2G Turbo convert--> oil pressure gone

[patman]

Hi
I've converted my N/A 4g63 to a T25 turbo build. Basically what I did is
T25 (OEM, freshly rebuilt)
- Stock GST exhaust housing (OEM)
- Dejon intake pipe
- OEM intercooler
- Forge style Epman BOV
- Depo racing mechanical boost gauge
- Walbro 190 LPh Fuel pump
- Ebay open dump O2 housing
- Custom 2,5' downpipe
- OEM GST ECU
- OEM black top GST injectors (450 cc, with resistor packof course)

The GST ecu and the fuel pump is not in yet, but I started the car and it has seriously low oil pressure, so low it creates black smoke puffs, and dies on me. I've changed the oil pressure switch to a new one from a Mitsubishi Galant, guessing they are mostly the same. The problem occurred after giving it a bit of a push on the road. Can I solve the problem by changing the ecu? I don't see where they are related in this problem

 

[silvreclips]

So you changed to larger injectors but didn't change the ecu yet? That sounds like your problem to me. Black smoke is fuel not oil.

 

[patman]

yeah, I hope so thats the problem. The only problem is the new ecu doesn't send signal to the fuel pump, do you think there is a guide somewhere here how to hook it up with the fuel pump?

 

[DSMPT]

Also should replace your non turbo MAF and fuel pressure regulator for turbo.

 

[Kryndon]

The MAFs on the EU 2Gs are the same type and part number as the turbo ones. Otherwise you're right about the regulator.

 

[DSMPT]

I am not sure about EDM 2G eclipse, but in general turbo and non turbo JDM cars with 4g63 have different MAF/FPR with different part number, such as eclipse, galant etc.

 

[patman]

MAF is the same, I didn't change that. The fpr is different, I changed that during changing the injectors, I just forgot to write that down at first

 

[DSMPT]

No need to change the maf if they are the same or the op has a method to adjust the airflow signal.
Should change it if the maf is different from the turbo model unless the OP has a method to tune the airflow signal.

 

[RamenPride]

How much oil pressure are you getting? I know you said "seriously low," but that doesn't really help much.

 

[patman]

I can't tell you excatly, I don't have an oil pressure meter only the OEM one, but the oem goes reaches halfway to the lower line, and the oil warning is flashing all the time.
I'll put try putting in the GST ecu, but I don't see how that can solve the problem
Can the problem be that I bought aftermarket Mambatek Oil feed line for the turbo? It has a 1,8mm reduction right where it connects to the turbo.
https://www.ebay.com/itm/273362873761

 

[silvreclips]

My guess is you don't have an oil pressure problem. The car is running like shit because you changed injectors and not the ecu and the car is almost dying and low rpm is causing the oil pressure to get low.

 

[patman]

yes it's possible the car idles at about 950rpm, I'll change the ecu later and I'll write about it if that didn't solve the problem

 

[pauleyman]

Highly likely youve got a ton of gas in the oil also. Fix this or let us know when you spin bearings

 

[Gsx-Dude]

You have to change PIN 8 with PIN 22 to get the fuel pump running with the turbo ECU.

 

[Kryndon]

I spoke with Patman and upon seeing where he tapped into for his T25 feed, I may have a clue to what's going on. I'll write my theory here maybe someone can chip in and say if it's a possibility or not?

Basically he currently has a T fitting in between the oil filter housing (N/A variant) and the oil pressure switch. So oil goes to the pressure switch, but also splits off to feed the T25 (with the little restrictor). Now, as far as I understand things, pressure sensors such as this oil pressure switch are designed to act as a dead end and receive certain amounts of oil pressure. Oil simply makes its way to it and stops there, pushing against it and making the switch sense X amount of oil pressure (which is then sent as a signal to the ecu). In Patman's case, right before the oil pressure switch, there is another line that diverts most of the oil towards the turbo. Thus, it stops being an actual dead end, so the certain amounts of oil pressure that the switch is designed to receive is now disrupted. It is no longer X amount of pressure per any given RPM, but rather X - Y (Y being the amount diverted to the T25 feed).

Based on this, I believe he should install the T25 feed line in the tapped oil hole to the right of the oil pressure switch. On a turbo oil filter housing, that is already installed as the factory restricted T25 feed. But on both N/A and turbo housings, there is an additional 3/8" BSPT tapered tap located on the same side of the housing. I believe he can remove that plug and install his aftermarket T25 feed line into there. This way the oil pressure switch will remain as a true 'dead end' and sense the correct amounts of oil pressure (and thus not put the ecu into limp mode), and he will also have a stand-alone oil source for the turbo.

The only last worry I have, is if this 3/8" tap actually plugs high pressure oil, or is just an empty cavity left over from manufacturing reasons. Also, here's an illustration of which plugs/taps I'm talking about, and the differences in turbo and N/A oil filter housings. The yellow circles indicate the stock oil pressure switches, the red circles show the stock T25 feed line on turbo housing, and the plug on the N/A housing.

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[Hickory-NC-2Ggsx]

Yes the fiiting from the turbo ofh fits right into the hole on the non turbo ofh. Its the same thing as putting a turbo on a 4g64. Just have to take out the plug of the ofh.