Vapor Lock on C4

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Jul 3, 2002 | 06:30 PM

dlsmith

Thread Starter

8th Gear

Joined: Nov 2001

Posts: 8

Likes: 0

From: Larkspur CO

Vapor Lock on C4

I have an 85 C4. In hot weather, after driving it and getting it hot and then parking for 30 - 45 minutes, it is hard to start. It will start and then die. If you give it a little gas, it sounds like it is dieseling and then die again. So far I have been able to finally get it to start and stay running.

Could this be a timing issue? Suggestions?

Thanks!!

:confused:

Jul 3, 2002 | 06:35 PM

scorp508

Team Owner

Joined: Mar 2000

Posts: 83,383

Likes: 87

From: Boston, MA

You most likely have leaky fuel injectors. I would look into getting a new set or having yours serviced.

Jul 3, 2002 | 06:36 PM

lowflyer

Burning Brakes

Joined: Dec 1999

Posts: 765

Likes: 11

Cruise-In I Veteran

Re: Vapor Lock on C4 (dlsmith)

I agree. With 30-40psi of fuel pressure, its pretty unlikely that you are getting a vapor lock problem. Put a fuel pressure guage on the rail and see what your pressure is after shutdown. Good luck.

Jul 3, 2002 | 06:36 PM

MagRed_04

Pro

Joined: Dec 2000

Posts: 513

Likes: 30

From: Tonawanda, NY USA

Re: Vapor Lock on C4 (dlsmith)

Mine did a similar thing... It turned out that when it was hot, the fuel injectors were leaking gas into the cylinders creating a "flooded" condition.
You might want to have your injectors checked. Are they original? My '85 injectors were shot at only 50,000 miles.

:cheers:

Jul 3, 2002 | 06:38 PM

KYVette90

Burning Brakes

Joined: Nov 2000

Posts: 1,040

Likes: 2

From: BowlingGreen KY

Re: (scorp508)

Mines doing the same thing. It's the injectors. I'm sending mine off pretty soon to be redone. :cheers:

Jul 3, 2002 | 06:59 PM

Rynda

Racer

Joined: Oct 2000

Posts: 476

Likes: 0

From: Socorro New Mexico

Re: Vapor Lock on C4 (dlsmith)

Mine is doing the same thing. I replaced all of my injectors with a new set of Accel injectors (24lb) from Summit a few months ago. I hope that it is not the injectors. After heat soaking for ~ 20 minutes, the vette starts right up and then dies after a few seconds (enough to get into traffic :eek: ). It does not pull that trick every time, but often enough. After cranking on it for a few seconds it will fire up and continue on as if nothing went wrong. I'm puzzled.

Jul 3, 2002 | 07:50 PM

jfb

Team Owner

Joined: Mar 2001

Posts: 54,124

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From: Cincinnati, Oh USA

Re: Vapor Lock on C4 (dlsmith)

Put a fuel pressure gauge on the shraeder valve on the fuel rail and turn on the ignition sw for more than 2 seconds. The fuel pump runs for 2 seconds and shuts off which will build fuel pressure. GM says that you shouldn't lose more than 1 psi in 30 minutes or the injectors are considered leaky. This test will prove it.