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sr20 will not start a little help please


Guest djhex36

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Guest djhex36

new to the forum but looked around and found not much.... SO.... after hours of wiring making sure every ground made a connection and each part of the block,head, intake manni were getting grounded... fuel injector plugs are seeing 12 volts on both wires when key is set to on , has 11volts of resistance on the ohm meter and it pulses on the ohm meter.

 

have spark on all cylinders, all wires on ECU that are labeled power on manuals have 12 volts to them ... yet it still doesnt want to start..

 

I know i have fuel as i took the FPR off and fuel dumped out.. i can hear the fuel pump on, becuase its hard wired to a relay with 10g wire.

 

so my question is anyone have any other ideas as to why it wont start?? also does anyone else know how to check if the injectors are firing without actually pulling them off and watching them squirt or hearing them click??

 

BTW this is a s13 sr20det in a 77' 280z

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Guest djhex36

i got 12v on ecu and all grounds are grounded per multimeter to the ecu grounds,

 

when i pulled the fuel rail and built up fuelpressure by turning the fuel pump switch(hardwired to a switch) on and then cranking it, it first gives a good burst of fuel , but there after it just hardly mists and dribbles out, like the fuel pump can't keep the pressure up... so that might mean a dying pump, the new pump should be here next week and new injectors... hopefully that'll get it started.

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  • 1 month later...
Guest Sil-Eighty SE-K

your fuel lines may be crossed....also check the base timing....make sure the dots on the cas line up with the notvh when cyl 1 is at tdc also get a hi flow pump for sure on an sr...i run a walbro 255 on both my sr's

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  • 5 months later...
Guest dmin1988

hey guys new member, and i'm having a similar issue. first time even looking at an sr. everything went in smoothly but the car doesnt start. it cranks but doesn't start up.

 

everything i see says make sure the fuel lines aren't crossed and make sure the CAS is right with the 1st cylinder.

 

i asked a buddy of mine for help my CAS but he never had to pull his out to align it. i had to replace mine due to it being chewed up at one point or another before i recieved the motor.

 

fuel lines aren't crossed, checked. but will CAS not being aligned stop the motor from starting up?

 

what would be the easiest way to go about TDC'ing my 1 cylinder?

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first off you shouldnt be seing 12 volts on both fuel injector wires, only one should read 12 when the ignition is on and the other should read nothing until the ecu sends it a 3ish volt signal when your cranking the engine over. Note the 3 volt signal from the ecu is very short so you will need a good volt meter to catch the pulse at all. Recheck your wiring because there is a big problem if you do have 12 volts on both injector wires. Possibly a bad ecu... but lets hope not.

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  • 1 month later...
  • 2 weeks later...

make sure the orange start signal wire is wired up. it's on the "dash plug." which is the little white plug that has a harness about 8" long right off of the ecu plug. that dash plug also has your tach signal Y/R, speed signal Y/G, coolant temp L/B (L=blue), park neutral sw G/O.

 

gl,

Dave

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first off you shouldnt be seing 12 volts on both fuel injector wires, only one should read 12 when the ignition is on and the other should read nothing until the ecu sends it a 3ish volt signal when your cranking the engine over.

 

Hmm? i thought the ecu grounded the injector,rather than sending a signal?.Maybe i'm wrong but i thought the ecu made a complete circuit by grounding-perhaps resulting in 3vt on the other side of the injector?

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correct, the injectors have 12volts on one leg, and the ecu gives the ground pulses to the other wire on the injectors at it gets it's references of when to fire them from the cam angle sensor. that ground pulse from the ecu to the injector is called "noid" signal.

 

Dave

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  • 1 year later...

Sorry for thread dig...

 

I just did an engine swap, i put an s14a engine into my s13. The motor is currently running on 3 cylinders :s I think it is the same problem as the OP as i have spark on all 4 and the fuel pump is going.

 

The other thing i noticed is that i have 12v on both of the injector wires on all 4 injectors. This seems a bit strange that number one cylinder is running fine even though it is giving the same readings as the other three.

 

Anyway, did you find a solution to your problem OP? Or has anyone got any ideas why i would be getting 12v to both wires :s? I have found a few people on other forums (after googlng) with the same problem, but so far i have found no reasons/solutions.

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the reason you have 12volts on both wires is because you're probing into teh wire with the injector plug plugged in. therefore the 12volt power supply (red wire) is feeding through the injector itself and back up through the signal wire.

 

that's normal.

 

if you unplug the injector, and probe the injector plug, you will find that one wire is powered, the other wire waits for the ecu to send the ground pulse to trigger it to open....

 

Dave

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the reason you have 12volts on both wires is because you're probing into teh wire with the injector plug plugged in. therefore the 12volt power supply (red wire) is feeding through the injector itself and back up through the signal wire.

 

that's normal.

 

if you unplug the injector, and probe the injector plug, you will find that one wire is powered, the other wire waits for the ecu to send the ground pulse to trigger it to open....

 

Dave

Ahhh i see. Thanks for that :D

 

Any ideas why it is only running on one cylinder then :s? Seems like it isnt the injectors OR the spark....

 

Could a weak spark cause it to do this? Even that would seem strange though as all the sparks should be the same, and one is working...

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  • 2 months later...

The easiest way to find if an injector is firing is to put a screwdriver to it while someone else cranks the car. put the screwdriver to your ear and listen for the "click" sound as the injector is energized. Or you can go to harbor freight and get a car stethoscope for probably $4 ...

 

make sure the stethoscope isnt touching anything else, or you'll get background noise...

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The easiest way to find if an injector is firing is to put a screwdriver to it while someone else cranks the car. put the screwdriver to your ear and listen for the "click" sound as the injector is energized. Or you can go to harbor freight and get a car stethoscope for probably $4 ...

 

make sure the stethoscope isnt touching anything else, or you'll get background noise...

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