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Old 07-26-2009, 11:14 AM
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3.1???

I have a 1991 3.1 gm engine in my camaro,that will not combust?I have tried a lot of things,replaced the fuel pump twice,changed the fuel filter twice,drained all old gas and replaced,new starter,new plugs-cap-rotor-wires,new relays,new pcm-ecm,fuel rail,injectors--probly a few other things also but yet it still will not fire over!!!!You can fire it ny shoving starting fluid within it,but it only lasts for a second ans then chokes itself out again???Anyone have any suggestions????

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Old 07-26-2009, 11:24 AM
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We you need to go to basics.
First check for fuel pressure and spark.
You are missing at least 1.
Throw away the starting fluid, you dont need it and it will only damage something and possibly hurt your troubleshooting. I have seen cars with no spark run on starting fluid.

A few common items if you have no fuel pressure would be a blown fuel pump fuse, bad relay or bad wiring. I would check for power at the relay and work out from there. You should get a priming pulse when you turn the key on. You should hear the pump run and the relay click.

If you have no spark, the module in the distributor is a good place to look. It sounds like you already changed the cap and rotor.

Once you find out what is missing, let us know and we can work from there.
DONT BUY ANY MORE PARTS UNLESS YOU KNOW FOR SURE YOU NEED THEM.
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Old 07-26-2009, 11:32 AM
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Quote:
Originally Posted by Tattoo Timy
Anyone have any suggestions????
Do you hear the fuel pump run for a couple seconds when you first turn the key to "ON"?

It should hum- then stop, this pressurizes the fuel system before starting the engine. If there's no fuel pump noise (this is w/key ON, w/o cranking the engine- just turn the key on, period, and listen), you should check the fuse and relay for the fuel pump as a start.

I believe you have spark- the engine doesn't have enough compression to auto-ignite (aka "diesel") by using starting fluid alone.
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Old 07-26-2009, 11:36 AM
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Quote:
Originally Posted by cobalt327

I believe you have spark- the engine doesn't have enough compression to auto-ignite (aka "diesel") by using starting fluid alone.
ya that is what I thought also. We had a cavalier that would run if you sprayed starting fluid in it. Spend 1.5 hours on it until we determined it had no spark. It was a hard lesson. I always check the conventional way now at the plug with a modified plug as a testing tool.
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Old 07-26-2009, 11:47 AM
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Had a 96 Monte w/3.1- I can guarantee that engine would not run on starting fluid alone. Ask me how I know.

If the OP's pos is so crapped up w/carbon that the CR is now high enough to diesel on SF, he's gonna play hell trying to drive it around w/pump gasoline for fuel.
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Old 07-26-2009, 12:41 PM
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Quote:
Originally Posted by T-bucket23
We you need to go to basics.
First check for fuel pressure and spark.
You are missing at least 1.
Throw away the starting fluid, you dont need it and it will only damage something and possibly hurt your troubleshooting. I have seen cars with no spark run on starting fluid.

A few common items if you have no fuel pressure would be a blown fuel pump fuse, bad relay or bad wiring. I would check for power at the relay and work out from there. You should get a priming pulse when you turn the key on. You should hear the pump run and the relay click.

If you have no spark, the module in the distributor is a good place to look. It sounds like you already changed the cap and rotor.

Once you find out what is missing, let us know and we can work from there.
DONT BUY ANY MORE PARTS UNLESS YOU KNOW FOR SURE YOU NEED THEM.
I have spark,put a noid light on each plug and wire and it lit up?You can hear the fuel pump prime itself each time the key is off then on,checked the psi at the fuel port and was getting great pressure(4.1psi maybe-)even turned the key over when replacing the fuel rail as I had the fuel hoses off and gas poured out of the hose?!
Thanx a million for your input....every lil' bit helps
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Old 07-26-2009, 12:44 PM
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Quote:
Originally Posted by cobalt327
Do you hear the fuel pump run for a couple seconds when you first turn the key to "ON"?

It should hum- then stop, this pressurizes the fuel system before starting the engine. If there's no fuel pump noise (this is w/key ON, w/o cranking the engine- just turn the key on, period, and listen), you should check the fuse and relay for the fuel pump as a start.

I believe you have spark- the engine doesn't have enough compression to auto-ignite (aka "diesel") by using starting fluid alone.
Yes,I can definetly hear the pump prime itself,had a pressure check done and was told that I was getting great pressure and I definetly have spark??
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Old 07-26-2009, 02:33 PM
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If your sure you have adequet fuel pressure (you have checked the fuel pressure?) and spark, then next I have to ask how many miles are on this engine? Next are you sure its in time? Has the timing chain went on it? when did it stop running? and how did it act when it did? Have you performed a compression check?
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Old 07-26-2009, 03:14 PM
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OK, You have fuel pressure, this does not mean you have injection pulse. The injectors have a fused battery source per side, and are grounded by the ECM.

The ECM has an internal 'PROM', or 'EPROM' that retains the 'memory' and adjusts the injection pulse width. This part does not come with a 'rebuilt' computer, and you must use your old one.

To test for a 'bad' PROM, use a test light to check for battery power, back probing(a sewing needle, or stick pin will work) a injector with the key on engine off, looking for the power wire. Now back probe the other wire with a test lead hooked to ground. You should hear a 'click' from the injector at this point, and it should inject some fuel.

Now to make sure you have spark when cranking, Remove a spark plug, and plug it back into the plug wire, and ground the ground strap, or the spark plug threads. You should see the spark arching across the plug while cranking.

If you have compression, fuel, and spark, it should run.

I have recently seen a 1994 3.8L that was pulsing the fuel injectors at 38.4-6 Milli-seconds, essentially flooding the engine with fuel. It was the EPROM at fault. A '89 Camaro RS had no injection pulse, and the PROM fixed it.

Check these two tests, and post back what you find.

We can help!
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Old 07-26-2009, 08:07 PM
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Quote:
Originally Posted by Tattoo Timy
I have spark,put a noid light on each plug and wire and it lit up?You can hear the fuel pump prime itself each time the key is off then on,checked the psi at the fuel port and was getting great pressure(4.1psi maybe-)even turned the key over when replacing the fuel rail as I had the fuel hoses off and gas poured out of the hose?!
Thanx a million for your input....every lil' bit helps
4.1 is not good fuel pressure
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Old 07-26-2009, 08:12 PM
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How many miles on the engine, Sounds like it may have jumped time. Cole
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Old 07-26-2009, 08:19 PM
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I agree 4.1 is not enough fuel pressure. I just gave that a benefit of a doubt towards a typing error.
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Old 07-27-2009, 08:18 AM
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Quote:
Originally Posted by carsavvycook
I agree 4.1 is not enough fuel pressure. I just gave that a benefit of a doubt towards a typing error.
True,the reason for putting maybe behind it is becouse I was not sure of the accurate number??I will definetly try the "prom"test and also check timing.
The engine has 124000 on it.
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Old 07-27-2009, 08:19 AM
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Quote:
Originally Posted by eloc431962
How many miles on the engine, Sounds like it may have jumped time. Cole
124000 miles on it.
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