Long story short....I built an LQ9 based H/c motor and put it in my 95 TA. I fired the motor the other day and had ZERO oil pressure. Before you all start throwing the usual oil pressure fixes at me, the pump is new, the o-ring is new, the gally plug is new, I have an autometer oil pressure gauge tapped in above the filter, and I retained the stock pressure sensor for the computer.

My question to you guys is this...

Are there any oil differnces between the LS family motor and the 6 liter motors? I am pretty sure there isn't but I want to make sure I didn't miss anything.

Here is the other thing that is on my mind. I had ZERO oil pressure. Autometer reads ZERO and the scanner says -15psi at the factory sensor. I thought maybe the assembly lube was thinning the oil. So, I change the oil and the filter. Fire the motor and still ZERO oil pressure. The oil looked good, no flakes, no gunk, no chunks. I took the valve cover off and the head is BONE DRY. This tells me that the pump isn't working or the pick up tube is blocked. You would think that unless there is a squirrel stuck in the pick-up, I would have a little bit of pressure. Even a bad pump will give you something.

I wanted rack some other brains, to see if there is anything I missed.

Alright, go ahead, fire away!

 

oil pumps are the same. how did you install the pickup tube into the oil pump? you may have pinched it.

 

truck oil pump pickup tube is diff. from ls1 car pickup tube,
which pickup tube did u use with which pan?

 

Even with a pinched o-ring, you should have SOME pressure. I haven't taken the front of the motor apart yet, but I'm 93.7% sure its not the O-ring.

 

LS1 pump, LS1 pick-up, LS1 pan. The only thing LQ9 is the block and the internals.

 

Any other thoughts?

 

Did you have to shim the oil deflector tray? If you did, that might have pushed the oil pickup screen too close to the bottom of the pan and it can't suck oil...

 

did you put that little dumbell looking thing into the back of the block?.............i forget what it's called.

 

If you are sure the o'ring is fine, plugs are in place, it could be the pump isn't priming. I usually pack the pump with light weight grease (Vaseline) to make sure it primes.

Steve

 

The dumbell only makes the oil go thru the filter without it u should have oil pres. but it does need to br there. Like the above post i think you have a prime problem .. Use an oil accumlator and pressure feed it through an external port "the factory sending unit port works best" this will let it drain down to the pump and help to prime it usally about a qt of oil will do it . If it doesnt get press next time you crank it the problem is internal . This has worked for us a couple times hope it helps..... It beats a teardown to find nothing wrong.. I know from exp. ......

 

Thanks guys. The gally plug is in the back of the block. I didn't use any shimms. Its a new pump, so I'm hoping it just needs a little time to start circulation. I haven't let it run for longer than 10 second without oil pressure. Usually thats enough, but its a new build and I didn't prime the thing before hand. We'll see. Thanks!

 

I had filled my pump with STP to help it prime on 1st startup.. as steve used Vaseline, some other type of heavy oil or light grease will help seal the pumps rotors and help in sucking the oil up and priming the system.

good luck...

 

x4 for packing the pump, never had an oil press issue with installing new pumps, and i always pack the pump with grease before hand...

 

The front half of the motor will come apart this weekend. I will take the pump off and pack it. Hopefully this will solve my problem. Thanks alot guys! I really appreciate it!

Grease? Vasoline? What is the best thing to pack it with?

 

the cheapest grease you have or Vaseline will work too...need something that's oil soluible so it wont clog the filter or oiling holes...but dont pack it full, just put a liberal amount on everything, i like to coat the back and front facing of the gear and rotor for dry start conditions..i mean after all the gerotor is hardened steel the pump housing is only aluminum....good luck

 

Awesome, thanks.

 

prime that pump, you'll be set if everything else is kosher.