# Blown Intake Manifold '93 LeSabre

**URL:** <https://community.cartalk.com/t/blown-intake-manifold-93-lesabre/24194>\
**Category:** Maintenance/Repairs\
**Tags:** lesabre, timing-belts, buick\
**Created:** [January 1, 2009, 6:48pm UTC](https://community.cartalk.com/t/blown-intake-manifold-93-lesabre/24194 "2009-01-01T18:48:22Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![fedde001](https://avatars.discourse-cdn.com/v4/letter/f/49beb7/32.png) [@fedde001](https://community.cartalk.com/u/fedde001)\
**Post date:** [January 1, 2009, 6:48pm UTC](https://community.cartalk.com/t/blown-intake-manifold-93-lesabre/24194/1 "2009-01-01T18:48:22Z")

</div>

1993 Buick LeSabre (140,00 miles)  
  
 Daughters college transportation vehicle  
  
 12/30/08 Upon MN cold driveway starting- a sound like a ‘gunshot’ was heard from under the hood followed by some smoke. Exam revealed fragmented plastic intake manifold and overlying engine decoration. Seems like a backfire that ignited fuel in manifold. New manifold offered online (via A1) suggests that original may be deficient and suspect to corrosion and failure.  
  
 Question- is it appropriate to JUST replace the intake manifold with IMPROVED version? Have additional concerns about timing belt, PCV and perhaps other things…?  
  
 Return to college: 01/19/09

---

<div class="post-metadata">

**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\
**Post date:** [January 1, 2009, 7:15pm UTC](https://community.cartalk.com/t/blown-intake-manifold-93-lesabre/24194/2 "2009-01-01T19:15:10Z")

</div>

First, the engine utilizes a timing chain, not a timing belt.

I’ve seen these GM intake manifolds explode before. And usually what happens is the fuel pressure regulator diaphram developes a leak allowing fuel to be pushed into the intake manifold via the regulator vacuum hose, or a fuel injector developes a leak and loads up one of the cylinders with raw gas. The ignition system on this engine is what is called a Wasted Spark Ignition System. This means each coil fires two sparkplugs for two cylinders at one time. Only one sparkplug fires in a cylinder where there’s an air/fuel mixture and the valves are closed for that cylinder. The other sparkplug fires in a cylinder where there should be no air/fuel mixture and the valves are open in that cylinder. Hense the name.

Now if for some reason gas gets into the intake manifold such as from a leaking fuel pressure regulator or in a cylinder with a leaking fuel injector, and this wasted spark occurs in the cylinder where the valves are open, it’s going to ignite the gas in that cylinder from a leaking injector, or ignite the gas sitting in the intake manifold. And when this happens, the intake manifold explodes.

Replace the manifold and then check for a leaking fuel pressure regulator or fuel injector to make sure the new intake manifold doesn’t explode.

Tester