Corvette C4 Forum 1984 through 1996

85" Cold Start Valve

Old Jul 10, 2007 | 03:19 PM
  #11  
cwb's Avatar
cwb
Senior Member
Joined: May 2007
Posts: 1,567
From: eastern NC
Default RE: 85" Cold Start Valve

ORIGINAL: 85L98

Fuel pum new. Fuel pressure-42--?
Whaddya mean? Pump is new, and you're assuming you got 42?

You said in post 3 it has to rev a few times while starting to get fuel. The battery turns on the fuel pump even before you attempt to start the motor. You can hear the pump prime the rails.

If you think you're not gettin' fuel, you gotta' put a guage on the schraeder valve on the motor, like the article says.


It's not tough at all - just like puttin' a bike pump on the valve stem...
 
Old Jul 10, 2007 | 06:57 PM
  #12  
Superdzzz's Avatar
Joined: May 2006
Posts: 343
From:
Default RE: 85" Cold Start Valve

ORIGINAL: cwb

ORIGINAL: 85L98

Fuel pum new. Fuel pressure-42--?
Whaddya mean? Pump is new, and you're assuming you got 42?

You said in post 3 it has to rev a few times while starting to get fuel. The battery turns on the fuel pump even before you attempt to start the motor. You can hear the pump prime the rails.

If you think you're not gettin' fuel, you gotta' put a guage on the schraeder valve on the motor, like the article says.


It's not tough at all - just like puttin' a bike pump on the valve stem...

cwb: I always thought that valve was on the fuel rail. Maybe I'm wrong[&o] Must just be mine.

BTW: Sometimes your typing sounds like you are yelling at the person. I was under the impression that we were here to help each other and share advice/stories not chastise.

No, I'm NOT picking on your post. I just would not want someone to become intimidated and therefore shy away from this forum[sm=icon_cheers.gif]
 
Old Jul 10, 2007 | 07:22 PM
  #13  
cwb's Avatar
cwb
Senior Member
Joined: May 2007
Posts: 1,567
From: eastern NC
Default RE: 85" Cold Start Valve

ORIGINAL: Superdzzz

ORIGINAL: cwb

ORIGINAL: 85L98

Fuel pum new. Fuel pressure-42--?
Whaddya mean? Pump is new, and you're assuming you got 42?

You said in post 3 it has to rev a few times while starting to get fuel. The battery turns on the fuel pump even before you attempt to start the motor. You can hear the pump prime the rails.

If you think you're not gettin' fuel, you gotta' put a guage on the schraeder valve on the motor, like the article says.


It's not tough at all - just like puttin' a bike pump on the valve stem...

cwb: I always thought that valve was on the fuel rail. Maybe I'm wrong[&o] Must just be mine.

BTW: Sometimes your typing sounds like you are yelling at the person. I was under the impression that we were here to help each other and share advice/stories not chastise.

No, I'm NOT picking on your post. I just would not want someone to become intimidated and therefore shy away from this forum[sm=icon_cheers.gif]
That's what I meant about the valve... Shoulda'said fuel rail.

I am tryin' to emphasize stuff sometimes... You know what they say about horses and water - ya' can throw 'em in the ocean, but sometimes they just drown ...

 
Old Jul 10, 2007 | 07:53 PM
  #14  
Superdzzz's Avatar
Joined: May 2006
Posts: 343
From:
Default RE: 85" Cold Start Valve



Right you are[8D]
 
Old Jul 11, 2007 | 07:36 AM
  #15  
85L98's Avatar
Thread Starter
Joined: Jul 2007
Posts: 6
Default RE: 85" Cold Start Valve

I have checked the fuel pressure with a fuel pressure guage and it read

42 llbs. I have been agear head all my life but fuel injection systemms

are new for me. Also all the electronics you have to consider on the vette.
 
Old Jul 12, 2007 | 04:15 PM
  #16  
cwb's Avatar
cwb
Senior Member
Joined: May 2007
Posts: 1,567
From: eastern NC
Default RE: 85" Cold Start Valve

ORIGINAL: 85L98

I have checked the fuel pressure with a fuel pressure guage and it read

42 llbs. I have been agear head all my life but fuel injection systemms

are new for me. Also all the electronics you have to consider on the vette.
Under what circumstances was the pressure 42 psi?

There's 3 conditions that the pressure has to be checked, according to the article. I'm not sure all three apply to your hard start condition, but you'll have to remember that for later.

For now, you PROBABLY can rule out fuel from the hard start condition (even though you said it's a fuel problem..

That leaves air, and fire. Is the filter clear?

You said the idle is smooth - no 'loping', so you probably have no vacuum leaks (although I'm inclined to think you do, and that you do have some loping on a warm motor).

After that, all that's left for the hard start is a fire problem.

SO... double check the 3 fuel pressure conditions. Check the air. Starting fire comes from the battery.

How's the battery? Does the motor turn REALLY STRONG, when starting? Or is it struggling?
 
Old Jul 12, 2007 | 09:58 PM
  #17  
RRT vette's Avatar
Joined: Jul 2007
Posts: 7
Default RE: 85" Cold Start Valve

Good googlymoogly. I see some good info in this thread, but none of it is going to help the OP's answer. The CSV (cold start valve), CSI (cold start injector), or 9th injector came on the 85-88 Corvettes. GM had not figured in the ECM how to calcutate enough fuel toenter the cylinders on cold starts where extra fuelis needed. The got it right by 89 and the CSV was deleted from the fuel rail. The CSV is located on the driversside and enters the manifold by way of the runner. The fuel supplyline wraps around the rear and connects to the rear left of the fuel rail.

The system is comprised of theinjector/valve, bi-thermal time switch, in dash fuse, and the starter solenoid....plus the wiring.

The CSVsystem is ONLY active when theengine temp is below 95* and only when cranking the engine. As soon as the starter stops turning, the switch times out and stops fuel flow. Thethermal switch can only activate the CSV for up to 8 seconds of cranking. The 12v for the system comes from the starter solenoid, as to why it's only active while cranking. The fuse for the system is located behind the DIC inthe dash. Easy to get to and is a 5 ampfuse. Thethermal switch is located on the front of the intake manifold and has a connector like the injectors.

Totest the CSV you can use a test light. It can only be tested when theengine temp is below 95*. Take the connector off theCSV and probe the wires with the test light. Crank the engine and see if it lights up as it should. If not, then I would check the fuse in the dash...there are 3 or 4 fuses in there butit is labled.If the fuse isgood, you can bet that it's either the thermal swtch or the connection on the starter solenoid.

This is my post on this forum, so please don'those me too much.
 
Old Jul 13, 2007 | 12:36 PM
  #18  
Superdzzz's Avatar
Joined: May 2006
Posts: 343
From:
Default RE: 85" Cold Start Valve

RRT, good informative post and

[sm=welcomesign.gif]
 
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