Chevy Silverado Ignition Timing Specifications

Chevy Silverado
  DarthArt/Getty Images 

Gone are the days of the distributor-based ignition system, which meant owners needed to set the timing on their vehicles on a regular basis. Today, computers make these changes as necessary, without you evening knowing it. But if you drive a late model car or pick-up you'll likely want to know how to set the ignition timing yourself. 

But sometimes the manual and/or info gleaned from the internet is confusing. In this case, let's look at a late-model Chevrolet Silverado pick-up truck, say, a 1988 with 5.7-liter fuel injected V-8 automatic transmission and 190,000 miles on the engine.​​

The Problem

A quick search of the manual and the internet makes it sound simple enough to set the timing for the Chevy. Just set the idle as if you were in drive and then adjust the timing to the factory-specified timing mark. The reality is a little more complex.

 

The manual says to do the above, plus disconnect the timing connector, which comes out of the harness conduit next to the distributor. This will put the system in the bypass mode. But what it doesn't make clear is which wire should be disconnected.

Furthermore, if the factory-recommended timing setting sticker has rubbed away where the number would be shown—which is to be expected in a late-model car—who should you contact for the factory timing specifications? The general repair manual suggests 4° BTDC, but online you read its more around 8° BTDC.

Timing Connector Location

The timing connector for the Chevy Silverado breaks out of the engine wiring harness conduit adjacent to the distributor. It is a single wire sealed connector that has a tan with black stripe lead. You can get a photo by calling your local Chevy dealer service center and requesting one. Or search online forums—someone has likely run into the exact same problem and is likely willing to share photos and advice with you.

Where to Find Timing Specifications

Your Chevy's timing specifications are located on the vehicle emissions control information label under the hood. You should also be able to get these from the manual. If you don't have the original from the factory, call your Chevy dealer or pick one up from an auto parts store.

Always follow the vehicle emissions control information label procedures first before doing the following. Again, you can consult the owner's manual, manufacturer's website, or call the dealer's service center to ask if you are working correctly.

How to Set the Ignition Timing

You should only set your timing if the following conditions are met: 

  • Engine is at normal operating temperature
  • Air cleaner or filter is new
  • Air-conditioning is off
  • Transmission is in neutral

Then you may proceed to disconnect the SET TIMING connector (tan/black wire), located in the harness close to the distributor. DO NOT disconnect the four-wire connector at the distributor. After you've done this, connect the timing light and adjust as necessary by loosening the hold-down bolt and rotating the distributor.

For base timing with manual and automatic transmissions (00 TDC), tighten the hold-down and recheck the timing. Stop the engine and connect the SET TIMING connector. Clear ECM trouble code by disconnecting the ECM power source.