CARB LSI Forklift Catalyst Compliance — Rebuild vs. Replace

If you run LPG or propane forklifts in California, the CARB Large Spark-Ignition (LSI) fleet rule applies to you — and a worn-out catalyst is both a compliance problem and an indoor-air problem. Here’s the short version, and how a rebuild fits in.

What the CARB LSI rule requires

California’s Large Spark-Ignition (LSI) regulation sets emission requirements on fleets of forklifts and other LSI equipment. In practice that means the trucks run certified 3-way catalyst systems (with a closed-loop O2 sensor and air/fuel controller) to keep hydrocarbons, CO, and NOx within limits. When a catalyst fails or is removed, the truck falls out of compliance.

The indoor-air / OSHA angle

LPG forklifts running indoors put carbon monoxide into the air your people breathe. The 3-way catalyst is the main thing keeping CO down. A dead catalyst isn’t just a CARB issue — it’s a worker-safety issue, which is why "cat-delete" pipes are a bad idea in an enclosed warehouse.

Rebuild vs. replace

A new certified catalytic muffler runs roughly $900–$2,000. A rebuilt-to-spec unit via core exchange restores the same 3-way catalyst function for less, and your old core carries real precious-metal value. We open the assembly, re-core it with a fresh 3-way catalyst, and reseal it to meet emissions standards.

Call 774-701-6374 with your forklift’s make, model, and engine and we’ll confirm the fit and give you a price.

Pricing: Forklift catalytic-muffler rebuilds are quoted per engine and unit — call 774-701-6374 for your price.

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Start here: forklift catalytic muffler program · rebuild by engine: GM 2.4L / 4.3L · Nissan K21 / K25 · Mitsubishi 4G63 / 4G64 · PSI 2.4L · Kubota WG-series · Toyota 4Y