Running rough 92’ 3FE FJ80 please help***

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Plamen said:
Hi mate, attached I am providing a modified Desmogged vacuum hose information. Its based on the Toyota one, but its color coded for easier line following and I have marked the capped ones with cap icons.

I have spent much time reading thought many desmogged threads here in the forum, inspected countless photos and even bought a spare manifold so that I follow the vacuum lines and correctly decide which must be capped. I hope that it helps you.

Disclaimer: The diagram has not been peer reviewed yet by experienced 3FE forum members such as @jonheld so if there are errors, I will fix them and update it right away so that it can be used as future reference.
Click to expand...
That diagram you made is outstanding....i wish it was available when i did mine 10 yrs ago.
FWIW, the VSV for the fuel pressure isn't necessary and most likely not your issue. (I have had mine disconnected for the past 8 yrs and had no affect on my engine performance) It might contribute to occasional hard start when engine is warm. WIth that said, i still think you have a major vacuum leak. ( PCV) etc.
The only source of vacuum leak i can see from Desmog potentially would be the vacuum port at the intake manifold check valve (the black round check valve with 2 nipples, the 2 vacuum port at the top of the intake manifold. Those are the only source of potential vacuum leak for the intake manifold.
 
Marco Lau said:
That diagram you made is outstanding....i wish it was available when i did mine 10 yrs ago.
FWIW, the VSV for the fuel pressure isn't necessary and most likely not your issue. (I have had mine disconnected for the past 8 yrs and had no affect on my engine performance) It might contribute to occasional hard start when engine is warm. WIth that said, i still think you have a major vacuum leak. ( PCV) etc.
The only source of vacuum leak i can see from Desmog potentially would be the vacuum port at the intake manifold check valve (the black round check valve with 2 nipples, the 2 vacuum port at the top of the intake manifold. Those are the only source of potential vacuum leak for the intake manifold.
Click to expand...
I took the valve cover off and ordered parts for the PCV valve and hose. I also added the VSV back in the mix as the diagram shows. Hopefully this takes care of a lot of my issues. Please chime in if something looks a miss? Thanks again!

IMG_1070.webp


IMG_1073.webp


IMG_1076.webp


IMG_1078.webp


IMG_1080.webp
 
CJF said:
How's your big rubber/plastic hose from the air cleaner box to the throttle body? Anything less than a perfect seal from one to the other will cause issues.
Click to expand...
Likely needs to be replaced. It’s definitely not perfect although it is still decent shape. I’ll look at it more closely.
 
@kangjinsoo another thing to note - what's the diameter of the caps you are using for the smaller lines? If I am correct (based on forum knowledge) they are 3.5mm. From my experience 4mm caps are a bit loose, and I used silicone 3mm which are a bit tighter but fit great.
 
Marco Lau said:
FWIW, the VSV for the fuel pressure isn't necessary and most likely not your issue. (I have had mine disconnected for the past 8 yrs and had no affect on my engine performance) It might contribute to occasional hard start when engine is warm.
Click to expand...
From the EWD:
"FUEL PRESSURE CONTROL SYSTEM
THE FUEL PRESSURE UP SYSTEM CAUSES THE VSV (FOR FUEL PRESSURE UP) TO COME ON FOR HIGH TEMP. STARTS AND
IMMEDIATELY AFTER STARTING IN ORDER TO INCREASE THE FUEL PRESSURE, IMPROVE STARTABILITY AT HIGH
TEMPERATURES AND PROVIDE STABLE IDLING. THE ECU EVALUATES THE INPUT SIGNALS FROM EACH SENSOR (1, 2, AND 4).
OUTPUTS CURRENT TO TERMINAL FPU AND CONTROLS THE VSV."

I wouldn't run without it, but that's just me.
 
Replaced vacuum plugs with more suitable silicone plugs. Installed the new PCV valve grommet and hose.
Still need to find a source for replacement hoses that runs from the throttle body hose into the valve cover and another routes into the intake. Does anyone have those part numbers?

IMG_1099.webp


IMG_1101.webp


IMG_1102.webp


IMG_1105.webp


IMG_1104.webp
 
update:

*Installed new PCV valve grommet, vacuum hoses.
*Installed fuel pressure regulator after same issue persisted.

Any further advice would be greatly appreciated?

image.webp


image.webp
 
kangjinsoo said:
My check engine light is dead. Been burnt out since I purchased the truck. Short answer is no.
Click to expand...
Yeah, just use any light or bulb and let the really simple system tell you what ails it.

Without digging back, have you messed with the Throttle Position Sensor yet?
 
RevISK said:
Yeah, just use any light or bulb and let the really simple system tell you what ails it.

Without digging back, have you messed with the Throttle Position Sensor yet?
Click to expand...
I have not messed with the throttle body sensor yet. Was looking into that. I am going to try to give her one more shot at making sure there are zero vacuum leaks because she’s acting as if she has a massive one.
 
kangjinsoo said:
I have not messed with the throttle body sensor yet. Was looking into that. I am going to try to give her one more shot at making sure there are zero vacuum leaks because she’s acting as if she has a massive one.
Click to expand...
Good call.
 
Long story short, I may have a blown HG my 3F, and have similar symptoms. Gotta get it into the barn and do a deep diag though...
 
You must log in or register to reply here.

Share this page

Back
Top Bottom