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in need of help

2687 Views 21 Replies 5 Participants Last post by  bberry09
Well i changed my valve cover gasket on the passenger side, put a new vaccum pump on, and replaced my fuel filter. I took my batteries out and had them charged. I found that i have red wire and black wire still unhooked and dont know where they go. I have a wire running to the alternator. Does one go to the vaccum pump? And i have a wire unplugged coming from the fuel filter. I know one goes under the fuel water seperator but idk where the other goes. I looked on ebay for a shop manual and found a 1993 but idk if it be the same on my 90. Can anyone help
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None of the wires at the fuel filter will keep the truck from starting & running if they're not hooked up, so ignore them for now. Same goes for the battery & engine lights. The first thing you need to do is ensure all the air is out of the filter & header. Remove the cap from the Schrader valve on the filter header and depress the core while someone cranks the engine over. You're looking for a good spray of fuel to come out, with no air. Don't crank for more than about 15 seconds at a time, and let the starter cool for about 2 minutes in between.

Once you've verified the majority of the air is out of the system, turn the key to "run" and check for power at the fuel solenoid on the injector pump. IIRC it's the forward connector on the driver's side of the pump, it's nice & peaceful outside now and I don't want to disconnect it and make noise cranking to find out. Anyway, either check for power using a test light or remove and reconnect the connector with the key on. If you get a spark and hear a click, the solenoid is OK. Start the engine in the normal manner, it may sputter and miss or die due to residual air in the lines. I like to rev mine up to 1200 or so to get the air out more quickly.

If you don't hear a click then jumper directly from the battery + terminal to the solenoid and listen for the click. If you don't get a click now, the solenoid is bad. If you do get a click, check the wiring between the ignition switch and fuel solenoid.

Once you get it running you can troubleshoot the warning lights and find where those wires go. IIRC there are a total of 4 wires that go to the alternator - a heavy gauge (12 or 10) red, heavy gauge black, and a connector with 2 14 or 16 gauge wires that I think are orange and white. They may not be in the connector, though.

The ENGINE light comes on for low oil pressure, high coolant temp, or a short anywhere in the switches or wiring. It's a known trouble spot with these engines; mine has been on for well over a year, with the coolant temp gauge pegged high, but I know it's inaccurate and keep telling myself I'll repair it someday. IIRC an open in the oil pressure switch circuit or a closed coolant temp circuit turns the light on.
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Is it cranking? How quickly? The absolute minimum rpm during cranking should be around 250. If you can count individual turns on the engine it's cranking too slowly. Did you have the batteries load tested as well when they were charged? The 7.3l starter draws around 400A. Are you getting any white smoke that smells strongly of diesel fuel from the tailpipe during cranking? Do the glow plugs come on? Watch the voltmeter, it should be down at around 10V when the plugs are on.
Then I'd loosen half the injector line nuts and crank 15 sec/cooldown 2 minutes till you see good spurts of fuel from the nuts, then tighten them down and it should start right up. It may even start & run on the 4 you don't loosen once enough air gets out of the lines.
Oil pressure sender, turbo oil feed or drain, valley pan gasket, or valve cover gasket, those are the biggies.
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