cold start issue
#1
cold start issue
ok so i have had my 98 disco for a few months now and have had no problems but yesterday i was leaving work and my ruck started then died.after srating its and i dieing for a hour it finaly stayed running no lights in he dash are present so im confused it has 4.0 and its a auto,thanks for any help im in desperate need
#2
#3
The no lights in the dash point to something that does not throw a code when failing at start.
Low fuel pressure (clogged filter, fuel pump problems, fuel pressure regulator bad or vac hose off/leaking) could be one. The fuel pump will only run for say 30 seconds if the engine does not start. There is a test valve on the passenger side fuel injection rail (looks like a tire valve). With pump running, pressure should be in the 32-34 PSI range. Side of the road test is depress the center pin in the valve with a something and have rag around it to catch fuel. You can also use a tire gauge to check pressure. If no fuel can be fuse, fuel pump relay, inertia switch on firewall (push top to reset), fuel pressure regulator, vac hose to regulator, fuel filter, fuel pump.
The crank position sensor is another, and frequently it also causes the truck to die when warmed up. If it is the culprit, there won't be any spark, and that can be confirmed by removing a spark plug wire, attaching a spare 99 cent spark plug, and lay it on the exhaust manifold. Crank truck, and some one check for sparks. Do not hold plug while doing this.
Low fuel pressure (clogged filter, fuel pump problems, fuel pressure regulator bad or vac hose off/leaking) could be one. The fuel pump will only run for say 30 seconds if the engine does not start. There is a test valve on the passenger side fuel injection rail (looks like a tire valve). With pump running, pressure should be in the 32-34 PSI range. Side of the road test is depress the center pin in the valve with a something and have rag around it to catch fuel. You can also use a tire gauge to check pressure. If no fuel can be fuse, fuel pump relay, inertia switch on firewall (push top to reset), fuel pressure regulator, vac hose to regulator, fuel filter, fuel pump.
The crank position sensor is another, and frequently it also causes the truck to die when warmed up. If it is the culprit, there won't be any spark, and that can be confirmed by removing a spark plug wire, attaching a spare 99 cent spark plug, and lay it on the exhaust manifold. Crank truck, and some one check for sparks. Do not hold plug while doing this.
#4
#5
#6
Keep in mind that mechanical guages are subject to errors in accuracy, and it is not uncommon to have five gauges and get 5 different readings. Digital ones are also, but errors are smaller usually. But a good reading like yours indicates a healthy fuel pump and a hard working fuel pressure regulator. The ECU sends a voltage pulse to each injector at exactly the right time to open and squirt fuel, and based on varying load conditions, it makes the pulses longer (wider) so more fuel is passed with each squirt. While this is complex, it allows the computer to control things over wide ranges, faster than a well trained right foot ever could.
Now that you checked the fuel, what about the oil pressure??
Now that you checked the fuel, what about the oil pressure??
#8
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