A grid heater delete removes a factory emissions control component from your 6.7 Cummins diesel engine, which changes how the engine starts in cold weather and affects your warranty and emissions compliance

The grid heater (also called a glow plug grid or intake heater) is a factory component that warms incoming air before combustion on cold starts. On a 6.7 Cummins, deleting it means removing the physical heater and reprogramming the engine control module (ECM) to stop calling for it. This is a permanent modification that affects cold-start performance, engine longevity, legal road use, and your manufacturer warranty.

This guide explains what the grid heater does, what happens when you remove it, the real trade-offs involved, and what you should know before making this decision. It is not a recommendation for or against deletion — that choice depends on your specific use, location, and priorities.

Key Takeaways

  • The grid heater warms intake air on cold starts to reduce white smoke and improve combustion; deleting it makes cold starts harder and slower, especially below freezing.
  • A grid heater delete requires both physical removal of the component and ECM tuning to prevent fault codes and drivability problems.
  • Deletion voids your powertrain warranty with Cummins and Dodge, and may violate emissions regulations depending on your state and vehicle use.
  • Cold-start white smoke increases after deletion, and some owners report higher idle temperatures and longer warm-up times in winter.
  • The decision hinges on your climate, how often you cold-start, whether you tow, and whether warranty coverage matters to you.

How the Grid Heater Works on a 6.7 Cummins

The grid heater is a resistive heating element mounted in the intake manifold. When you turn the key to the on position in cold weather, the ECM energizes it for several seconds before allowing the starter to crank. The heater raises the temperature of incoming air, which helps diesel fuel ignite more easily and reduces the white smoke (unburned fuel) that comes out of the exhaust during a cold start.

On a 6.7 Cummins, the grid heater typically cycles for 5 to 15 seconds depending on ambient temperature. Below 32°F, it runs longer. Below 0°F, it may cycle multiple times. The factory design assumes you will wait for the glow plug light to go out before starting, though many drivers start when ready without waiting.

The grid heater is part of the emissions control system because white smoke contains unburned hydrocarbons. Reducing it at startup helps the engine meet EPA standards. It also reduces wear on the turbo and injectors by improving combustion quality on the first few seconds of running.

What Physically Happens During a Delete

A grid heater delete involves two separate steps: mechanical removal and electronic tuning. Both must be done for the modification to work without causing problems.

The mechanical part means removing the grid heater element from the intake manifold. This is usually done by a diesel shop and requires intake manifold removal or partial disassembly. The component itself is not expensive, but labor is. Once removed, the opening is sealed with a blank plate or cap.

The electronic part is ECM tuning. The engine control module still sends a signal to fire the grid heater on every cold start if you do not reprogram it. Without the physical heater present, this causes a fault code (usually P0670 or similar), which triggers the check engine light and may put the truck in limp mode. A tuner uses specialized software to disable the grid heater command in the ECM, so the computer never tries to use it.

Some shops offer this as a standalone delete. Others bundle it into a larger tune that also adjusts fuel timing, boost, or other parameters. A standalone delete is simpler and more reversible; a larger tune makes more power but is harder to undo if you need warranty service.

Cold-Start Performance After Deletion

The most when ready change is cold-start behavior. Without the grid heater, intake air temperature is lower when the engine cranks, which makes ignition harder and slower. In mild weather (40°F to 60°F), most owners report only a slight difference — the engine still starts, just takes a half-second longer. Below freezing, the difference is more noticeable.

White smoke increases noticeably after deletion, especially on the first few seconds of running. This is unburned diesel fuel in the exhaust. It clears once the engine warms up, usually within 30 seconds to a minute, but it is visible and can be thick in very cold weather. If you live in a cold climate or start your truck frequently in winter, this is a daily reality, not an edge case.

Some owners report that idle temperature runs higher after deletion, and warm-up time is longer. This is because the engine is working harder to burn fuel efficiently without the pre-heated air. Turbo spool-up may also feel slightly slower on cold starts. None of these are safety issues, but they are real changes to how the truck behaves.

Warranty and Legal Implications

Deleting the grid heater voids your powertrain warranty with Cummins and Dodge. This is not a gray area — the modification is visible to a technician, and Cummins explicitly does not cover engines that have been tuned or had emissions components removed. If your engine fails while under warranty, you will pay for the repair out of pocket, even if the failure is unrelated to the delete.

On the legal side, the grid heater is an emissions control device. Removing it is illegal for on-road use in all 50 states under the Clean Air Act. The EPA can fine you, and some states conduct emissions inspections that would catch a delete. If you are caught, fines can range from hundreds to thousands of dollars depending on your state. In practice, enforcement is rare for individual vehicles, but it is technically illegal.

If your truck is used for commercial purposes, towing for hire, or fleet work, the legal risk is higher because those operations are more likely to be inspected. If it is a personal vehicle used only off-road or on private property, the legal risk is lower but still exists if you ever sell it or take it to a shop for unrelated work.

Why Owners Delete the Grid Heater

The most common reason is to eliminate the glow plug wait time and speed up cold starts. Some owners find the delay annoying, especially if they start their truck multiple times a day. Others delete it as part of a larger performance tune and do not prioritize the cold-start issue.

A smaller number of owners delete it because they believe the grid heater causes reliability problems. This is not supported by widespread failure data — the grid heater itself is fairly durable — but individual failures do happen, and some owners choose deletion over replacement.

Cost is rarely the primary reason. The grid heater itself is inexpensive (under $200 for the part), but removal and tuning labor can run $500 to $1,500 depending on the shop and whether it is bundled with other work. Most owners who delete it are doing so for perceived performance or convenience, not to save money.

Alternatives to Full Deletion

If you want to improve cold-start performance without a full delete, you have other options. The simplest is to wait for the glow plug light to go out before starting — this is what the factory recommends and what the grid heater is designed to support. It adds only a few seconds and is free.

You can also replace a failed grid heater with a new OEM unit. This restores factory function and keeps your warranty intact. If the grid heater is not actually failing, replacement is unnecessary, but if it is, this is the warranty-safe path.

Some owners use block heaters or engine warmers in very cold climates. These warm the coolant overnight and make cold starts easier without modifying the engine. They are legal, reversible, and do not affect warranty. They do require planning ahead and access to an outlet.

Frequently Asked Questions

Will my truck run worse after a grid heater delete?

Not worse overall, but differently. Cold starts will be slower and smokier, especially below freezing. Once the engine is warm, performance is the same. If you rarely cold-start in winter, you may not notice much difference. If you start frequently in cold weather, the change is real and daily.

Can I reverse a grid heater delete?

Mechanically, yes — a shop can reinstall the grid heater and seal the manifold. Electronically, it depends on your tune. If you have a standalone delete tune, a tuner can reflash the ECM back to stock. If the delete was part of a larger performance tune, reverting may require buying a new tune or returning to stock, which loses the other modifications.

Does a grid heater delete hurt fuel economy?

Not significantly in normal driving. Cold-start combustion is less efficient without the heater, so you may see a small hit during winter warm-up, but once the engine is at operating temperature, fuel economy is the same. The effect is usually too small to measure.

What if I delete the grid heater but keep everything else stock?

A standalone delete with no other tuning is the least invasive option. You still void your warranty and break emissions law, but you avoid the complexity of a larger tune. However, you still get the cold-start smoke and slower starts — the downsides remain even if the upsides are minimal.

Is white smoke after a grid heater delete normal?

Yes. It is unburned fuel in the exhaust and is expected after deletion. It is not a sign of damage or a problem — it is the direct result of removing the component that prevented it. It clears within a minute of running and does not indicate engine trouble.