s14 sr no injector pulse

[dyost]

so my s14 sr20det isnt getting injector pulse i know they have power going to them. ive done some searching and all i can find that controls them is the cas ive adjusted it and still nothing maybe i did it wrong but what could be some other causes of no pulse?

[racepar1]

Mis-adjusting the CAS will not cause no pulse. It would cause an incorrect pulse and maybe a no-start condition, but the injectors would still pulse. The CAS would have to be completely bad, as in no signal at all, to cause no injector pulse. You need to check the CAS signal to the ECU. If the ECU is getting signal then the ECU is likely bad.

[dyost]

i just replaced the ecu. i got it from zerolift my techer told me he thought it was bad so i took it back to them and they said it works they took it out of one of there cars to go with a stand alone then they told me to check my cas because if its even one degree off it could cause no pulse

[stance]

I had this problem. It turned out to be bad injectors. Try looking into that

[brndck]

then they told me to check my cas because if its even one degree off it could cause no pulse

sorry, this just isnt true.
imagine that the cas is a distributor (basically thats pretty much what it is)
would you still get spark if you advanced or retarded it a degree?

also, are you getting spark?
if you have spark, then you know the cas is functioning properly.

how are you checking your injectors? if you are not using a noid light or a picoscope/oscilloscope, you need to be.

[racepar1]

I had this problem. It turned out to be bad injectors. Try looking into that

There is no possible way that all 4 injectors went bad at the same time... To test the injectors simply ohm them out. Resistance should be 12-14 ohms on a good nissan injector.

OP: The shop that told you that is either retarded or you mis-understood. The CAS sends a signal to the ECU that tells it when to spark/inject fuel. If the CAS was incorrectly adjusted it would simply spark/inject fuel at the WRONG time. In order to have NO pulse there would have to be NO signal. I second the question "how are you testing for injector pulse?" You can't do it with a test light or a DVOM. You need a noid light setup or a scope to do it.

[army240]

Easy way to check your injectors could be :

1. Disconnect the Igniter

2. Take the CAS off the engine head

3. Turn the CAS by hand with the Ignition ON, you should hear the injectors "Click"

4. If it you don't hear the injectors "Click" then check for 12V on one of the two wire going to the injectors (should be hot at all time)

5. If you have 12V, it could be your injector pulse is missing, bad injector driver, bad ECU grounds. If you don't have spark also, could be CAS.


Also, as other said, if you got spark, your CAS is good.


Have fun,

Frank

[dyost]

i have spark and ive tested the injectors with a noid light and got nothing and they all have 12v to them and ive taken the cas out turned the ignition on and turned the cas by hand and never heard the injectors click

[bcyamaha10]

Do a quick test on your inputs like crank shaft position sensor, cam shaft position sensor. It's a long shot, but if the ECU doesn't know timing it might not squirt

[brndck]

i have spark and ive tested the injectors with a noid light and got nothing and they all have 12v to them and ive taken the cas out turned the ignition on and turned the cas by hand and never heard the injectors click

the way the injectors work is, they have a 12v feed to them at all times, when the ecu triggers them, it GROUNDS the other side, then goes back open. you may have a bad injector driver, but if you have spark, then your cas is functioning properly.

personally the next step i would take is to bust out a pinout for the ecu you have, and trace and double check all grounds and wires and make sure you don't have any shorts/broken wires or bad connections.

i know its tedious, but you hafta confirm a lot of things to eliminate all possibilities.

[racepar1]

the way the injectors work is, they have a 12v feed to them at all times, when the ecu triggers them, it GROUNDS the other side, then goes back open. you may have a bad injector driver, but if you have spark, then your cas is functioning properly.

personally the next step i would take is to bust out a pinout for the ecu you have, and trace and double check all grounds and wires and make sure you don't have any shorts/broken wires or bad connections.

i know its tedious, but you hafta confirm a lot of things to eliminate all possibilities.


^^^What he said^^^

I'm not an SR expert, but I have seen before in ignition systems with distributors where there are 2 sensors in the distributor. One "cam" and one "crank". I wonder if the SR CAS may have 2 outputs or only one? If it has 2 outputs it COULD still be the CAS. I would have to see a wiring diagram (in english) to be sure. It is unlikely, but possible. If it only has one output to the computer then I would suspect a bad ECU. It's unlikely to have a wiring issue that would affect all 4 injectors, since they're all controlled individually.

[brndck]

this is just an example of what i'm talking about. OP i don't know what ecu you're using, but.....
http://www.google.com/url?sa=i&source=images&cd=&docid=oN4N6XpR8XInFM&tbnid=QcuGUHjEEGuuNM:&ved=0CAUQjBwwAA&url=http%3A%2F%2Fwww.s-chassis.com%2Fresources%2Fwiki%2Fimages%2F6%2F60%2 FECUS13SR20DET.jpg&ei=n7VfUabIGeOziwKL2oH4Dg&psig=AFQjCNGkkx6hbdOGSVGn5hAE7Sm5TYz1sg&ust=1365313311470403

pins 1,2,7,8 are the ecu commanding each individual coil pack to fire.

101,103, 110, and 112 are the ecu grounding out the injectors to complete the circuit so they will fire

22,30,31, and 40 are all CAS. if any of these are damaged/broken, it may affect performance. best to check all 4 of these to make sure they are not frayed/damaged/shorted.

[dyost]

turned out to be broken wires shes running now