VG has a cute little growler / Swifty Cent

[Vintage Grumble]

So when I test drove this thing, it seemed a bit down on power, but the ex owner was a very large gentleman, and I sort of assumed the two of us might be slowing the car down a bit during the test, as a few weeks before I had driven a brand new one, and it went HARD. It had also just had a new battery installed so thought maybe that had something to do with it. I took the risk of it being a minor issue as everything else seemed to check out fine, and obviously purchased the car thinking it would be an easy fix. I found the boost gauge screen on the dash and its only letting it boost to around 2 of the 5 segments, and it very much feels like its being limited by the ECU. I text the old owner that night and asked what octane fuel his partner had been running it on, the reply was 91  They have a big ass sticker on the fuel flap saying use only 95 or higher. SO I then assume its the gas causing knocking and the ECU is limiting power due to this, so I drive around all over the place (which even in its low power state is still soooo much fun) to use up all the gas (which took ages due to that economy) and then last night I filled it up with 98, but dang nabbit its still not unlocking fully hektik boosts. I read on line that this is a known issue in the swifts, but luckily I know a truly outstanding gentleman known here as @keltik and he has access to a legit Suzuki scan tool, so tonight we are going to have a gork. There was talk online of firmware updates to fix the issue, but also other people still unable to sort it, so place your bets now on how big of a mistake I've made, lololols.     

[kws]

On 12/01/2026 at 11:28, Vintage Grumble said:

So when I test drove this thing, it seemed a bit down on power, but the ex owner was a very large gentleman, and I sort of assumed the two of us might be slowing the car down a bit during the test, as a few weeks before I had driven a brand new one, and it went HARD. It had also just had a new battery installed so thought maybe that had something to do with it. I took the risk of it being a minor issue as everything else seemed to check out fine, and obviously purchased the car thinking it would be an easy fix. I found the boost gauge screen on the dash and its only letting it boost to around 2 of the 5 segments, and it very much feels like its being limited by the ECU. I text the old owner that night and asked what octane fuel his partner had been running it on, the reply was 91  They have a big ass sticker on the fuel flap saying use only 95 or higher. SO I then assume its the gas causing knocking and the ECU is limiting power due to this, so I drive around all over the place (which even in its low power state is still soooo much fun) to use up all the gas (which took ages due to that economy) and then last night I filled it up with 98, but dang nabbit its still not unlocking fully hektik boosts. I read on line that this is a known issue in the swifts, but luckily I know a truly outstanding gentleman known here as @keltik and he has access to a legit Suzuki scan tool, so tonight we are going to have a gork. There was talk online of firmware updates to fix the issue, but also other people still unable to sort it, so place your bets now on how big of a mistake I've made, lololols.     

I had similar on the ZC31 Sports I bought, previous owners running on 91 and it really killed the power on them (even being NA). A tank of 98, disconnecting the battery for 10 mins and away it went. 

Mate has one of these Swifts and they are a hell of a lot of value for what they are. His does double duty as track/daily, and he loves it. I kinda regret pumping all the money into the current Alto instead of just buying one of these. The BRZ, unsurprisingly, was faster.

 

[Vintage Grumble]

11 hours ago, kws said:

I had similar on the ZC31 Sports I bought, previous owners running on 91 and it really killed the power on them (even being NA). A tank of 98, disconnecting the battery for 10 mins and away it went. 

Mate has one of these Swifts and they are a hell of a lot of value for what they are. His does double duty as track/daily, and he loves it. I kinda regret pumping all the money into the current Alto instead of just buying one of these. The BRZ, unsurprisingly, was faster.

Yeh I'm still not getting full power, might give the battery a disconnect and give that a try, see if it picks up on the octane change.

And while I'm here, I may as well do an update:

In regards to the hunt for the lost power, I took it to visit Ben/Keltik on Monday, and he plugged it into the scan tool. Its not bringing up any codes currently. We took it for a drive while Ben looked at the live data, and its defo pulling timing and limiting boost. He was unable to get the laptop to get along with one of the Suzuki programs, so the ECU firmware hasn't been updated yet. Ben also let me know the car had an outstanding recall for dodgy vacuum pumps, of which he has complete new units on the shelf, so its going in to have that changed on Friday. One of the symptoms of a dodgy vac pump can be low boost, so I'm really hoping that fixes the issue. I have also changed the spark plugs as they looked to be OG, and should have been changed 25K ago.

In other news, I did more research and the jimny rear view mirrors are different on the attachment end, so I cant use the stubby mount I was looking at. I might have to find a nice person to scan/print me one at some point.

In other other news, I have ordered my first upgrade part!!

     

Its an insert for the rear gearbox mount, stiffens it up and apparently makes a huge difference to gear shift feel, reduces wheel hop, and somehow makes the handling better according to people on the internet. 

Regards, VG.

[mjrstar]

Maybe a lean condition due to fuel filter blockage?

 

I had assumed the boost and torque were just gimmick attached to output from throttle position.  But it sounds like it's getting some actual data from somewhere?

 

Did you log tps in case it's a bit dead?

[locost_bryan]

1 hour ago, Vintage Grumble said:

Its an insert for the rear gearbox mount, stiffens it up and apparently makes a huge difference to gear shift feel, reduces wheel hop, and somehow makes the handling better according to people on the internet. 

Regards, VG.

Sounds like the old Classic Mini engine movement issue, solved by fitting stiffer mounts and twin steady bars. Helps to stop the diff moving relative to the wheel hubs and the suspension bush compliance effectively pushing the wheels briefly out of alignment.

[keltik]

TPS is good, fuel trims are within 5% and rail pressure matches commanded values. Just for whatever reason the poost is lower than expected. Only seeing 150Kpa MAP.

Unfortunately there's no knock retard value to monitor and no info in the service manual - so I'm just making guesses at what the timing curve should look like. Only seeing 4-6degrees at peak torque.

[xsspeed]

I heard this will fix it, https://auctions.yahoo.co.jp/jp/auction/w1191945604 and https://auctions.yahoo.co.jp/jp/auction/q1215146534

[mjrstar]

Time to wire the wastegate shut and send it to oblivion. 

Y'know to test the turbo and intercooler piping / plastic manifold for leaks

[Vintage Grumble]

13 minutes ago, mjrstar said:

Time to wire the wastegate shut and send it to oblivion. 

Y'know to test the turbo and intercooler piping / plastic manifold for leaks

I'm 99.99% sure the ECU is limiting the boost based on how it feels and acts. When you hoof it, it builds hard and fast like it should then at about half boosts WHAM it stops it and pulls it back to 2/5ths boosts, It feels very intentional. If the vac pump and firmware update dont work, I'll have to start trying other stuff.

[yoeddynz]

Actually sounds like your turbo is struggling to get enough air. I think you need one of these..

[Vintage Grumble]

49 minutes ago, yoeddynz said:

Actually sounds like your turbo is struggling to get enough air. I think you need one of these..

Bro, are you mad, you know what would happen,

 

[Vintage Grumble]

P.S. the battery reset has not changed anything/preformed the miracle I had hoped.

[sheepers]

Sounds like someone should have bought a KZN185.

[Vintage Grumble]

47 minutes ago, sheepers said:

Sounds like someone should have bought a KZN185.

This boost issue is pretty much the swift equivalent of a 1KZ BHG or warped head 

[sheepers]

thats fake news, they never do that. 

[Vintage Grumble]

Its fixed! 

Bens chap changed out the vac pump, and Ben won the battle against the laptop and updated the ECU to the latest firmware, and its now boosting how it should and going MUCH better. VG happy.

I must of had a senior moment, and was convinced the new one I drove was getting 5 segments of boost, but Ben took a brand new one from his lot out and it was getting 4 segments, so I had a look online and it turns out that 4 is the correct amount of boost segments for a standard car, which is around 16psi.

Ben has also recommended to run a carbon cleaner through it, one you hook up to a vac line and spray in, so if anyone has any recommendations on that, please let me know.

Huge thanks to Ben for his help!

Now that its running properly, time to start ruining it! I think my first waste of money mod might be an intake. Theres a few available in NZ, but they either look like they will eat a ton of hot air (gets real hot under bonnet, I think due to the cat being right in the front of the motor) or are crazy expensive. HKS does a hot air eater and a super spendy one:

One I've found that looks like it should get cooler air, and isn't rapishly expensive is from MST,

Thats the current front runner.

Regards, V "full boost" G.

P.S. my wife keeps referring to me as a swifty, and it's upsetting me.

[sheepers]

would you prefer "old bought not built Thomas"?

[Vintage Grumble]

9 hours ago, sheepers said:

would you prefer "old bought not built Thomas"?

Bolt on the world! I CBF making things for this when there's so many bolt on bits to be had, time saved here could be (but likely won't be) spent on reviving my old car 😉

[anglia4]

On 17/01/2026 at 09:13, Vintage Grumble said:

P.S. my wife keeps referring to me as a swifty, and it's upsetting me.

[Vintage Grumble]

I decided to try shortening the mirror the old fashioned way. Did some half assed figurings, hacksawed ~25mm out of it,