The best flex fuel conversion option depends on whether you need a vehicle-specific kit, a sensor installation adapter, a replacement sensor, or a wiring pigtail. The ATS/CTS kit is intended for owners who can use its required ZZPerformance PCM tune. The universal adapter suits compatible sensor and fuel-line setups, while the GM sensor and pigtail options address replacement needs rather than providing a complete conversion by themselves.
| Product | Best For | Key Requirement |
|---|---|---|
| ATS/CTS E85 kit | ATS/CTS conversion | Requires ZZPerformance PCM tune |
| Universal sensor adapter kit | Installing a compatible sensor | Check sensor dimensions and fittings |
| FUSCH flex fuel sensor | GM sensor replacement | Confirm vehicle fitment |
| Hoypeyfiy connector pigtail | GM sensor connector replacement | Check listed part numbers |
| GM E85 connector pigtail | Second-generation GM wiring repair | Check vehicle year and fitment |
E85 Flex Fuel Conversion Kit For ATS/CTS
This is the most directly targeted choice for ATS and CTS owners seeking a flex fuel conversion kit. Listed features include ethanol-percentage monitoring and the ability to run different blends of E85 and premium gasoline. Its vehicle-specific focus makes it a better starting point than a universal adapter for the named applications.
Best for: ATS/CTS owners whose vehicle and tuning plans match the kit. Important limitation: The listing says a ZZPerformance PCM tune is required. Confirm the tune and vehicle fitment before purchase; the product information does not establish compatibility with every ATS or CTS configuration.
Motoparty Universal E85 Sensor Adapter Kit
This adapter kit is designed to install and connect a flex fuel sensor while maintaining fuel flow toward the fuel rail. It includes 6AN and 8AN interfaces, assorted O-rings, and a 6061 aluminum alloy adapter. The listing identifies compatibility with sensors measuring ⅜ inch (9.5 mm) in diameter and 95 mm long, including several listed GM, AC Delco, Continental, VDO, and AEM sensor types.
Best for: Buyers assembling a sensor installation who need the listed fitting options. Limitation: It is not suitable for sensors measuring 105 mm long. Check sensor dimensions and fuel-line connections carefully; this adapter alone is not a complete vehicle conversion system.
FUSCH GM E85 Flex Fuel Sensor
This GM-series replacement sensor is listed with a connector pigtail. Its stated function is to detect ethanol proportion in fuel, allowing the engine control module to use the sensor signal when adjusting air-fuel mixture and ignition timing. That makes it a sensor replacement option, not a standalone conversion kit.
Best for: A buyer who has verified that this GM-series sensor matches the original part and vehicle. Limitation: The provided product details do not identify specific model years or a complete fitment list. Confirm the vehicle application and connector before ordering.
Hoypeyfiy GM E85 Sensor Connector Pigtail
This replacement connector is intended for GM E85 or ethanol sensor applications. The listing gives manufacturer part number PT-E85-2 and interchange numbers 13577394, 13577379, and 13577429. Its plug-and-play description makes it relevant when the sensor connector or pigtail needs replacement, rather than when the sensor itself or engine tuning is the issue.
Best for: GM owners whose existing connector corresponds to one of the listed numbers. Limitation: The product information does not provide a full vehicle fitment chart. Match the part number and connector configuration before purchase.
GM Second-Generation E85 Connector Pigtail
This GM plastic connector pigtail is listed for second-generation GM E85 applications manufactured by Continental, with “2006-up” stated in the product details. It replaces part numbers 13577394, 13577379, 13577429, and PT-E85-2. The listing describes it as a direct replacement, but buyers should use the stated application and replacement numbers to verify fit.
Best for: Buyers repairing a matching second-generation GM E85 sensor connection. Limitation: “2006-up” is broad, so it should not be treated as proof of fit for every GM vehicle from 2006 onward. Check the exact application before ordering.
Buying Guide: How To Choose A Flex Fuel Conversion Kit
Do you need a complete conversion or one replacement part?
Start by identifying the missing component. A vehicle-specific conversion kit, such as the ATS/CTS option above, is different from a sensor adapter, sensor, or wiring pigtail. An adapter connects a compatible sensor into a fuel system; a sensor detects ethanol content; and a pigtail replaces a connector. These parts do not automatically provide tuning or complete conversion functionality.
Will the kit fit your vehicle and sensor?
Check the exact vehicle application, sensor part number, connector shape, and any dimensions stated by the seller. For the Motoparty adapter, verify the 95 mm sensor length, ⅜-inch diameter, and 6AN or 8AN connection needs. Do not assume that a GM label alone confirms compatibility with every GM model.
Does the vehicle require tuning?
Engine management must account for the sensor signal for flex fuel operation. The ATS/CTS kit listing explicitly requires a ZZPerformance PCM tune. Confirm tuning requirements for any other setup rather than assuming that installing a sensor or connector enables the vehicle to use varying ethanol blends.
How should you compare replacement pigtails?
Compare the replacement part numbers first. The Hoypeyfiy and GM second-generation pigtails share several listed interchange numbers, but the latter specifies Continental-manufactured second-generation GM applications and a 2006-up range. Use the vehicle’s original part information and connector details to distinguish them.
Frequently Asked Questions
Is a flex fuel sensor the same as a conversion kit?
No. A sensor detects ethanol content, while a conversion may also require compatible wiring, installation hardware, and engine-control tuning. Review what each product actually includes.
Can I use any ethanol blend with the ATS/CTS kit?
The listing says it supports different mixes of E85 and premium gasoline. It also says a ZZPerformance PCM tune is required. Confirm vehicle fitment and tuning before using blended fuel.
Will the universal adapter fit a 105 mm sensor?
No. Its listing says it is not suitable for sensors with a 105 mm length. It specifies compatible sensors measuring 95 mm long and ⅜ inch in diameter.
Are the two GM pigtails interchangeable?
They share listed replacement numbers, but their application descriptions differ. Verify the original part number, connector, and vehicle fitment rather than assuming they are interchangeable.
Does replacing a pigtail enable E85 operation?
No. A pigtail replaces an electrical connector. It does not, by itself, add a flex fuel sensor, conversion hardware, or required engine tuning.