Jump to content
CaddyInfo Cadillac Forum

90 Seville -- Vapor Lock??


Recommended Posts

My 90 Seville starts and runs fine when cold. But after driving 20-30 minutes, if I shut the engine off it's hard to restart and runs rough. In extreme cases, the engine won't restart until it's had a chance to cool down for half an hour. It acts like vapor lock but I understand that is uncommon in fuel injected engines. The car seemed ok through the winter, but now that warmer temperatures are returning, so is the problem. Any comments will be appreciated. Thanks.

Link to comment
Share on other sites


That is usually a sign that your Fuel Pressure Regulator needs replacing

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Link to comment
Share on other sites

Thank you for your prompt and insightful response. I pulled the vacuum tube off the FPR as suggested on another forum to check for a ruptured diaphragm. Unfortunately, there were no signs of leaking fuel. The engine was warm (30 minutes of driving, including traffic) and running.

What's next?

A related(?) problem: I didn't mention it in the previous post as I wasn't sure if it was relevant. I tussled with the car last summer trying to figure out the source(s) of several dubious error codes and poor performance. After much testing, I decided the ECM computer was bad. I replaced it with an aftermarket unit. The rebuilt ECM seemed to solve all the problems and the car ran fine.

Shortly thereafter (1-2 weeks), the "service engine soon" telltale light came on. The source was an EO49 air diverter solenoid problem. I tested according to my Factory Service Manual and could find nothing wrong. The "hard starting when hot" problem commenced a few days later when the engine refused to start after a 40 minute drive in 80-degree weather. The E049 problem still exists. The telltale light comes on at approximately 223 degrees. When I clear the codes, the telltale stays off until the engine again reaches that temperature. I cannot detect any adverse effects from the E049 situation. And the only correlation I can find between the E049 and the hard starting is the fact that they both happen when the ambient temperature approaches 80 degrees. But the hard starting occurs even when the E049 is not current.

I'm confused and dreading the really hot temperatures to come (Omaha,NE).

Any thoughts or suggestions will be greatly appreciated. Thanks.

Link to comment
Share on other sites

I recommended to check the FPR because if it is leaking, it will cause hard starting. I found this. A leaky injector can cause that code, and possibly cause a problem with hard starting. I don't know your engine well at all. If there a fuel rail? You might try lifting the fuel rail, turn the key to ON, not start, that will pressurize the rail and you may see a leaky injector. Do you smell fuel when it won't start?

The next time you have a hard start problem push the accelerator pedal to the floor, I am not sure if it is true for your year, but in subsequent years, pressing the pedal to the floor turns off the injectors to clear a flooding condition.

Q. I am getting a diagnostic code E049 on a 1990 Cadillac Deville FWD. Any ideas what the cause is? Snap-On diagnostic tool, stated air system fault. Do you know what this might be? Car has new 02 sensor and air filter.

A. E049 Air Management System Problem. This diagnostic test monitors the AIR system to detect operating problems with the Electric Divert Valve (EDV) and Electric Switching Valve (ESV). It performs these tests using the oxygen sensor and ECM integrator function to monitor valve function.

Basically the computer has detected a malfunction in the EDV, the ESV or the wiring. A leaking injector may also cause this code to set

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...