explicitgst said:

I used a fitting at the filter housing to split in two directions, one to the turbo

Click to expand...

Your turbo is a journal bearing, so it will be using a fair amount of oil. That would drop the pressure some in this fitting that goes 2 ways.
Do you have like a filter/restrictor in the oil line closer to the turbo? If not, the pressure drop in the 2-way fitting will be worse (because more flow to the turbo). It will also be worse if the 2-way fitting is kind of small internally (pipe and AN size).

I guess your new OFH is the Mighty Max one, MD189888?
Did you try this with the old housing? Was the old housing a regular 2g housing MD199775?

What are your crankshaft bearing clearances - rod and main bearings?

Want to show though that your oil pressures as stated are pretty much right in there on Jafro's chart, except at low rpm. Here's that:



That's a video from 2013, link here.

Also a really small point is that you are measuring I guess after the oil filter, which will drop pressure by 2 or 3 psi compared to where we usually measure which is before the oil filter. Hopefully you are after the filter. I don't know how that housing works. But you sure don't want unfiltered oil going to the turbo.

Thank you for the through and informative reply.

I don't believe I have a restrictor on the line to the turbo, but I can confirm tomorrow. Makes sense as to why I'd lose pressure to the junction/adapter if the turbo is taking a lot of it. What size should I get for the big 16g? (I'll be creeping the forums to find my answer most likely)

It is the mighty max OFH, and I do believe it's only port is a filtered port. I've attached two images of how I currently have it hooked up.

I had low oil pressure with the 2g OEM OFH one you linked as well, though it was not hooked up as I have done the mighty max. It had more ports and thus, I didn't need the adapter. Turbo was fed the clean oil, the junction was fed pre-filter.
This is what I am currently using to give the additional ports. https://k-tuned.com/products/oil-pressure-sensor-adapter?_pos=1&_ss=r. I didn't want it hanging off the mighty max OFH, so I moved it away from vibrations and heat.

I haven't checked the bearing clearances since I bought the car, but it is something I was planning to check next oil change. Thank you again for the information!

The oil pressure gauge sensor idelay should be in it's own port. Like mentioned above it's split between the turbo feed. Also that adapter deal you have going on is no good. It can crack from vibration. I would use a sandwich plate.

We're on Boost said:

Your turbo is a journal bearing, so it will be using a fair amount of oil. That would drop the pressure some in this fitting that goes 2 ways.

Click to expand...

Agreed.
And another possibility, could be the junction block still has the air trapped inside and causing the pressure sensor reads improperly. Did you check by locating it below the OFH?

explicitgst said:

the dummy light sensor.

Click to expand...

Also you should confirm this. You said you have a oil pressure warning switch at the same location as the AEM pressure sensor. Is it the factory one? If so, if the oil pressure is really that low 5 psi at idle, the low pressure warning light in dash should always turn on. The light should come on below approxi 7 psi, so if you don't see the warning light you probably have at least 7+ psi if the switch is in good working condition.

explicitgst said:

I don't believe I have a restrictor on the line to the turbo, but I can confirm tomorrow. Makes sense as to why I'd lose pressure to the junction/adapter if the turbo is taking a lot of it. What size should I get for the big 16g?

Click to expand...

Well, the filter/restrictor FP sells for journal bearing turbos is 0.125" ID. They call it the "Full Flow" size.
I just measured the ID of some Vibrant -4AN fittings that I have here (part numbers 10771 and 10781) and they are only 0.168 ID in the 2 places where they are small inside (gauging with numbered drill bits and then measuring the drill bit diameter with a good dial caliper).
So a 0.125 ID would add a little bit of restriction to that, but not a lot. I don't think that will change your measurement much. So if you did add a filter/restrictor I think all it would get you is another filter before the turbo. I guess they have it right calling it the Full Flow, figuring you'd be using -4AN oil lines.

Since you did have it together with the 2g OEM OFH with the oil lines run separately and still got about the same oil pressure numbers, there was probably nothing wrong with your old one, and you probably won't have much to gain by better oil line routing (separate). That's too bad. I suppose since it's off the car now and easy to work on, you could take that hex plug out where the relief piston is and see if it's stuck open a little bit. But I doubt that if it was matching the new one for pressure. I did notice that Amayama has those available supposedly, the MD199775. Don't know what it's like buying things from them these days with the extra bucks to get it through customs. Used to be just fine.

What do you know about the history of your old OFH?
Is there any possibility that it was modified - like ported or different spring?

Which sensor do you have with your AEM gauge - the 100 or the 150 psi?

I suppose what you are worried about mostly is the crankshaft thrust bearing? I don't know what to tell you. Think you need some help from people who know more about 2g internals, and how much (how low) oil pressure that type of thrust bearing is ok with, given such and such a clutch.
I can see being worried about 5 psi at idle though, because the 2g FSM says "11.4 psi or more" for oil pressure at idle (750 rpm).
From page 11B-3:

DSMPT said:

If so, if the oil pressure is really that low 5 psi at idle, the low pressure warning light in dash should always turn on. The light should come on below approxi 7 psi, so if you don't see the warning light you probably have at least 7+ psi if the switch is in good working condition.

Click to expand...

Yes this could happen, especially if his AEM sensor is the 150 psig one, because the 150 psig sensor will have less resolution at these low pressures. Also, the sensors AEM gives you in the kits are the brass ones which they only rate at 3% accuracy.
Mine came with a brass 150 and I thought it was ok, but I wasn't looking at low numbers with it. After a few years I replaced it with a stainless 150 psig which they rate at 1% of full scale.

Thank you all again for the input!

DSMPT said:

Did you check by locating it below the OFH?

Click to expand...

I took my bumper off this morning, lowered the adapter below the OFH, and opened up a port, 4 air bubbles came out. I let it sit in a little container for a few minutes, but it was just the 4 bubbles that came out.

DSMPT said:

Also you should confirm this. You said you have a oil pressure warning switch at the same location as the AEM pressure sensor. Is it the factory one? If so, if the oil pressure is really that low 5 psi at idle, the low pressure warning light in dash should always turn on. The light should come on below approxi 7 psi, so if you don't see the warning light you probably have at least 7+ psi if the switch is in good working condition.

Click to expand...

So the dummy light was not plumbed in after the relocation. I need to extend the wire to reach the new location. I will do that today.

Imback said:

The oil pressure gauge sensor idelay should be in it's own port. Like mentioned above it's split between the turbo feed. Also that adapter deal you have going on is no good. It can crack from vibration. I would use a sandwich plate.

Click to expand...

I appreciate your input, but I've only got the one port off the OFH. I don't really have a choice, aside from feeding it from the head, which is not something I'm keen on doing at this time. Where I've located the adapter is free from vibration, it's been held there with rubber padded clamps just in case. There shows no signs of fatigue or cracks developing, at least at this time.

We're on Boost said:

I suppose since it's off the car now and easy to work on, you could take that hex plug out where the relief piston is and see if it's stuck open a little bit. But I doubt that if it was matching the new one for pressure.

Click to expand...

We're on Boost said:

What do you know about the history of your old OFH?
Is there any possibility that it was modified - like ported or different spring?

Click to expand...

I did compare the two relief valve springs. Spring rate seemed to be identical. They both sat at the same height, the old one did not look to have been damaged or smaller in comparison to the new one. Since I spent the money on the new one already, and the old one was leaking from a port or two that may have been cross-threaded, I just put the whole assembly on.
I don't know the history, or whether it was ported. I didn't notice any modifications. The car was purchased it off an 18 yr old, who made some questionable modifications/repairs to the car during his ownership from someone who really cared for it seems. At least there were signs someone loved it at one point.

We're on Boost said:

Which sensor do you have with your AEM gauge - the 100 or the 150 psi?

Click to expand...

100psi, not a genuine AEM sensor though.

We're on Boost said:

I can see being worried about 5 psi at idle though, because the 2g FSM says "11.4 psi or more" for oil pressure at idle (750 rpm).
From page 11B-3:

Click to expand...

This!

We're on Boost said:

I suppose what you are worried about mostly is the crankshaft thrust bearing? I don't know what to tell you. Think you need some help from people who know more about 2g internals, and how much (how low) oil pressure that type of thrust bearing is ok with, given such and such a clutch.

Click to expand...

I didn't go there, not mentally anyways.
Maybe it is a tired engine and the bearings need replacing. I want to break in the clutch another 700-800 miles before I change the oil and drop the pan. SouthBend SS-TZ clutch.
Do you think if I bump my rpms to 1000-1200 it would be safe to continue driving?

Sorry if I missed this in the thread somewhere, but didn't see it...have you tried attaching a mechanical gauge in place of the sender to double check the pressure? That would immediately tell you if the pressure is actually that low or if there is a problem with the electric sender.

Drewpy Dawg said:

Sorry if I missed this in the thread somewhere, but didn't see it...have you tried attaching a mechanical gauge in place of the sender to double check the pressure? That would immediately tell you if the pressure is actually that low or if there is a problem with the electric sender.

Click to expand...

Not yet, but I was planning to do that soon. A buddy of mine recommended it, I just haven't had the chance to go down and see him.

I’m sure your oil pressure is fine and it’s just the set up/sensor that’s causing a lower reading. Wouldn’t worry about it tbh

explicitgst said:

100psi, not a genuine AEM sensor though.

Click to expand...

Is the gauge an AEM? This could be a problem if you have an AEM gauge with a non-AEM sensor.
The AEM psig type sensors are all shown on this page. Notice they don't show any MAP sensors on this page. This is just gauge sensors.
The stainless 100 psig is the 30-2130-100
The brass 100 psig is the 30-2131-100
You can see there's a big difference in price. I've saved a few bucks by buying the stainless ones from Amazon, and they come in a proper AEM box and seem fine.
The stainless and brass ones have the same pressure vs volts chart, so they are interchangeable electrically.
You could check out the one you have for pressure vs volts to see if it is the same. I'll post the chart for the 30-2130-100 (pdf) at the bottom. This is what the gauge is expecting, if it's an AEM gauge.

explicitgst said:

Not yet, but I was planning to do that soon. A buddy of mine recommended it, I just haven't had the chance to go down and see him.

Click to expand...

Yeah this you should do. But try to do it with a gauge that only reads up to 30 psi or so. That way it has a chance of being pretty accurate below 10 psi. One of the guys in here tried something like this with a 0-100 psi gauge and it was pretty inconclusive.

Also the best would be if you could hook up the mechanical gauge without disconnecting the AEM gauge! That way you could be reading them both at the same time in the same conditions. Sounds to me like there are 3 NPT ports on that K-Tuned adapter, and either 1 or 2 BSPT ports, I can't tell. Anyway you'd only need the BSPT port for the stock dummy light sensor. The 3 NPT ports could be for the AEM gauge, the mechanical gauge, and the -4AN hose coming from the OFH. I think? If you can get at them all.

explicitgst said:

Do you think if I bump my rpms to 1000-1200 it would be safe to continue driving?

Click to expand...

I would do that actually, since it makes a good amount of difference in the pressure you are measuring. At least until you get it all sorted out.
I mean, my idle is 1100 rpm and my hot idle oil pressure is about 34 psi. That's on a 6-bolt with 20w-50 oil. Squirters and balance shafts are removed. But my bearing clearances are greater than stock so that brings it down some. (.0022")

You remove the oil filler cap and if you can see the rocker arm is jetting oil strongly to cam lobe/roller bearing, usually at least you have the minimum required oil pressure. If you have really only 5 psi at the oil filter housing, at the cylinder head under the oil filler cap should have much lower oil pressure especially after the oil temp gets higher, and it wouldn't be enough to jet the oil.
In case if you see the rocker arm is not jetting oil, like just seeping out from rocker arm's oil jet hole, you may have oil pressure issue.

chrisman287 said:

I’m sure your oil pressure is fine and it’s just the set up/sensor that’s causing a lower reading. Wouldn’t worry about it tbh

Click to expand...

I may be starting to think this as well. I drove it 150 miles yesterday, side roads to pick up some parts for the car. Coming to stops, the pressure never dropped below 5, often times settling around 7-8psi. I wonder if the pockets of air I bled out helped?

We're on Boost said:

Is the gauge an AEM? This could be a problem if you have an AEM gauge with a non-AEM sensor.

Click to expand...

The gauge is an AEM one. I will go back and see if I can get the specs for this sensor and compare to the pdf you provided. Thank you!
Also, yeah...I noticed the price difference
I'm going to attempt to find a 30psi gauge with 1/8npt fitting, or make one and verify the sensor is reading accurately. Nice to have a backup anyways.

DSMPT said:

You remove the oil filler cap and if you can see the rocker arm is jetting oil strongly to cam lobe/roller bearing, usually at least you have the minimum required oil pressure. If you have really only 5 psi at the oil filter housing, at the cylinder head under the oil filler cap should have much lower oil pressure especially after the oil temp gets higher, and it wouldn't be enough to jet the oil.
In case if you see the rocker arm is not jetting oil, like just seeping out from rocker arm's oil jet hole, you may have oil pressure issue.

Click to expand...

It seems totally obvious when you say it, but it never occurred to me to open it up and look at the cams and rockers while running to check the oil flow. If I get time today, I'll check it out and report back in here.

Test it with a mechanical gauge, even if it’s a cheap sunpro gauge from Oreillys or Autozone to verify oil pressure.

I’ve never recommended an oil pressure gauge for these cars because their idle psi is very low unless you have the balance shaft removed. The idiot light at 7 psi has always been my barometer of oil pressure on a factory style car with balance shafts. Oil temp and oil pressure is the main thing I’d like to see from these cars but they have low idle oil pressure

explicitgst said:

I'm going to attempt to find a 30psi gauge with 1/8npt fitting, or make one and verify the sensor is reading accurately.

Click to expand...

Yeah, 0-30 is what I'd get for this. I think that your cold start oil pressure will go well over 30 though, so you will probably have to get the car fully warmed up, then shut it off and put the gauge on. Then don't just leave it on the car forever like some people do with fuel pressure gauges. (I don't even do that).
Usually mechanical gauges can't take much over-pressure. Mechanical gauges still use a Bourdon tube inside. So if they are over pressured, they might never be accurate afterwards, and they can rupture and leak.
I noticed that 0-30 psi gauges are not so easy to buy locally, but Amazon shows several. They are liquid filled to damp spikes, and some are stated for water, oil and air. They're all about $10. Like this one which has pretty good reviews. Note these are pretty big (2.5" diameter) and are 1/4" NPT.
Anyway, make sure first that you can do a warm start without going over 30 psi oil pressure on the AEM gauge at least.

Install a distribution block to the frame of the car. Run a flexible turbo oil feed to this. Replace the oil pressure sensor with an AEM one.

Direct mounting sensors to the engine results them failing faster. Your setup is at risk of failing.

danl said:

Install a distribution block to the frame of the car. Run a flexible turbo oil feed to this. Replace the oil pressure sensor with an AEM one.

Direct mounting sensors to the engine results them failing faster. Your setup is at risk of failing.

Click to expand...

That is my current setup, minus the AEM sensor. I posted pictures above in a previous reply with the remote setup.
I just bought a mechanical gauge to verify the current ones functionality before dropping any more money on those sensors.

explicitgst said:

That is my current setup, minus the AEM sensor. I posted pictures above in a previous reply with the remote setup.
I just bought a mechanical gauge to verify the current ones functionality before dropping any more money on those sensors.

Click to expand...

Want to show you what my oil pressure logs look like during cold start, with the 150 psig stainless AEM sensor going to a logger with better voltage resolution than ECMlink. I consistently see 5 psi of oil pressure during cold cranking in these logs.
Here I've expanded vertically the oil pressure part of the log so you can see that it shows smaller numbers than 5 psi. In the picture you can only read a number where I have the pointer, where you see Y: 0.5 That is 5 psi.
The vertical scale on that chart is scaled to one-tenth of the actual psi.

So for example at the right end of it which is after the engine is running at about 1300 rpm, the pressure there is 92 to 97 psi.
On the first crank, it is at 1 psi for 0.12 seconds before it jumps up to 4 psi, then 5 psi.
Then after the 2nd crank, as the engine catches on, it doesn't waste any time getting up to 90 psi, jumps right up there and goes past 90 as the engine goes past 1300 rpm.

In the ECMlink part of the log I'm showing only battery voltage, MAP psi (LinBoost), RPM, and Throttle.
It seems like the RPM signal is slightly delayed to ECMlink in the 1st crank?
But battery voltage and LinBoost are right on timewise. Battery voltage tells me exactly when I pushed the starter button (huge sudden drop in voltage).



BTW at this cold start (March 27), the car had not been run for over 3 weeks (since March 1).

My sensor is on 3 feet of -4AN hose from the unfiltered part of the OFH, all by itself.
You can see my hookup in posts #52 and #53 here.

Your T at the OFH is problematic. You can feed the turbo off the distribution block.

Sad update...
Drove it 40 miles yesterday, oil pressure at idle dropped to 0. Across the powerband I was down 10-12psi from my previous post. Dropped the pan, crank is walking.
Welp.
Guess it's time to build the spare 6 bolt I have.... Won't get to break the clutch this year it seems.

Whomp whomp.

That sucks man. Time for a rebuild.

explicitgst said:

Sad update...
Drove it 40 miles yesterday, oil pressure at idle dropped to 0. Across the powerband I was down 10-12psi from my previous post. Dropped the pan, crank is walking.

Click to expand...

Bummer!

Going to build a 6-bolt then? Check this out, this is what a dry-run through Amayama check-out looks like right now, today.
Did this with a 6-bolt OFH, MD132912



Then, the "Duties, taxes and fees -- All covered -- Worry-free customs" -- Here's what that looks like:



And that's as far as I went with it. So there could be other surprises that I don't know about.
Normally I don't put in the parcel dimensions, I let them fill that in later, and that changes the price a little. In this case I knew the approx dimensions because I have one sitting here, so I filled that in for a closer result.
Section 122 Tariffs are the ones that were implemented Feb 24, 2026.
Looking at how they get the $ total, because it's a little unclear, but it checks out to be $97.67 + $32.29 + $39.65 = $169.61

I just received an Amayama order today. I ordered $120 worth of parts. After shipping and duties it was $200. But some of those parts aren't available in the US, and a couple of them were far cheaper than the ones that are in the US, so it ended up being worth it. But it's not the bargain it used to be.