Skip the auto shop - Our mechanics make house calls

How Long Does an Automatic Timing Advance Unit Last?

timing advance unit

The automatic timing advance unit is a component in vehicles with diesel engines. Of course gas and diesel engines both work on the internal combustion principle, but they are quite different, and require different means of controlling the flow of fuel during operation.

Gas combusts much more quickly than diesel. With diesel fuel, combustion can take place long after the timing reaches TDC (top dead center). When this happens, lag occurs and adversely affects performance. To prevent lag, the diesel fuel has to be injected before TDC. This is the function of that automatic timing advance unit – basically, it makes sure that no matter what the engine speed, the fuel is delivered in time for combustion to take place before TDC. The unit is located on the fuel pump, and operated by means of the primary drive gear on the engine.

Whenever you are driving your diesel vehicle, the automatic timing advance unit has to do its job. If it doesn’t, the engine will not get a consistent fuel supply. There is no specific point at which you should replace the automatic timing advance unit – essentially, it lasts as long as it lasts. It could last the life of your vehicle, or it could start to go bad, or even fail entirely with little warning. Signs that your automatic timing advance unit needs to be replaced include:

  • Sluggish engine
  • More black smoke from exhaust than is usual with diesel operation
  • White exhaust smoke
  • Engine knock

Performance issues can make for dangerous driving, so if you think that your automatic timing advance unit is failing or has failed, consult a qualified mechanic to further assist you in replacing the failing part.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

How to Find the Keyless Code on a Ford Explorer or Mercury Mountaineer
Many Ford Explorers and Mercury Mountaineers were manufactured with an option known as the Ford keyless entry keypad. Some models refer to it as SecuriCode as well. It...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How to Get a Louisiana Driver's Permit
s licensing program. The first step in this program is to obtain...


Related questions

Q: Car knocks and dies while accelerating

A battery replacement won't have an effect on your fuel system. Instead, you should have a complete check on your fuel system for the proper fuel pressures and flow through the fuel filter. The fuel filter is on the fuel...

Q: Overdue for an oil change. Now the car won't run without foot on the gas.

Hi - first task is to get oil back up to level - then check for problem codes, whether the Check Engine Light is illuminated or not. This engine has a large history of ejecting spark plugs out of the...

Q: Adjusting the camshaft and crankshaft for the timing chain

I believe the "official" procedure for these M30 engines is to: Leave the tensioner until last Install the chain with the crank and cam sprockets on TDC, and the chain tight on the driver side of the chain Use...