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Discussion Starter #1
I have been reading through various ways to test the glow plug system. I put an amp clamp on the two wires on the driver side on one wire I get 80 amps the next I get 50 but then I tested the first again and only got 50. I also notice the amp meter drops fast. Starts at 80 or 50 but in seconds drops to half that. Is that normal?

Tested each plug with a test lamp from the valve cover gasket plug. Each glow plug is connected inside and all glow plugs and valve covers (with harness) are new.

Issue truck does not start easy cold and smokes and stumbles for 5 or more seconds before it cleans up and runs right.

also after replacing my injectors I notice that cold idle varies, sometimes spikes up a couple 100 rpm or drops down for a quick second.

All is fine after a it gets some heat into the engine.

Days are around 40 degrees right now.
 

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how long are you waiting after the wait to start light goes out before you start cranking?

On a cold start not plugged in down at 10F i wait about 45 seconds after the wait to start light goes out and then crank with my foot depressing the pedal slightly. It fires up a lil rough for about 5 seconds and goes to fast idle about 850-900 and will stumble down 100 rpm a couple times.


At 40 degrees i give it maybe another 10 seconds to light the gp's after the light goes out and it fires up (no fast idle)

Mind you all 8 gps are new motorcrafts that are a couple months old.
 

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Discussion Starter #3
I usually start right when the light goes off. isn't that whats if for. Today I waited 30 seconds from the time I turned the key on and it started but was not firing on all 8 for a couple of seconds. Then it cleared up. I have the autoenginutity software coming. hopefully that will tell me if I am not getting good fuel pressure at start up. maybe the IPR is bleeding out.
 

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In the coldest of winter days the wait to start light on mine might stay on 12 seconds. Definately not long enough. The gp's can stay on for 1 min 30 seconds.

Any cold diesel engine will run kind of rough for a few seconds when its cold out, just the nature of the beast.

That being said you should still be able to start a 7.3L Psd down at 5-10F not plugged in. It might not be a pretty start but it should.

Test the resistance of the gp's threw the VCG and if its infinite they are no good.
 

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Discussion Starter #6
this isn't running rough this is like riding a bull. the whole truck rocks back and fourth with huge puffs of smoke. Giving it a little peddle smooths it out quicker.

I have tested each glow plug at the valve cover harness and they all test 1.4 - 1.6. also tested the B+ and glow plug side of the relay. They difference is .15 V when the relay is activated.

I have split shot stage 2 B injectors with a factory HPOP and hypertech III programmer. I am getting a custom chip and tune from Bill at Power Hungry. This problem happened before and after the injector swap.

Last year this happened and I took it to the dealer and they told me I had a bad injector and another one was showing wear but still within specs. So this year when it happened I thought that other injector finally went but that doesn't seem to be the cause of my issue.

I think I am either flooding or starving the engine. Don't know how to tell which until I get the scope program.
 

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Discussion Starter #7
the resistence on the glow plugs, should be 0 not 1. something
really, from what I read it should be between .5 and 2 ohms. hard to believe that all 8 of my new plugs would be bad.
 
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