2000 7.3 6 speed no start unless I change the oil in HPOP resv.

Jeff B

Jeff B

Thanos was right
Joined
Dec 23, 2006
Location
Lincolnton N.C.
2 weeks ago I changed the oil in the truck. Same way I have for the 10 years I have owned it. I went to start it & it would not fire. Spin over however no fuel. I did a little reading on line & thought there may be air in the injector oil lines. So I changed the oil in the HPOP. BAM! fired right up.

Drove & ran fine.

I let it sit for 3 days, went to take the truck to church & it would not start. Took the gf's car.

Got back from church & I though maybe it's HPOP resv. is draining back, check valve trash or something. I topped it off & no start, spin over just fine but would not fire.

I changed to oil in HPOP & the fucker fired right up.



What's going bad that I need to replace?
 
Jeff B said:
2 weeks ago I changed the oil in the truck. Same way I have for the 10 years I have owned it. I went to start it & it would not fire. Spin over however no fuel. I did a little reading on line & thought there may be air in the injector oil lines. So I changed the oil in the HPOP. BAM! fired right up.

Drove & ran fine.

I let it sit for 3 days, went to take the truck to church & it would not start. Took the gf's car.

Got back from church & I though maybe it's HPOP resv. is draining back, check valve trash or something. I topped it off & no start, spin over just fine but would not fire.

I changed to oil in HPOP & the fucker fired right up.



What's going bad that I need to replace?
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I'd probably be most concerned with lube oil pressure being the reservoir can be filled and the truck will start. Injector o-rings can cause hard starts when hot but typically not a cold hard start. Best to start with a manual oil pressure gauge amd scan tool. Watching icp pressures will typically give you a starting place. Typically if lube oil pressure is low performance and stalling issues are present but every truck is different.

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I filled it & it would not start though. Wouldn't start until after I changed it, new oil & it fired right up?

Never stalls & runs great. Once it's running... This is only the second time it's happened.

Where do I plug in the manual oil pressure gage & how much should I expect to see?
 
Jeff B said:
I filled it & it would not start though. Wouldn't start until after I changed it, new oil & it fired right up?

Never stalls & runs great. Once it's running... This is only the second time it's happened.

Where do I plug in the manual oil pressure gage & how much should I expect to see?
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You could check at the eop (sensor on the reservoir) or a plug on the filter housing .
My concern is that if I'm understanding correctly, the reservoir is full which typically doesn't indicate a low lube oil condition. Might be worth emptying the reservoir and using a light to verify theres no debris or obstuctions.
To be honest the only way to know the true cause of a hard or no start would be some pid data or dtc's. In theory changing the oil in the hp reservoir wouldn't change anything.
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Glad to hear you made it to church, since you didnt bother showing up at our halloween party.


Dick.
 
GotWood said:
Glad to hear you made it to church, since you didnt bother showing up at our halloween party.


Dick.
Click to expand...



Damn, I was thinking about that today. I totally forgot. I wanted to go too!

Edit..

*you could have reminded me with a text* dork...
 
Last edited:
mysterync said:
You could check at the eop (sensor on the reservoir) or a plug on the filter housing .
My concern is that if I'm understanding correctly, the reservoir is full which typically doesn't indicate a low lube oil condition. Might be worth emptying the reservoir and using a light to verify theres no debris or obstuctions.
To be honest the only way to know the true cause of a hard or no start would be some pid data or dtc's. In theory changing the oil in the hp reservoir wouldn't change anything.
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Click to expand...



That's my mindset also. Just changing the oil should make no difference. What about the viscosity of the new oil versus the old oil being thicker? (kinda guessing at this)

The EOP sensor is this on top passenger side of the resv.?
 
Would the EOP sensor throw a code? I have a superchips tuner that will read & clear codes & it reads only the ebpv code from the exhaust brake mod.
 
Jeff B said:
Would the EOP sensor throw a code? I have a superchips tuner that will read & clear codes & it reads only the ebpv code from the exhaust brake mod.
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Seems like I remember something about them being just a switch and not a variable resistance sensor. That being said typically switches like this are not monitored shorts or opens by the powertrain controls. In this case a bias voltage is provided and when the switch reaches the set point that bias voltage is pulled to ground and indicates theres oil pressure. The injection circuit is almost instantly effected when low lube oil pressure is present. If low pressure was causing your hard start typically a code would be thrown after one or two good cranking cycles indicating icp to low for to long or something similar.

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I hate to just start throwing parts at this thing. How does one test it?
 
Jeff B said:
I hate to just start throwing parts at this thing. How does one test it?
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You could spend thousands throwing parts and never fix it. First step would re-create thenl issue with the scan tool on the truck and evaluate the data such as high pressure oil, crank and cam signals and so on. This should get you a starting point. Considering you say it runs ok most of the time it'll be important to perform test while the malfunction is occuring. This may include pressure checks, lube oil pressure checks, wiring checks and wiggle test on all injection related circuits (uvch, icp, ipr etc), cam sensors and cranks sensors can be replaced fairly inexpensively however 30 minutes with a good oscilloscope will provide much better results without replacing good parts.
I find it unlikely that you have a lube oil issue (some trucks did have failing oil pumps or atleast symptoms of around 200k), if a lube oil issue is present typically the hpo reservoir is empty.
Hope this helps.

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The truck is at. Approx 209k,

Lube oil? Refer into the high pressure oil pump? Should I replace it?

The scan tool you speak of, is this something I could buy or a specific expensive tool?


The hop resv. Has been full every time. The only thing that has been the difference between running and not is new oil in it.
 
Jeff B said:
The truck is at. Approx 209k,

Lube oil? Refer into the high pressure oil pump? Should I replace it?

The scan tool you speak of, is this something I could buy or a specific expensive tool?


The hop resv. Has been full every time. The only thing that has been the difference between running and not is new oil in it.
Click to expand...
If the reservoir is full, lube oil is likely fine. Not a proof positive but a good notion that it would be anyway.
You could purchase auto enginuity which would use your laptop and give you scan tool abilities or you could just have a local shop do it for you. Im not sure how much auto enginuity runs but typical shop rates in these parts run $65-$150.00 Typically the top of the line new scan tool runs $5,000-$15,000 new and would be a bit much unless you wrench on many makes and models 7 days a week.
Dont replace anything until you know whats wrong and you've proven it. You could create a bigger headache by doing so. Lube oil is the low pressure engine lubrication pump. The low pressure pump feeds the hpop.
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Well shit....

Thanks, Guess I will be calling the 7.3 mechanic tomorrow..
 
In Lincolnton, I brought that fuel tank from you last year.
 
Jeff B said:
In Lincolnton, I brought that fuel tank from you last year.
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I remember that! I dont have any contacts down that way. However anyone with on of the snap on scan tools could provide you with the data you need!

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Thanks
 
Been reading on a few different diesel forums, sounding like the pop may be the issue. I will be measuring the pressures there tomorrow after work.
 
Jeff B said:
Been reading on a few different diesel forums, sounding like the pop may be the issue. I will be measuring the pressures there tomorrow after work.
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I posted a voltage chart years ago on diesel bombers that will allow you to use voltages at the icp sensor signal wire without a scan tool..if it'll help ill try to find it.

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it may help, if it's not that much trouble. please.

I was on my tablet last night meant to type lpop.
 
Jeff,
Im no expert but in my limited experience the fact that your hpop reservoir wasnt half empty (or worse)when you changed the hpop oil to me means its unlikely that is the cause...not impossible I suppose but Ive never personally seen a lpop fail that would result in a no start YET ALSO keep the hpop reservoir full.
 
Thanks Ron, I am going to put a gauge on this evening to verify the lpop. I hope i have good pressures, if so I am going to get it scanned. I need this truck reliable. Can't ride the kid to school in the am on the bike in this cooler weather.
 
Talked to a 7.3 specialist today. He thinks it's the timing cover on the lpop. The Lpop looses it's prime & then when I refill the Hpop resv. I am really putting more in then I took out. re priming lpop through the dip tube that fills the hpop resv.
 
Jeff B said:
Talked to a 7.3 specialist today. He thinks it's the timing cover on the lpop. The Lpop looses it's prime & then when I refill the Hpop resv. I am really putting more in then I took out. re priming lpop through the dip tube that fills the hpop resv.
Click to expand...
Thats sounds like a logical answer!

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