View Single Post
  #2  
Old 12-11-2007, 10:31 AM
BNaylor's Avatar
BNaylor BNaylor is offline
AF Moderator
 
Join Date: Jan 2005
Posts: 18,017
Thanks: 30
Thanked 54 Times in 42 Posts
Re: 98 Grand Prix - Hard Starting and Higher Than Normal Fuel Consumption

How about the fuel filter? How old is it or when was it last replaced?

You can check fuel pressure at the front fuel rail Schrader valve located towards the supercharger snout. 48-55 psi. Low fuel pressure may cause a lean trim mode so the PCM will compensate by adding more fuel to the fuel injection system to compensate.

Also, remove the vacuum line at the fuel pressure regulator and check for raw fuel indicating a ruptured diaphragm. A flaky fuel pressure regulator may cause longer than normal starting but the fuel pressure check will test it. Check at fuel pump prime, at idle and with the vacuum line at the fuel pressure regulator on and off. Readings will vary as you do this.



__________________

'08 Pontiac Grand Prix GXP (Dark Slate Metallic) - LS4 5.3L V8
'02 Oldsmobile Alero GL2 - LA1 3400 V6
'99 Buick Regal LS - L36 Series II 3800 V6
'03 Honda CR250R MX - 2 Stroke 250cc
'97 Pontiac Grand Prix GTP - L67 Series II 3800 V6 Supercharged (Sold)
Timeslip 08/12/06

AF Community Guidelines
Reply With Quote