No Start after 3 days off

[Popeye2347]

First off, this is a co-workers 1994/5 F250 4x4 PStroke, auto w/~175k miles. If he fails to start it for about 3 days or so, it will need ether to start-and yes, before anyone flames me, I have discouraged its use but it is his truck so I can only report and not prevent its use.

He reports cranking speed seems normal, filters changed, good fuel,etc. He tells me he has blue smoke out the tailpipe when he cranks it over and for a longggg time afterwards, **Clue #1**

I asked about the tach reading while he cranks it over, he reported just a few minutes ago it went to minus 200 or so-no misprint-the needle goes below 0 instead of plus 200 or thereabouts.{he has never paid attention to indicated cranking speed when it was starting normally]***Clue #2***

The 'Wait to start' light appears to operate normally.

Using ether [a squirt after the 'wait' light goes out down the air inlet before the air cleaner,] will allow the motor to start rather easily, again with blue smoke out the tailpipe for an extended period of time.***Clue #3***

After once started it will start as it should as long as he does not allow 3 days or so to pass without starting.

I own a 7.3 IDI and am not too familiar with the Power Stroke ins-and-outs, so what item is most likely bad?

He has a digital meter but does not know much about using it nor has much troubleshooting experience with electrical problems. In any event the Wait to Start Light appears to work as advertised so I tend to discount glow plug problems.

My thoughts are twofold---First is the CPS due to the tach indication, but doubtful because it works if started daily....???

Second are an o-ring problem, as evedinced by failing to start after a few days of sitting, maybe allowing air into the fuel system???

Anyway, I don't want to steer him wrong and suggest replacing parts he does not need to replace, so help me out here.

Thanks...

 

[Popeye2347]

P.S.

I forgot to add that I have looked over prior problems but have not found one near enough to this one to effect repair.

 

[Double-S-Diesel]

good possibility the hpop resivoir is loosing oil common on 94s, before ya go much further, let it sit, then pull the plug on top of the hpop res, and see if it is full or not.

 

[BigRigTech]

Could be loosing it's fuel prime too....I would check the HPOP first as noted above.

 

[93turbo_animal]

if hes getting a lot of blue smoke that means everything is working but not enough heat to light it off. I've had my relay stick before and not turn the gp's on but other times it does but never that consistent as to every time it sits 3 days

 

[Tim the 2lman]

Due to the fact that he has to wait 3 days between troubleshots, this could last for a while. However, one way to check for lack of fuel or air in fuel is to let it set for the 3 days, then while someone cranks it, have someone else open the schrader valve on the driver's side of the fuel filter assembly and check for a good solid stream of fuel being pumped out. If you've got that thenI would tend to think that it's ok.

If it's oil, again, let it set the three days needed and then check the reservoir. If it's not full, top it off, put the cap on and then try it. He should check his oil level in the crank case as well.

Based on the description it does sound like a lack of heat at startup. Does it run rough when it kicks off and while the blue smoke is present? If he's getting smoke out of the tailpipe on a no start complaint, that really tells me that your getting both fuel and have oil pressure. A lack of either should result in nothing out of the tailpipe with a no start. Same is true of a faulty CPS.