I'm trying to wrap up my head replacement and am finally down to putting all of the hoses back on top of the engine when I came across a broken air port for the FP VSV on the back driver's side of the head. It looks like this one I found on 4crawler's site:

http://www.4crawler.com/4x4/CheapTri...ine_Pix/9.html

the air port on the left rear of the switch is broken off

where does this port plumb to? where does the front port plumb to?

what' s the best option here? go to the stealership for a new one? do I have to connect that port? can i bypass it?

 

I would try finding one at a junk yard first, it would probably be very expensive at the dealer.

 

3 ports on that VSV, one comes from the intake plenum (supplies vacuum to the VSV), one port connects to the fuel pressure regulator and the 3rd port is simply a vent to the atmosphere (usually covered with a small air filter). So see which connection you are missing and go from there.

Or better yet, just get rid of that VSV:
- http://www.4crawler.com/4x4/CheapTri...ne_Pix/10.html

 

I'm glad you responded, I have another question.

From the vacuum diagram in the FSM, I connected a hose from the FPR to the upper port of the 3 port fitting on the intake plenum, just like you suggest in getting rid of the VSV..
So you're saying I can take the VSV completely off of the truck and eliminate a vacuum hose, 2 wires and a VSV altogether? In your pics and write-ups, you still have that VSV plumbed and wired on your truck..

Also, where is the forward port of the 3 port fitting on the intake plenum connected to? It looks like it goes underneath the VSV, but to where?
(I have mine connected to the forward port of the VSV)

Thanks for the quick response!

 

All 3 of the ports on the intake are the same, it is just a fitting screwed into the intake with 3 vacuum nipples on it, so make no difference which one of those 3 connects to what. On mine, one goes to the cruise control servo, one used to go to the VSV (and now goes directly to the fuel pressure regulator) and the 3rd had a cap on it, but I now run that to a vacuum gauge inside.

And to bypass that VSV, just connect a vacuum hose from any of those 3 posts on the intake directly to the FPR, don't pass GO, don't collect $200 and get rid of the VSV. You can leave it on the top of the valve cover or you can take it off. Mine is removed and the wire that used to connect to it is tucked out of the way.

Not sure where the forward of the 3 ports is connected to on your engine (if that is what you are asking), like I said, makes no difference what port connects to what. Follow the line and see where it ends. On my engine, they are connected as noted above.

 

Thanks a lot man. I really appreciate all of the responses.

Now I have to track down that coolant leak and time it up and I'll be back on the road!

 

Hi, my name is Daniel. I have a 91 pickup 4cyl 4x4. I also have a broken air port on my FP VSV. I read this article about bypassing it. You said to add a vaccuum line from the FPR to the 3-way port. Where do the other 2 hoses go (the intake plenum hose connected to FP VSV & vent hose).

 

Re-read the article:
- http://www.4crawler.com/4x4/CheapTri...ne_Pix/10.html



The other two hoses and the VSV go into the parts box or garbage as you desire. Since you have bypassed the VSV it is no longer needed nor the hoses connected to it, thus the term bypass.

 

Ok, so I will have an open port on the top front (1st vacuum port) of my throttle body?

 

Nope, you take the line that used to run from the intake port to the VSV and instead run that to the FPR directly. Don't pass GO, don't collect $200, etc.

See the green arrows in the image above.

 

Ok, now it seems I have a pressure problem. The more I push the throttle, the more it dies or bogs out. I have tried everything from front to back! Can not get it right.

 

Do you have vacuum to the FPR? Make sure there is actual vacuum (as in the ports are clear and the lines are clear and connected) at the top of the fuel pressure regulator. And if you have a hand vacuum pump, you can jumper the fuel pump on and manually apply vacuum to the FPR and the sound of the returning fuel hiss should change in relation to the vacuum applied. If not, the FPR may not be working right.

And you might also have an air/vacuum leak around the intake air plumbing. That can show up as the engine bogging/dieing when you open the throttle. Check for cracks in all the rubber bellows sections.

 

There is no fuel making it to the fuel return hose. I am getting fuel to the fuel rail. Does this mean I have a bad FPR?

 

Well that could mean there is not enough fuel pressure from the pump to open the FPR (low fuel pressure) or that the FPR is stuck closed and that could cause too high a fuel pressure. Test the pressure and see which it is, FMS has the procedure and values.

 

Ok, so I finally got a fuel pressure tester and tested it... I only had about 12-14psi when the truck was off and 20-22psi when it was running! So I finally found the problem! But what would cause a fuel pump to get weak and is there any way to fix it without buying a new pump? I just replaced it about 2 yrs ago! Not a cheap fix!

 

Might be low voltage, measure the voltage at the pump while running and if it is not within 0.5 volts of the battery, that may be the issue. Why that cause? Well, engine off = battery only voltage = 12-14 psi. Start engine, now alternator is running, voltage = higher and pressure = 20-22 psi. More voltage = more pressure, so you might have too low a voltage.