s13 sr20 redtop no Start- Have Spark, fuel injectors not spraying!?!?!

[ticklemeermuel]

Alright guys just like the title says. I tried searching but no luck...The motor is an s13 sr20 redtop freshly swapped. Fuel lines are not reversed.For some reason the car will crank but the fuel injectors will not spray. Fuel pump primes, I get spark in each cylinder, but the injectors JUST won't spray. I pulled the fuel rail to verify this. I check continuity between the ecu and injector harness to see if I'm getting a pulse and I am! I double check the injector grounds. Any input would be great I've never personally ran into this so please chime in. I've been on this car for a minute so I'm sure I'm overlooking something very simple.Funny thing was I thought I knew these motors fairly well...At the bottom is a list of stuff of replaced for known good working parts.

-wiring harness
-ecu
-injectors
-cas
-ignitor

any input would be great...feel like this is a minor problem that shouldn't have me stumped!

[s14unimog]

If you can pull the CAS, or have an extra CAS, then plug it in and set it aside. Remove the fuel pump fuse and turn the ignition to "on". If you turn the CAS with your fingers you should hear the injectors "click". If they don't, check the voltage on the power wire. Since all of the injectors share the power lower in the harness a problem will effect them all. If you see less than battery voltage, you need to either make a jumper from a power source or find where the short is. I had this exact problem and it ended up being a corroded cold solder connection. Check the FSM diagnosis area. there is a a set by step of what to check also.

[ticklemeermuel]

If you can pull the CAS, or have an extra CAS, then plug it in and set it aside. Remove the fuel pump fuse and turn the ignition to "on". If you turn the CAS with your fingers you should hear the injectors "click". If they don't, check the voltage on the power wire. Since all of the injectors share the power lower in the harness a problem will effect them all. If you see less than battery voltage, you need to either make a jumper from a power source or find where the short is. I had this exact problem and it ended up being a corroded cold solder connection. Check the FSM diagnosis area. there is a a set by step of what to check also.This is the answer I was looking for. Injectors don't click but I do get a pulse. So I need to trace it the power source on the lower harness. Now my question is where is it sourced to on the lower harness?

[Carta]

Sorry for a thread revival but I am having the exact same problem on my 180sx import with redtop. Where would the lower harness be. Sorry if its an obvious question but I am going crazy here. I have changed ECU, Fuses, Relays and fuel pumps! Any help or even better pictures of where to check would be superb!

[opponheimer]

had the same problem it was my ecu

[opponheimer]

Sorry for a thread revival but I am having the exact same problem on my 180sx import with redtop. Where would the lower harness be. Sorry if its an obvious question but I am going crazy here. I have changed ECU, Fuses, Relays and fuel pumps! Any help or even better pictures of where to check would be superb!


are you getting pulses to ur injectors? def. getting spark? check for both.. Is your fuel pump priming?

[slider2828]

I ecu I have one for sale.

[Carta]

Fuel Pump Priming - Check
Spark - Check, tho not sure on colour will check again
Injectors firing - No, as there is no fuel in cylinder and spark plugs are dry.

Swapped ECU out for a Mines one and the same problem. Been reading up people seem to swap oil because of leaky injectors, what you recon?

[rex2sx]

Get a FSM and look at signal/voltage wires going to the injectors and plugs. Ground a screwdriveror a test light to see if it fires the plugs. Look at grounds too.

[Carta]

I have tested this afternoon, and I have earth to all the injectors. No live/voltage/power to any of them though. When testing the live the multimeter needle moves down ever so slightly which is confusing!

[Z U L8R]

the ecu is what provides the ground pulse to the injectors aka noid signal

the injectors get constant 12 volts (red wire) that taps into the red constant 12 volts at the ecu aka "ecu backup power". this battery 12 volt power supply is NOT found in the lower harness. it is all in the main engine harness.

bottom line, one wire out of the 2 that go to the injector needs to be power, because the ecu is going to fire that injector by giving it a ground pulse.

Dave

[Spencer dougherty]

its a wireing problem bring the car to me and ill have it fixed in one day

[RedSVTFlareside]

Any light shed on this problem yet? I'm having the same problem. I can't think of why my injectors aren't firing. This thread has given me some ideas but I'd like to know what the cause was on the previous questions.

[wangan_cruiser]

i know this thread is old but i just want to throw out what i found because im having the same problem. my injectors werent firing because the solder of the wire for main ignition broken off.


you might want to check that

[stance]

Having the same problem here. Already tried other ecus,cas

[waltzone11]

I have same problem too but only injector #1, I check the ECM voltage pin 101,103,110,112 while the car is running(idle). The reference voltage is 11-14 volts<<<<<this is from the service manual.
This my reading:
Injector #1 ECM 101 pin= No volts reading but it read Milli volt = Bad
Injector #2 ECM 103 pin= 14 volts = Good
Injector #3 ECM 110 pin= 14 volts = Good
Injector #4 ECM 112 pin= 13 volts = Good

Also check all the continuity of injector harness all reading 0hms = Good

[carnagexxxx]

I am having the same problem. So far in this thread there are 4-5 people who say they have this issue but there has not been any replies with a cause/solution.

I have new injectors, have 12V power to each, ECU was tested by Jim Wolf Technology and was deemed to be "good".

What sensors, plugs, switches, circuits, anything, could go bad and prevent the injectors from getting a pulse?

[T0fuman]

So iv'e kinda solved the problem I was having with this. I just unplugged the power being sent to my fuel pump and the thing started up 3x. With pump hooked up I was getting nothing. Idk why. A buddy of mine said it might be the fuel pressure regulator doing something while the pump is priming. Also might be why im only getting 15mpg.