Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help

Go Back   Pelican Parts Technical BBS > 1- Porsche Technical Forums > Porsche 928 Technical Forum

LinkBack Thread Tools Rate Thread
Thread Post New Thread    Reply
Registered User
Join Date: Aug 2014
Posts: 7
928 starts and runs good, then after a bit dies and won't do more than idle

My 17 year old son got a 1979 928 as a Christmas gift form one of my best friends who had it for about 4 years and did nothing with it.

We have since got it running and he has really been enjoying it but lately we have been having what seems like fuel issues. It starts and runs perfect but after driving it for a while, it seems to starve for fuel and will not do much more than idle. If you give it gas, it misses and pops and farts.

We replaced the external fuel pump but it still does the same thing. It runs great up until the time when all of a sudden it doesn't. HELP!!!

Last edited by challengergary; 02-04-2018 at 08:31 AM..
Old 02-04-2018, 08:25 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Registered User
JK McDonald's Avatar
Join Date: Oct 2003
Location: Texas
Posts: 835
Warm-Up Regulator -

Hey Challenger - I guess you've replaced the fuel filters (internal and external of the fuel tank ? Have you worked on the Bosch CIS fuel injection system before? It is not difficult to troubleshoot but to determine if you have a fuel pressure (supply or control) issue you will need the CIS pressure test gauge and hoses. There are set pressures that must be met to determine the air/fuel mixture which controls how the motor runs when transitioning from cold to warm. This control pressure is regulated by the "Warm-Up Regulator".

Where are you located ? Perhaps there is someone near by that can help you sort this out ?

1984 928S - "Miss Purdy"
1987 911SC - "Frau Helga"
1986 930 - "Well Hung"

Last edited by JK McDonald; 02-04-2018 at 03:02 PM..
Old 02-04-2018, 01:59 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Registered User
stepson's Avatar
Join Date: Mar 2010
Location: Texas
Posts: 1,488
Absolutely is necessary to have the pressure gauges to adjust CIS 928 engine as pointed out by Michael in post 2

In addition, where did you source the fuel pump with which you replaced the original? CIS systems run at greatly increased pressures from EFI cars. A fuel pump with insufficient pressure may allow the engine to start and idle, but will run out of fuel much above idle. Make very sure that the fuel pump is correct for your model 928.
John Curry (Drift King) 928OC member
Grand Prix White 1994 GTS AT (The GTS)
Cobalt Blue 1989 S4 AT (The Blue Car)
Indishrot 1984 Euro S AT (The Stepson)
Black Metallic 1984 Euro S 5 speed (The Schwartz)
Old 02-04-2018, 09:44 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Registered User
Join Date: Aug 2014
Posts: 7
We only replaced the external pump. I will pull the one in the tank and see if the strainer is clogged. Never worked on one of these systems before so it is all Greek to me...
Old 02-05-2018, 04:07 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)

Thread Tools
Rate This Thread
Rate This Thread:


All times are GMT -8. The time now is 03:14 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.