Fuel system question...

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cruiserhound

cruiserhound

Joined
Feb 8, 2017
Threads
38
Messages
346
Location
Portland Maine
Website
www.dogwashetc.com
Let me first say that my newly acquired 80 was running like a three legged pig from the get go. I've been slowly doing some tune up maintenance/repairs when the weather allows. I got to the point where it seemed like some of these tune-up items were paying off (fuel filter, air filter, oil and oil filter, pcv valve and grommet, coolant flush, plugs, wires, distributor). I changed the fuel pressure regulator, just because it was easy to get to and it seemed like I had a lot of pressure when taking off the gas cap. I now know the pressure in the tank and the fuel pressure regulator are unrelated. I also have fuel pressure damper that i will replace too. Sooo today she's running rough. Don't really no why. When I changed the fuel pressure regulator the rubber o-ring may have ended up in the fuel rail. I had to replace the o-ring with the original and never could find it. I still feel like the o-ring in the fuel rail shouldn't cause too much of an issue as the o-ring is an unusual shape and it shouldn't completely block of the injectors or whatever else is in the fuel rail. Does anyone know if the small o-ring could create a blockage or is it unlikely? Is there a way I can get it out easily it if is in the fuel rail?

I also have a throttle body gasket I'm going to replace as well as clean out the throttle body and I'm currently replacing the vacuum hoses with oem hose. Should I do or replace anything else that may result in a better running engine?
 
cruiserhound said:
Let me first say that my newly acquired 80 was running like a three legged pig from the get go. I've been slowly doing some tune up maintenance/repairs when the weather allows. I got to the point where it seemed like some of these tune-up items were paying off (fuel filter, air filter, oil and oil filter, pcv valve and grommet, coolant flush, plugs, wires, distributor). I changed the fuel pressure regulator, just because it was easy to get to and it seemed like I had a lot of pressure when taking off the gas cap. I now know the pressure in the tank and the fuel pressure regulator are unrelated. I also have fuel pressure damper that i will replace too. Sooo today she's running rough. Don't really no why. When I changed the fuel pressure regulator the rubber o-ring may have ended up in the fuel rail. I had to replace the o-ring with the original and never could find it. I still feel like the o-ring in the fuel rail shouldn't cause too much of an issue as the o-ring is an unusual shape and it shouldn't completely block of the injectors or whatever else is in the fuel rail. Does anyone know if the small o-ring could create a blockage or is it unlikely? Is there a way I can get it out easily it if is in the fuel rail?

I also have a throttle body gasket I'm going to replace as well as clean out the throttle body and I'm currently replacing the vacuum hoses with oem hose. Should I do or replace anything else that may result in a better running engine?
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You should do more diagnosis and less parts replacement. How many miles are on it? Is it an fzj80 or an Fj80? What are the running symptoms? Do they change, appear or go away at certain RPMs? Does it run worse when in gear or the same as it does when it park? Have you done a compression test, leak down test, propane enrichment to find leaks? Have you checked that the timing and idle are properly set? Did you disconnect your battery cable and turn the ignition on and hold the brake down to purge any residual energy from the ECU to reset it? You've done maintenance and you should reset the ECU afterwards and let it relearn before throwing more money at it.
 
Foreign objects were not introduced into the fuel rail until the 100 series came out in 1998 so it's reasonable to say that your 80 series can't run it's best with foreign objects inside the fuel rail.

Do you have the FSM for your particular model?

Does it run smoother at higher rpm's.
 
LandCruisinMy93 said:
You should do more diagnosis and less parts replacement. How many miles are on it? Is it an fzj80 or an Fj80? What are the running symptoms? Do they change, appear or go away at certain RPMs? Does it run worse when in gear or the same as it does when it park? Have you done a compression test, leak down test, propane enrichment to find leaks? Have you checked that the timing and idle are properly set? Did you disconnect your battery cable and turn the ignition on and hold the brake down to purge any residual energy from the ECU to reset it? You've done maintenance and you should reset the ECU afterwards and let it relearn before throwing more money at it.
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Thanks for the advise. FJ80 3FE engine. 243k miles. It currently doesn't have a smooth idle but it is intermittent. It ran good at some points today and at other times it wasn't smooth but kind of sputtering. After my joy ride today I started it back up in the driveway and it almost seemed like it was about to stall out. I also replaced the battery the other day with a Die Hard AGM. I have done none of the things you have suggested but should. I don't have the depth of knowledge that a lot of you guys have. I will try this resetting of the ECU you speak of....is it relevent if I have the 3FE?
 
baldilocks said:
Foreign objects were not introduced into the fuel rail until the 100 series came out in 1998 so it's reasonable to say that your 80 series can't run it's best with foreign objects inside the fuel rail.

Do you have the FSM for your particular model?

Does it run smoother at higher rpm's.
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I do not have the FSM but I do have the 3FE repair manual. It does seem to run better at higher rpm's.
 
FPR: fuel flows to it and then back to the tank only, right? If correct, the o-ring would've flushed into the tank?
 
cruiserhound said:
I do not have the FSM but I do have the 3FE repair manual. It does seem to run better at higher rpm's.
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You probably have vacuum leaks. Buy the proper metric sized vacuum hose and go to town.
 
Maleficio said:
FPR: fuel flows to it and then back to the tank only, right? If correct, the o-ring would've flushed into the tank?
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That I don't know, but I think it is doubtful. The o-ring is somewhere between the Fuel Pressure Regulator and the fuel injectors on the engine side and would be impossible to get back to the tank since it would get stuck at the fuel filter.
 
Sounds like you are on the right track. If you plan on doing your own maintenance, you need to have the fsm.

your egr valve may be stuck slightly open causing the rough running performance at low rpms.
 
cruiserhound said:
That I don't know, but I think it is doubtful. The o-ring is somewhere between the Fuel Pressure Regulator and the fuel injectors on the engine side and would be impossible to get back to the tank since it would get stuck at the fuel filter.
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Fuel return should be a direct route to the tank, and not through the filter. As far as I understand basic operation of a FPR it's purpose is stay closed until pressure builds up and it opens to relieve pressure by bleeding fuel off to the tank.
 
Maleficio said:
Fuel return should be a direct route to the tank, and not through the filter. As far as I understand basic operation of a FPR it's purpose is stay closed until pressure builds up and it opens to relieve pressure by bleeding fuel off to the tank.
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I'm not sure how the system works but I thought that is what the charcoal canister is for? The FPR is connected directly to the fuel rail and injectors and I would find it odd for fuel to go away from the engine. But then again my knowledge is fairly limited concerning mechanics.
 
baldilocks said:
Sounds like you are on the right track. If you plan on doing your own maintenance, you need to have the fsm.

your egr valve may be stuck slightly open causing the rough running performance at low rpms.
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I have a feeling the egr is causing me problems. I cannot find a replacement and they are discontinued through Toyota. My thinking is to do away with the egr system.
 
Maleficio said:
Charcoal canister collects fuel vapor while the engine is off, and feeds the vapor into the intake during startup.
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That makes sense. But you are saying that the fuel goes both ways? That I do not understand. Or are you saying the FPR is a fuel return function? I thought incoming fuel went through the FPR and into the engine? I have a lot to learn.
 
cruiserhound said:
That makes sense. But you are saying that the fuel goes both ways? That I do not understand. Or are you saying the FPR is a fuel return function? I thought incoming fuel went through the FPR and into the engine? I have a lot to learn.
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If I could see a pic I could tell you more. Right now I'm going by how my old Porsche 928 worked.
 
The O-ring is not going to make it through the fuel system. It would have to be smaller than the inner diameter of the fuel return line in order to do so. If it did get pushed into the fuel rail it's likely Lodged in the back or somewhere inside the rail. If you want to be educated on the 3FE then all you need to do is say...... @jonheld ....Help. He is the resident guru of all things 3FE and is your best source of insight and knowledge into your problems.
 
LandCruisinMy93 said:
The O-ring is not going to make it through the fuel system. It would have to be smaller than the inner diameter of the fuel return line in order to do so. If it did get pushed into the fuel rail it's likely Lodged in the back or somewhere inside the rail. If you want to be educated on the 3FE then all you need to do is say...... @jonheld ....Help. He is the resident guru of all things 3FE and is your best source of insight and knowledge into your problems.
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Thanks for the advise and for tagging "the guru", maybe @jonheld will know if I should start tearing apart the fuel rail. I'm crossing my fingers and hoping the o-ring issue is something that is not an imminent threat. If the rubber starts to breakdown, I could see that as a problem but they seem to be pretty resistant to petrol.
 
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