Fuel injectors not getting signal

Tiny
GARY J. WILLIAMS
  • MEMBER
  • 1986 NISSAN 300ZX
  • 6 CYL
  • 2WD
  • MANUAL
  • 250,000 MILES
Car cranks, no start. The fuel pump works but do not know if it is getting full power, for the injectors to fire. Pump harness is damaged from moisture in rear hatch. Should I repair the wire to get full power to the injectors?
Or is it a bad ground also? Thank you, Gary
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Sunday, February 18th, 2018 AT 3:35 PM

16 Replies

Tiny
GARY J. WILLIAMS
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  • 8 POSTS
My plugs at fuel pump harness are corroded. Need to get back in on the road!
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Monday, February 19th, 2018 AT 4:11 PM
Tiny
KEN L
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Hello, sorry for the slow response. Did you find the problem or do you still need help?
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Tuesday, February 20th, 2018 AT 3:51 PM
Tiny
GARY J. WILLIAMS
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Ken. Wired fuel pump to work, the connectors were corroded, so bypassed the plugs on harness and have gas past the fuel filter, but have not pressure tested. Plenty of gas when key on, but not sure if pressure is high enough to energize the injectors. Starts with starter fluid.
Replaced original ECU with one from different Z. Does it need to be reprogrammed? I am not getting injector pulse for motor to run. What forces the gas to reach the injectors? ECU, injector signal to ecu, from injectors?
Is it possible the injectors are all bad at the same time? Is ECU no good? It starts with fluid so I suspect injectors or computer.
Any feedback would be appreciated. Thank you, Gary
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Wednesday, February 21st, 2018 AT 4:58 AM
Tiny
KEN L
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Hi Gary.

Lets see if the injectors are getting pulse for the ECU first. I have seen where the injector resistor box goes out in theses cars.

Check out this guide.

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

Please let us know what happens.

Cheers, Ken

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Wednesday, February 21st, 2018 AT 9:51 AM
Tiny
GARY J. WILLIAMS
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Hi Ken, I had forgotten that I had changed the motor in my Z about five years ago. So now I do not know if I have the right ECU or not. However, it was running for the last five years with the one I have.
I had gotten a used ECU off of eBay for an 1986 that is when I started running into the problem of crank but no start. I need an ECU for an 1988 motor? Or 1986 for the body?
I am going to try a new distributor, with a new crank angle sensor.
The car fires on starter fluid, but the fuel is getting to the fuel filter but not reaching the fuel injectors, because of the wrong ECU, which is for an 1986?
Would it even fire with starter fluid, if it was the wrong ECU? The ECU looks the same, has same number of pins in the plugs. I have to check part numbers and make sure that they match.
I am stumped on what to do. I have to match the part numbers on the original ECU that the car was running with for the last five years, and I am getting a new distributor for an 1988 engine. That is what is in there now.
Need to get my "baby" running soon!
Any insight to my dilemma would be greatly appreciated. Thank you, Gary
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Thursday, February 22nd, 2018 AT 4:52 AM
Tiny
KEN L
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It sounds like the ECU might be okay. Can you run codes on it?

Here is a guide:

https://www.2carpros.com/articles/nissan-obd1-diagnostic-trouble-codes-and-retrieval-procedure-1984-to-1994

Next I would do the distributor and crankshaft sensor.

Please let us know what you find.

Cheers, Ken
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Thursday, February 22nd, 2018 AT 11:51 AM
Tiny
GARY J. WILLIAMS
  • MEMBER
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Should I use the ECU that was in it and running for the last five years. I bought a "used" ECU and it still will not start! If I try and the codes, they would be from the car it came from? It could I pull the codes out of new ECU, just by hooking it up without driving it?
I have got a new distributor with crank angle sensor I believe coming.
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Friday, February 23rd, 2018 AT 5:11 PM
Tiny
GARY J. WILLIAMS
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I brought my original ecu that had been running my car for the last 5 years, with a motor from an 88, to a automotive computer shop and they tell me that computer was beyond repair
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Friday, February 23rd, 2018 AT 5:15 PM
Tiny
KEN L
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Makes sense of why it wont start with a bad computer. Can you get a third computer?
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Saturday, February 24th, 2018 AT 10:55 AM
Tiny
GARY J. WILLIAMS
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I received my "new" used computer from a guy in Virginia and installed it, but it is still not getting injector pulse. It starts with starter fluid. I do not know if computer is good or bad? It must be good? I have an 1988 motor in a 1986 body. Could the fuel pump possibly be bad? Gas is getting past the filter when key is turned, but have not tested how much pressure is in the line. And the injectors do still not get signal to open and close!

I have a new distributor coming Tuesday with the crank angle sensor.
Thanks for trying to help. I will let you know how I am making out.
Yes, it is the same car.
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Monday, February 26th, 2018 AT 11:02 AM
Tiny
KEN L
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I am thinking the new distributor should fix it. Please let me know.
Cheers, Ken
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Monday, March 5th, 2018 AT 11:04 AM
Tiny
GARY J. WILLIAMS
  • MEMBER
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Hi Ken, I put in my new distributor and I noticed all gas in the bottom of the shaft. Time for a new distributor o-ring in the block. I have to read up on how to do it.

That could be part of the reason it will not start.
I may also have an injector that us stuck open. I will let you know. Gary
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Tuesday, March 6th, 2018 AT 12:15 PM
Tiny
KEN L
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Please do. :)
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Tuesday, March 6th, 2018 AT 12:17 PM
Tiny
GARY J. WILLIAMS
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  • 8 POSTS
I brought my original ECU that had been running my car for the last five years, with a motor from an 1988, to a automotive computer shop and they me that computer was beyond repair.
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Friday, April 6th, 2018 AT 2:54 PM
Tiny
KEN L
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Yes, it sounds like this could be the problem, did you find a used one to replace it?
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Saturday, April 7th, 2018 AT 11:58 AM
Tiny
GARY J. WILLIAMS
  • MEMBER
  • 8 POSTS
Should I use the ecu that was in it and running for the last 5 years.I bought a "used" ecu and it still won't start! If I try and the codes, they would be from the car it came from? It could I pull the codes out of new ecu, just by hooking it up without driving it?
I've got a new distributor with crank angle sensor I believe coming.
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Friday, April 27th, 2018 AT 7:07 PM

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