Easy Answer???

[dieselwezel]

First thanks for looking. I have just replaced my oil cooler in a 95 OBS (driveway repair). Installed new oil filter nearly full before installing,went to start and it rolled over fine but wouldn't start or even bite on a little. I didn't notice any smoke or smell coming from tailpipe. Would a broken/cracked GPR cause a no-start? I am thinking that this got cracked by a few 20 second cranks,i tried to cross both thick wires on GPR for about 10-15 seconds then had a friend bump the key while i still made connection but still nothing.
So i will try a new GPR in the morning and hope that is it! Just that i would still get some smoke/fuel out of tailpipe even with broken GPR.

Thanks-Again

[alberta 7.3]

It takes some cranking until the oil cooler is filled, and there is oil pressure. Is the gauge registering oil pressure? If not, remove the PCM fuse, and crank until the gauge shows pressure. Re-install the fuse, and the truck should fire.

[dieselwezel]

I haven't seen oil pressure while cranking,i was kinda concerned about that aswell,this is a new to me truck but knew it needed its cooler replaced(pinholes in tube),i will for sure take your advice (alberta 7.3) Tomorrow morning i will pull the pcm fuse and crank till pressure on gauge with GPR.
Also i am not sure what its called,looks like a pressure relief valve that fits into rear oil cooler housing,is this a one-way fit,it feel apart on disassembly i took a guess using wear marks from spring if that makes any sense.

Well Thanks-Again

[alberta 7.3]

Inside the area of the oil filter? A small plate "staked" in place? That would be the oil by-pass valve.

[dieselwezel]

It goes into a bore into that part,like a barrel and plunger with a spring that sandwiched between plunger and oil cooler body. It seemed if i reversed the barell part that it would fall inside engine block.

[madpogue]

Originally Posted by alberta 7.3

.... and crank until the gauge shows pressure.

I don't think that'll work. IIRC, the "gauge" is de-energized while the key is in the CRANK position.

[alberta 7.3]

No. The gauge does recieve power. I was cranking my OBS until I had oil pressure after the rebuild with the stock gauge.

[dieselwezel]

Ok i just got in,replaced GPR i had batteries load tested and they are fine. I am thinking that this is something to do with that oil bypass valve.That fell ouy when i replaced oil cooler so i kinda took an educated guess on how it sat in there lol...So would this being not put back together will cause a no start? RPM needle bumps when cranking also.Fuel bowl is full but i smell or see nothing at tailpipe when cranking,is this normal? Any help on what to check next would be great! I also ran a code reader and it gave me a P0476(exhaust pres. ctrl valve range/perf ) thinking this is not stopping it from starting.

Thanks

[dieselwezel]

Originally Posted by alberta 7.3

No. The gauge does recieve power. I was cranking my OBS until I had oil pressure after the rebuild with the stock gauge.

So if this is correct,i should remove that oil cooler and see if i could get a exploded view of cooler to see exactly how the pressure relief valve sits in there. The factory oil gauge doesn't budge while cranking at all

[dieselwezel]

What type of diagnostics can be done for seeing if injectors are working? I heard of the buzz test but not too sure how to do. Just that there is nothing from tailpipe during cranking.kinda lost with this one...