# 1996 Oldsmobile Ninety-Eight won't start til engine cools

**URL:** <https://community.cartalk.com/t/1996-oldsmobile-ninety-eight-wont-start-til-engine-cools/114665>\
**Category:** Maintenance/Repairs\
**Tags:** ninety-eight, oldsmobile\
**Created:** [March 29, 2018, 3:52pm UTC](https://community.cartalk.com/t/1996-oldsmobile-ninety-eight-wont-start-til-engine-cools/114665 "2018-03-29T15:52:18Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Michael59](https://avatars.discourse-cdn.com/v4/letter/m/5e9695/32.png) [@Michael59](https://community.cartalk.com/u/Michael59)\
**Post date:** [March 29, 2018, 3:52pm UTC](https://community.cartalk.com/t/1996-oldsmobile-ninety-eight-wont-start-til-engine-cools/114665/1 "2018-03-29T15:52:18Z")

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I have a 1995 Oldsmobile 98 Regency. When I’ve been driving the car for a bit, shut the car off, run into the store, for example, come back out and try to start the car, it won’t start. In fact it won’t start until the motor cools down to below 150 degrees, according to the temp gauge. The check engine light comes on. The code is for multiple cylinder misfires. Once the engine cools down, it will fire right up. I just replaced the Ignition Control Module with a Delphi module. Any suggestions as to what I should try next? Crankshaft position sensor? The engine gets gas, i can smell it after pumping the accelerator when trying to start it.

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**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:** [March 29, 2018, 11:18pm UTC](https://community.cartalk.com/t/1996-oldsmobile-ninety-eight-wont-start-til-engine-cools/114665/2 "2018-03-29T23:18:30Z")

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The problem might be caused by vapor lock.

Vapor lock occurs when the fuel in the fuel rails begins to boil.

On a fuel injected engine, the fuel system should hold what is called residual fuel pressure when the hot engine is shut off.

This residual fuel pressure slowly bleeds down as the engine cools off.

If the residual fuel pressure bleeds off too quickly, you get vapor lock.

[http://vnc.thewpp.ca/stuff/bentley/ep0niks.ctech.ca/vw/eva2/FU01/ch5.5.3.html](http://vnc.thewpp.ca/stuff/bentley/ep0niks.ctech.ca/vw/eva2/FU01/ch5.5.3.html)

Tester

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**Author:** ![insightful](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/insightful/32/2732_2.png) [@insightful](https://community.cartalk.com/u/insightful)\
**Post date:** [March 29, 2018, 11:39pm UTC](https://community.cartalk.com/t/1996-oldsmobile-ninety-eight-wont-start-til-engine-cools/114665/3 "2018-03-29T23:39:36Z")

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> [@Michael59](#):
>
> Crankshaft position sensor?

A common failure. It might be worth it to take it out of the equation.