Losing prime...?

greenskeeper · Jan 22, 2020

m67tang said:
Tell me about the CPS. I don’t know much at all about this PSD. Coming from IDI world. What’s it stand for???

here’s what happened:
Truck wouldn’t start. Like no fuel. I shot some spray silicone into the intake. Thinking I’d lost prime. It then fired right up. I’ve already replaced my GPs and harness. Seems to be ok starting last few days. But I smell fuel at the front grill after I shut it off. Don’t see any leaks anywhere. That’s all I got for now.
Is this like a CPS?

could be "quick disconnect fittings" for the fuel lines just above the drivers wheel well. If they leak you'd smell it and not be obvious. However that wouldn't effect your starting condition.

Next time prior to starting I'd remove the fuel bowl lid and check that it is full....it probably is.

m67tang · Jan 23, 2020

I’ve ordered a new motor craft CPS for the truck this morning. I’ll share whatever happens.

greenskeeper · Jan 23, 2020

m67tang said:
I’ve ordered a new motor craft CPS for the truck this morning. I’ll share whatever happens.

On both my trucks I've had 2 CPS failures and both times it threw a CEL or SES light for what it's worth. I guess CPS are cheap enough to throw a part at it these days.

13fcolt · Jan 23, 2020

it's not uncommon to get no codes with a faulty CPS even when it has completely died. I still have a grey Motorcraft CPS from a few years ago, that caused me much headache. It will just randomly quit, no codes, no warning signs, no consistency to it. Cranking with no start like it's not getting fuel, so I dug into the fuel system......

Oledirtypearl86 · Jan 24, 2020

I'm with thease guys a random crank no start ona 7.3 I usally go straight for the CPS

m67tang · Jan 26, 2020

New CPS arrived. I installed it today. Guess I’ll see if “no start” happens again. The old was gray. The new is dark blue?? I’m not sure what that means.... new one is motor craft.

lotzagoodstuff · Jan 26, 2020

Although I agree that CPS can die and come back sporadically, every CPS no start I’ve witnessed was accompanied with a tachometer showing no rpms when cranking. I’m sure others will chime in on the CPS/tach piece, but based on your past diagnosis of adding a whiff of spray/fuel and getting it to light off, I’m not sure I’d point to the CPS.

Good luck

13fcolt · Jan 26, 2020

I forget the year it changes, but the tach doesn't show anything during cranking on certain years.
The reason I don't think it's a fuel problem is because any fuel leak bad enough to prevent starting will leave a puddle. Not saying there isn't an issue with fuel, just that it's less likely to be the cause. Other likely causes are bad IPC, or IPR needs cleaning or has a bad coil.
But going with the simplest, easiest, cheapest things first.

Losing prime...?

greenskeeper

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m67tang

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greenskeeper

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13fcolt

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Oledirtypearl86

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m67tang

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lotzagoodstuff

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13fcolt

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