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starting problem --4.6L in 49 ford
I’m hoping one of you smarter folks can help me with this problem
The background: I have a 2006 Mustang GT 4.6L engine that I have installed into a 49 Ford Convertible. I have completed the wiring (I think) but I can’t get her to start. I have a non-mustang fuel pump but it is connected to the Fuel pump driver module and when I put the key in run I can measure 50-60 PSI going into the fuel rail so I think this is good. I have checked that I am getting power to the coils (only checked one) and I do get a spark in the plug that I checked. I tried removing one side of the fuel rails and injectors, and after hooking back up the FRPT sensor and the injector wires, I don’t get any spray from any of the injectors. This is probably not a good test of the injectors but it was the best I could come up with. Of interest though is that I did spray some gas into the cylinders when the injectors were removed, and when I tried to start it later did get the engine to turn over a few times. In summary—I have good cranking, power to the coils with confirmed spark, good fuel pressure, but I have no way to actually check that the injectors are functioning OK Also, I did re-program the computer to ignore the PATS system. On the first reprogram the starter would not turn so I had my guy recheck the PATS setting and there was a second item that needed to be turned off. When the new program was downloaded the starter functions normally. He tells me that if the starter is turning the PATS system is turned off but I’m still not sure since it seems to me that if I am getting power to the injectors (I do) in start and run, it must be the computer that is not allowing the injectors to function. Only other thing I can think of is that since this engine has sat for 3 years, ALL of the injectors are gummed up—which I think is unlikely. Can anyone help me with just where I go from here? Can anyone tell me how much voltage I should be able to measure at the fuel injector plugs? Thanks in advance Bill |
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Quote:
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Artificial Intelligence is no match for Natural Stupidity Chet |
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I left the Linc/Merc dealer in '99 but I believe the system still works the same. The red wire is the hot (common) side of the circuit. All red wires at the injectors should be hot when cranking and/or running. The other wires go to eight separate (multiport) ground drivers in the PCM. To test injectors for contamination remove the injector and jump in a hot wire to one side and ground the other. (use a small insulated alligator clip so you dont short the wires together in the very tight fit in the connector) You should hear a click every time you ground the neg side. Spray carb cleaner into the injector to verify it is flowing when the electrical circuit is complete.
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I agree, check for plugged injectors. And yes, I would say it's possible for all of them to be stuck after sitting for three years. Hit them with 12 volts like 2-manytoyzs says to make sure.
Otherwise it could be as simlple as a bad ground somewhere. Have you checked for any codes being thrown by the computer? |
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Thanks guys for your answers. I have ordered a set of noid lights to check whether the fuel injector circuits are OK. I do believe that they are. As improbable as I originally thought, after sitting around for three years I suppose that the injectors are fouled. I did try to energize one and could hear absolutely nothing to indicate that the magnetic coil inside was working. If the noid lights confirm that the injector circuits are OK, I'll have my answer
Bill |
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Do you have a wiring diagram for the donor vehicle. You will need to verify all grounds are installed. Injectors will not pulse if the PCM "sees" a TP sensor voltage simulating a WOT condition. This is a strategy built into the PCM. Holding a throttle down at WOT cuts off injector flow to help start a flooded engine. Also a cheap stethoscope will help to find injector issues. Shelf life of todays fuels are 3 to 6 months before it starts to turn to varnish. I just removed fuel from a older car (1975) that had been stored for the last 3 years. Car barely ran on the old stuff, was milky (moisture contamination), and stinks.
Last edited by 2-manytoyzs; 11-18-2009 at 12:23 AM. |
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