Completely lost...
Thread Starter
Intermediate
Joined: Mar 2018
Posts: 48
Likes: 2
Completely lost...
I’m going to try and keep this as short as possible. So here it goes.
I bought an 86 with a rod knock. I drove it into my shop pulled the motor (left the trans in) rebuilt the motor and set it back in. Now I can not for the life of me get it started back up. What I’ve come down to is that I’m getting no fuel through the injectors. My timing is set (the best it can be without it running to actually set it) I’m getting plenty of fire through every plug, I’ve jumped the VATS (and kept it hooked up properly and tried as well) I’m getting plenty of fuel to the rail itself. it’s got compression on all cylinders, I’ve checked my grounds and all seem well. The only thing I can think of is the ECM/ECU. My only problem is that it drove on the trailer and from the trailer into my garage and I took it apart. 0 signs of it being or going bad. Could it have gone bad just sitting there ....? Somebody please help...
I bought an 86 with a rod knock. I drove it into my shop pulled the motor (left the trans in) rebuilt the motor and set it back in. Now I can not for the life of me get it started back up. What I’ve come down to is that I’m getting no fuel through the injectors. My timing is set (the best it can be without it running to actually set it) I’m getting plenty of fire through every plug, I’ve jumped the VATS (and kept it hooked up properly and tried as well) I’m getting plenty of fuel to the rail itself. it’s got compression on all cylinders, I’ve checked my grounds and all seem well. The only thing I can think of is the ECM/ECU. My only problem is that it drove on the trailer and from the trailer into my garage and I took it apart. 0 signs of it being or going bad. Could it have gone bad just sitting there ....? Somebody please help...
Tech Contributor
Joined: Oct 2008
Posts: 3,729
Likes: 190
From: Custer, WI
If you have fuel at the rail, you could rent a set of noid lights from Vatozone which will tell you for sure if your injectors are pulsing. If they are I would assume that your timing could be off just enough that it won't fire.
If they aren't, I'd start with looking at fuses
If they aren't, I'd start with looking at fuses
Thread Starter
Intermediate
Joined: Mar 2018
Posts: 48
Likes: 2
If you have fuel at the rail, you could rent a set of noid lights from Vatozone which will tell you for sure if your injectors are pulsing. If they are I would assume that your timing could be off just enough that it won't fire.
If they aren't, I'd start with looking at fuses
If they aren't, I'd start with looking at fuses
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
If you have a helper, you can you a test light to see if injectors are being turned on. Pink wire should have 12v with key on. The other is the ground side. The ecm grounds injectors to turn them on. If clamp it on + terminal the probe it can be used to look for pulse signal. You will want to check multiple injector connector. If the injectors are being pulsed the distributor may 180 degrees out.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
You have it set up to look for voltage Injectors are in two groups of 4. Each are fused. If the test lamp is attached to the positive terminal now lamp will light when probe is grounded. ECM grounds injectors to turn them on. So if you touch probe to the injector connector when engine is cranked one side should blink.
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Thread Starter
Intermediate
Joined: Mar 2018
Posts: 48
Likes: 2
Check the ECM for Code 46. If = YES, this is a VATS problem. The ECM did not receive a valid fuel-enable signal from the VATS module.
To check the injectors. Key = ON, there should be +12 V on one of the terminals on each injector. IIRC, the pink wire. If = YES, put your test light or meter between two terminals on the SAME injector connector. Crank the engine. There should be a change in the voltage as the ECM pulses the injector to ground. If there is NO change in voltage while cranking, no pulses were received. See "Code 46" above.
Have you tried starting fluid? If it fires, at least you know you have spark and the basics other than fueling are correct.
To check the injectors. Key = ON, there should be +12 V on one of the terminals on each injector. IIRC, the pink wire. If = YES, put your test light or meter between two terminals on the SAME injector connector. Crank the engine. There should be a change in the voltage as the ECM pulses the injector to ground. If there is NO change in voltage while cranking, no pulses were received. See "Code 46" above.
Have you tried starting fluid? If it fires, at least you know you have spark and the basics other than fueling are correct.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
Is distributor 4 wire connector(EST) plugged in? The purple wire in connector is for the reference signal for ECM to turn on injectors. If you touch harness side on connector terminal with a test light attached to positive battery post. When the probe is taken away you should hear injectors click. Do you have factory service manuals?
Safety Car
Joined: Sep 2004
Posts: 3,953
Likes: 550
From: Mission Viejo CA
What is your fuel pressure at the rails when you initially turn on your key, and while you are cranking the engine? How long does your fuel pressure stay high after you stop cranking the engine? Are your plugs wet or dry after you have attempted to start the engine?
Safety Car
Joined: Sep 2001
Posts: 4,157
Likes: 554
From: Glenbeulah Wi
One more thing, you must crank the engine to see if the negative side of the injector drops to zero, if you tested when it was not cranking both sdes will have power. That is why people are suggesting that you use a noid light between each connection on one injector to see if it flashes while you crank the car.
Last edited by bjankuski; Apr 6, 2018 at 09:34 AM.
Thread Starter
Intermediate
Joined: Mar 2018
Posts: 48
Likes: 2
Thread Starter
Intermediate
Joined: Mar 2018
Posts: 48
Likes: 2
That means the computer is not grounding the injectors. To make the injectors fire.the ground side must be grouned, otherwise it will read power on both sides of the plug since the other three injectors on that side are still hooked up. Check for a vats code or trace the injector wires to the computer and make sure they are a complete circuit and did not breat while you were pulling the engine.
One more thing, you must crank the engine to see if the negative side of the injector drops to zero, if you tested when it was not cranking both sdes will have power. That is why people are suggesting that you use a noid light between each connection on one injector to see if it flashes while you crank the car.
One more thing, you must crank the engine to see if the negative side of the injector drops to zero, if you tested when it was not cranking both sdes will have power. That is why people are suggesting that you use a noid light between each connection on one injector to see if it flashes while you crank the car.
Thread Starter
Intermediate
Joined: Mar 2018
Posts: 48
Likes: 2
Thread Starter
Intermediate
Joined: Mar 2018
Posts: 48
Likes: 2
and also, I couldn’t imagine them all being stuck?
Thread Starter
Intermediate
Joined: Mar 2018
Posts: 48
Likes: 2
Is distributor 4 wire connector(EST) plugged in? The purple wire in connector is for the reference signal for ECM to turn on injectors. If you touch harness side on connector terminal with a test light attached to positive battery post. When the probe is taken away you should hear injectors click. Do you have factory service manuals?
Thread Starter
Intermediate
Joined: Mar 2018
Posts: 48
Likes: 2
You have it set up to look for voltage Injectors are in two groups of 4. Each are fused. If the test lamp is attached to the positive terminal now lamp will light when probe is grounded. ECM grounds injectors to turn them on. So if you touch probe to the injector connector when engine is cranked one side should blink.
