|
Register or Log In To remove these advertisements. |
|
|
|
|||||||
 |
|
|
Thread Tools | Display Modes |
|
|
11-18-2024, 06:35 PM
|
#1 |
|
Registered User
Join Date: Aug 2022
Location: winneconne, wisco
Posts: 53
|
1991 r3500n 454 cfi, cold start issues....
this cfi 454 on start up runs really rough and backfires sometimes, any idea what is going on???
|
|
|
|
11-18-2024, 11:06 PM
|
#2 |
|
Senior Member
 Join Date: Aug 2005
Location: Los Angeles
Posts: 1,365
|
Re: 1991 r3500n 454 cfi, cold start issues....
When you shut the engine off, is there fuel leaking from the injectors flooding the intake manifold? Also check to make sure the engine coolant temp. sensor (the one for the computer, not the gauge) is reading properly. You can check it with a scan tool. Sometimes they can be way off and cause hard start problems. Does in run O.K. once it warms up?
__________________
1967 GMC CM-2500 Camper Cruiser, 351E V-6, NP 435 4 speed, Dana 60, and factory A/C. 2012 GMC K-3500 WT regular cab, 6.0L Vortec, 6L90. |
|
|
|
|
11-19-2024, 12:26 AM
|
#3 |
|
Senior Member
Join Date: Mar 2003
Location: Colfax-California
Posts: 8,631
|
Re: 1991 r3500n 454 cfi, cold start issues....
1991 big block is going to be a TBI so first I would check the EGR spacer underneath the throttle body for vacuum leaks. Then I would move on to the coolant temp sensor by the t-stat and make sure the wiring is not messed up. After that?? maintenance for a tune up, plugs wires? what shape are they in. Plugged fuel filter etc.
|
|
|
|
|
11-19-2024, 08:54 AM
|
#4 | |
|
Registered User
Join Date: Aug 2022
Location: winneconne, wisco
Posts: 53
|
Re: 1991 r3500n 454 cfi, cold start issues....
Quote:
|
|
|
|
|
|
11-19-2024, 11:20 AM
|
#5 |
|
Senior Member
Join Date: Mar 2003
Location: Colfax-California
Posts: 8,631
|
Re: 1991 r3500n 454 cfi, cold start issues....
So that leaves us with a vacuum leak or a CTS and/or black and yellow wiring at the connector.
|
|
|
|
|
11-20-2024, 01:43 AM
|
#6 |
|
Registered User
Join Date: Jul 2011
Location: back 40, bc
Posts: 3,905
|
Re: 1991 r3500n 454 cfi, cold start issues....
try the vacuum line from your MAP.
my hose had a small hole in it and my 454 ran like sheet till i found it. just throwing something out there... |
|
|
|
|
11-20-2024, 02:02 PM
|
#7 | |
|
Registered User
Join Date: Aug 2022
Location: winneconne, wisco
Posts: 53
|
Re: 1991 r3500n 454 cfi, cold start issues....
Quote:
|
|
|
|
|
|
11-19-2024, 08:53 AM
|
#8 | |
|
Registered User
Join Date: Aug 2022
Location: winneconne, wisco
Posts: 53
|
Re: 1991 r3500n 454 cfi, cold start issues....
Quote:
|
|
|
|
|
|
12-16-2024, 05:11 PM
|
#9 |
|
Registered User
Join Date: Dec 2011
Location: Boise, Idaho
Posts: 585
|
Re: 1991 r3500n 454 cfi, cold start issues....
download WINaldl.. it is free,, only need a cable to see in real time what is going on or data log while you drive.
https://winaldl.joby.se/ |
|
|
|
|
| Bookmarks |
| Thread Tools | |
| Display Modes | |
|
|
Hybrid Mode
