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bratboy1

Fuel still getting in oil...ej swapped brat

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Hello all,

 

I have an 82 brat with a 91 Legacy L 2.2 EJ and 5psd that I swapped into it.

 

I have been fighting this problem going on 3+ months now and I am not sure what I did/didn't do, really could use some insight. I am getting fuel in my oil and can't figure out why. I have replaced the fuel injectors with rebuilt ones, and got them tested so I know they are good.

I have a fuel pressure regulator for the ej in the mail so will do that when it gets here, same with the PCV valve.

 

When I swapped the EJ in, I put an in line Carter fuel pump. Was there some sort of check valve that was in the legacy tank that kept fuel from coming back in from the return side once the car shuts off? I really don't know how fuel keeps getting back in but I am going crazy and spending a lot of $ on oil and filters every time I swap it lol!

 

Thanks for looking and any insight would be appreciated.

 

 

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The only thing I can suggest is dirty fuel clogging the new injectors so they’re stuck open. I hope you have an EFI rated fuel filter after the fuel pump. 

Is it hard to start when cold and hot? 

Only way fuel can be getting into the sump is via the injectors and the cylinders on shut down. Even then, the correct inlet valve of the leaking injector(s) needs to be cracked open enough to let the fuel past them.

After immediate engine shut off, are all injectors also shut off or is some sort of residual power getting in there and activating the injectors (extreme long shot!)? 

How long does it take your oil to be fuel contaminated, and what makes you think you’re getting that amount of fuel in the sump? 

Cheers 

Bennie

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if the engine temp sensor were bad, it might signal the ECU to continue 'choking' the engine as if it were cold. I'd expect poor running and maybe a fuel smell in the exhaust...?

the diaphragm in the fuel pressure regulator can leak,  look in the vacuum line for fuel.

 

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Could it be unburnt fuel that flooded and washed out of the cylinder, left over from troubleshooting the initial swap?

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Does it run OK? Any codes?

 

If you're washing the cylinders walls enough to get fuel past the rings and into the oil, I expect it to be running pig rich. Sound about right?

 

EA81s have a smaller return line, not intended for fuel injection. What's the volume of that pump you're running? If it's higher than stock EJ22, it's possible your return line is restricting and overpowering the regulator. You could put a fuel pressure gauge in after the regulator to see if that side of the circuit is pressurizing.

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On 2/8/2021 at 1:22 AM, el_freddo said:

The only thing I can suggest is dirty fuel clogging the new injectors so they’re stuck open. I hope you have an EFI rated fuel filter after the fuel pump. 

 Is it hard to start when cold and hot? 

 Only way fuel can be getting into the sump is via the injectors and the cylinders on shut down. Even then, the correct inlet valve of the leaking injector(s) needs to be cracked open enough to let the fuel past them.

 After immediate engine shut off, are all injectors also shut off or is some sort of residual power getting in there and activating the injectors (extreme long shot!)? 

 How long does it take your oil to be fuel contaminated, and what makes you think you’re getting that amount of fuel in the sump? 

 Cheers 

Bennie

 

On 2/8/2021 at 2:18 AM, 1 Lucky Texan said:

if the engine temp sensor were bad, it might signal the ECU to continue 'choking' the engine as if it were cold. I'd expect poor running and maybe a fuel smell in the exhaust...?

 the diaphragm in the fuel pressure regulator can leak,  look in the vacuum line for fuel.

  

 

19 hours ago, carfreak85 said:

Could it be unburnt fuel that flooded and washed out of the cylinder, left over from troubleshooting the initial swap?

 

17 hours ago, Numbchux said:

Does it run OK? Any codes?

  

 If you're washing the cylinders walls enough to get fuel past the rings and into the oil, I expect it to be running pig rich. Sound about right?

 

 EA81s have a smaller return line, not intended for fuel injection. What's the volume of that pump you're running? If it's higher than stock EJ22, it's possible your return line is restricting and overpowering the regulator. You could put a fuel pressure gauge in after the regulator to see if that side of the circuit is pressurizing.

 

Hey everyone thanks for the replies! I am gonna address all of them in this reply.

 

Freddo- I actually do not have an EFI rated filter, just a newer legacy filter. That is something I will look into getting now. It is hard to start cold and hot, but more so when hot. What is happening is that I have been fighting this problem, I would change a part or something and then after I would change the oil and oil filter (fuel would come out of the drain, and a good amount too). So for instance we put the injectors on with new seals and changed the oil, it was tough to start it and after I drove it for a bit I parked it, smelled the oil, and it smelled like fuel. When it shuts off not sure if the injectors are still running, any clue how to check that other than just a circuit tester that lights up?

 

Texan- I can replace the temp sensor and the Fuel pressure regulator is in the mail so I will do that too. I will also looking in the vacuum lines.

 

car freak- I am not sure, I completed the swap over a year ago and it was running fine for about 6-7 months before this issue started to occur. However the first day that I put new injectors on and changed the oil it ran so good I had never heard it like that before. That is what made me think it was just the injectors. But by the end of that day, it was getting fuel in the oil again and I have been fighting it since.

 

Numbchux- No codes, don't have and OBDII and running on the stock ECU. I would say its running rich, you can definitely tell. This is the fuel pump I am running: https://www.amazon.com/gp/product/B0015RC4MY/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

Looks to be about 55-60 psi which I think is a bit higher than the ea81 lol! I have a fuel pressure gauge that I can see what its reading on the inlet and return. I have no doubt that could be attributed to what is going on.

 

Thank you all for the reply, I am going to accumulate the parts over the next few weeks. I am going to replace the engine temp sensor, the fuel pressure regulator, put an EFI filter on, check the vacuum lines, check the pressure in the lines, and see what else can be done and provide an update. Thanks a bunch seriously it feels good to have a direction to go after all this troubleshooting. I really appreciate all the help!

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Don't just throw parts at it. Test. Diagnose.

 

'91 Legacy can still display trouble codes even though it's not OBD II.

ASSuming the Legacy that the fuel filter was designed for was fuel injected, than you have an EFI filter.

Yes, the carbed EA81 uses considerably less pressure than the EJ22. You should have upgraded all rubber hoses and clamps on the pressure side to handle that. But I'm not asking about pressure, I'm asking about volume/flow. Carter's web site says minimum free flow is 21 (no mention of unit. The only one that sort of make sense is Gallons per hour, but even that seems low). '92 Legacy FSM specs the MPFI N/A EJ22 with a 21.1gph pump at 36.3psi, so on paper that actually sounds low, but since it's meant to supply fuel injected V8s up to 7.5L....I would think it would have enough.

 

You have fuel pressure gauges on inlet and return? What do they say?

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My 2 cents.  If you have a fuel pressure gauge hooked into the source fuel line, watch the pressure at idle, 2500 rpm, then after shut off to get some base line readings.  Then watch the fuel pressure for 20 minutes after shutoff, it typically should hold within a few psi.  If you're feeling frisky and have a bore camera, or even a good phone camera, safely take out the spark plugs after shut off and look inside to see if you can see fuel draining into the cylinders.

Good luck.

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On 2/9/2021 at 10:15 AM, Numbchux said:

Don't just throw parts at it. Test. Diagnose.

 

'91 Legacy can still display trouble codes even though it's not OBD II.

ASSuming the Legacy that the fuel filter was designed for was fuel injected, than you have an EFI filter.

 Yes, the carbed EA81 uses considerably less pressure than the EJ22. You should have upgraded all rubber hoses and clamps on the pressure side to handle that. But I'm not asking about pressure, I'm asking about volume/flow. Carter's web site says minimum free flow is 21 (no mention of unit. The only one that sort of make sense is Gallons per hour, but even that seems low). '92 Legacy FSM specs the MPFI N/A EJ22 with a 21.1gph pump at 36.3psi, so on paper that actually sounds low, but since it's meant to supply fuel injected V8s up to 7.5L....I would think it would have enough.

  

 You have fuel pressure gauges on inlet and return? What do they say?

 

On 2/12/2021 at 6:51 PM, UnorganizedMechanic said:

My 2 cents.  If you have a fuel pressure gauge hooked into the source fuel line, watch the pressure at idle, 2500 rpm, then after shut off to get some base line readings.  Then watch the fuel pressure for 20 minutes after shutoff, it typically should hold within a few psi.  If you're feeling frisky and have a bore camera, or even a good phone camera, safely take out the spark plugs after shut off and look inside to see if you can see fuel draining into the cylinders.

 Good luck.

 

Hey guys,

 

Good point, the filter should be an EFI filter then.

Thanks for the replies. I have learned a lot from your responses. I was able to find the Carter fuel pump and Chux, it is 21gph for the free flow and 43psi for the pressure: https://carter.opticatonline.com/part/bcqs-0-carter-p74028?ctx_pt=6256&ctx_p=8&ctx_iam=1

 

I hooked up the gauges and got some readings and here is what I found...

 

Cold start return side:

Fuel pump running before engine turns on: 19 psi

Engine Idle @ 800 rpms: 30psi

Engine off: 0 psi, dropped here immediately 

 

Waited 15 minutes and did return side again:

Fuel pump running before engine on: 20psi

at 2500 rpms: 36 psi

Idle: 30psi

Engine off: 0 psi dropped immediately 

 

Waited 10 mins and hooked up feed side:

Fuel pump running before engine on: 36psi

idle: 36-38psi

@ 2500 rpms: 38-40psi

engine off: 26psi

after 10 mins: 16psi

after 20 mins: 10psi

after 40 mins: 6 psi

 

Do these numbers seem okay? I wasn't sure if that gradual drop on the intake side should be immediate or not.   

If it would help I can bypass the inlets and return  and just run some temp high pressure fuel lines for the intake and return sides back to the fuel pump and the tank and change the oil. Then after running I could see if the newer fuel lines would allow fuel to flow back more freely. I also haven't changed any of the parts like I said before hand yet just for studious purposes.

 

Thanks for the help!! I really appreciate you guys sticking around and giving me all this good advice!!

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5 hours ago, bratboy1 said:

Do these numbers seem okay? I wasn't sure if that gradual drop on the intake side should be immediate or not.   

I also haven't changed any of the parts like I said before hand yet just for studious purposes.

The running pressure is right. The bleed down is to fast.

The fuel pump should have a check valve to hold pressure, and the Fuel Pressure Regulator is rated 36 psi, so the pressure should stay at 36 for a very long time.

Change the FPR and monitor the inlet pressure with the gauge.

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17 hours ago, bratboy1 said:

 

Waited 15 minutes and did return side again:

Fuel pump running before engine on: 20psi

at 2500 rpms: 36 psi

 

Idle: 30psi

 

You're getting 30+psi in the return line? Yikes! Definitely have a restriction there. Was it idling that 15 minutes?

Theoretically, as long as the pressure in the return line is lower than in the rails, it should be OK. But as the revs come down, or under engine braking, it could spike up as the ECU shuts the injectors off.

 

I would definitely run a new return line (or a new feed line, and use the old feed as the return) to get those return pressures down.

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22 hours ago, Numbchux said:

I would definitely run a new return line (or a new feed line, and use the old feed as the return) to get those return pressures down.

Or blow compressed air from front to rear with the fuel cap removed. That might dislodge something in the fuel return line. 

Only do this from the return line that disappears into the firewall. DO NOt try blowing compressed air through the inlet fuel lines before the regulator ;) 

Cheers 

Bennie

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does the fuel return line go to a jetpump like in newer models? maybe it is clogged?

(I'm ignorant of older models, just asking)

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