Oil pressure issues in boost

MaverickA70

MaverickA70

desperate parts beggar
Sep 17, 2007
82
1
8
36
arkansas
I have a rebuilt 7mgte, and suddenly after 8,000 miles when i get into boost the oil pressure drops dramatically. At warm idle, i generally have about 5-10psi and high 30's to 50 under load depending on rpm. my turbo has a lot of shaftplay in it, leading me to believe that is the cause. I don't hear any knocking, i've heard many 7m's rod knock and i think i can say with confidence that mine is not knocking. Also as soon as i saw that the pressure dropped under boost, i drove it home and parked it.

some specs on the motor:
0w-30 german castrol
mobil 1 filter
upgraded oil feed hose from driftmotion
new toyota oil pump
toyota hg with arp headstuds
i was running an mbc at about 9psi on the stock ct26 with a bosch bypass valve

anyone have any ideas or suggestions?
 
gaboonviper85

gaboonviper85

Supramania Contributor
Jan 13, 2008
3,236
0
0
39
Northeast Philly
oil pressure is rpm dependent only...load and boost play no part..

are you 100% sure you have 5-6 quarts of oil in the system?

the turbo shouldnt effect pressure reguardless...if it did then it would effect psi across the board and not just in the high rpm...

this is a very strange problem...is there anyway you can get a video of this?
 
Poodles

Poodles

I play with fire
Jul 22, 2006
16,757
0
0
43
Fort Worth, TX
meh, turbo isn't going to cause oil pressure issues...

I'd bet more on uncovering the pickup or the stock cooler circuit/oil squirter bleeds.
 
MaverickA70

MaverickA70

desperate parts beggar
Sep 17, 2007
82
1
8
36
arkansas
I have an aftermarket electric gauge. I checked the oil level, and its fine. I have to add oil every once in a while because the turbo leaks.

I'm not sure i have a good way to get this on video, so i'll try to describe it as best as possible.

The oil pressure is normal during light driving and shifting at 2.5-3k, but when i get on it a little bit the pressure glides closer to 0 psi the longer i stay in boost...and at a pretty quick rate. it will be 35ish psi and then after just 2-3 seconds of boost it will be less than 15psi. If i downshift to bring the rpm up while staying in vacuum, it seems unaffected. I'm not really sure what would cause this.
 
gaboonviper85

gaboonviper85

Supramania Contributor
Jan 13, 2008
3,236
0
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39
Northeast Philly
mr taco;1487666 said:
I have an aftermarket electric gauge. I checked the oil level, and its fine. I have to add oil every once in a while because the turbo leaks.

I'm not sure i have a good way to get this on video, so i'll try to describe it as best as possible.

The oil pressure is normal during light driving and shifting at 2.5-3k, but when i get on it a little bit the pressure glides closer to 0 psi the longer i stay in boost...and at a pretty quick rate. it will be 35ish psi and then after just 2-3 seconds of boost it will be less than 15psi. If i downshift to bring the rpm up while staying in vacuum, it seems unaffected. I'm not really sure what would cause this.
Click to expand...

what oil are you useing? and are you sure your voltage isnt dropping off causing the aftermarket guage to drop its needle? when you rebuilt the engine did you accidentally bend the oil pump pickup away from the pan?

so basicly...the faster you spin the engine the less oil psi you see after a few seconds of high rpm pulls?

edit. sorry i see 0-30 gc for oil...my bad lol
 
MaverickA70

MaverickA70

desperate parts beggar
Sep 17, 2007
82
1
8
36
arkansas
gaboonviper85;1487669 said:
what oil are you useing? and are you sure your voltage isnt dropping off causing the aftermarket guage to drop its needle? when you rebuilt the engine did you accidentally bend the oil pump pickup away from the pan?

so basicly...the faster you spin the engine the less oil psi you see after a few seconds of high rpm pulls?
Click to expand...

i'm using 0w-30 german castrol synthetic. I checked the connections between the sending unit and the gauge, and it all seems fine. I actually lowered the pickup a little during the rebuild.

That sounds about right, it feels synonymous with boost but that doesn't make any sense. Any ideas other than the oil cooling circuit? i'll check that out tomorrow..
I'll also change the oil and filter as well, since its about time to anyway.
 
bountykilla0118

bountykilla0118

In Pursuit of 500rwhp
Jul 16, 2005
1,088
0
36
39
Atlanta GA
Don’t turn this is to a fight over what oil to use and not use. Do your research and take in consideration the condition of your motor. Older motors or high mileage motors are not the same as a new or freshly rebuilt motor. So saying 1oil fits all situation no matter what is like saying 1 tune fits all, which we all know its not realistic but moving on….

Have you checked your oil level? A while back I had the same thing going on .... as the RPM's went up the oil pressure would drop and when I left off the gas it would go back up ..... Popped my hood and I was 3 quarts low and on top of that my turbo was its last leg b/c it had too much shaft play.

Check your oil man ....
 
aznboik1mva

aznboik1mva

New Member
Aug 20, 2009
328
0
0
Manchester,Ct
bountykilla0118;1487964 said:
Don’t turn this is to a fight over what oil to use and not use. Do your research and take in consideration the condition of your motor. Older motors or high mileage motors are not the same as a new or freshly rebuilt motor. So saying 1oil fits all situation no matter what is like saying 1 tune fits all, which we all know its not realistic but moving on….

Have you checked your oil level? A while back I had the same thing going on .... as the RPM's went up the oil pressure would drop and when I left off the gas it would go back up ..... Popped my hood and I was 3 quarts low and on top of that my turbo was its last leg b/c it had too much shaft play.

Check your oil man ....
Click to expand...


well i had a fresh rebuilt motor with 20,000miles and i switched to the german castrol synthetic oil, i mean thats what the guys up here in ct are running
 
MaverickA70

MaverickA70

desperate parts beggar
Sep 17, 2007
82
1
8
36
arkansas
The oil level is fine. I measured the depth of the pan with a straight edge and ever so slightly bent the pickup tube to come about 3/8" from the bottom of the pan. Should i not have done this? I've had 8,000 miles of good oil pressure, why would it do this now?

I know that my turbo is pretty bad, the oil seals leak quite a bit.
 
dumbo

dumbo

Supramania Contributor
Jul 16, 2008
1,911
0
0
Albera, Too Far North
Why did you feel the need to bend a brand new oil pump!??
If it were me I would pull the pan and make sure the pump is still good and nothing is cracked or loose. Check your squirters, pump relief, and cooler relief. That's just me though.
 
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