First Start in 20 Years

samsquanch

New Member
Joined
Mar 28, 2021
Hello,

My 1986 GN has been sitting for around 20 years without running. Probably cranked it over about ten years ago. I grew up since before birth riding in the car until it was parked around 2001. I replaced the fuel pump, and new gas. All fluids were replaced. Fuel pump relay only cuts on 50% of the times I cycle the key. I'm getting clean fuel and good pressure to the rail. Have spark. I'm thinking the injectors are stuck or not firing.

Oddly enough the gas that was in the tank and fuel rail was actually pretty clean. Most likely due to being ethanol free premium from back in the day. I'm thinking injectors aren't getting power. I don't know where they get power from or where to look. Fuses are all good. Wiring seems okay. I read somewhere injectors get power off fuel pump relay, but can't rely on that. I can't find my service manual anywhere.

Any help will be appreciated.
 
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samsquanch

New Member
Joined
Mar 28, 2021
Thanks or the links. I got in a little more work this afternoon. I was able to get it to run for a few seconds on starter fluid. I pulled an injector connector and could see voltage spike to about 6.8 volts. Not sure if this is enough to fire an injector I'm still looking for the details. Have good fuel pressure, and spark.

Trying to figure out where the ecm gets voltage from to fire injectors. I'm not seeing any service engine light so I will have to troubleshoot that further. I'm kind of suspecting a bad connection in the firewall harness under the wiper motor. As long as the car sat, I'm thinking injectors need to come off and be cleaned or replaced.
 

michael evans

Well-Known Member
Joined
Feb 27, 2008
injectors get power from the fuse box. The computer provides a ground to "fire" the injector a the correct time
 

michael evans

Well-Known Member
Joined
Feb 27, 2008
one
 

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Chuck Leeper

Toxic old bastard
Staff member
Joined
May 28, 2001
I pulled an injector connector and could see voltage spike to about 6.8 volts. Not sure if this is enough to fire an injector
Doubt it....
How are you measuring that?
If you are trying to catch a reading by cranking the engine...Not an accurate method.
KOEO: Pull a inj plug, measure from 1 terminal to the VOM probe, with the other to ground.
May have to go to other terminal, to get a read. If it's not batt voltage, something wrong.
All 6 inj s should be hot.
You can also use a NOID lite. That will check to verify that the inj circuits are actually firing.
NOID lites are cheap.
As mentioned above, it's time for a new set of injs and a matching chip.....
 

SCOOBY DOO

I'M NOT A MONSTER, I'M JUST AHEAD OF THE CURVE!!!
Joined
Feb 18, 2007
Pull the cam sensor and prime it...before starting. If you don't wanna do it...then I have vids on pulling the engine and rebuild vids.
 

samsquanch

New Member
Joined
Mar 28, 2021
I will take those videos on engine removal and rebuild.

Got oil primed. Gave the injectors a few good taps with a ratchet. Pulsed them with a small 6v power supply to make sure they were moving. It started right up. Let it idle for about thirty seconds, and shut it down. I did this about five or so times to check things out and let the internals settle in and find their sweet spots. Then I got to revving it a little bit. Seemed to be doing fine. It kind of bogs down with more then half throttle. Idles pretty smooth for just starting up. No smoke or anything too odd, just a bunch of rusty crap from the tail pipes. Let it idle for a bit longer until the cooling fan cut on then I shut it down.

I'm not entirely certain why the car was parked as I was still a little kid. I think it may have been the transmission. Still trying to get answers from family. I have a new in box transmission and new torque converter my granddad bought from a magazine add for GN performance transmissions. I might try a few things before I swap it in, but thats what its looking like.

Car is kind of rough, but has unlimited potential. I'm thinking about building a spare engine just in case, and rebuilding the bad transmission. I'm very budget minded, but will spare no expense in restoring this car.

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