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Discussion Starter #1
OK We finally got the buggy ready to start. I got a fuel pump hooked up through the relay and we have an ignition. It just wont crank. I have a spark. I THINK I have power to the computer. Not sure what to do. Maybe a ground needs to be connected. Any suggestions?

Travis
 

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Definately make sure you have a good ground! Depending on how the engine is mounted and transmission is mounted it may not have a good ground and the starter uses the engine as a ground. Engines usually have a grounding strap goin from one of the heads to the fire wall or frame or body somewhere. Power to the computer would be good too. Can't start with out fuel!
 

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if it wont crank how do you know you have spark? i assume you mean it wont idle? are you able to pull codes from the ecm? do you have some sort of check engine light? what year engine?
 

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Discussion Starter #4
Moxj85: I ahve the strap from the heads mounted to the frame. Is there any other ground.

pfco3: It will turn over but not crank. It will spark by turning it over. It is a 96 out of a truck. It is a comp buggy so there isnt a check engine light.

It dont even act like it wants to crank. How do I check to see if there is power going to the injector? Is there a seperate ground for the computer?

Travis
 

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it needs the check engine light or it will go into limpmode. and there are grounds in the computer harness. high 5 did the exact swap about a year ago. he will be on the board in a couple of hours. mike
 

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I might be wrong on this one but you need to have a check engine light. because it supplys a power to the PCM. I'll go look in a manual to be sure. To check for injector pulse use a noid light, if you don't have one you can use a test light it just wont be as accurate due to reistance reasons.
 

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Discussion Starter #11
OK I have been playing with it for awhile and I get a noise coming from the throttle body area both when I turn the switch on and off. So I ASSUME that the injectors are working. I have what appears to bee a connector that would go to the inside of the vehicle with alot of prongs. I have grounded the wires that are black/white but no good yet. With so many wires being the same color, it is hard to determine which ones do what.

Travis
 

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Discussion Starter #15
heep86 said:
the noise you hear is the iac (idle air control motor) spray it with some starting fluid, if it starts, then you have no fuel. you say you have spark, this means your computer is on. check the fuel lines, i have hooked them up backwords before, try the starting fluid!
Not being argumentative but I thought that if you sprayed anything, whether gas, starting fluid, etc., in a fuel injected motor that it could blow a cylinder. And a buddy had a 302 fuel injected motor that would spark without power on the computer. Now gm may be different. I dont know.

Travis
 

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you do not need a check eng. light. i do not run one. i have the wire available but i do not run the check eng light. you will need to wire a light in line to the exciter wire for the alt. your alt will not charge without the light. GET A FSM FOR THE DONOR RIG!!!!!! you need the detailed schematics.
 

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Discussion Starter #17
OK I must be missing a ground somewhere. I tested the injectors and the positive side is hot but there is noting when I turn it over. The light doesnt light up. I would think that I dont have the vcm grounded but the fuel pump is working. Is there any place else that needs to be grounded.
 

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i assume you have checked all the grounds coming off the ecm right? you probably have just 1 or 2 grounds off the ecm. this is kinda hard without schematics. if i was you i would go to alldatadiy.com (not sure of that address) and triple check all your wiring. trust me its worth the 20 bucks to get a really good basic wiring diagram or 2. it sounds to me like you either wired something wrong or something worse:(
 

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rockcrawl said:
I tested the injectors and the positive side is hot but there is noting when I turn it over.
I think that whatever is powering the injectors is hooked up to an ingintion-hot power source, not a permanently-hot power source, based on this scentence.

In other words, you know how your radio loses power while cranking the motor? Well, lots of OTHER circuits in the rig will lose power while the ingnition switch is in the START position too. This sends more of the available juice to the starter.

A buddy of mine had his ingition system hooked up this way. Kept assuming he was flooding the carb... what was really happening was that as soon as you tried to start it, there was no spark. Once we figured this out he tried giving the motor brief bumps with the key over&over so that it was still spinning when the spark plugsgot power. Worked like a charm until he got home after the ride that weekend and re-wired the ignition to a switched power source that still had power when starting the motor.

Something to keep in mind. :)
 

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rockcrawl said:
OK I must be missing a ground somewhere. I tested the injectors and the positive side is hot but there is noting when I turn it over. The light doesnt light up. I would think that I dont have the vcm grounded but the fuel pump is working. Is there any place else that needs to be grounded.
are you saying that you loose power tot he injectors when you crank it? you should always have power to the injectors with the key in the run position and the vcm grounds the circuit to make them fire/spray.
 
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