This thread is to give insights on replacing one the most important, yet underestimated, part in fuel system called Fuel Pulsation Damper in your LS430 2001-2006.

Here are the introductory statements to consider before going through this easy DIY:
1) Your engine is not as quiet as before and you clearly hear ticking noise from cylinders.
2) You cleaned your air/fuel system and still not satisfied with engine performance / vibration / acceleration.
3) Your spark plugs, injectors, MAF and throttle assembly are in mint condition.
4) Your gearbox does not shift smooth as before.
5) You feel gasoline smell in the cabin.
6) Your mileage is worse than before.
7) Your warm engine starts are slightly longer than usually or even don’t happen after first engine cranking.
8) You have tried everything else but your engine is still vibrating at idle and you feel something is not right with the way how it works.

I have the solution for you. LS430 double fuel pulsation dampers will most likely solve all the problems listed above. Definitely worth to give it a try IF other factors are being eliminated.

The cost of the DIY - less than 130 dollars in total (if ordering OEM parts from Arab Emirates).

The complexity - 3 of 10.

The results - 9/10 on satisfactory scale ( you WILL see an improvement).

The dampers are located in the following area:


The dampers are designed in return-less fuel system meaning that their function is highly important to stabilize injectors performance. This cause serious noise reduction and much smoother engine performance if components are not broken or worn.

You start with removing negative battery terminal and the battery itself.
Remove Lexus engine cover.
Start disconnecting multiple electronic hoses from upper engine area.


Try to move engine wires a little bit up to free up space near driver side fuel damper.
Use your 22 wrench to unbolt both passenger and driver fuel dampers. BEFORE you do so, make sure your fuel system doesn’t have any pressure (leave car overnight).
When removing fuel dampers, make sure you see the both gaskets that are used in this part. Remove them as well.
Install new fuel dampers and two new gaskets.
Proceed with the same steps in back order.

That’s it! You just rebalanced your whole fuel system and will most likely gain more comfort in driving your car.

Interesting information from Toyota related to symptoms and causes of failing fuel pulsation dampers.

Description of Problem:
The subject vehicles are equipped with a 3.5L V6 2GR-FSE gasoline engine with an intake port injection system containing a fuel delivery pipe and two fuel pulsation dampers. The diaphragm material in the fuel pulsation dampers may harden over time due to a chemical process involving amine in the fuel, higher ethanol content in fuels used in countries such as the U.S., Canada, and China, and high temperatures. If this were to occur, cracks could develop on the diaphragm, causing fuel to leak. A fuel leak in the presence of an ignition source can increase the risk of a vehicle fire.

6. Chronology of Principal Events: March 2014

In March 2014, Toyota received a dealer report from the U.S. market indicating fuel smell and fuel leakage from a pulsation damper on the fuel delivery pipe of the intake port injection system on a 2007MY Lexus GS350. Toyota was unable to recover the part for investigation, so Toyota monitored the field.

January 2015 - December 2015
In January 2015, Toyota began to receive additional field technical reports from the U.S. market indicating fuel smell or fuel leakage from the pulsation damper. Toyota investigated recovered fuel pulsation dampers and found that the diaphragms had become harder. Cracks were observed on the diaphragms causing fuel to leak.

The diaphragm material is amine cross-linked fluorine rubber, Toyota theorized that amine in fuel additives could cross-link the rubber, causing the diaphragm to become harder, and potentially leading to the diaphragm cracking. Based on this theory, Toyota began an investigation.
Toyota had received reports from the U.S. market. However, no reports were received from the Japan market. Therefore, Toyota compared fuel in the U.S. with fuel in Japan and found that amine content in U.S. fuel is higher than the amine content in the fuel from Japan.

January 2016 - December 2016
To investigate the difference of the level of amine cross-linking of the rubber diaphragm between the U.S. and Japan markets, Toyota conducted random parts recovery in the U.S. and in Japan.
Toyota measured the volume of fluorine in the diaphragm from pulsation dampers on recovered fuel delivery pipes, because fluorine in the rubber decreases when the rubber is cross-linked by amine. As a result of the recovered parts investigation, Toyota found that the fluorine volume in parts recovered from the Japan market have no correlation with vehicle mileage and are similar to new parts. However, the fluorine volume in parts from the U.S. market decreased as the vehicle mileage increased. Based on this parts recovery activity, Toyota believed that the level of amine cross-linking of the rubber is related to the amine concentration in fuel. However, Toyota had not determined whether a sufficient amount of cross-linking could occur in the field so as to produce a crack in the diaphragm.
To further investigate the rate at which the diaphragm material could harden, Toyota conducted immersion testing under various amine concentration levels using sample pieces of rubber and testing fuels. As a result of the testing, Toyota found that the rate at which the rubber hardens increased as the amine concentration was increased. Toyota also conducted immersion testing under various temperature conditions, because, in general, cross-linking is accelerated under high temperature. As a result of the testing, Toyota found that the hardening of the diaphragm was also accelerated by higher temperatures.
To determine whether hardening as a result of these two factors could then lead to cracks on the diaphragm and fuel leakage, Toyota conducted endurance testing in Japan of the fuel pulsation damper. A large amount of fuel is necessary for testing so Toyota conducted the testing using Japan fuel and added the same level of amine as the U.S. fuel. The testing continued for approximately. 150,000km of field usage. However, cracks on the diaphragm and fuel leakage were not duplicated.

January 2017- June 2018
Because cracks on the diaphragm and fuel leakage were not duplicated by the aforementioned testing, Toyota continued the investigation—focusing on other factors that could accelerate amine cross-linking sufficiently to potentially produce a diaphragm crack in the field. Toyota began investigating the influence of ethanol in fuel, because the ethanol content in U.S. fuel is higher than the ethanol content in fuel from Japan. Toyota conducted immersion testing and found that fuel with 10% ethanol content further accelerated the rate at which the rubber hardens.
To determine whether this higher rate of hardening from all three factors (higher temperature, higher amine content, and higher ethanol content) could lead to cracks on the diaphragm in the field, Toyota conducted additional endurance testing in Japan. Toyota sent fuel from the U.S. market to Japan and conducted the testing. As a result of the testing, fuel leakage was duplicated at approximately 95,000km of field usage. The tested part was investigated and cracks on the diaphragm, similar to failed parts in the field, were found. Toyota also found that the amount of fluorine in the diaphragm had decreased. Endurance testing was also conducted concurrently using fuel from Japan. The testing had continued for approximately 150,000km of field usage, but cracks on the diaphragm and fuel leakage did not occur.
Toyota concluded that the diaphragm material could be cross-linked by influence of amine, higher ethanol content in U.S. fuel, and higher temperatures causing the diaphragm to harden over time. If this were to occur at a sufficient rate, cracks could develop on the diaphragm resulting in fuel leakage from the pulsation damper.

Thank you for bringing very good point about SST.

In my case, I aligned parts by hand, then slowly rotated Union bolt until it stopped, and then i issued long 22mm wrench to torque it by hand.

Yeah, no problem, thanks for checking my tutorial.

My Lexus was built in 2006, it’s a non Ultra Luxury version with pioneer audio and currently has around 111k miles. Lol it drives better now than when I bought it with 80k miles several years ago.

To help you with your Landcruiser (by the way I have huge respect for these cars and I know them very well), May I know if you have checked the fuel filter condition any time recently? These cars are highly dependent on clean fuel system, starting with correctly working fuel pump. May I ask if you hear some sort of hissing sound coming from the rear seats?

Update.

Replacing fuel dampers was one of the best decisions I made lately to improve comfort of driving my ls430. As of today, I am noticing consistent smoothness of acceleration, which far exceeded the smoothness level achieved by switching from bad to good MAF sensor.

I do believe returnless fuel system in cars like ls430 requires (!) clean fuel filter, properly working fuel pump and appropriate fuel pressure (!) all the way from gas tank to the injectors in the fuel rails.

So far I am extremely happy with this DIY and recommend forum members to look at these parts if you want to restore Lexus smoothness if other methods haven’t worked or if you are just considering a substantial improvement in quality of your everyday rides to work.

Can anyone share their experience with fuel pulsation dampers and if replacing them did anything good/bad for the car performance?