug holes in an attempt to build a little compression. put the plugs and EGI back in, and attempted to start the car normally, not touching the throttle at all. i can hear the motor firing erratically, but it won't start, and it reeks of fuel, especially out the exhaust, with some wisps of smoke.
i suspected maybe a stuck open injector, making it way too rich to start. so i bought a fuel pressure tester to test the hold pressure. it was about 30psi after 5 minutes, the fsm says above 18psi is good. so, i'm now thinking it is something else, since if an injector was open, the pressure would drop off pretty fast, correct?
i tested the fuel pump resistor relay's resistance. there is none, between all 3 pairs of terminals.
from what i gather, this will make the fuel pump run at the full 12 volts, which may be too much for cranking.
has anyone ever experienced a similar situation, or even had one go bad? i did see the thread where RETed's took a dump, however. anybody have any insight to this? anyone have a spare relay laying around they'd like to sell me?
thanks!
i haven't been able to get it started. i tried unflooding it using several different methods, but still no beans. i have not tried using ATF with brand new spark plugs, however. also, i have yet to recheck the compression. so those two things are still possibilities.
what i did was pull the plugs and EGI fuse, and cranked it 3 times for a good 10-15 seconds each time. then put a little regular 20w-50 oil in the lower plug holes in an attempt to build a little compression. put the plugs and EGI back in, and attempted to start the car normally, not touching the throttle at all. i can hear the motor firing erratically, but it won't start, and it reeks of fuel, especially out the exhaust, with some wisps of smoke.
i suspected maybe a stuck open injector, making it way too rich to start. so i bought a fuel pressure tester to test the hold pressure. it was about 30psi after 5 minutes, the fsm says above 18psi is good. so, i'm now thinking it is something else, since if an injector was open, the pressure would drop off pretty fast, correct?
i tested the fuel pump resistor relay's resistance. there is none, between all 3 pairs of terminals.
from what i gather, this will make the fuel pump run at the full 12 volts, which may be too much for cranking.
has anyone ever experienced a similar situation, or even had one go bad? i did see the thread where RETed's took a dump, however. anybody have any insight to this? anyone have a spare relay laying around they'd like to sell me?
thanks!
07-24-06, 01:57 PM
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hmm ok, thanks for the tip!
if my resistor relay is indeed bad, what sort of symptoms would show up then? i can only think of worse gas mileage and running rich while cruising. under what conditions does the voltage switch?
is it safe to assume my injectors are not stuck open since my hold pressure was above the 18psi spec in the fsm?
other things i've noticed is that my plugs are covered in a black sludge. could this just be fuel mixed with carbon deposits?
some more history: the starting problem arose very suddenly. i drove the car for a good hour, parked it for 10 minutes, walked back, attempted to start it and failed. i have never had a flooding/starting problem with the car previously. I pulled the EGI fuse, cranked it over a bunch while opening the throttle all the way, put the fuse back, and was able to get it barely idling, but very very roughly, and it was backfiring like crazy, very very violently, i thought my exhaust might blow off, so i shut it off, and towed it home.
i tried cranking while playing with the gas pedal, and the car seems more inclined to starting at part throttle, as compared to full throttle. since its an S5, that should cut the fuel, correct?
as of right now, my plan is to buy new plugs and atf, and try to unflood it again. any comments are welcomed.
if my resistor relay is indeed bad, what sort of symptoms would show up then? i can only think of worse gas mileage and running rich while cruising. under what conditions does the voltage switch?
is it safe to assume my injectors are not stuck open since my hold pressure was above the 18psi spec in the fsm?
other things i've noticed is that my plugs are covered in a black sludge. could this just be fuel mixed with carbon deposits?
some more history: the starting problem arose very suddenly. i drove the car for a good hour, parked it for 10 minutes, walked back, attempted to start it and failed. i have never had a flooding/starting problem with the car previously. I pulled the EGI fuse, cranked it over a bunch while opening the throttle all the way, put the fuse back, and was able to get it barely idling, but very very roughly, and it was backfiring like crazy, very very violently, i thought my exhaust might blow off, so i shut it off, and towed it home.
i tried cranking while playing with the gas pedal, and the car seems more inclined to starting at part throttle, as compared to full throttle. since its an S5, that should cut the fuel, correct?
as of right now, my plan is to buy new plugs and atf, and try to unflood it again. any comments are welcomed.
07-24-06, 02:27 PM
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Go to the RELATIONSHIP CHART in the free online S5 manual and it shows the items that effect the Fuel PUmp Resistor Relay.
On the whole, it's putting a LOAD on the engine that triggers the ECU to apply/remove a gnd signal from the ECU to the Fuel Pump Resistor Relay that does the trick.
On the whole, it's putting a LOAD on the engine that triggers the ECU to apply/remove a gnd signal from the ECU to the Fuel Pump Resistor Relay that does the trick.
07-30-06, 06:15 PM
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i have the same problem with my 91 rx7 the only thing i did is i bought new everything brand new spark plugs and wires and it still will just turn over and over. It seems to turn really slow so we put jumpin cables on it and it would almost start but wouldnt. I have pulled the 30A fuse out and started it for like 10-15 sec put back in and try starting and still will not start but would almost start but wouldnt. and mine did the same thing it was running one day then try again the next day and nothing wtf.
i also have other problems to when it ran it would run bad like it would have no power u try to go up a hill and it would almost go died, when it first started it would stutter a lot then catch b ack up with itself and run a lil smoother so i dont know im outta thoughts to what to do next so if you find out whats wrong with urs might be the same with mine
i also have other problems to when it ran it would run bad like it would have no power u try to go up a hill and it would almost go died, when it first started it would stutter a lot then catch b ack up with itself and run a lil smoother so i dont know im outta thoughts to what to do next so if you find out whats wrong with urs might be the same with mine
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