Getting aggrivated with my Gen I not starting.... Maybe my ECU?

-FROG-

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Some of you have been keeping up and helping me out and I greatly appreciate it. My car stopped running out of the blue back in December and I had it towed home. Thinking it was my fuel pump, I yanked out my tank, fuel pump, etc.. Then later discovered I had a "cooked" wire from a bad connector in the 50 pin bulkhead connector in passenger foot well - to under the heater blower fan in the engine compartment.

SO, I repaired the burned wire today (I didn't see anywhere where it grounded out or shorted to anything, it had a rubber boot around it so the wire was isolated safely, so I was skeptical about it being the actual problem and more of, "part of the problem").

Here is what the problem/issue is... My car will not start BECAUSE the fuel pump is not getting the voltage/signal it needs to turn on. The fuel pump does NOT prime when I turn the key and the Schroeder valve does not release any pressurized fuel, because none builds up. I have replaced the fuel pump relay in the trunk and all the relays under the heater core (fan/AC/starter, etc...) and double checked the pump itself by applying voltage from a battery charger for a split second.

The wire that was burned.... (I TRACED IT FROM END TO END). It's a grey wire, about a 12 or 14 gage wire. It begins at the Alternator with a few other wires in the same bundle. It runs from the alternator, down to the row of relays, under the heater blower fan and then into the bulkhead connector next to the relays. This is where the wire burned and from the looks of it, it burned because the connector was not allowing a good connection, to the constant arching/sparking made the wire get HOT and burn off all the insulation. Like I said the wire was NOT touching anything else, so in theory, the wire should have still been working as it should, except that pin out on the connector was melted and distorted so the connector may have not been connected. After the bulkhead connector, the gray wire runs behind the dash and then Back up into the engine bay and over to the LARGE red wire that is the main battery wire on the drivers side of engine, where you can connect a battery charger. There is a fusible link and I confirmed it's ok as well as all of the other fusible links in that area.

I don't think it would be the crankshaft sensor, because the pump never even primes when the key is turned, so I ruled this out.

I know this is alot to read and follow, but I think my next step should be to replace the ECU, however they are hard to come by I know. I'll probably call A.R.T. tomorrow and see if they have one I can borrow for testing.

I'm going to post this on both boards simply because I am running out of ideas and growing tired of getting nowhere. I troubleshoot electronic products for a living and I have done tons of mechanic work and built hot rods, so I'm no newbie and I ALWAYS try to do my own work, unless I have to take it to a shop, it's just the way I am. Any thoughts and ideas are appreciated.
-The frustrated -FROG-
 

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No clue Frog...but I hope that this gets resolved quickly. The Viper Round Up is in a month and we have to get you up and running by then ;) Still have your soft top...
 

mbccenter

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Have you tested the wire that got hot to make sure there is a connectoin from one end to another? What is that wire for?
 

PSilverGTS

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Not sure about th eGen 1s, but the Gen 2s fuel pump is shut off by the alarm and has to be reset to get the fuel pump to work again. Also make sure you have a good fully charged battery, Vipers do odd things with weak batteries. Not sure about that burned wire, you could call the Viper Wizard, he knows all.
 

Tom F&L GoR

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Test for power at the pump - the power should be supplied all the time the key is on. It is the ECU closing the connection to ground that makes it turn on.

If you get power to the pump, you could temporarily connect the other side to ground to see if the pump will run. You can ground it using the wire entering the ECU. Don't leave it connected to ground, big safety issue, obviously.

If that lets you start it, then it does seem like the ECU isn't making the switch to ground.
 
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-FROG-

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Not sure about th eGen 1s, but the Gen 2s fuel pump is shut off by the alarm and has to be reset to get the fuel pump to work again. Also make sure you have a good fully charged battery, Vipers do odd things with weak batteries. Not sure about that burned wire, you could call the Viper Wizard, he knows all.

My alarm has been reset many times, as I have had my battery disconnected and keeping it charged too. People keep telling me to call the wizard, but it would be like me calling one of you, saying.... My car won't start, do you know why? I need more debugging and what not before I call him, if I need to. Thanks though.
 
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-FROG-

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Test for power at the pump - the power should be supplied all the time the key is on. It is the ECU closing the connection to ground that makes it turn on.

If you get power to the pump, you could temporarily connect the other side to ground to see if the pump will run. You can ground it using the wire entering the ECU. Don't leave it connected to ground, big safety issue, obviously.

If that lets you start it, then it does seem like the ECU isn't making the switch to ground.


There is no power at the connector that plugs into the pump. If the ECO is the direct power source for the pump, then that may be the problem.... Howecer, I'm worried that the "Automatic Shut Down" may be causeing the pump to NOT recieve power. I am leaning towards the ECU too... I KNOW the pump works... I tested it when out of the tank so I still think the power source to the pump is not coming on ei...ECU.
 

dansauto

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My alarm has been reset many times, as I have had my battery disconnected and keeping it charged too. People keep telling me to call the wizard, but it would be like me calling one of you, saying.... My car won't start, do you know why? I need more debugging and what not before I call him, if I need to. Thanks though.

like i said on the alley, get a wiring dia and trace the wire from the ECU to make sure its not open/broke. then check to see that there is voltage out of the ecu when switched on.
 

97 B/W GTS

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I Have a GTS. I was just going thru the same thing. Wouldn't start. New battery, no fuel pump prime sound, no fuel pump relay click, swapped the ASD relay with another, reset the alarm many times, no spark at the plugs...no start. Turned out to be a bad PCM. Try swapping with one that works. Your burnt wire may just be coincidental??
 
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-FROG-

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I Have a GTS. I was just going thru the same thing. Wouldn't start. New battery, no fuel pump prime sound, no fuel pump relay click, swapped the ASD relay with another, reset the alarm many times, no spark at the plugs...no start. Turned out to be a bad PCM. Try swapping with one that works. Your burnt wire may just be coincidental??

I will look into this too. I built a race car a few years ago and had the same type issues I'm having now... It was the ECU in that car too... This will definitely be on the list of "next steps"...
 
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-FROG-

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LATEST UPDATE........

I bypassed the fuel pump relay, so the fuel pump had power and it was totally obvious it was spinning and building pressure. I checked the Schroeder valve and fuel shot out nicely, so good pressure.

I then tried to start the car, to get rid of the excess pressure in the lines and the motor just spun... I then applied power to the fuel pump and then tried starting the car once again and still no start.

This is telling me the computer may not be working to allow the car to start, although it is getting fuel.

Also I checked the injector wires (2 wires per injector) typically one would be power and the other ground............ but both wires registered as GROUND. Is this normal? Maybe the computer sends a ground signal to both wires, until it operates properly?

I think I'm going to start looking for another ECU for testing...
 
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-FROG-

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hmmmmmmmm My PCM is making a very high pitched whine, when I turn the key to the on position. Can one of you go out in your garage and see if your PCM makes the same high pitched whine?

It's like a TV thata on in another room.... you know, that high frequiency that drives you nuts....

I'm wondering if that is a fried diode oscillating.....
 

Tom F&L GoR

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Sounds like you'll find an ECU to try. But both the pump and injectors always get 12V supplied to them whenever the key is on. There is no on-off action of the supply. The ECU turns them on and off by connecting the other wire to ground. If you weren't getting power to the pump, then the problem is outside the ECU and somewhere in the wiring, key, or relay. I didn't look in the service manual, but all the injectors get power supplied to them all the time and they fire individually when the ECU momentarily grounds the second wire.

I'm only trying to clear this up since it sounds like you might have a ways to go to fix it and I'm a little concerned that a new ECU won't cure everything. Hiope it does, though.
 

dansauto

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LATEST UPDATE........

I bypassed the fuel pump relay, so the fuel pump had power and it was totally obvious it was spinning and building pressure. I checked the Schroeder valve and fuel shot out nicely, so good pressure.

I then tried to start the car, to get rid of the excess pressure in the lines and the motor just spun... I then applied power to the fuel pump and then tried starting the car once again and still no start.

This is telling me the computer may not be working to allow the car to start, although it is getting fuel.

Also I checked the injector wires (2 wires per injector) typically one would be power and the other ground............ but both wires registered as GROUND. Is this normal? Maybe the computer sends a ground signal to both wires, until it operates properly?

I think I'm going to start looking for another ECU for testing...

As tom said with the key on the injectors will have power all the time and ground when firing, but only when the car is cranking. You need a noid light to check and see if the injectors are seeing voltage. Did you put a scan tool on to check and see if there is a crank and cam sensor reading? If you have fuel and compression then you are missing spark.
 
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-FROG-

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Sounds like you'll find an ECU to try. But both the pump and injectors always get 12V supplied to them whenever the key is on. There is no on-off action of the supply. The ECU turns them on and off by connecting the other wire to ground. If you weren't getting power to the pump, then the problem is outside the ECU and somewhere in the wiring, key, or relay. I didn't look in the service manual, but all the injectors get power supplied to them all the time and they fire individually when the ECU momentarily grounds the second wire.

I'm only trying to clear this up since it sounds like you might have a ways to go to fix it and I'm a little concerned that a new ECU won't cure everything. Hiope it does, though.


Thanks for the advise... My fuel supply is getting nothing like it should out of the PCM... which is way before all the relays and such. I checked the voltage on the injectore and they only get about 2 Volts and I think they are suposed to get 8+ volts. The way my PCM is whining, it just doesn't sound right..... I hate to spend money on a another one and it NOT be the problem, but everything else checks out ok. Crank/cam/MAP sensor only effect when the car is running... With my problem, the car is not getting power where it is needed to start. I have checked all the wires from my radiator to the trunk and the only problem was that burned wire, which I fixed now and still same problems... Thanks for the help!!! :)
 
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-FROG-

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As tom said with the key on the injectors will have power all the time and ground when firing, but only when the car is cranking. You need a noid light to check and see if the injectors are seeing voltage. Did you put a scan tool on to check and see if there is a crank and cam sensor reading? If you have fuel and compression then you are missing spark.


I see... thank you. Problem is... I don't have fuel... Shouldn't you be able to probe the injector wires with a volt meter to see the voltage being supplied? Thanks for the information!!!
 

dansauto

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I see... thank you. Problem is... I don't have fuel... Shouldn't you be able to probe the injector wires with a volt meter to see the voltage being supplied? Thanks for the information!!!

??/You have fuel if it is coming out the schrader valve. You may not be firing the injectors, the cam postion sensor also controls those as well as spark. hence my questions about checking to see if it is putting out a signal. Also a scan tool will quickly tell you if your PCM is messed up. no dont be probing those wires, use a noid light, they are cheap and easy to use. You install them then crank the car, if they blink they your injectors are working and your cam sensor is working.
 

TS6

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??/You have fuel if it is coming out the schrader valve.


He only had fuel because he hotwired the pump. The ecu is not powering the fuel pump on its own.

I'd buy an ECU, and if that doesn't fix it, sell it, or keep it for a spare.
 

paul fettig

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You mentioned the cam sensor only affects operation of the car when engine is running. I have a GMC with the 8.1 liter and one day the truck would not start. Finally after 15 times of turning the key off and on , it started. Turned out to be a cracked cam sensor.
 

TS6

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Unless the Viper is different from every other car, the cam sensor isn't needed for the car to run, just for it to start.
 

dansauto

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He only had fuel because he hotwired the pump. The ecu is not powering the fuel pump on its own.

yes, but I assumed he left it hot wired and tried to start the car. if the internal rails had some fuel and the injectors were firing it should have at least stuttered a little when he cranked it even with the pump not working.

and if he has a short some place he could end up damaging the replacement PCM.
 
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-FROG-

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He only had fuel because he hotwired the pump. The ecu is not powering the fuel pump on its own.

yes, but I assumed he left it hot wired and tried to start the car. if the internal rails had some fuel and the injectors were firing it should have at least stuttered a little when he cranked it even with the pump not working.

and if he has a short some place he could end up damaging the replacement PCM.

Yes, I did also "hot wire" the pump for a brief second and the car still did not start... I assumed it would "shutter" too, because of the amount of pressurized fuel in the rails and obviosely I do have air.... so yes, in theory, the third component I would be missing is spark. When I tried this test, it didn't do anything whatsoever. My thought is, whatever is causing me to NOT get fuel, is ALSO causing me to NOT get spark. The PCM controls all of that and that terrible whine coming directly from the ECU talls me something is wrong with it. Also I don't know where I would get a scan tool and how much it would cost.

I have not checked the crankshaft sensor.... but how would that effect the turning of the key, to the "on" position and not allowing my fuel pump to "prime"? I think the problem is deeper than the crank sensor. It just doesn't deem logical that that, sensor, with no motion would cause so many problems. Or would it? And if it would... how?

I agree on "and if he has a short some place he could end up damaging the replacement PCM." but I have been through all the wires a few times and see nothing that is causing a short.
 
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-FROG-

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Unless the Viper is different from every other car, the cam sensor isn't needed for the car to run, just for it to start.

But is it needed for the fuel pump to prime, before the motor is even turned on?
 
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-FROG-

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You mentioned the cam sensor only affects operation of the car when engine is running. I have a GMC with the 8.1 liter and one day the truck would not start. Finally after 15 times of turning the key off and on , it started. Turned out to be a cracked cam sensor.

Did your fuel pump prime before, or when you tried to start it? Also, did it "try" to start any at all, like choke and burp a little or did the motor just spin (my motor just spins). Do you remember if you could smell fuel any at all?
 
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