1991 3F-E De-Smog Performed

[Curtice]

Hi all - bumping this thread with another question. This in regards to the fuel pressure VSV. I've rebuilt my 3FE (from a 1992 FJ80) desmogged. In desmogging, I eliminated all VSV, including the FPR one. Engine runs pretty well, but fuel pressure is just a bit low, and I'm getting some backfire (I think from a lean mixture problem).

So i'm thinking I need to re-connect the FPR VSV, which might help me better regulate the fuel pressure. The problem is, i'm getting confused on which VSV I actually need. According to everything I see on this forum, and according to Toyodiy diagrams, I need the VSV part number 25860-61020 (older 3fe I think as pn 61010 here). See diagram:

Now looking at all other photos that folks have, it is the VSV with the cylindrical vent on the side and two vacuum nipples, like this photo:

In looking through my 3FE smog parts, the VSV labeled with the correct part number is NOT this same VSV. It has 3 vacuum nipples, one going to a check valve. See here:

The VSV that does look like the correct one (picture below) is labeled with PN 90910-12043:

Can someone tell me which is the VSV for the fuel pressure regulator? If it really is the one with 3 vacuum lines going out, I do not know what to do with the 3rd line (knowing one goes to the FPR and another goes to the "gas filter" fitting in the intake manifold). Everywhere I read says the correct VSV is the one with pn 25860 and i've even seen it mentioned that it needs to have the cylindrical vent thing.

I'm super confused here, so would appreciate any help.

 

[ToyotaMatt]

Hi all - bumping this thread with another question. This in regards to the fuel pressure VSV. I've rebuilt my 3FE (from a 1992 FJ80) desmogged. In desmogging, I eliminated all VSV, including the FPR one. Engine runs pretty well, but fuel pressure is just a bit low, and I'm getting some backfire (I think from a lean mixture problem).

So i'm thinking I need to re-connect the FPR VSV, which might help me better regulate the fuel pressure. The problem is, i'm getting confused on which VSV I actually need. According to everything I see on this forum, and according to Toyodiy diagrams, I need the VSV part number 25860-61020 (older 3fe I think as pn 61010 here). See diagram:
View attachment 2917023

Now looking at all other photos that folks have, it is the VSV with the cylindrical vent on the side and two vacuum nipples, like this photo:
View attachment 2917028
In looking through my 3FE smog parts, the VSV labeled with the correct part number is NOT this same VSV. It has 3 vacuum nipples, one going to a check valve. See here:
View attachment 2917024

The VSV that does look like the correct one (picture below) is labeled with PN 90910-12043:
View attachment 2917026

View attachment 2917025

Can someone tell me which is the VSV for the fuel pressure regulator? If it really is the one with 3 vacuum lines going out, I do not know what to do with the 3rd line (knowing one goes to the FPR and another goes to the "gas filter" fitting in the intake manifold). Everywhere I read says the correct VSV is the one with pn 25860 and i've even seen it mentioned that it needs to have the cylindrical vent thing.

I'm super confused here, so would appreciate any help.

do u need a replacement Curtice or simply correct clarification on the ones u currently have ?

 

[Curtice]

Thanks Matt. First I want to know which one it is so I can test to see if this fixes my problem. If it does work, I'd probably like a new replacement if there is one, since everything else on the engine is new, and so I can sell my smog parts as a complete set.

But for now, I just want to know which one to use, cause as I said, i'm quite confused here

 

[CUMAPART]

I'm in the process of SLOWLY bringing a 91 back to life and I believe it's the brown one you keep( the one in your second pic, no check valve). I remember searching through a lot of info on desmogging the 3FE.

 

[Curtice]

Thanks. That’s what I think too, but the part number doesn’t match to that. I'm either really dumb, or missing something. On my other 3FE, the one that the fpr vacuum lines go to is the one that looks like that, but it has the correct pn stamped on it (the one beginning in 25860). The only thing I can think is that the pn is stamped wrong, but that would be hard to believe. If someone has a 1991 or 92 stock 3FE still smogged, would really appreciate taking a look at what you have.

Incidentally, while I still want to know this and try, I am now not sure fuel pressure is the cause of my problems. I did the fuel pressure testing per the fsm and everything is in spec. So I am now not sure hooking this VSV back up will do anything, but I want to try and see. I thought fuel pressure was low, but I was only looking at it at idle. It goes up when in gear and driving.

 

[vsatking]

Subbed

 

[hl krawler]

I just got my 91 a couple of weeks ago and it runs like poop under 2k rpm's, it was desmogged already so Im not sure whats done correctly and whats not but looking through here again I noticed from Curtice photos I am missing a solenoid, is this ok or do I need to replace that solenoid?

 

[Curtice]

@hl krawler which solenoid?

 

[hl krawler]

@hl krawler which solenoid?

In the first photo you posted it shows the hose come off the intake, go to the solenoid and then a new hose goes to the fpr. On mine it just comes off the intake and the hose goes straight to the fpr.

 

[Marco Lau]

In the first photo you posted it shows the hose come off the intake, go to the solenoid and then a new hose goes to the fpr. On mine it just comes off the intake and the hose goes straight to the fpr.

Thats your problem. The FPR needs to see vacuum and is controlled by a solenoid. You will need to find and relocate the solenoid and connect to harness plug.

 

[ToyotaMatt]

I just got my 91 a couple of weeks ago and it runs like poop under 2k rpm's, it was desmogged already so Im not sure whats done correctly and whats not but looking through here again I noticed from Curtice photos I am missing a solenoid, is this ok or do I need to replace that solenoid?



View attachment 2933647

i have these Solenoid's if u need one ?

PM me

thanks

 

[Curtice]

So this has been my same question. I thought maybe my engine was sputtering a bit and stalling because fuel pressure wasn't working properly since I have it set up like you (no solenoid (vsv) ). So I added it, but it made no difference in how my engine ran. So I took it back off.

I ultimately realized my problem was the incorrect spark plug gap. I had gapped it according to 3FE specs from an FJ62. But an FJ80 gap is different. Fixed that and my engine seems to be running waaaaay better.

So I currently do not have the solenoid/vsv between the vacuum and the FPR. I have vacuum going straight to the FPR from the intake and currently running well. Although I haven't run my engine enough to know if I am getting poor mileage or not.

Here is a picture of mine now (running well):

I have the wiring for it if I need it, but currently not planning to put it on.

@hl krawler

 

[GRiP]

best

 

[GRiP]

anyone know the best way to fix this above or below picture red shows part swapped over from a v6 4runner from when i de smogged it yrs ago the pink t junction appears to be cracked

 

[UsedLuxury]

I just got my 91 a couple of weeks ago and it runs like poop under 2k rpm's, it was desmogged already so Im not sure whats done correctly and whats not but looking through here again I noticed from Curtice photos I am missing a solenoid, is this ok or do I need to replace that solenoid?

I think you have a massive vacuum leak somewhere, but if you don't replace this heater control valve soon the leak wont be a problem for long.

 

[hl krawler]

Thanks, ya its on the list Ive been watching it.

 

[ColoradoBoy]

Thanks. That’s what I think too, but the part number doesn’t match to that. I'm either really dumb, or missing something. On my other 3FE, the one that the fpr vacuum lines go to is the one that looks like that, but it has the correct pn stamped on it (the one beginning in 25860). The only thing I can think is that the pn is stamped wrong, but that would be hard to believe. If someone has a 1991 or 92 stock 3FE still smogged, would really appreciate taking a look at what you have.

Incidentally, while I still want to know this and try, I am now not sure fuel pressure is the cause of my problems. I did the fuel pressure testing per the fsm and everything is in spec. So I am now not sure hooking this VSV back up will do anything, but I want to try and see. I thought fuel pressure was low, but I was only looking at it at idle. It goes up when in gear and driving.

I'll try to get a pic for you, if you like.

 

[Curtice]

@ColoradoBoy that would be awesome! Still didn’t figure this out. I might still want to hook it up if it helps with mpg.

 

[Marco Lau]

I will try to take a pic of my engine bay. Mine is de-smogged and it has been running excellent for 4 yrs now.

 

[80JDM]

I did my 3FE desmog and its been running like the tractor engine it is for about 12k miles. No VSVs installed and really does run perfectly smooth. I suggest that you use a propane bottle with a length of vacuum hose to find the vacuum leak that I believe you may have. Turn the bottle on a bit to know thats its flowing and then move the hose end around the all the intake surfaces, when the RPMs increase you have found the leak, or one of them. Pay particular attention to all of the air intake hose fittings from the air filter to the throttle body. Good luck and keep us posted.