Join Date: Mar 2000
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A Strange EngineProblem
Last Monday morning, after a problem free night of wheeling, Poison Spider Mesa in Moab, I went to start the 5.0, and it wouldnt jump to life. It cranked over fine, I could here the fuel pump whirrring but not fire. This all after a 1000 miles of good performance and hundreds of trouble free engine start ups. This engine usually doesnt take more than a second or 2 on the key to fire it up, in any condition.
I checked the coild and sure enough there was no spark, well naturally I suspected it had to be some of my electrical work. So I started checking everything. But I was getting good voltages at the coil, and I had 12v present at all computer power inputs. I was getting annoyed, and it was time to get out on the trail, but I couldnt find any problem. I told my freinds to hit the trail and I called the local parts stores and went down and picked up a TFI module and a new Stator module, I removed the distributer and replaced both modules, fought with the oil pump drive shaft until I finally accidentally pulled it out of the pump and heard it fall into the oil pan. So I put the distributer back in and tried to fire it, and.... still no spark.
I went back to my manuals from Ford Racing, and just happened to notice I picture of the EEC Power Relay, and could not recall installing one into the socket provided. they had conveniently supplied the Fuel Pump relay and wide open throttle relay, but I still couldnt recall seeing the EEC power relay, so I pulled out the computer from behind the glove box, and low and behold,..."no relay".
I had never been able to get the fuel pump relay to work propperly from the start so I had rigged, my own pump relay off of the ignition switch, and had not thought anymore about it.
So I went back to town and purchased a 12 dollar EEC power relay, but didnt think it would make any difference since I have been running without it for months, plugged it in and whaaaala the engine fires right up(although i shut it right off due to no oil pressure). I also picked up a oil pump shaft at the parts store,, so I dropped the pan installed the new shaft, applied a shload of silicone to the oil pan gasket and main seals, bolted it back up, filled it with oil and went wheelin. It has ran great since, and the Ford Harness fuel pump relay now works(which is nice because it shuts off the pump after pressurizing if the engine isnt started right away).
How could it have ran for so long if the EEC power relay is neccessary for the engine to run?
Why did it not start after running so long, if the EEC power relay, is not neccessary for the engine to run?
I wonder if it recieved some signal from the computer that required a reset signal that could not be generated without the relay? Very confusing, the techs at Ford dont think it should have ran without the relay. No other changes in engine performance were observed.
Anyone care to try to hypothysize on this electrical conundrum?
Wow, you can get a nice tan on your arms, from welding with no shirt on.