Starting problems
10-29-16, 03:53 PM
#1
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Starting problems
ok heres the background on the old girl, 1991 rx7, auto to manual swap, new fd fuel pump, new fuel relay, new spark plugs who are getting spark. when i got the car it was a stolen car so a bunch of random pieces were missing, slowly putting it all together. Now it cranks but wont start. new fuses aswell
10-29-16, 04:25 PM
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Its an NA, i dont think its the pump causing the no start, its going to run rich because of it but other than that i shouldnt be having problems until its turbo next year. i do think the pump isnt getting power
10-30-16, 10:17 AM
#5
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It should start with the FD pump (I have in fact done it on my original turbo-NA project combined with 550CC injectors) but will run very rich due to raised fuel pressure. You'll be a whole point or more richer in AFRs.
As mentioned above, check that the fuel pump has voltage and is running first.
As mentioned above, check that the fuel pump has voltage and is running first.
10-30-16, 02:24 PM
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It should start with the FD pump (I have in fact done it on my original turbo-NA project combined with 550CC injectors) but will run very rich due to raised fuel pressure. You'll be a whole point or more richer in AFRs.
As mentioned above, check that the fuel pump has voltage and is running first.
As mentioned above, check that the fuel pump has voltage and is running first.
10-30-16, 02:59 PM
#7
Were you checking the Blue wire w/key to start or on? If you were checking w/key to on and fuel check connector jumpered then check the 15 amp engine fuse. If you were checking w/key to start then that is a different issue then w/key to on and checker jumpered and should be diagnosed in a different manner.
If the fuse was good then there would be power at the following wires w/key to on. Main relay has two plugs. Plug w/2 wires has a Black/White wire. That wire has power w/key to on. Circuit opening relay (located just under the dash and to the right of the steering column). Top row center Black/White wire has power w/key to on. Alternator two wire plug has a B/W wire and it would have power w/key to on.
If the fuse was good then there would be power at the following wires w/key to on. Main relay has two plugs. Plug w/2 wires has a Black/White wire. That wire has power w/key to on. Circuit opening relay (located just under the dash and to the right of the steering column). Top row center Black/White wire has power w/key to on. Alternator two wire plug has a B/W wire and it would have power w/key to on.
Last edited by satch; 10-30-16 at 03:46 PM.
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10-30-16, 04:53 PM
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Were you checking the Blue wire w/key to start or on? If you were checking w/key to on and fuel check connector jumpered then check the 15 amp engine fuse. If you were checking w/key to start then that is a different issue then w/key to on and checker jumpered and should be diagnosed in a different manner.
If the fuse was good then there would be power at the following wires w/key to on. Main relay has two plugs. Plug w/2 wires has a Black/White wire. That wire has power w/key to on. Circuit opening relay (located just under the dash and to the right of the steering column). Top row center Black/White wire has power w/key to on. Alternator two wire plug has a B/W wire and it would have power w/key to on.
If the fuse was good then there would be power at the following wires w/key to on. Main relay has two plugs. Plug w/2 wires has a Black/White wire. That wire has power w/key to on. Circuit opening relay (located just under the dash and to the right of the steering column). Top row center Black/White wire has power w/key to on. Alternator two wire plug has a B/W wire and it would have power w/key to on.
10-30-16, 05:24 PM
#10
Do you mean voltage? And the Blue wire at the pump should not have voltage w/key to on unless the fuel check connector was jumpered. Also, w/key to start the Blue wire would also have voltage but the power comes from the main fuse in the engine bay fuse box.
Last edited by satch; 10-30-16 at 05:50 PM.
10-30-16, 06:10 PM
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Yeah voltage long day ahaha, but also the picture on the FAQ doesnt work anymore i got one from the FSM and i noticed it said 100A is the main fuse? I have 80A in my car could that be the problem?
10-30-16, 06:16 PM
#12
W/key to start there should also be voltage (no jumper needed).
Lastly, an S5 should have a 100 amp main fuse but that shouldn't affect the tests you are doing if in fact you are doing them correctly and you have no voltage.
Last edited by satch; 10-30-16 at 06:24 PM.
10-30-16, 06:32 PM
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You need to clarify how you tested for voltage. Again, the Blue wire will only have voltage w/key to on if you jumpered the fuel check connector. Now you either had the jumper in place or you did not. If you did not then there should not be voltage at the Blue wire w/key to on. So, which is it??????
W/key to start there should also be voltage (no jumper needed).
Lastly, an S5 should have a 100 amp main fuse but that shouldn't affect the tests you are doing if in fact you are doing them correctly and you have no voltage.
W/key to start there should also be voltage (no jumper needed).
Lastly, an S5 should have a 100 amp main fuse but that shouldn't affect the tests you are doing if in fact you are doing them correctly and you have no voltage.
10-30-16, 06:57 PM
#14
it had no voltage with the key on on, and .15 on start, i then jumpered the connection and still did not get it to start. i then remembered in low on gas and went on the hunt for the correct fuse box. it started to rain here so i didnt have time to test it again with actual fuel in the tank. ill grab a 100a and test again
Last edited by satch; 10-30-16 at 08:47 PM.
10-30-16, 10:48 PM
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Im an idiot i was doing 3 things at once and miss read what you said. So i had no voltage with key on and didnt have time to check the voltage with it jumpered because of rain
11-05-16, 10:46 AM
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You will only get voltage if the car is running or the test connector has been jumpered. The ECU cuts the fuel pump if the engine isn't running unless the jumper is in place.
11-05-16, 11:06 AM
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ok voltage when jumpered and the puel pump whines. an idea on what is going on or what other times i should run?
11-05-16, 11:40 AM
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it catches with starter fluid then dies out and yeah i the changed the main fuse to 100a. could it be a bad ecu? an idiot AAA guy connected jumper cables backwards which could mess with it. that was why i change my main fuse incorrectly in the first place.
11-05-16, 11:48 AM
#20
One thing you need to check is fuel pressure. A gauge placed in line should read 30 psi or so. You could also check to see if the ECU is triggering the primary injectors w/key to start. And was their anything missing from the car that would make one think it would prevent the car from running?
Pins 3W (Light Green wire) and 3Y (Light Green/Black wire) are the primary injectors. Take an LED light (has resistor built in) and take one wire and place it into the back of the ECU plug of pin 3W and the other LED lead to pin 1B (Black/White wire) and w/key to start the light should flicker. Do this for pin 3Y also.
And check the Brown/White wire at the pressure sensor w/key to on for 5 volts. This will tell you if the ECU is being powered w/key to on (you know it's powered w/key to start because you have spark).
Pins 3W (Light Green wire) and 3Y (Light Green/Black wire) are the primary injectors. Take an LED light (has resistor built in) and take one wire and place it into the back of the ECU plug of pin 3W and the other LED lead to pin 1B (Black/White wire) and w/key to start the light should flicker. Do this for pin 3Y also.
And check the Brown/White wire at the pressure sensor w/key to on for 5 volts. This will tell you if the ECU is being powered w/key to on (you know it's powered w/key to start because you have spark).
Last edited by satch; 11-05-16 at 12:07 PM.
11-05-16, 12:21 PM
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One thing you need to check is fuel pressure. A gauge placed in line should read 30 psi or so. You could also check to see if the ECU is triggering the primary injectors w/key to start. And was their anything missing from the car that would make one think it would prevent the car from running?
Pins 3W (Light Green wire) and 3Y (Light Green/Black wire) are the primary injectors. Take an LED light (has resistor built in) and take one wire and place it into the back of the ECU plug of pin 3W and the other LED lead to pin 1B (Black/White wire) and w/key to start the light should flicker. Do this for pin 3Y also.
Pins 3W (Light Green wire) and 3Y (Light Green/Black wire) are the primary injectors. Take an LED light (has resistor built in) and take one wire and place it into the back of the ECU plug of pin 3W and the other LED lead to pin 1B (Black/White wire) and w/key to start the light should flicker. Do this for pin 3Y also.
11-05-16, 02:56 PM
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11-06-16, 06:31 PM
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ok the fuel pump is working the engine is getting fuel, i pulled off the feed and return lines, ill do a pressure test tomorrow to make 100% sure, but right after i switch out my main fuse non of the interior or dash lights work. i the fuse itself is fine, i check it with a multi. i do have vacuum lines missing from my fuel rail and intake manifold which i think might be the problem. ill post a picture in a second, im not too familiar with what is supposed to go where since this is my first rx7 i worked on. the car is cranking and stumbling but not catching still.