Suzuki APV engine swap

[pwuser174394390989]

My 2013 Suzuki APV has finally coughed its last breath; terrible mileage, random stalling, and no power under load. I’m weighing three replacement engines:

Suzuki G15A (stock 1.5 L)

Suzuki G16B (1.6 L)

Toyota 1NZ-FE (1.5 L VVT-i)

Rather than guessing, I’d love to hear from people who’ve actually done these swaps.

Questions for anyone who’s been there, done that
Fit & clearance

Did the G16B’s slightly taller block force you to raise the seat or cut metal?

For 1NZ-FE swappers: how did you mount it under-seat, and what custom brackets or adapter plates were truly necessary?

Gearbox & driveline

Does the stock APV 5-speed bolt straight onto the G16B?

If you went 1NZ-FE, did you keep the Suzuki gearbox with an adapter plate or move to a Toyota box? Any driveshaft mods?

Wiring and ECU headaches

How messy was the loom splice for the G16B?

With the 1NZ-FE, did you run the full Toyota harness or integrate sensors into the Suzuki loom? Any immobilizer issues?

Cooling & heat-soak

What radiator/fan combo keeps the under-seat bay from cooking?

Any tips on insulating the seat pan so passengers don’t bake?

Real-world fuel economy

Post-swap city/highway figures for each engine?

Did gearing changes (e.g., diff swap) help your mileage?

Parts & reliability

Are G16B parts still easy to source locally?

For the 1NZ-FE crowd: any recurring issues with coil-packs, O2 sensors, or throttle bodies?

Cost breakdown

Ballpark totals you actually paid (engine, wiring, fabrication, labor)?

Hidden expenses I should budget for?

Registration & inspection

Was engine-number change a hassle with excise/insurance?

Any extra taxes when moving from 1.5 L to 1.6 L?

What I’m aiming for
Good daily-drivable mileage (family hauler + A/C on).

Minimal downtime; ideally a weekend swap.

Reliability on long trips into the mountains.

If you’ve got photos, dyno sheets, or even horror stories, please share. The more details the better—I don’t want to reinvent the wheel or burn cash on the wrong setup.

Thanks in advance!

[Xulfiqar]

Firstly make sure your engine is actually bad. Not just using childish behavior symptoms of “missing, stalling etc.

Those can occur on a good engine too if you had a bad ignition coil or crank/cam sensor too.

Repair or replace with same engine and for heat and noise management aftermarket genny canopy material. But also make sure that all airflow panelling and ducting is in place in the front and under the van.

[ali.7861]

My 2013 Suzuki APV has finally coughed its last breath; terrible mileage, random stalling, and no power under load. I’m weighing three replacement engines:

Suzuki G15A (stock 1.5 L)

Suzuki G16B (1.6 L)

Toyota 1NZ-FE (1.5 L VVT-i)

Rather than guessing, I’d love to hear from people who’ve actually done these swaps.

Questions for anyone who’s been there, done that
Fit & clearance

Did the G16B’s slightly taller block force you to raise the seat or cut metal?

For 1NZ-FE swappers: how did you mount it under-seat, and what custom brackets or adapter plates were truly necessary?

Gearbox & driveline

Does the stock APV 5-speed bolt straight onto the G16B?

If you went 1NZ-FE, did you keep the Suzuki gearbox with an adapter plate or move to a Toyota box? Any driveshaft mods?

Wiring and ECU headaches

How messy was the loom splice for the G16B?

With the 1NZ-FE, did you run the full Toyota harness or integrate sensors into the Suzuki loom? Any immobilizer issues?

Cooling & heat-soak

What radiator/fan combo keeps the under-seat bay from cooking?

Any tips on insulating the seat pan so passengers don’t bake?

Real-world fuel economy

Post-swap city/highway figures for each engine?

Did gearing changes (e.g., diff swap) help your mileage?

Parts & reliability

Are G16B parts still easy to source locally?

For the 1NZ-FE crowd: any recurring issues with coil-packs, O2 sensors, or throttle bodies?

Cost breakdown

Ballpark totals you actually paid (engine, wiring, fabrication, labor)?

Hidden expenses I should budget for?

Registration & inspection

Was engine-number change a hassle with excise/insurance?

Any extra taxes when moving from 1.5 L to 1.6 L?

What I’m aiming for
Good daily-drivable mileage (family hauler + A/C on).

Minimal downtime; ideally a weekend swap.

Reliability on long trips into the mountains.

If you’ve got photos, dyno sheets, or even horror stories, please share. The more details the better—I don’t want to reinvent the wheel or burn cash on the wrong setup.

Thanks in advance!

Do a compression test on the engine check it properly if it is really that bad!!
These things you mensioned in the post could happen with bad coil plugs spark plug engine oil or bad quality of fuel/Petrol,