{"title":"Harness \u0026 ECM Bundles","description":"\u003cp\u003eShop complete matched wiring harness and ECM\/ECU packages for supported GM and Toyota applications. These bundles simplify engine-swap, race, and derby builds; verify engine, model year, and application fitment before ordering.\u003c\/p\u003e","products":[{"product_id":"96-2005-3100-3400-harness-ecm-bundle-package","title":"1996–2005 GM 3100\/3400 Harness + Tuned ECM Package — No Core Required","description":"\u003ch2\u003e1996–2005 GM 3100\/3400 Harness + Tuned ECM Package\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eComplete simplified wiring solution — no ECM core required.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eBuilt for 1996–2005 GM 3100 and 3400 V6 engines, this LMMF package gives you the major wiring and computer components needed for a clean, dependable demolition derby, race, off-road, or engine-swap build. No hunting down a usable ECM. No sending in a core. No trying to piece together mismatched wiring.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eNo core required • Kept in stock • Usually ships within 1–2 business days\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003ch3\u003eFits\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e1996–2005 GM 3100 \/ 3400 V6 engines\u003c\/li\u003e\n  \u003cli\u003e1996–1999 and 2000–2005 injector setups\u003c\/li\u003e\n  \u003cli\u003eDemolition derby, race, off-road, and simplified engine-swap builds\u003c\/li\u003e\n  \u003cli\u003eLA1-platform applications where applicable\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat’s Included\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eProfessionally built simplified 3100\/3400 engine harness\u003c\/li\u003e\n  \u003cli\u003eAll-new wiring, new connectors, and quality components\u003c\/li\u003e\n  \u003cli\u003eTuned ECM matched to the package\u003c\/li\u003e\n  \u003cli\u003eInjector adapter, allowing the package to work across 1996–2005 injector setups\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eNo Core Required\u003c\/h3\u003e\n\u003cp\u003eYour tuned ECM is included with the package. You do \u003cstrong\u003enot\u003c\/strong\u003e need to send us an ECM core or return one after purchase.\u003c\/p\u003e\n\n\u003ch3\u003eIn Stock \u0026amp; Fast Shipping\u003c\/h3\u003e\n\u003cp\u003eThese harness and ECM packages are kept in stock and usually ship within \u003cstrong\u003e1–2 business days\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003ch3\u003eWhy Choose an LMMF Package?\u003c\/h3\u003e\n\u003cp\u003eThis is more than a replacement harness—it is a ready-to-run setup designed to remove unnecessary factory wiring and give you a cleaner, more reliable installation. Every harness is built with new wire and connectors, not brittle, worn-out junkyard wiring.\u003c\/p\u003e\n\n\u003cp\u003eWe simplify the wiring, match the ECM to the package, and build it for the abuse of derby, race, off-road, and swap use.\u003c\/p\u003e\n\n\u003ch3\u003eBefore You Order\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eConfirm that your engine is a 1996–2005 GM 3100 or 3400 V6.\u003c\/li\u003e\n  \u003cli\u003eThe included injector adapter supports both 1996–1999 and 2000–2005 injector configurations.\u003c\/li\u003e\n  \u003cli\u003eContact LMMF before ordering if you are unsure about engine year, engine family, or vehicle compatibility.\u003c\/li\u003e\n  \u003cli\u003eSee the related products below for compatible ignition, sensor, switch-box, and wiring accessories.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003e\u003cstrong\u003ePlug it in. Fire it up. Send it.\u003c\/strong\u003e\u003c\/p\u003e","brand":"LMMF SIMPLIFIED WIRING","offers":[{"title":"Default Title","offer_id":50012253061414,"sku":"96-2005-3100-3400-harness-ecm-bundle-package","price":495.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0868\/0505\/3734\/files\/96-2005-3100-3400-harness-ecm-bundle-package.jpg?v=1745169322"},{"product_id":"89-99-3100-harness-and-ecm-bundle","title":"1989–1999 GM 3.1 \/ 3100 Harness + Tuned ECM Package — No Core Required","description":"\u003ch2\u003e1989–1999 GM 3.1 \/ 3100 Harness + Tuned ECM Package\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eComplete simplified wiring package for 1989–1999 GM 3.1 and 3100 builds — tuned ECM included and no core required.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eThis LMMF package is built for the older GM 3.1 and 3100 platform, covering 1989–1994 3.1 flat-top engines, 1995 3100 engines, and 1996–1999 3100 engines. It gives you a clean, dependable simplified wiring solution without chasing down parts or sending in an ECM core.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eKept in stock • Usually ships within 1–2 business days • Tuned ECM included • No core required • Injector harness included\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003ch3\u003eFits\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e1989–1994 GM 3.1 flat-top engine applications\u003c\/li\u003e\n  \u003cli\u003e1995 GM 3100 engine applications\u003c\/li\u003e\n  \u003cli\u003e1996–1999 GM 3100 engine applications\u003c\/li\u003e\n  \u003cli\u003eDemolition derby, race, off-road, and simplified engine-swap builds\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat’s Included\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eProfessionally built simplified standalone engine harness\u003c\/li\u003e\n  \u003cli\u003eTuned ECM matched to the package\u003c\/li\u003e\n  \u003cli\u003eInjector harness for 1989–1995 3.1 \/ 3100 applications\u003c\/li\u003e\n  \u003cli\u003eAll-new wiring, new connectors, and quality components\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eInjector Harness Details\u003c\/h3\u003e\n\u003cp\u003eThe included injector harness is used for 1989–1994 3.1 flat-top and 1995 3100 engine applications. It is included with every package, but it is \u003cstrong\u003enot required\u003c\/strong\u003e for 1996–1999 3100 engines.\u003c\/p\u003e\n\n\u003ch3\u003eWhat This ECM Includes\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eSecurity \/ VATS delete\u003c\/li\u003e\n  \u003cli\u003eRaised rev limiter\u003c\/li\u003e\n  \u003cli\u003eFueling adjustments for derby, race, and off-road use\u003c\/li\u003e\n  \u003cli\u003eTiming adjustments\u003c\/li\u003e\n  \u003cli\u003eAdjusted temperature parameters\u003c\/li\u003e\n  \u003cli\u003eUnused sensors removed to reduce unwanted shutdown and fault issues\u003c\/li\u003e\n  \u003cli\u003eMAF delete\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eNo Core Required\u003c\/h3\u003e\n\u003cp\u003eYour tuned ECM is included. You do \u003cstrong\u003enot\u003c\/strong\u003e need to send in an ECM core or return one after purchase.\u003c\/p\u003e\n\n\u003ch3\u003eWe Buy Cores\u003c\/h3\u003e\n\u003cp\u003eLMMF buys compatible ECM cores separately. Contact us before sending one in so we can confirm compatibility and provide current purchase details.\u003c\/p\u003e\n\n\u003ch3\u003eIn Stock \u0026amp; Fast Shipping\u003c\/h3\u003e\n\u003cp\u003eThese complete harness and ECM packages are kept in stock and usually ship within \u003cstrong\u003e1–2 business days\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003ch3\u003eBefore You Order\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eConfirm whether your engine is a 1989–1994 3.1 flat-top, a 1995 3100, or a 1996–1999 3100.\u003c\/li\u003e\n  \u003cli\u003eThe included injector harness is needed for 1989–1995 applications and is not needed for 1996–1999 3100 engines.\u003c\/li\u003e\n  \u003cli\u003eThis is not the correct package for 2000–2005 3100\/3400 applications.\u003c\/li\u003e\n  \u003cli\u003eFor newer 1996–2005 3100\/3400 applications, shop the LMMF 1996–2005 GM 3100\/3400 Harness + Tuned ECM Package.\u003c\/li\u003e\n  \u003cli\u003eContact LMMF before ordering if you are unsure about engine year, engine configuration, or vehicle compatibility.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003e\u003cstrong\u003eComplete wiring. Included ECM. No core hassle. Plug it in and send it.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eOff-road, race, engine-swap, and demolition derby use only. Not intended for emissions-controlled or street-driven vehicles.\u003c\/strong\u003e\u003c\/p\u003e","brand":"LMMF SIMPLIFIED WIRING","offers":[{"title":"Default Title","offer_id":50012253126950,"sku":"LMMF-89-99-3100-HARNESS-AND-EC-DEFAULT-TITLE","price":525.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0868\/0505\/3734\/files\/89-99-3100-harness-and-ecm-bundle.jpg?v=1745169321"},{"product_id":"98-05-3800-series-ii-simplified-harness-bundle","title":"1998–2005 GM 3800 Series II Harness + Tuned ECM Package — No Core Required","description":"\u003ch2\u003e1998–2005 GM 3800 Series II Harness + Tuned ECM Package\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eComplete simplified wiring solution — tuned ECM included and no core required.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eBuilt for 1998–2005 GM 3800 Series II engines, this LMMF package gives you the major wiring and computer components needed for a clean, dependable demolition derby, race, off-road, or engine-swap build. Choose the injector connector style that matches your engine, install the simplified harness, and get your build running without chasing down a usable ECM.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eTuned ECM included • No core required • Choose EV1 or Multec injectors • Kept in stock • Usually ships within 1–2 business days\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003ch3\u003eFits\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e1998–2005 GM 3800 Series II engines\u003c\/li\u003e\n  \u003cli\u003eEV1 injector configurations\u003c\/li\u003e\n  \u003cli\u003eMultec injector configurations\u003c\/li\u003e\n  \u003cli\u003eDemolition derby, race, off-road, and simplified engine-swap builds\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eChoose Your Injector Style\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eEV1 Injectors:\u003c\/strong\u003e Select this option if your engine uses EV1 injector connectors.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMultec Injectors:\u003c\/strong\u003e Select this option if your engine uses Multec injector connectors.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eBoth EV1 and Multec configurations are kept in stock. If you are unsure which injector connection you have, contact LMMF before ordering.\u003c\/p\u003e\n\n\u003ch3\u003eWhat’s Included\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eProfessionally built simplified standalone 3800 Series II engine harness\u003c\/li\u003e\n  \u003cli\u003eAll-new wiring, new connectors, and quality components\u003c\/li\u003e\n  \u003cli\u003eTuned ECM matched to the package\u003c\/li\u003e\n  \u003cli\u003eYour selected EV1 or Multec injector connector configuration\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eNo Core Required\u003c\/h3\u003e\n\u003cp\u003eYour tuned ECM is included with the package. You do \u003cstrong\u003enot\u003c\/strong\u003e need to send us an ECM core or return one after purchase.\u003c\/p\u003e\n\n\u003ch3\u003eSimple Hookup\u003c\/h3\u003e\n\u003cp\u003eThis simplified setup requires only a basic two-wire power-and-ground hookup to get your engine running.\u003c\/p\u003e\n\n\u003ch3\u003eIn Stock \u0026amp; Fast Shipping\u003c\/h3\u003e\n\u003cp\u003eBoth EV1 and Multec versions are kept in stock and usually ship within \u003cstrong\u003e1–2 business days\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003ch3\u003eBefore You Order\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eConfirm that your engine is a 1998–2005 GM 3800 Series II.\u003c\/li\u003e\n  \u003cli\u003eSelect the injector style that matches your engine: EV1 or Multec.\u003c\/li\u003e\n  \u003cli\u003eContact LMMF before ordering if you are unsure about engine year, injector connection, or vehicle compatibility.\u003c\/li\u003e\n  \u003cli\u003eFor supercharged applications, shop the separate 3800 Supercharged Simplified Harness listing.\u003c\/li\u003e\n  \u003cli\u003eIntended for off-road, race, engine-swap, and demolition derby use; not intended for emissions-controlled or street-driven vehicles.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003e\u003cstrong\u003ePlug it in. Fire it up. Send it.\u003c\/strong\u003e\u003c\/p\u003e","brand":"LMMF SIMPLIFIED WIRING","offers":[{"title":"EV1 Injectors","offer_id":50400722157862,"sku":"LMMF-98-05-3800-SERIES-II-SIMP-EV-1-INJECTORS","price":460.0,"currency_code":"USD","in_stock":true},{"title":"Multec Injectors","offer_id":50400722190630,"sku":"LMMF-98-05-3800-SERIES-II-SIMP-MULTEC-INJECTORS","price":460.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0868\/0505\/3734\/files\/98-05-3800-series-ii-simplified-harness-bundle.webp?v=1773672696"},{"product_id":"97-99-camry-modded-ecu-harness-bundle","title":"97-99 Camry Modded ECU \u0026 Harness Bundle","description":"\u003cp\u003eThis computer is physically modified (not tuned) for demo derby use to help keep your engine running as long as possible. It prevents limp mode and other issues for your derby car.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFeatures\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eAll extra pins removed for wider fitment\u003c\/li\u003e\n\u003cli\u003eLights on board\u003cbr\u003e\n\u003cul\u003e\n\u003cli\u003ePower\u003c\/li\u003e\n\u003cli\u003eCheck Engine Light\u003c\/li\u003e\n\u003cli\u003eInjector Power\u003c\/li\u003e\n\u003cli\u003eInjector Pulse\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003eLimp mode prevented\u003c\/li\u003e\n\u003cli\u003eIGF signal spoofed (feedback from ignition coils)\u003c\/li\u003e\n\u003cli\u003eTrans hot wired for 1st gear (all forward gears are now 1st)\u003c\/li\u003e\n\u003cli\u003ePossiblity of spoofing coolant temp sensor - requires special setup - see below.\u003c\/li\u003e\n\u003cli\u003eCoolant temp sensor limited (maxing out the signal is prevented)\u003c\/li\u003e\n\u003cli\u003eWorks in stock cars or derby cars with a power harness.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eRequired Sensors\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eMust be installed in a car that did not have an immo computer (must be white connectors at the computer)\u003c\/li\u003e\n\u003cli\u003eCoolant Temp Sensor (unless spoofed) - computer comes configured to use stock sensor\u003c\/li\u003e\n\u003cli\u003eCrank Sensor\u003c\/li\u003e\n\u003cli\u003eIgnition Coils (2)\u003c\/li\u003e\n\u003cli\u003eInjectors (4)\u003c\/li\u003e\n\u003cli\u003eMAP (Move vacuum port and MAP to a safe location, stock is a bad location, see the vacuum blockoff kit listing)\u003c\/li\u003e\n\u003cli\u003eTPS (better throttle responce)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eOptional Sensors\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eCam Sensor (should make it run slightly better if kept stock)\u003c\/li\u003e\n\u003cli\u003eIAC (controls the engine's idle, generally best to keep stock)\u003c\/li\u003e\n\u003cli\u003eTransmission Shift Solenoids - If disconnected then the trans will perform it's normal limp mode where you have to shift all the way back to first to get first gear.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003eSpecial case\u003c\/span\u003e\u003cspan\u003e \u003c\/span\u003efor the coolant temp sensor, there's an adjustable resistor inside the computer that can be calibrated to make the computer see any temp you desire. If you set it to 200F for example, cold starts will be difficult because it will be lean. This is only intended for advanced users or I can calibrate it before shipping. I suggest keeping the temp sensor stock so it runs good cold and hot.\u003c\/p\u003e\n\u003cp\u003eTo calibrate the adjustable resistor, hook the computer up in a stock car, disconnect coolant temp sensor, and use an OBD2 scanner to view what the computer reports the temp sensor reading is. Adjust the screw on the brown box inside the computer until you see the temp you desire on the scanner. When installed in a derby car, be sure the temp sensor is disconnected when setup this way. Adjusting it to the lowest temp possible (resistor clicks when maxed out) will disable the coolant temp spoofing. Resistor is 12 full turns from max hot to max cold and adjustments change very slowly at first and progressively gets quicker the warmer the reading gets.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFitment\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e1997-1999 Toyota Camry (4cyl)*\u003c\/li\u003e\n\u003cli\u003e1999 Toyota Solara (4cyl)*\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e* Must be used in cars with the no immo computer (3 white connectors)\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eChange Log\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003ev4.0 - New naming scheme, new circuit board design that mounts to PCB header. Combined stage 2 and stage 3 features and dropped the stage 3 features that some had issues with. New addition of a new concept for IAC spoofing and the ability to spoof coolant temp while also giving the option for using stock setup. Has 4 diag lights on board:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003ePower (computer physically getting power)\u003c\/li\u003e\n\u003cli\u003eCEL (computer's self test passed)\u003c\/li\u003e\n\u003cli\u003eInjector power (lights when #1 injector receives power)\u003c\/li\u003e\n\u003cli\u003eInjector pulse (pulses when it injects fuel, tied into #1 injector)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eStage 3 - Expermental sensor spoofing, some users had issues with the setup\/usage with this design. New concept of IGF signal spoofing so if a coil fails it doesn't make the engine die.\u003c\/p\u003e\n\u003cp\u003eStage 2 - Original design, prevents limp mode, extra pins removed.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003eLMMF is just a reseller for these, DWS manufactures and mods the ECUS\u003c\/p\u003e","brand":"LMMF SIMPLIFIED WIRING","offers":[{"title":"Default Title","offer_id":50412107596070,"sku":"97-99-camry-bundle","price":285.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0868\/0505\/3734\/files\/IMG_2803.jpg?v=1745169246"}],"url":"https:\/\/www.lmmfsimplifiedwiring.com\/collections\/harness-ecm-bundles.oembed","provider":"LMMF SIMPLIFIED WIRING","version":"1.0","type":"link"}