jjyoda_86

so my 93 v6 3.0 has been running like hell when its cold I talked to a couple of people and they told me to check my fuel pulsation damper screw and see if it has backed itself out. Well I cant find it for the life of me so if anyone knows exactly where its at or has a picture of it please let me know or post a pic

BLKNBLU

iTrader: (1)

#23270 on this schematic

http://www.utoyot8.com/FullImage.asp...8808-++++)3VZE

jjyoda_86

I read a thing that told to me to pull the cap off and check the screw on it b/c they said if that screw backs out it can cause driveability and mpg issues. have u ever heard of anything like that

MudHippy

It's not adjustable and requires no periodic maintenance. The screw is left in after it leaves the factory to serve as quick reference check for fuel pressure. Watch, someone will want to argue with me over this. Even though they will have no basis or actual proof stating otherwise.


It's not uncommon for the screw to fall out, and be left sitting in the plastic cover. This has ABSOLUTELY no effect on the functionality of the damper. If that's the case, all you need to do is screw it back in untill it bottoms out. Or don't. Like I said, it's only purpose is so that it's easier to check for fuel pressure when it's there.

scope103

And this is surprising to you? (Alas, I can't help you out, because I think you are correct. Maybe next time.)

jjyoda_86

thanks for all the help I will check it out tomorrow and see if that screw has fallen. I just read something of identifix saying that it could possibly be the the cause of my code 14. Im stumped at the moment until I get more time to figure out why Im getting that code. I checked my coil wave and it was ok but that was after I drove it to the shop. I have new plugs and wires cap & rotor. So if anyone has any tips or diag tips to figure out whats wrong let me know.

myyota

Code 14 is usually related to the TPS. MudHippy is correct that there is no maintenance required for the fuel pulsation damper, but if the screw comes out of the bottom you will have a fuel leak, i had the happen on my 86 4Runner, and i had to replace mine. It is an expensive part, but i was able to find a used one, and what i did on the new one was put a little JB Weld around the screw so it can`t come out.

874runnersr5

i though code 14 was ignition system?

myyota

I was thinking of a 22RE, and i see he has a 3.0, so it could be for the ignition system in his case.

MudHippy

I had my suspicions about what other function(s) the screw might have. What I'd speculated was that the screw needed to be there in the event that the fuel pressure in the system was lost, or lowered drastically. This should never happen barring any massive fuel leaks or disassembly of the systems components. The system is designed to maintain a constant high pressure, even during times of inoperation or long-term storage.

My hypothesis was that the screw keeps the diaphragm from over-extending by force of the return spring when fuel pressure is lost, or falls below a given threshold(is nearly lost). Which I'd assumed could possibly damage the diaphragm, causing it to leak or not function as intended. I've stated this assumption in a previous thread.

It seems to me as if your case verifies my hypothesis. Which, if so, makes it now a theory. If you want my opinion atleast. Possibly more supporting evidence would be required by others, but I'm satisfied as to it's truthfulness at this point.

Thanks for sharing!
Yes, code 14 is ignition return(IGF)signal loss.

myyota

MudHippy, another thing of interest is that on the later model 22RE`s the fuel pulse damper is no longer used, it was replace with a banjo bolt, maybe they found that its not really needed so it was replaced with the banjo bolt ?.

fork

i was wondering about this also. i know the one on my 86 has, and my 89 does not. i'd definitely like to know more about this part, can't seem to find much on it. the one on my 86 appears to have problems

MudHippy

I wasn't aware of that.

I do know that they're very similar in design to a fuel pressure regulator. Possibly the FPR was redesigned/repurposed to perform a dual function as a regulator and a damper on those systems. The main difference between them appears to be that the regulator is vacuum controlled, as well as spring loaded. So essentially it's just a vacuum assisted pulsation damper. The damper is only used in conjunction with the regulator on some systems to smooth out/dampen minor fluctuations in the fuel rail pressure caused by the injectors firing. Some systems use ECM programming and higher fuel pressure to eliminate the need for the regulator. And some have the regulator in the fuel tank, or as a part of the fuel pump.

So maybe the systems without dampers have similar characteristics of higher fuel pressure and ECM programming too, like those without regulators. I dunno.

Everything I've found on the subject is found in these pdfs.

Pages 8 & 9 of this one. http://autoshop101.com/forms/h22.pdf

Pages 14-16 of this one. http://autoshop101.com/forms/h42.pdf

fork

o'reilly is showing me a BWD one for $90.99. ouch

myyota

When i had to replace mine, i found a used one for 45.00 dollars. I didn`t have an extra 90.00 dollars laying around at the time to buy a new one.

spectraowner

What is the difference of the fuel pulsation damper and a fuel pressure damper if any?

Walker199

Hi I have a 1991 Toyota 4Runner with the 3.0 and recently had a shop tell me my fuel pressure was low due to a bad pulsation dampener so instead of paying them a bunch of money to do it I did it myself with the help of a friend we replaced it and put it all back together and now it has a taping sound like something is hitting the fan but there's nothing in the fan I heard it could be the fuel pressure regulator.... It's coming from the drivers side of the engine bay anyone have any ideas on where this sound is coming from?

scope103

No. Try this: http://www.harborfreight.com/mechani...ope-69913.html
(Or the tube from inside a roll of paper towels will work, or a 1 ft length of large (3/4"?) diameter hose.)

Unless you have fuel just pouring out of the damper, I can't imagine how it could cause low fuel pressure. But that's done now. Or is it? Did you use NEW crush washers? They cannot be reused; if you did, I fear you may find out the hard way ....

When you report back, here's some commas and periods you can use ,,, ... It will make your post a WHOLE lot easier to understand. And while you're at it, you don't have a fuel pressure DAMPENER, and a "taping" sound is what a tape recorder makes (or maybe that zzZT! sound when you pull off a piece of duct tape?) I'll bet you're asking about a tapping sound, but it's hard to tell.

Walker199

What do you mean I don't have a fuel pressure dampener? But did reuse the crush o rings I shouldn't have I know but I did

scope103

A "dampener" is something that makes something else "damp." Like a steam iron, or a lawn sprinkler. Do you have something in your 4runner that sprays water onto your fuel? I'm not usually so testy with people who make up their own words, but you must have read the rest of the posts in this thread. Did you see the word "dampener" anywhere?

Should you care? Do you want people on this site to try to help you? Then you probably want to make your posts clear, easy to understand, (and interesting.)

Since you know you "shouldn't have" reused the crush washers, you must know why that is. You run the very real risk of having gasoline dribble out onto the rt side exhaust manifold. What happens then? I know you wanted to save a "bunch" of money, but those crush washers cost me $1.21 each (you need two) the last time I replaced mine.

Oh, and welcome to Yotatech.