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99 Isuzu npr 4he1tc starting issues

Jetfiremuck

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Picked up as non runner. Tried cranking after bleeding etc. Did compression test got 400 psi. Checked static timing Ok. pulled injectors and pop tested. Found 2 injectors dribbled won’t hold pressure. Replaced with 2 rebuilds . Will only start with shot of ether. Once running no smoke. Let run 15mins. Turn off try cranking will not start.... does with a whiff of ether. Diesel is fresh running from a clean jug. Bled using 12v diesel pump. No air in system. So question could bad delivery valves cause leak down in the lines? Does the engine need the ecu to start? It’s a zexel Bosch in-line pump. Injectors are mechanical. Pump has advance solenoid that has 12v continually should that be so. Truck is in 80f weather
 
Welcome.
Many diesel engines are ‘cold’ and advanced timing& use glowplugs until coolant temperature is over 160 degrees.

Pull and bench test them heaters to see them glow red.

You said compression 400- what was actual compression of all cylinders?
 
400psi or thereabout on all 4 cylinders. I’ve put new glow plugs in . Engine should start I’ve 2 fresh batteries hooked up. Would advancing timing when cold make it easier to start? Does the engine need the ecu to start? It’s an early 99 midel
 
What's the cranking RPM? A starter can loose a brush and still spin, but, not fast enough to start. Thus my suggestion to check cranking RPM and related items affecting the starter. If it sounds like it's cranking slow, frankly, IT IS! Diesels won't barley turn and then spark and roar to life like a gasoline engine.

The cranking RPM is the "heat" angle of thing as well as glow plugs. Are the plugs actually working? Getting voltage etc? I use a heat gun to check the head area after several cycle to see if the system works as "our" glow plugs are hard to get to. Hook one of your GP's off the engine grounded in a vise grip and see if it gets hot. Troubleshoot the GP system as required/indicated.

Ether has answered your question that you don't have enough heat to start. NOW STOP USING IT!!! You will be fixing it to start properly without it. If it doesn't start you haven't fixed it so keep working on it without ether. You ruined the glow plugs if you didn't disable them when using ether.

After it starts is it smoking white? This indicates something too cold or not enough timing. As it doesn't smoke after startup I suggest your timing is fine.

What's with the ECU needed to start question?

You are running it from a diesel jug. What was the fuel in the tank like? Water, gasoline, bugs? Are we looking at a ruined IP from who knows what in the tank or just troubleshooting?
 
If the vehicle had an ECM, it absolutely will be necessary to get the ECM functioning before it will start.
BUT, I`ve been proven wrong before. LOL
 
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