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No injector pulse...

Kenny_Kline

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Dec 27, 2007
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Seekonk, MA
Have all day today to try to figure this issue out. Need to diagnose why no injector pulse on my personal car. 92 Eagle Talon Lets start from scratch.

Currently during crank, I get spark across the board but no injector pulse. I am getting power (11.9v) at every injector plug. I know what to check first and so on but ive been there done that now its time to start over. Please help
 
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strokin4dr

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Aug 30, 2005
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Savannah, GA
I'd start with the ecu. If you are getting spark then you know the CAS is working.
If the ecu is seeing this signal and not grounding the injectors my thoughts are it's probably the culprit.

-Ryan
 

Kenny_Kline

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Seekonk, MA
Not only did I send my ecu out to ECMlink to have it tested/caps replaced, but I questioned thier work/test and have another 1G ecu here to test and still no injector pulse.
 
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thecman02

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Did you do a continuity check from the ECU to each injector? Are you running low impedance or high impedance injectors? If your running low impedance injectors I'd make sure your resistor pack didn't open up.
 

Kenny_Kline

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Impedance has nothing to do with injector pulse. My injectors are unplugged. But to answer your question, low impedance FIC 1350cc with injector resistor pack installed. Also, even if i was running a bad injector resistor pack, that would be a power issue, not a ground issue. I have confirmed the wires are good from the ECU to each injector. I also tested each wire at the ECU output to injector ruling out wire to see if it gets ground when I crank and it doesnt output a ground pulse from the ecu eliminating the engine harness
 
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prove_it

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Try swapping the CAS then. Otherwise, you've addressed the wiring and ECU. You have link, so check your datalog, pull up anything relevant on the graph and look for an odd reading.

It really sounds like the ECU is at fault, but with two that don't work, sounds like the ECU does not know your starting the car/engine rpms. Check all powers and grounds to the ECU also. Can't remember if a bad Main relay would cause this or not. Check into that guy.
 

Kenny_Kline

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Seekonk, MA
CAS is working properly and I bench tested it also but I guess I could swap it. It would be a deperation move.

Log looks fine and even looked at by Tom himself at ECMlink.

Maybe this is connected but I couldnt connect to ecmlink and I had to actually jump the wire at the ecu to ground to connect. Not sure if that is related to the issue. I can start jumping grounds. TDC and CAS both input signals 5v into the ECU I tested it at the ECU side. What are the chances that I picked up a 2nd bad ecu and ecmlink didnt test/repair my other ecu Highly unlikely.

The main relay I will have to look up where that is located but I think that powers my fuel pump and fuel pump is working correctly during cranking 40psi on the gauge

Ill make a quick video and post on youtube for you to see whats going on
 
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prove_it

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Check your ecu grounds. You could have a loose or bad ground. That seems likely at this point. If I remember right, the ECU has multiple grounds and the sensors/injectors have their own dedicated ground from the ecu.
 

Kenny_Kline

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Do you happen to know where they all ground out at? I have a bunch of wires that ground near the ecu on the radio bracket. The only other ground I noticed in the engine bay are a ground from firewall to manifold, ground for starter bolt to neg battery terminal then a ground from the battery terminal to strut tower. I bought the car as a rolling shell and I dont know what was taken out of it but previous owner cant think of anything that would cause this. i know the car ran before because I raced it a few times lol

Also during cranking I am getting no tach signal but im getting spark?

Upddate nevermind my coil pack in unplugged not allowing tach signal disregard. I have tach signal
 
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thecman02

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Quoting Kenny_Kline:
Impedance has nothing to do with injector pulse. My injectors are unplugged. But to answer your question, low impedance FIC 1350cc with injector resistor pack installed. Also, even if i was running a bad injector resistor pack, that would be a power issue, not a ground issue. I have confirmed the wires are good from the ECU to each injector. I also tested each wire at the ECU output to injector ruling out wire to see if it gets ground when I crank and it doesnt output a ground pulse from the ecu eliminating the engine harness



I only asked to know if you have the resistor pack inline or not. There was a guy with high z injectors with resistor pack that had the same issues.

How long ago was your car running? Just curious.
 

thecman02

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I'm trying to figure out what things could have happened between the time you said you raced it to the time you got it as a rolling shell. What's the battery voltage of the car when you crank it? If the battery is too low the injectors won't fire. Do you have another set of injectors you could put in? Was the no injector pulse from the ecmlink log or did you have a noid light plugged in?
 
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prove_it

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Quoting Kenny_Kline:
It has never ran since I owned it. I bought it as a shell. Not sure what that has to do with injector pulse though.



We're just trying to help. Don't get frustrated with weird questions. Use this to check for power and ground at each pin that needs power/ground.

Start with this. Really sounds like a power/ground issue. Also with the grounds, be sure to measure the resistance to ground from the connector. It could have continuity, but too much resistance will cause issues.

Ecmlink ECU pinout
 
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Kenny_Kline

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Seekonk, MA
Injectors are irrelevant! I have a noid light plugged in. Injectors arent even plugged in. I threw the injectors in the woods and now I have no injectors. No more injector questions

The car was a running car until oil pump failed and took out the motor. he sold the motor, ecu, injector resistor pack out of it. I bought the rest. Not sure what this has to do with diagnosing injector pulse but I just checked tire pressure, all 4 tires were at 32psi.

I jumped ground at the ECU pin #101 and #106 and still no pulse. Only other ground the ecu pins are are pin #17 & #24 (output ground to sensors). ECU only has 2 major ground inputs and ive jumped them both eliminating all wiring of grounds.

Ideas?
 

prove_it

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Power comes in at different pins. How do those look?
 

prove_it

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Which type of noid light are you using? Some won't trigger due to the resistor pack.
 

prove_it

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Quoting Kenny_Kline:
Noid light works, I verified this on other cars.



Other dsms... Point is there are high and low impedance noid lights. Just making sure so I can help you out.
 
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