R32 GTS (RB20DE) Injectors Replacement

[GabsReDeal]

On 06/06/2025 at 1:21 AM, GTSBoy said:

Stock RB fuel pressure is near enough 43.5 psi, so the latency in that table at 31.6 will be close. You can see that 7 or 8 psi equates to about 0.4µs extra latency. So if you wanted to interpolate between the 31.6 and 39.9 psi values you could say you're going up about 2 psi out of those 8, so add about 0.1µs, which is barely worth talking about and is quite possibly wrong because ideally you would fix the latency while running at the appropriate conditions on the dyno, with a wideband sniffing its butt.

Yes I was planning to get it to a tuner with a dyno, but they told me to wait till September because the heat really started now and it is not ideal to do it in this heat.

Edited June 10 by GabsReDeal
Changed October to September

[GabsReDeal]

It seems that after 3 days of usage, it started missing again on one cylinder. Then eventually stopped missing but was stalling after a few minutes.

The spark plugs, injectors, and fuel pump are all alright. So I am considering the tune might be wrong. Weirdly enough though, it took 3 days of running perfectly for it to start giving issues.

On 06/06/2025 at 1:21 AM, GTSBoy said:

Stock RB fuel pressure is near enough 43.5 psi

Just an FYI, the fuel pump which is stock is constantly 3 Bar (43.5 psi). So you were absolutely spot on.

[GTSBoy]

4 hours ago, GabsReDeal said:

the fuel pump which is stock is constantly 3 Bar (43.5 psi)

That's a function of the fuel pressure reg, not the pump. The pump can do more, needs to be able to do more. The reg keeps the pressure in the rail constant above whatever the manifold pressure is.

[GabsReDeal]

On 12th June, the mechanic could not figure out what the issue was, but the car seems to be flooding with fuel. He was suspecting the tune, thus referred me to a tuner. Although the tuner is not familiar with Nistune, last Monday (30th June), he came over to try and re-map it. Despite the tuner trying to completely stop fuel, it kept sounding like it was pushing fuel. Tuner ended up suspecting either the ECU or Injectors.

I do not believe the ECU or Nistune is the issue, as the Nistune software reads and communicates properly.

Today, I removed the (new) injectors to see if they are clogged or leaking. Surprisingly enough, after those 3 days of driving, injectors 2 and 3 look very blocked. You can see the difference in the picture. I blew a bit on 3, that is why it doesn't look as clogged as 2.

I am still unsure if this is what is causing the no start issue, but I am now feeling that I may have bought the injectors and Nistune without the need to do so, as the problem seems to be coming from somewhere else.


 

[GTSBoy]

You've got a shitty fuel system.

[GabsReDeal]

On 03/07/2025 at 10:09 AM, GTSBoy said:

You've got a shitty fuel system.

That is what I have deduced, unfortunately. I had a suspicion that the fuel tank has a leak as I start smelling fuel when filling around half of it and can visibly see some liquid streaks. I imagine it was opened before, possibly previous owner suffered from this issue.

I have asked my mechanic to investigate this when I took it to him before, but may have focused on the issue at hand instead.

[Murray_Calavera]

@GabsReDeal Any chance of finding a new mechanic?

[GabsReDeal]

I removed the fuel pump to take a look at the tank. The sender unit is very rusty.

 

Took a look at the tank and it is also quite rusty. 

Right at the base of where the fuel pump sits, there's a buildup of what seems to be rust particles.

I did find new OEM fuel tank (17202-01U01) and sender unit (25060-01U00) from amayama which would set me back around €900 including shipping and customs. I most likely would need a new fuel pump as well.

On 03/07/2025 at 12:57 PM, Murray_Calavera said:

@GabsReDeal Any chance of finding a new mechanic?

I'm going to be honest, I have been driving for around 6 years now and this is the only mechanic I went to apart for once (Last year I took my Porsche 924 to a guy who specializes on them). I've got a good relationship with him and he's always there to assist, even coming over to my garage at times for my convenience since the car was not starting. I believe he's got over 20 years of experience, but this is not the first time he let me a bit down on some basic diagnosing. I do not want to switch over to someone else, but I'd be lying if I said that it did not cross my mind.

Edited July 3 by GabsReDeal
Added the Porsche 924 part

[MBS206]

How you pulled your fuel filter and split it open to take a look inside of it?

[GabsReDeal]

On 03/07/2025 at 10:47 PM, MBS206 said:

How you pulled your fuel filter and split it open to take a look inside of it?

I haven't yet, but the fuel filter has only 2 months of usage on it (1800kms at most). But considering how the new injectors got very dirty in 3 days, I can only imagine what's inside the filter right now.

[MBS206]

1 hour ago, GabsReDeal said:

I haven't yet, but the fuel filter has only 2 months of usage on it (1800kms at most). But considering how the new injectors got very dirty in 3 days, I can only imagine what's inside the filter right now.

I suspect with the way your tank is, your fuel filter will be clogging/clogged, or purely not working at all. I honestly wouldn't be surprised if someone hasn't put the fuel lines the wrong way too, and the filter is now in the return...

[GTSBoy]

3 minutes ago, MBS206 said:

I honestly wouldn't be surprised if someone hasn't put the fuel lines the wrong way too, and the filter is now in the return...

The peril of assuming that things are configured correctly while trying to diagnose weird shit over the 'net.

[GabsReDeal]

On 04/07/2025 at 1:48 AM, MBS206 said:

I honestly wouldn't be surprised if someone hasn't put the fuel lines the wrong way too, and the filter is now in the return...

That would really suck. I'll have to check that out as well. The older injectors did get clogged before changing the filter, but having them switched would obviously peed up the process greatly.

[joshuaho96]

13 hours ago, GabsReDeal said:

I removed the fuel pump to take a look at the tank. The sender unit is very rusty.

 

Took a look at the tank and it is also quite rusty. 

Right at the base of where the fuel pump sits, there's a buildup of what seems to be rust particles.

I did find new OEM fuel tank (17202-01U01) and sender unit (25060-01U00) from amayama which would set me back around €900 including shipping and customs. I most likely would need a new fuel pump as well.

I'm going to be honest, I have been driving for around 6 years now and this is the only mechanic I went to apart for once (Last year I took my Porsche 924 to a guy who specializes on them). I've got a good relationship with him and he's always there to assist, even coming over to my garage at times for my convenience since the car was not starting. I believe he's got over 20 years of experience, but this is not the first time he let me a bit down on some basic diagnosing. I do not want to switch over to someone else, but I'd be lying if I said that it did not cross my mind.

Take the fuel pump out of the hanger, purge the fuel tank of gasoline, try cleaning it with a soaking of this sodium acetate and dish soap solution. If there's no rust holes this should get the tank and hanger clean.

[GabsReDeal]

On 04/07/2025 at 10:04 AM, joshuaho96 said:

Take the fuel pump out of the hanger, purge the fuel tank of gasoline, try cleaning it with a soaking of this sodium acetate and dish soap solution. If there's no rust holes this should get the tank and hanger clean.

Thanks a lot for this, it does look promising. I imagine I'm going to need a lot of the solution for the tank to get fully clean (or I guess I could rotate it around especially since it does not lose its effectivity). I will see if I can get the ingredients to try this out with the hanger first.

[joshuaho96]

17 hours ago, GabsReDeal said:

Thanks a lot for this, it does look promising. I imagine I'm going to need a lot of the solution for the tank to get fully clean (or I guess I could rotate it around especially since it does not lose its effectivity). I will see if I can get the ingredients to try this out with the hanger first.

Yes, it will take a fair amount of solution but the sodium citrate + citric acid + detergent is cheap stuff. Use laundry detergent instead of dish soap if you want to reduce the bubbles, also you could just buy sodium citrate and add some citric acid to the mix until you get to a weakly acidic solution if you don't feel like dealing with all the bubbling generated by adding everything together. For a fuel tank you need quite a lot of distilled water but it's probably worth the effort.

[GabsReDeal]

I found the ingredients at larger amounts from a Coffee Shop.

1kg Citric Acid for €8.50

500g Baking Soda for €2.50

I tried it out tonight distilled water (I got from my ACs) and dish soap. It does get bubbly with dish soap.

In just two hours the hanger has improved significantly and rubbing against any remaining rust seems to flake it off. I'm going to leave it a little bit longer and see how it goes.

I have read that someone even used this solution in an ultrasonic cleaner to clean a seized water pump which brought it back to life.

[MBS206]

1 hour ago, GabsReDeal said:

I found the ingredients at larger amounts from a Coffee Shop.

1kg Citric Acid for €8.50

500g Baking Soda for €2.50

I tried it out tonight distilled water (I got from my ACs) and dish soap. It does get bubbly with dish soap.

In just two hours the hanger has improved significantly and rubbing against any remaining rust seems to flake it off. I'm going to leave it a little bit longer and see how it goes.

I have read that someone even used this solution in an ultrasonic cleaner to clean a seized water pump which brought it back to life.

Get something that can spray a bit, something like I'd use is a pressure pack for weed sprayer. I use one with degreaser. Spray it on (make sure you're fully covered up, you don't want that shit on you, especially face/eyes).

Alternatively, a paint brush will help here as you can brush and work at the stuff quite aggressively.

 

Be aware, citric acid can eat metal away and will cause it to rust more later.

So make sure you neutralise it when done, and give the fresh metal some protection.

That hanger, I'd honestly bin and get something like the Frenchy's drop in replacement.

The tank, again, I'd look for something else to replace it with. Remember, as metal turns to rust, it means there's less metal there now. So some patches of your fuel tank are likely to be quite thin.

 

Personally, Id focus on the front end of things, IE, how did the injectors get clogged if they're meant to be after a fuel filter. Then, once the front is sorted, I'd rig something up, even like a small surge tank, and make sure the engine is now running and all behaving. Then I'd replace the fuel tank and fuel hanger and pump.

Also, I'd already be preparing to ditch your fuel filter...

 

[joshuaho96]

5 hours ago, MBS206 said:

Get something that can spray a bit, something like I'd use is a pressure pack for weed sprayer. I use one with degreaser. Spray it on (make sure you're fully covered up, you don't want that shit on you, especially face/eyes).

Alternatively, a paint brush will help here as you can brush and work at the stuff quite aggressively.

 

Be aware, citric acid can eat metal away and will cause it to rust more later.

So make sure you neutralise it when done, and give the fresh metal some protection.

That hanger, I'd honestly bin and get something like the Frenchy's drop in replacement.

The tank, again, I'd look for something else to replace it with. Remember, as metal turns to rust, it means there's less metal there now. So some patches of your fuel tank are likely to be quite thin.

 

Personally, Id focus on the front end of things, IE, how did the injectors get clogged if they're meant to be after a fuel filter. Then, once the front is sorted, I'd rig something up, even like a small surge tank, and make sure the engine is now running and all behaving. Then I'd replace the fuel tank and fuel hanger and pump.

Also, I'd already be preparing to ditch your fuel filter...

 

The sodium citrate solution is designed to buffer the citric acid to keep it from attacking metal quite so much, the guy that came up with that recipe did a ton of testing on how much metal loss occurs over time and it's nothing crazy unless you forget about it for months: 

 

[joshuaho96]

7 hours ago, GabsReDeal said:

I found the ingredients at larger amounts from a Coffee Shop.

1kg Citric Acid for €8.50

500g Baking Soda for €2.50

I tried it out tonight distilled water (I got from my ACs) and dish soap. It does get bubbly with dish soap.

In just two hours the hanger has improved significantly and rubbing against any remaining rust seems to flake it off. I'm going to leave it a little bit longer and see how it goes.

I have read that someone even used this solution in an ultrasonic cleaner to clean a seized water pump which brought it back to life.

You can probably scrub the rust with a toothbrush or something. After you get the rust off flush well with water to neutralize and you will probably want to also use a fuel tank sealer to keep it from rusting again.