85 corvette injectors won’t fire
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Joined: May 2010
Posts: 50
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From: Flint Michigan
85 corvette injectors won’t fire
I have a 85 all stock. The car ran great, but needed head gaskets replaced. Got everything put back together and now the car won’t start. I have spark, fuel pressure in the rails but the injectors don’t seem to be firing fuel into the chamber. I tried a bit of started fluid and she sputtered a bit. When I turn the key off, there is a clunking noise from the passenger side. Any ideas?
Tech Contributor
Joined: Oct 2008
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From: Custer, WI
I believe there is a theft deterrent system on 85, my car will set the horns off and **** if you do some magic sequence of locking the door and closing it then trying to open it right away or something like that. Not sure if it had any shutoff to the engine tho
Safety Car
Joined: Oct 2007
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From: Pennsylvania
The theft deterrent system on an 85 won't even allow the engine to crank until you disarm it with the keys, or you wait something like 15 minutes for it to reset. It's a goofy system, but it WILL stop someone trying to take it quickly.
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Purchase a Noid light set at Auto Zone or other auto parts store. They give you most of your money back when you remove them. The light will glow on the tester when the injector pulses.
Here is the L98 starting sequence to help you diagnose your problem: http://corvettebuyers.com/c4vettes/l98.htm
Noid light video:
Here is the L98 starting sequence to help you diagnose your problem: http://corvettebuyers.com/c4vettes/l98.htm
Noid light video:
Thread Starter
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Joined: May 2010
Posts: 50
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From: Flint Michigan
So far....
- Pulled spark plugs, no fuel coming out of cylinders.
- noid tested injector harness. Not lighting up
- tach wire seems to be connected(to distributor) I believe and is registering to the dash 100 rpm when starting.
- Ground wire near left bank front seems correct as I added an additional temporary ground line to the header.
- oil pressure sending unit seems to be right. 1 red wire connects to it as far as I can see. Oil psi reading out on dash as I turn it over.
- fuel pressure checked during cranking. adjusted pressure regulator 35-50 psi with no change other than pitch of clunking in the fuel system.
- clunking when turning key off is in the fuel system as it registers on the fuel pressure gauge.
- noid tested injector harness. Not lighting up
- tach wire seems to be connected(to distributor) I believe and is registering to the dash 100 rpm when starting.
- Ground wire near left bank front seems correct as I added an additional temporary ground line to the header.
- oil pressure sending unit seems to be right. 1 red wire connects to it as far as I can see. Oil psi reading out on dash as I turn it over.
- fuel pressure checked during cranking. adjusted pressure regulator 35-50 psi with no change other than pitch of clunking in the fuel system.
- clunking when turning key off is in the fuel system as it registers on the fuel pressure gauge.
Last edited by Beyond Budget; Dec 1, 2019 at 03:14 PM.
Pro
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From: Wisconsin
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Have you checked the fuses? I'd have to check my FSM, but I am almost certain that there are two fuses that feed the positive side of the injectors. I believe they are INJ1 and INJ2.
Thread Starter
Advanced
Joined: May 2010
Posts: 50
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From: Flint Michigan
The injectors not pulsing and the clunking sound in the fuel system are the only anomalies I can find
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Drifting
Joined: Mar 2013
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From: Venice Cali.
You checked the oil sender orange wire but what about the other sender it is to check oil pressure and if engine dies it cuts off injectors. Some disagree but make sure it is good and connected.
Good Luck
Good Luck
Pro
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From: Wisconsin
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one wire goes to the pressure gauge, the other the fuel pump. The ECM doesn't know what the oil pressure is.
Drifting
Joined: Mar 2013
Posts: 1,952
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From: Venice Cali.
Ok the pump not injectors, so his injectors are shorted out because if the worked before they didn't break, a wire must be misconnected
I will upload a diagram from the manual if you need it.
Good Luck
I will upload a diagram from the manual if you need it.
Good Luck
Last edited by xrav22; Dec 1, 2019 at 09:42 PM.
Pro
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From: Wisconsin
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OP: You could see if theres 12V at the injector with the key in run. If memory serves me, it's the pink wire on the injectors.
Melting Slicks
Joined: Jun 2011
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From: Leland , North Carolina
