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Old 09-19-2005, 09:12 PM
justa3.8 justa3.8 is offline
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Default No fuel pressure.

Hello,I parked my 86 GN about 1 year ago after breaking the crank sensor bracket. Ready to get it back on the road I have replaced the crank sensor and bracket. Got as much of the old gas out of the tank and added 10 gallons to it. Have changed the plugs and getting fire to all 6. Tried to start the car, would not start. Put some gas in the throttle body and it fired right up, but only ran for about 10 sec. or long enough to burn the gas I had put in the throttle body. I did this about 4 times and still would not run. When I turn the switch on never did hear the relay up front come on. Unpluged the hood light pluged into test relay connector. Now I can hear the relay come on when I turn on the switch but the car still will not start. So I put some more gas in the throttle body ran same as before, about 10-15 sec. but this time I did hear the turbo spool, not sure why but the turbo never did spool when I did not have the test relay pluged up. Not sure what is going on here. Fule pump?,fule pump relay?, maybe something else? I am lost. Car ran like a top when I parked it. Should not have let it set so long. Maybe someone has had this problem and can help me out.Thank you in advance for your time.
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Old 09-19-2005, 09:49 PM
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Exclamation Re: No fuel pressure.

Uh...if the car is idling, your turbo will definitely not be doing any 'spooling'. It takes a lot of fast exhaust flow to get it to 'spool'. Wait until the car is running and warmed up.

If you have the intake tract open, the MAF will not be reading any signal. I'm surprised if it would run at all. Try disconnecting the MAF sensor electrical connection if you want to see if it will run all opened up like that. It will run, but not optimally.

Otherwise, try putting it back together first.

If you are not getting any pump prime, your pump relay may have failed or you may have a blown fuse.
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Last edited by Keller; 09-19-2005 at 09:52 PM.
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Old 09-19-2005, 11:41 PM
justa3.8 justa3.8 is offline
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Default Re: No fuel pressure.

The turbo did spool because I was giving it gas to try to keep it running. The first 4 times I tried I did not have the test relay wire hooked up to the hood light wire the turbo did not spool then. Anyway the problem I have is with fuel. I am taking the hose off the front of the intake, then pouring a little gas in. I put the hose back on the intake before trying to start the car. It will run but only long enough to burn the gas I have put in the intake. It is not getting any gas from the tank. If the wire that goes to the hood light is plugged into the relay test wire I can hear the relay come on before and after trying to start the car. If I do not have the wire plugged in the relay does not come on at all. Also when I have the hood light wire plugged in the chime (for example the alarm you hear when you open the door) never goes off when trying to start the car. Sorry but alot is going on that is hard for me to explain.
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Old 09-20-2005, 02:15 AM
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Lightbulb Re: No fuel pressure.

http://www.gnttype.org/techarea/images/wiring.gif

If you have the wire described under power (via the hood light connection), the pump should be on all the time and should be audible. Even if the engine is off. See the diagram. However, there are still two fuses that must be good for the fuel injection and igniton circuits to work. If the pump is not on continuously before you stick a key in it, there is another problem. The fuses may be blown. I don't think the relay needs to be functional in this scenario, but I know when I use this method for fuel change out, my relay gets activated. So yours should be getting kicked as well.

You state that the relay is activated. Can you hear the pump run as well? Is the wire harness at the tank connected?

The chime noise should be ignition circuit related and not fuel circuit related. Perhaps that is a sign of a blown fuse.

And, not that it is relevant here, but I consider a 'spooled' turbo to have been spun up enough to where it is actually generating boost and not just idilly spinning because the engine happens to be running. It doesn't sound as if your engine has been running long enough at one sitting to drop the car in gear and run it up hard against the converter.
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Old 09-20-2005, 09:47 AM
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Default Re: No fuel pressure.

Electronics issues aside, if the car has been sitting for a long time then there is a really good chance that the fuel pump is gummed up and isn't pumping the proper pressure and volume, if it's pumping at all.

I would check to see if you are getting the correct fuel pressure and flow at the rail.

Doc
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Old 09-20-2005, 10:11 PM
justa3.8 justa3.8 is offline
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Bang Head Re: No fuel pressure.

Can not hear pump running. Wire harness is connected. Have not checked fuel pump to see if it is gummed up. Checked all fuses in fuse box, all ok. Any fuses at other locations besides fuse box? Not sure what fuses to check other than what is in the fuse box. I do not know how to check pressure or flow at the rail. I would assume the fuel injection and ignition circuits work as it will run as long as I put gas in at intake, after it burns the gas up I put in it dies. I am plugging the hood light wire into a connector that was unplugged just under the altenator. Is this the correct plug for testing the fule pump? Why was it unplugged? It is the only one the hood light wire would fit into that I could find. But it was allready unplugged. Thanks for any help, I need it.
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Old 09-20-2005, 10:27 PM
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Default Re: No fuel pressure.

I'm not experienced with GNs specifically, so understand that this advice is based on my experience with various other cars...

If you can hear the fuel pump running then you know that the fuel pump is getting power. Therefore you don't need to worry about fuel pump fuses. You know they're good.

Here are some things I would check:

1. Make sure the injectors are getting power. That means checking the fuse(s) related to fuel injection and the ECM. You can also get test devices called "noid lights" that light up when an injector fires. They are pretty cheap and you should be able to buy a set or maybe borrow a set from an auto parts store. That will allow you to verify that your injectors are getting power.

2. If the injectors are getting power, they could be stuck closed...but I find that unlikely. Maybe one of them would be stuck, but then the engine would still run, just rough. Again, unlikely.

3. The fuel pump might be putting out low pressure or volume--in other words, it could be running, but not well enough. You can hook up a pressure gage to the fuel line at the rail and check to see if it is giving you the correct pressure. There is also a "volume/flow rate" test. To do this, you disconnect the gas line at the rail and point the end into a measuring container. Then turn the ignition to "on". The fuel pump should deliver a minimum amount of gas in the few seconds that it runs. I don't know the specific pressure/volume numbers to look for, but maybe someone else can chime in about that....or get a Chilton's or Hayne's manual. They usually describe how to do this. If the volume and/or pressure isn't right, then you may need to replace the fuel pump, fuel pump wiring, regulator, or filter.
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Old 09-21-2005, 12:54 AM
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Question Re: No fuel pressure.

Quote:
Originally Posted by justa3.8
Can not hear pump running. Wire harness is connected. Have not checked fuel pump to see if it is gummed up. Checked all fuses in fuse box, all ok. Any fuses at other locations besides fuse box?
There are two connectors. The green one is a tap for a tach. DO NOT USE. There should be a black one that is the fuel pump test lead. That is the one to use.

When you hit it with power, you should hear the relay click (it is under the hood) and the pump run (it is in the rear of the car, inside the tank). Note that your fuse for the hood light must not be blown, either.

You have already said the pump is not running. That may indicate you are hooking it up to the wrong circuit, the relay is bad, you have no power on the hood light circuit (i.e. blown fuse), or there is a fault in the wiring.

Having a voltmeter would not hurt right now.

Are you on the right connector?

Do you have power for the hood light? Is the fuse good? (Might be the signal light or interior light circuit)

Do you hear the relay click when it is connected?
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Old 09-21-2005, 06:44 PM
justa3.8 justa3.8 is offline
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Default Re: No fuel pressure.

Using the black connector plugged into the hood lamp wire I do hear the relay come on before and after trying to start the engine. When trying to start door chime goes off continously, also boost and rpm gauges are maxed out. It does this with the test wire and hood lamp wire plugged in, when not plugged in it does not. The fuel gauge is also past full mark with only about 10 gallons of gas in the tank.. No sound from fuel pump or tank. Still troubleshooting. Thank you all for the help.
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Old 09-22-2005, 02:10 AM
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Question Re: No fuel pressure.

If your gauge is off the scale, your pump is not connected. Check the connector between the rear bumper and tank that leads to the pump. It is probably open. Or that circuit is.

Is the tach maxed out ONLY with the pump connector hooked up? (Hard to understand from description) If so, you may actually be on the tach connector. Can you post a pic of the connector/wire? It should have a black connector and grey wire, I belive. Tach should be green with a white wire.
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